IC Reball is a kind of rework technique, which is used to repair faulty circuit board components such as ICs, resistors, capacitors etc. It also can be used to diagnose and repair PCBs.

Reballing is mainly used for BGA and PGA chips with BGA balls cracked or missing that are unrepairable by other means. It can be used to repair ICs, resistors, capacitors on circuit boards with damaged or missing solder pads that are not repairable by other means.

The IC Reballing process is a very time consuming, labor intensive process. If you have a circuit board that has been damaged to the point where the components are no longer repairable, then Reballing may be an option to consider in order to save the PCB from being scrapped.

There are many steps involved in Reballing and it’s a process that takes time and knowledge to complete successfully.

IC Reballing is a process that uses solder paste and a dedicated stencil printer to place solder paste onto all of the pads on the circuit board. The ICs, resistors, capacitors or diodes are then removed from the old PCB and placed on top of the new solder paste using tweezers or forceps. The new component is placed on the solder paste covered pad and pressed down firmly onto it. This is repeated until all of the pads have been replaced with new components. Power is applied to the circuit board and then the resistors, capacitors and diodes are tested. If everything checks out then the board is returned to the user for use.

Rebalancing is a process that is used to repair BGA balls that have cracked or been missing for some time. BGA balls are typically used on motherboards and in place of solder pads on IC sockets. They are designed to be hot-soldered into place but over time they may become loosened or damaged. This can result in instability and intermittent operation of the socket so it needs to be repaired as soon as possible.

How to Reball a circuit board:

The first step in reballing is to remove the defective component from the circuit board. This can be done using a soldering iron, tweezers or forceps. The old solder is then removed using a desoldering braid or wick. A new BGA reballing station is used to place the new BGA component on the circuit board using a solder paste stencil and laser head. The new BGA component is then soldered onto the circuit board. The new component is tested and then the circuit board is returned to the customer.

What is the process of reballing BGA chip?

BGA chips have solder balls on the underside of the chip which transfer power and data to the PCB. The ICs, resistors, capacitors and diodes need to be replaced with new components with new solder balls since the old solder balls have cracked or been missing for some time.

The process of reballing BGA chip is as follows:

1) First remove all of the old ICs, resistors, capacitors and diodes from the PCB.

2) Clean the PCB with Acetone or Isopropyl Alcohol and allow it to dry.

3) Reball the ICs, resistors, capacitors and diodes by placing them on a BGA Reballing Station. Press down firmly onto the solder balls with your fingers and apply power. The ICs, resistors, capacitors or diodes should be tested for operation and then returned to the PCB.

4) Using tweezers or forceps, place the new BGA ICs, resistors, capacitors or diodes onto the solder balls. The BGA chips are placed directly onto the solder balls or on top of a new substrate. Once in place they should be pressed down firmly and then power applied again.

5) Wipe away any excess solder paste with a sponge using Acetone or Isopropyl Alcohol. Remove any excess liquid with a cloth and allow to dry.

6) Using a magnifying glass, check the solder balls for solder bridges. If you find any then they should be removed with a solder wick.

7) The final step is to use a multimeter to test all of the new components and make sure that they are functioning properly.

What is a BGA Reballing Station:

A BGA Reballing Station is used to Reball ICs, resistors and capacitors. It is a dedicated station that will allow you to replace the damaged BGA components on circuit boards with the same type of components.

A standard BGA reball station is made up of an X-Axis,Y-Axis,Z-Axis and a laser head that can be rotated 360 degrees for reballing of different types of boards. It will have a heated PCB bed which allows for better soldering quality and a stencil printer that will allow you to print the reballing stencils.

Reballing PCBs can be very time consuming and labor intensive, especially when you have multiple boards to restencil in one day. A BGA Reballing Station will allow you to quickly and accurately reball your circuit boards.

What is an IC Reballing Stencil?

A Reballing Stencil is a piece of paper that has a pattern printed on it and contains all of the information that you need to Reball your circuit board.

The stencil is printed on paper with a conductive ink so that it can be used to apply solder paste to the circuit board when you are reballing. The stencil also contains the pattern for the ICs, resistors and capacitors that you will be replacing.

IC Reballing Stencils are available with different types of patterns.

Must you use an IC Reballing Stencil?

If you have never worked with Reballing before, it is suggested that you use a stencil to start. Not only will the stencil make your first Reballing project easier to complete, but it will also ensure that all of your solder paste is applied evenly to the pads on the PCB. You may get away without using a stencil for your first few Reballing projects, but it is highly recommended that you use one as you gain more experience in the process.

However, after you get good at reballing, you may not need to use one. It depends on the BGA chips or process of reballing PCBs that are used. If you like to learn how reballing ic without stencil is done, we’re covering it in the next section.

There are methods to effectively Reballing ic without stencil.

There are some reballing techniques that don’t use a stencil or a PCB with solder paste already on it. Instead, you may have to use a paste dispenser to apply the solder paste to each of the areas where you will be replacing components. This is not an easy thing to do and takes a lot of practice so that you can become proficient in this process.

The best Reballing without stencil method is as follows.

When you don’t use a stencil, you have to do more steps.

Step 1: Clean the old solder paste from ball pads.

Firstly, you will need to clean the old solder paste from the ball pads. You might need to use some chemicals to remove old solder paste.

Step 2: Apply new solder paste on ball pads.

After all old solder paste is removed, you need to apply new solder paste on the ball pads. Use a paste dispenser for this step.

Step 3: Remove ICs, resistors and capacitors from the old PCB board.

You can remove ICs, resistors and capacitors from the old PCB board by using tweezers.

Step 4: Place ICs, resistors and capacitors on the new solder paste.

After all ICs, resistors and capacitors are removed from the old PCB boards, you can place them on the new solder paste.

Step 5: Place ICs, resistors and capacitors on ball pads.

After all components are placed on the new solder paste, you can place them on the ball pads.

Step 6: Remove ICs, resistors and capacitors from the new solder paste.

Then you will need to remove ICs, resistors and capacitors from the new solder paste. Use tweezers for this step.

Step 7: Reball the PCB board.

After all ICs, resistors and capacitors are removed from the new solder paste, you can reball the PCB board. Power is applied to the PCB board and then all components are tested. If all components work, you can return the PCB board to the users.

Almost every circuit board repair service today has IC Reballing as part of their services. The ability to repair a circuit board that would otherwise be scrapped because it is beyond repair by other means is what makes IC Reballing such an important service for PCB assembly companies and end users alike.

IC Reballing is a very time consuming process that requires a lot of patience and practice to master. It is not a process that can be learned in a few days or a week. It takes time to learn and master this process and it is a skill that requires constant practice to keep sharp.

PCB Shielding is the mechanical method of using conductive, magnetic or both materials to prevent EMI in the system. Mechanical shields are closed, conductive containers, connected to the ground of the PCB. They effectively decrease loop antenna sizes, and absorb and/or reflect some of the radiation.

Undesired Electromagnetic Emissions in Printed Circuit Boards

Any product with contains wires or traces and operating at high-frequency emits radio waves. As Printed Circuited Boards – PCBs become smaller and faster, one drawback of this emergent technology is severe Electromagnetic Compatibility (EMC) problems. Electronic systems consists of printed circuit boards (PCBs), interconnect, integrated chips, and I/O cables. Based on the current carried by the conductors, and the length of interconnects, these interconnects imitate antennas when working at high frequencies, sending out EMI.

Electromagnetic Compatibility – EMC

EMC determines if a device is compatible with its electromagnetic environment, and does not cause interference. If it does not emit levels of EM energy that causes electromagnetic interference (EMI) in other devices in the vicinity, it is said to be Electromagnetically Compatible. There are international standards that specify the level of emissions. Thus, manufacturers must monitor and measure electromagnetic radiation to control them. Lack of compatibility can cause narrow and broad band interference to other electronic equipment in close range, as well as data leakage.

Effects of EMI

Energy causing EMI can be in the form of conducted, radiated, and electrostatic discharge (ESD). EMI may even physically damage operational equipment, hence undesired electromagnetic (EM) emissions represent one of the most critical issues to be accounted for in electronic system design. EMC makes sure that systems perform as intended under the defined safety measures. The EMC process monitors testing requirements, and interference between the equipment placed in close proximity to each other on the PCB. Although it can occur in any frequency range, it usually occurs above 50MHz, in such cases, grounding, EMI shielding and focusing on trace spacing and layout during design phase.

Designing PCBs with EMC

There are certain simple PCB design guidelines for electromagnetic compatibility that save time and costs.

• All high-speed signals on a PCB should be referenced to a solid plane. A model return path for such signals on the circuit board is a large area of metal (ground copper polygon placed in adjacent layers to the differential pair signal), or a plane layer. This becomes the reference plane.
• Current flow in any trace on a PCB must complete the entire circuit loop and come back to the source through the reference plane. Current in a performing PCB flows from the power supply or from outputs to further downstream components.
• Return current should always choose the path of least “impedance” and will form the smallest loop with respect to the incident current path to minimize loop inductance.

One way of handling unwanted EMI is through PCB shielding.

Arduino Circuit Boards

Arduino circuit boards are produced as ready to use, and contain all required operational circuitry. Its core contains a compacted Atmega328 chip microcontroller/computer. The Arduino platform contains LEDs, connections, microcontrollers, and more. Arduino circuit boards power themselves through current supply through USB port using a USB cable. AC-to-DC power adapters can be used for external power supply.

Types of Arduino Circuit Boards

Arduino circuit boards are open source. This makes it easy for users to tailor-make projects and instruments. There are several Arduino boards available including:

• Arduino UNO,
• Red Board,
• LilyPad Arduino,
• Arduino Leonardo,
• Arduino Mega.

Each of the above are different in specifications, features and uses, and how they are used in different electronics projects. For the purpose of this article, we will focus on the Arduino Mega boards and Arduino Mega Protoshield.

Reflection and Absorption

EMI/EMC shielding can be used to encase a part of the system or the whole system. This protects the signal transmission from external noise and prevents information loss. Shielding has two chief purposes:

• Reflection (R) occurs when energy from an electromagnetic wave runs into the shield and is reflected back. and
• Absorption (A) takes place when any residual energy from the electromagnetic wave that is not reflected is absorbed in the shield, and the residual energy exits from the other side.

How to Shield a PCB

Metal shields or cans are added to shield a circuit board from EMI, in order to contain critical areas on the PCB. Shielding covering four sides and the top is soldered down to the ground plane under the components. This type of shielding is called a Faraday cage. Ideally the shield should completely enclose components to block off all emissions. However, shield openings are required for thermal cooling, seams, adjustments, and solder points to the board.

Types of PCB Shielding

PCB RF Shielding

Electromagnetic Interference shielding or EMI shielding that impedes radio frequencies and electromagnetic radiation is called RF shielding. This type of shielding reduces the coupling of radio waves, electromagnetic fields and electrostatic. A conductive enclosure used to block electrostatic fields is also known as a Faraday cage.

Arduino Shielding

The Arduino EMI PCB shield is a board that can be mounted on top of the Arduino board. Its shield pins are inserted into the sockets located down both sides of the Arduino board. Arduino has a large, range of shields designed for prototyping.

Why Are Arduino Shields Better than Others?

Arduino is an Open Source Hardware Design with a great variety of low cost shields from multiple suppliers. These shields are boards plugged on top of the Arduino PCB to enhance its capabilities. Shields are easy to mount, and cheap to produce.

Arduino Shields Are Simple to Use.

Arduino Shields have an extensive sample library that makes them easy to learn and use. The library includes sample code that users can customize for tailoring assembly.

Arduino Shields Are Inexpensive.

The standard Arduino Uno is very good on the pocket, similarly most shields are also inexpensive and provide great functionality.

Arduino Shields Are Stackable

Multiple shields can be stacked on top of each other to combine their features, since there is no specific number of “slots” on the Arduino. To connect the shields, shield pins are inserted into the sockets located down both sides of the Arduino board. Stacking Arduino Mega Proto Shields together creates an entire system.

Why are Arduino Shields Stackable?

Arduino shields allow the PCB to be multi-purposed. They are stackable to combine different functionalities and package the electronics for that circuit in the same footprint as an Arduino. Arduino shields must use the pins of the Arduino board itself, so stacked shields, must use the same pins and/or GND pins, because any communication by your Arduino and another device needs a common GND.

Use of Arduino Shields

The Arduino shields placed on top of Arduino boards enhance board capabilities for the following purposes:

• Connecting to internet networks,
• Motor control,
• LCD control and
• Establishing wireless communication.

Shields may be simple or complex based on their purpose, and are sold as kits or preassembled. Kits give the flexibility of purpose building/assembling the Arduino shield as per specific needs. Some kits require you to assemble the circuitry of the boards, although more complex shields may already be largely assembled, needing only header pins.

Types of Arduino Shields

The different shields available for the use. Arduino shields are pre-built circuit boards that connect with other Arduino boards and increase compatibility between Arduino boards. Arduino Shields include:

• Wireless Shields,
• Ethernet Shield,
• GSM shield, and
• Proto Shield.

For the purpose of this article, we will focus on the Arduino Mega boards and Arduino Mega Protoshield.

Arduino Mega Shield Specifications

The Arduino Mega Proto Shield has 54 input pins and output pins. 4 of these pins are for the hardware port, 14 pins are for PWM output, and 16 pins are used as analog inputs. The Mega also has an ICSP header, power jack, one USB connection, and one REST pin.

Arduino Mega boards can be connected to computers through USB connections and is powered by using battery or AC – DC adapter.

What is a Protoshield?

The ProtoShield is one of many Arduino shields. A Prototyping Shield is made to facilitate prototyping, it simplifies designing custom circuits. You can custom your project by soldering parts to the prototyping area. You can also use solderless breadboards to test circuit ideas prior to soldering. The ProtoShield creates easy connections between a breadboard and an Arduino.

Arduino Mega ProtoShield

The Arduino MEGA 2560 is used for projects that need extensive RAM, I/O lines, and sketch memory. Its recommended use is 3D printers and robotics projects as it has 54 digital I/O pins, 16 analog inputs and a larger space for your sketch. The Arduino Mega Proto Shield is an extra-large proto-shield, specifically designed to protect the Arduino Mega from potential damage or scratches from a new device.

The Arduino Mega Proto Shield casing placed on the Arduino Mega Circuit Board makes it easy to connect and control motors or for more complicated operation such as turning the PCB into a complex electronic device. The Arduino Mega Protoshield components are 2 buttons and a full set of extra-long, female stacking headers.

The Arduino Mega Proto Shield has extra connections for all of the Arduino MEGA I/O pins. It also has space to mount surface mount integrated and through-hole circuits, allowing you to turn your custom Arduino circuit into a single module.

Arduino Eagle Mega ProtoShield

Using AUTOCAD EAGLE design software you can custom your Arduino Mega Proto Shield easily and effectively.

What is EAGLE?

EAGLE is electronic design automation (EDA) software. It allows printed circuit board (PCB) designers connect PCB routing, component placement, and schematic diagrams. EAGLE has a comprehensive library content making it very easy for PCB designers to use. It only supports 64-bit operating systems, a minimum graphics resolution of 1024×768 pixels and a 3-button wheel mouse. Autodesk EAGLE works well with the following operating systems:

• Microsoft® Windows® 7 or newer is required.
• Linux® based on kernel 2.6 for Intel computers, X11 with a minimum color depth of 8 bpp, the following runtime libraries: libssl.so.1.0.0, libcrypto.so.1.0.0, and CUPS for printing.
• Apple® Mac OS® X version 10.10 or above for Intel computers.

Using AUTOCAD EAGLE for Arduino Mega Shield

The Arduino library has 12 variants, including the mega. Converting any design into the EAGLE Arduino Mega Shield library is not difficult. The following steps should help. While creating the design the first thing you may need to do is remove everything except for the board outline and connectors. Using a Designblock may seem easier, but creating a library is always better.

• Load the schematic from the EAGLE schematic editor.  
• Select on File/Export/Libraries and choose the option of “merge into one library” to customize the library with all your components.  
• Using design blocks saves the complete schematic and the board layout into the library.
• Choose File/Save as Design Block from the schematic editor to select the entire schematic and board file as a Block.  
• Upload your project and click on Add a Design Block to display a list of blocks you can choose from.
• Click on the block you created a few minutes ago from the Arduino Shield.

You may have to draw in the pads at the correct locations for the board, and create a symbol for the board template and map as a device. This allows you to include the template in the schematic and design your shield or cape around that. By default EAGLE Arduino Mega Shield design program has a standard set of layers for diverse purposes and these should not be removed in the general case. Since the Arduino mega is a two layer board, the AUTOCAD Eagle template will appear as such.

Remember Arduino shields translate hardware complexity and simplify it into an easy to use interface.  In doing so, you are able to design and implement your idea fast. The Arduino shield programming libraries easily integrate hardware features available on the shield. This should help you design your EAGLE Arduino Mega ProtoType Shield. All the best.

The technological revolution moves fast, and you cannot lag if you want to remain relevant and competitive. Such has proved the trend with printed circuit boards, especially in electronic design, manufacturing, and assembly. So are you an electronics PCB designer or enthusiast ready to understand more about the embedded PCB, new kid on the block? You cannot imagine a modern printed circuit board without the embedded PCB design coming to the fore.

Embedded PCB

More recently, an increase in demand for wearable, electro-medical, and mobile devices has permeated every corner of the world. Consequently, demand for embedded PCBs increased, but a progressive size reduction of embedded PCBs. However, with the need for new attributes such as high-resolution display and wireless connectivity on devices, an increased pressure regarding increased component density on a reducing size poses exist and poses an unprecedented challenge that this PCB seeks to solve.  

So what does an embedded PCB implies? An embedded PCB infers a printed circuit board containing embedded components to increase its efficiency and ensure high performance.  It always features an embedding technology that becomes instrumental in reducing transmission losses and shrinking the interconnection path among components. It plays a central role in the miniaturization of printed circuit boards, function integration, IP protection, and increased reliability.

The Assembly Process for Component Embedded Printed Circuit Board

One key feature of an embedded PCB design entails embedded components in PCB, with the embedding process encompassing the embedded technology.  The embedding technology includes mounting and involves two types: the Solder pad and the Thru-hole mounting methods.

• Solder pad mounting method.  It involves the Bare dire and the Chip mounting processes. Firstly, the Bare method entails a wire mounting process or Flip-flop mounting. It would help if you chose which to go through with when trying to embed components on the PCB. Secondly, PCB in embedded system can also entail Chip mounting, where you can decide to adopt Wave soldering or Conductive resin.
• Thru-hole mounting method. It also entails the Bare and Chip mounting processes, though the subsequent options differ from the Solder pad mounting methods. Here, the Bare mounting entails the Plated thru-hole or Conductive adhesive thru-hole options. The Chip mounting route also contains the same options: Plated thru-hole or Conductive adhesive thru-hole options.

Please note that the mounting method involving the embedded PCB with pad requires assembling the components on the formed electrodes besides developing the electrical connections. The application of the insulating resin can then get carried out to bury and fill the electrode and components, respectively.

Assembly Procedure for Embedded Components in PCB

Before looking at the assembly procedure, it becomes necessary to note the following down during the assembly process. Firstly, use the die bonding for bare die components and mold package for pad components. You can also use WLCSP, CCCC, Ultrasonic wave bonding, ESC, and conductive resin. However, for AD mounting, you can opt for conductive resin and wave solder.

To better understand the assembly process for component embedded PCB, it becomes crucial to take one mounting method in perspective and look at it in depth. So in this article, the embedded tech involving pads will become the mounting method on focus as an incredible example.

Assembly Procedure for Embedded Tech with Pads

• Firstly, it becomes prudent to research technological and design procedures, especially when it comes to AD (buried into the PCB) tech feasibility and SMDs also embedded into the cavity of the PCB.
• Trace design is the next integral step.
• The embedded PCB’s manufacturing procedure comes as the subsequent step, and it involves a process. For a double layer PCB, it starts with the fabrication of the double-layer substrate before the coating of the solder paste. It then continues with the IC assembly and waves soldering before the insulation filling and mid-stack-up. Finally, the process ends with the top layer stack-up and hot pressing.
• Assembly embedded components in the cavity
• One key challenge with embedded that anyone will attest to involves the assembly of components in the cavity. You can face the possibility of failing to apply the old-fashioned solder paste printing tech of the planar pattern. In contrast, the smooth exhaustion of the gas in the cavity fails during the wave soldering. Consequently, it can all lead to high solder voidage. To avoid the occurrence of this scenario when using the vacuum wave soldering and solder printing techniques, the adoption of this workflow becomes crucial—printing of solder paste, mounting, and vacuum wave soldering. After that, plugging, cleaning, and spray coating ensues before the process ends.  

Printed Circuit Boards Design for Embedded Systems

The PCB design when it comes to embedded systems proves critical in an embedded PCB manufacturing process. Because of this, it becomes instrumental in knowing a few things about the PCB designs for such embedded systems.

• PCB size. Size often represents a major obstacle in the design of PCBs. Therefore, the printed circuit board size and layout need every party, from the designers to engineers, to agree on everything. However, one non-negotiable includes a specific minimum size limit that PCBs cannot go beyond. It cannot get too small because you have to ensure that the right component positioning happens and avoids overheating. The embedded system has passive components, and thus the need for an SMD tech becomes mandatory. It reduces the distance and footprint between components and thus results in a compact printed circuit board layout. The second aspect entails the optimization of the PCB routing. Additionally, if space permits, it becomes crucial to increase the layer number and trace placement.
• Components placement.  Placement of the components often follows and reflects the PCB design rules. The rules involve an excellent alignment that allows a simple assembly and soldering process. Additionally, a proper separation has to get enforced between digital and analog devices. Finally, try and avoid placing some of the heavier components at or near the PCB edge, as the board can bend.
• Thermal management. Heat tends to get produced on a printed circuit trace whenever a high-intensity current flows through it. Therefore, it becomes crucial to enhance thermal dissipation as you keep the size of the PCB small.  You can accomplish this through one of two techniques or a mix of both. It can involve increasing the thickness of the trace or develop the PCB regions to achieve heat dissipation. Because of this, ensure that you adhere to the suggested IPC2221A standard. It entails the copper planes having a thickness of 10 ounces, though the value can always increase. Additionally, the creation of hot spots should get eliminated by keeping the PCB maximum temperature under 170 ͦ C. You can always use a thermal imager to determine these hotspots. Another crucial way of enhancing heat dissipation also entails the insertion of thermal vias (holes drilled in the PCB substrate)
• Embedded components. Most embedded systems feature small footprints and an elevated device density, all aimed at simplifying the assembly and design phases. Consequently, the resistors, inductors, and capacitors have to get embedded within the printed circuit board. It reduces the trace length, the number of solder points, besides the costs. What you achieve through this entails improved electrical performance besides circuit reliability. Capacitors, inductors, and resistors get placed on inner layers by etching in the PCB manufacturing process.  Subsequently, these components get incorporated during the PCB’s multi-layer lamination process. Inductors include those with magnetic cores, as the cores composed of ferromagnetic components get embedded within the substrate. Finally, the inductive windings get developed through photolithography.

Based on the components, diverse embedded tech variants can get deployed during the incorporation process. It results in new solution approaches and apps. However, in this, you will have to delve deeper into the different embedding technology variants, the process flows, design rules, selection criteria for the correct embedding variant, and the ET project’s workflow. Fortunately, you have already covered some of these processes by this point, and it should not become harder to comprehend.  

Step-Wise Process of Planning and Designing a Printed Circuit Board Assembly for Embedded Systems

• Define the requirements. All designs need specified requirements, and you will have to set some before embarking on the assembling process. Define what the assembly requires and what will not become necessary in the process. Such entails the connection of parts and the size of the PCB.
• Create a schematic. Once you have stipulated all the design requirements besides creating a concept to satisfy these needs, you will need to develop a comprehensive schematic. It should elaborate on all the components the PCB requires, the positions on the board, and the necessary connections between them. Of course, you also have to develop the bill for all components at this stage, and these involve material needs, current, and voltage requirements.
• Automation software for electronic design. It helps when it comes to the incorporation of details once the schematic gets developed. The set of instruction here become instrumental in the assembly process.
• Picking the method of fabrication
• Here, the original requirements, budget, time required, and available resources will dictate what fabrication method to pick. However, all these bases get covered at RayMing PCB & Assembly Company to ensure your design specifications get produced.  
• Testing. It encompasses the last step, and it involves the prescription of what tests to subject the PCB assembly in ensuring that all design requirements get fulfilled.  However, diverse testing techniques exist, and you will have to pick one that covers all the bases.

Conclusion

Embedded PCBs have become integral to all electronic devices because of the diverse specification needs users require. Therefore, if you want universal success and acceptance to your PCB design and one that outlives this period, an embedded PCB has to be your go-to PCB. Further, where better to get these services but on RayMing PCB & Assembly.  

Gluing is an important process used in PCB fabrication and assembly for functions ranging from laminate bonding to strain relief. Selecting the proper adhesive or glue for the application helps ensure strong, reliable mechanical connections on printed circuit boards. This article provides an overview of the key uses of PCB glue as well as glue material properties and common glue types.

PCB Gluing Applications

Glue serves a variety of roles in PCB manufacturing:

• Laminate bonding – Bonds layers of fibreglass in multilayer PCBs
• Component attach – Glues components like resistors or capacitors to the PCB
• Wire tacking – Temporary bonding of wires before soldering
• Strain relief – Reinforces soldered connections against vibration/shock
• Edge bonding – Bonds the edge of flex PCB layers
• Masking – Protective coating over components or traces
• Thermal interface – Glues heat sinks to devices

Choosing a PCB glue optimized for the specific application ensures the adhesive meets required performance criteria.

Glue Material Properties

PCB glues exhibit a range of material characteristics that determine their suitability for particular applications:

Bond Strength

• Shear strength – Ability to withstand lateral force
• Tensile strength – Withstand pulling/stretching force
• Impact resistance – Absorb sudden impacts without breaking bond

Cure Process

• Room temperature cure – Cures through oxidation at room temperature
• UV light cure – Cures quickly under UV exposure
• Heat cure – Cures at elevated temperature

Thermal Properties

• Operating temperature range
• Glass transition temperature
• Coefficient of thermal expansion
• Thermal conductivity

Electrical Properties

• Dielectric strength – Resists electrical breakdown under voltage
• Volume resistivity – Resists conduction of electricity
• Dielectric constant – Ability to store charge in an electric field

Outgassing – Release of gaseous vapors during cure. Important for aerospace applications.

Reworkability – Ability to detach/rework bonds for repair needs

PCB Glue Types

Here are some of the common adhesive types used in PCB fabrication and assembly.

Epoxy

Epoxies are the primary adhesives used to laminate multilayer PCBs. They cure through a chemical reaction between epoxide resin and a curative hardener. Key properties:

• Exceptional bond strength and temperature resistance
• Low outgassing and high dielectric strength
• Long working life for easier application

Epoxies come in a variety of formulations tuned for flexibility, thermal shock resistance, etc.

Acrylic

Acrylic adhesives cure through exposure to ultraviolet radiation. They are often used for component attachment on the PCB surface. Benefits include:

• Cure rapidly under UV light
• Room temperature storage before curing
• Good dielectric and thermal properties

Cyanoacrylate

Cyanoacrylates, or super glues, are fast-curing adhesives used for wire tacking and temporary bonding during assembly. Properties:

• Extremely rapid room temperature cure
• Low viscosity for wicking into joints
• Ability to cure with minimal moisture
• High shear and impact strength

CA glues provide quick, strong, temporary bonds.

Silicone

Silicone adhesives cure at room temperature through reaction with moisture in the air. Applications include:

• Flexible strain relief for cables or connectors
• Thermal insulation or heat transfer
• Edge bonding of conformal electronics
• Masking sensitive components on the PCB

Silicones provide good flexibility, dielectric strength, and thermal conductivity.

Urethane

Urethane adhesives cure with moisture at room temperature. They are used when flexibility is needed:

• Bonding rigid and flexible circuits
• Absorbing vibration, shock, and stress
• Edge sealing flexible PCBs
• Adhering metal component tabs

Urethanes have good impact and chemical resistance.

Selecting a PCB Glue

Factors to consider when selecting an appropriate PCB glue include:

Strength – Tensile, shear, impact needs

Flexibility – Rigid or flexible cured bond

Temperature Range – Max operating temperature

Cure Process – Heat, UV, room temperature

Dielectric Properties – Dielectric strength, resistance

Conductivity – Thermal and/or electrical

Chemical Resistance – Solvent, moisture, etc.

Outgassing – For vacuum or aerospace environments

Reworkability – May need temporary or removable bond

Discuss application requirements with glue suppliers to identify the best adhesive product fit.

PCB Glue Application Methods

Common methods for applying PCB glues include:

• Dispensing – Depositing precise dots or lines through needles
• Screen Printing – Using a stencil to print adhesive
• Roller Coating – Rolling a thin adhesive film onto bonding surfaces
• Spraying – Aerosol spraying in open or controlled environments
• Brushing – Manual application with brushes

Automated precision dispensing or printing ensures consistency and minimizes waste.

Quality Control

To achieve reliable, consistent bonds, PCB gluing processes require controls including:

• Testing bond strength of each batch with destructive tests
• Monitoring adhesive viscosity, especially for dispensed dots
• Keeping cold storage within specified temperature range
• Avoiding exposure to moisture before application
• Using glue within recommended shelf life
• Curing bonds fully with thermal ramps or UV cycles
• Inspecting visually for complete coverage without voids
• Tracking process parameters like time, temperature, pressure

Like soldering, gluing is a manufacturing process requiring close monitoring and control.

Conclusion

Gluing is a critical process used across PCB fabrication, component attachment, wire bonding, and protecting assemblies. The wide range of PCB glues available allows selecting formulations optimized for specific applications and performance requirements. Keeping gluing processes under tight quality control ensures boards with strong, reliable adhesive bonds.

PCB Glue FAQ

Q: What are some key considerations when selecting a PCB laminate bonding glue?

A: Matching Tg, thermal conductivity, dielectric properties, temperature resistance, and flexibility needs of the board. Also consider resin flow viscosity and working life.

Q: How is cured glue reworked on a PCB?

A: Removing cured glue mechanically can damage boards. Rework generally involves heating to soften the glue for removal. Laser ablation can also detach glue.

Q: What processes can help improve adhesion of PCB glues?

A: Surface roughening through chemical or mechanical abrasion gives more surface area. Plasma surface activation also improves bond strength. Match coefficients of thermal expansion.

Q: What safety precautions are important when working with PCB glues?

A: Adhesive fumes require good ventilation. Cured blobs can be sharp. Cured cyanoacrylates generate heat. Follow all material safety datasheet (MSDS) guidelines.

Q: How is PCB glue viscosity monitored and controlled?

A: Viscometers measure viscosity. Adhesives are kept in cold storage to inhibit curing and maintain viscosity. Dispense process parameters may need adjustment to account for viscosity shifts over adhesive lifetime.

Uses of PCB glue on electronics

The electronic industry largely depends on printed circuit boards as the main components. The PCB utilizes adhesive materials in encapsulating components, conformal coating, wire tacking, and bonding surface-mount components.

A distinctive PCB is a multi-overlay built-up plastic board with a defensive plastic covering. At first, manufacturers used hardware to cover boards. They interconnected multi-facet boards ‘thru-hole innovation using drilled holes. Component and board scaling down prompted ‘surface-mount innovation’ during the 1980s. With surface-mount innovation, segment contacts are bound straightforwardly to pad sections on the outside of the board. It made it conceivable to dispose of through-board connections and drilled openings.

There is significant utilization for PCB glue, basically natural, are as per the following:

• Conformal coating of circuit boards
• Potting and encapsulating electronic components
• Wire tacking
• Bonding of surface-mount components (SMCs)

Bonding activities

1. Conformal coatings

While it is not rigorously the aftereffect of a glue holding measure,  you can use similar substance kinds of gum. For example, silicones, acrylics, polyurethanes, and epoxy glue for PCB. The point is to deliver a covering that certainly sticks to and covers all the board and its parts. A conformal covering is commonly used to shield the board from natural factors, for example,

• Short circuits.
• Dampness and mold changes in help temperature (ordinarily from – 40ºC to +200ºC)
• Corrosion

Conformally covered PCBs are shielded from natural harm and mechanical and electrical obstruction.

•  Encapsulation and potting

It is a strategy for covering little surfaces or spaces with a material that will shield parts from physical and ecological harm. Encapsulation parts likewise give extra protection ability.

Potting compounds typically display excellent synthetic properties and high grip to plastics and metals, these being the materials of development of the holders and the parts.

Regular saps utilized for encapsulating are acrylics, silicones, polyurethanes, and epoxies, the last as a rule being UV-relieving definitions.

Similarly, there are different techniques for exemplifying electronic segments, to be specific projecting and trim. Projecting utilizes similar glue as preparing, albeit the compartment is generally eliminated after the pitch has been relieved.

Dissimilar to the potting cycle where the holder turns into a fundamental piece of the segment. For the most part, Embellishment includes the infusion of pre-dissolved thermoplastic pitches into a form containing the electronic components or hardware.

• Wire-tacking glues

Connection using wires is normal on PCBs. The utilization of wires permits substitution as well as an increase of printed wiring on the PCB. A portion of the explanations behind this is as per the following:

• To fix board harm or defeat the impacts of ill-advised assembling.
• To redesign or change a PCB.
• To conquer a plan imperfection found during board testing.

Typically, a protected wire is stripped and bound at each finish to cushions and part drives, at that point fortified or marked to the board substrate. The holding keeps the wire from moving around and goes about as an underlying glue in conditions where vibration could happen.

The glue that one can choose for wire attaching incorporates light-reparable acrylics, epoxies, and cyanoacrylates. Practically speaking, cyanoacrylates are generally utilized, regularly related to a suitable activator to speed the fixed time to around half a minute.

• Surface-mount devices (chip holding)

Surface-mount devices (SMDs) are set on little dots or spots of uncured glue and afterward relieved set up by warming or openness to UV radiation. It gets the SMDs solidly set up during resulting measure tasks like leaded-gadget addition or cleaning until they can be fastened to the board’s patch pads. Surface-mount glue can serve two capacities: they go about as a handling help (for example, holding a section briefly until it tends to be for all time appended by patching). They can likewise give pressure alleviation to bind connection during administration to forestall untimely disappointment of the electrical bonds. Subsequent to soldering, the now repetitive glue should not any effect on the hardware at all.

To meet the necessities for effectively holding SMDs, the accompanying properties are expected of the glue:

• Good electrical properties after curing
• High strength and good flexibility
• Non-slumping during the heated cure cycle
• Rapid curing
• High wet strength
• Non-stringing
• Suitability for high-speed dispensing of very small dots of consistent profile and size
• Long shelf life

Contingent upon the specific capacity of the surface-mount glue, it tends to be electrically conductive, electrically non-conductive, and thermally conductive. Three compound kinds of glue are generally utilized for surface-mount segment holding: acrylics, epoxy glue, and urethane acrylates. These glue variants, along with different sorts utilized in hardware applications, are talked about in more prominent detail beneath.

Preferably, surface-mount glues should be of the single component type. It maintains a strategic distance from pot-life issues, air entanglement, and changes in thickness ordinarily connected with double or multi-part frameworks. Usually, the glues will fix inside two minutes at raised temperatures alright for PCBs and related parts.

Types of glue for circuit boards

We need to consider three diverse handling stages while choosing circuit board adhesive applications. They include the solid-material or cured phase, the curing (transitional) phase, and the liquid-resin or uncured phase. The presentation of the solid-material adhesive is eventually the most significant since it enhances quality.

The technique for applying the PCB component glue is critical, specifically given the need to guarantee that the right sum is applied in the right spot. Significant techniques for applying glues in hardware applications are syringe application, pin transfer, and screen printing. Syringe application is presumably the most famous strategy, ordinarily via electro-pneumatically controlled syringes for moderate creation of a wide range of kinds of PCB.

The different kinds of glue for circuit boards include:

1. Ultraviolet curing glues

Light-curing encapsulants, coatings, and adhesives are being utilized in the hardware producing industry, expanding recurrence since they meet the necessities for materials and preparing inside this industry. Those elements incorporate ecological protection policies (environmentally damaging solvents and added substances are not needed), fabricating yield improvement, and item cost. Light-curing glues are easy to utilize and are immediately relieved without the requirement for raised temperature relieving.

The glues are regularly acrylic-based details and contain photograph initiators that actuated by bright radiation, structure-free revolutionaries to start the polymer-shaping (relieving) measure. Bright light should have the option to infiltrate into the uncured sap, a downside of light-curing glues. Stores of pitch that are dimly shaded, blocked off, or thick are hard to fix.

• Thermally conductive glues

Scaling down electronic hardware may bring about issues of heat arise, which can cause untimely malfunction of electronic parts if their most fantastic working temperature is surpassed. Thermally conductive glue can give a heat-directing way, securing semiconductors, diodes, or other force gadgets to appropriate heat sinks to guarantee such a temperature does not happen.

Non-metallic (insulating) or metallic (electrically conductive) powders are mixed into the glue plan to make high-thickness glues, which are exceptionally thermally conductive. The most well-known hot glue PCB is formed with acrylics, silicone, and epoxy.

• Electrically conductive PCB adhesive

By their inclination, most glues, both natural and inorganic, are not electrically conductive. It applies to the principle types utilized in electronic applications. They include cyanoacrylates, urethane acrylates, silicones, cyanoacrylates, acrylics, and epoxy glue for PCB. Notwithstanding, in numerous applications, including coordinated circuits and surface-mount gadgets, electrically conductive glues are required.

There are two sorts of electrically conductive glues, which are anisotropic and isotropic. Anisotropic glues are good conductors in all directions. However, an isotropic glue conducts in the upward (z-pivot) heading just and is in this way uni-directional. The isotropic glues loan themselves to almost negligible difference interconnection. It ought to be noticed that valuable as conductive glues are, they cannot be essentially ‘dropped in’ as patch choices. They are bad with tin or aluminum, nor where there are enormous holes or where they are probably going to be presented to wet conditions in help.

The typical method of changing non-conductive glues over to electrically conductive materials is to add reasonable filler to the base material. Generally, the last is an epoxy pitch. Commonplace fillers used to give electrical conductivity are carbon, nickel, and silver. Silver is the most broadly utilized. The conductive glues themselves are either in a fluid or pre-structure.

• Other glue types

The glues referenced above are the significant sorts utilized in ordinary gadgets fabricating strategies. There are others, nonetheless, which are still generally utilized:

• Polyimides: These are high-temperature saps (enduring up to 300ºC or somewhere in the vicinity) utilized in high technology hardware applications (ordinarily aviation) for wire coatings and adaptable circuits. They usually are utilized as polyamic corrosive forerunners and require troublesome and delayed restoring cycles before shaping the average adaptable, heat-safe polyamide material.
• Silicone resins: More a sealant than a primary glue, silicone sap is utilized as an encapsulant just as for conformal covering. Silicone pitches have excellent low and high warmth resilience (regularly – 60ºC to +200ºC) yet can mess up optional activities on account of the arrival of low-sub-atomic weight silicone compounds, which sully surfaces over a wide region.
• Cyanoacrylates: These have effectively been referenced for their utilization in wire-attaching applications. Cyanoacrylates are single-part glues, which fix quickly when presented to dampness noticeable all around. The utilization of these glues with an activator speeds up the relieving interaction significantly more.

There are significantly more glues, which have discovered use in hardware applications, and without a doubt, more will follow. Nonetheless, the sorts referenced above are grounded and generally utilized and structure a fundamental piece of the gadgets fabricating industry.

Conclusions

The gadgets market involves a wide range of enterprises, including media communications, customer, PC, and car areas, utilizing the PCB as the fundamental structure block for their items. Several years ago, the measure of glues utilized in creating PCBs and other electronic parts was insignificant. Presently the shortfall of glues from gadgets producing is incomprehensible. Natural, wellbeing, cost, and assembling speed are driving variables for the proceeding and always growing utilization of glues in the business.

The days when soldering was the elite joining technique in PCBA have a distant memory. The point currently is to zero in on the utilization of glues as patch choices. There is still some best approach, as the glue should assume control over the mechanical properties of the bind and be electrically and thermally conductive to a serious level.

The term DFM (Design for Manufacturing) refers to the process of designing a product with the specific goal of simplifying its manufacturing, resulting in a better product at a reduced cost. Ideally, DFM should be implemented during the early stages of a project and should involve the entire product development team, not just the hardware designers. As the project advances through the various phases of the product life cycle, any changes to the original design become increasingly costly and complex to implement, sometimes to the point of being impractical.

On the other hand, applying DFM principles during the initial stages of PCB (Printed Circuit Board) development enables potential modifications to be made quickly, at minimal cost, while preserving the product’s original performance. Technology plays a pivotal role in many aspects of modern life. From smartphones and smartwatches to household appliances and connected vehicles, nearly every device relies on smart technology and connectivity. These applications demand increasingly complex printed circuits, which must be produced at the lowest possible cost, in the shortest time frame, and with the highest level of quality. DFM helps meet these challenges by optimizing the design process for efficient and cost-effective manufacturing.

Learn more about:

• PCB DFA
• DFM Vs. DFA

What is Design for Manufacturability for PCBs?

Design for Manufacturability (DFM) in the context of PCBs refers to the practice of designing circuit boards with manufacturing processes and limitations in mind. The goal is to create designs that can be easily, reliably, and cost-effectively manufactured at scale.

DFM considerations encompass various aspects of PCB design, including:

1. Component placement
2. Trace routing
3. Layer stackup
4. Material selection
5. Drill hole specifications
6. Solder mask and silkscreen applications

By incorporating DFM principles from the outset of your design process, you can significantly reduce the likelihood of manufacturing issues, minimize production costs, and improve the overall quality of your PCBs.

What Happens When You Ignore Your Manufacturer’s Capabilities

Ignoring your manufacturer’s capabilities can lead to a host of problems:

1. Increased production costs due to necessary design revisions
2. Manufacturing delays
3. Quality issues in the final product
4. Reduced yield rates
5. Potential functionality problems in the finished PCBs

By adhering to DFM guidelines and working closely with your manufacturer, you can avoid these pitfalls and ensure a smooth transition from design to production.

What is DFM Analysis?

DFM analysis is a systematic review of a PCB design to identify potential manufacturing issues before production begins. This process typically involves software tools that check the design against a set of predefined rules based on manufacturing capabilities and industry standards.

Key aspects of DFM analysis include:

1. Checking for violations of minimum spacing requirements
2. Verifying drill hole sizes and locations
3. Ensuring adequate copper thickness for current-carrying capacity
4. Confirming that components can be placed and soldered correctly
5. Verifying that the design meets the manufacturer’s specific capabilities

DFM analysis helps designers catch and correct potential issues early in the design process, saving time and money in the long run.

Files Required for Fabrication

To ensure successful PCB fabrication, manufacturers typically require the following files:

1. Gerber files: These contain information about the copper layers, solder mask, and silkscreen.
2. Drill files: These specify the location, size, and type of all holes in the PCB.
3. Bill of Materials (BOM): This lists all components used in the design.
4. Assembly drawings: These show the placement and orientation of components on the board.
5. Fabrication drawing: This includes board dimensions, layer stackup, and other special requirements.
6. ODB++ or IPC-2581 files: These newer formats can replace multiple separate files with a single, comprehensive data package.

Providing complete and accurate files is crucial for avoiding misunderstandings and ensuring that the manufactured PCB matches your design intent.

DFM Checks for Drill Holes

Proper drill hole design is critical for PCB functionality and manufacturability. Two key aspects to consider are aspect ratio and drill-to-copper spacing.

Aspect Ratio

Aspect ratio in PCB drilling refers to the ratio of the hole depth to its diameter. A high aspect ratio (deep, narrow holes) can be challenging to drill accurately and plate properly.

• Most manufacturers prefer aspect ratios of 10:1 or less
• Higher aspect ratios may require special processes and increase costs
• Consider using stacked or staggered vias for high-density designs

Drill-to-Copper

Drill-to-copper spacing refers to the distance between a drilled hole and nearby copper features. Insufficient spacing can lead to:

• Breakouts (where the drill bit intersects with nearby copper)
• Electrical shorts
• Reduced structural integrity

Typical minimum drill-to-copper distances range from 5 to 10 mils, depending on the manufacturer’s capabilities and the specific design requirements.

DFM Signal Checks

Signal integrity is crucial for PCB performance. Two primary considerations in DFM signal checks are conductor width and spacing.

Conductor Width

Conductor width affects both the current-carrying capacity and the impedance of traces. DFM checks ensure that:

• Trace widths are within manufacturable limits (typically 3-5 mils minimum)
• Traces are wide enough to handle expected current loads
• Trace widths are consistent for controlled impedance requirements

Spacing

Proper spacing between conductive elements is essential to prevent shorts and maintain signal integrity. DFM checks verify:

• Minimum spacing between traces (typically 3-5 mils)
• Adequate clearance between traces and board edges
• Proper spacing around vias and pads

Maintaining appropriate spacing helps ensure reliable PCB performance and reduces the risk of manufacturing defects.

Solder Mask Checks

Solder mask is a crucial element in PCB manufacturing, providing insulation and protection to the copper layers. Several aspects of solder mask design require careful consideration in DFM checks.

Solder Mask Clearance

Solder mask clearance refers to the space between the solder mask and exposed copper areas (like pads and vias). Proper clearance ensures:

• Adequate space for soldering components
• Prevention of solder bridges between adjacent pads
• Reduced risk of solder mask dam failure

Typical minimum solder mask clearances range from 2 to 4 mils, depending on the manufacturer’s capabilities.

Solder Mask Opening

Solder mask openings are areas where the copper is intentionally exposed for soldering or testing. DFM checks ensure that:

• Openings are large enough for reliable soldering
• Openings are properly aligned with underlying copper features
• There are no unintended openings that could lead to shorts or corrosion

Solder Mask Expansion

Solder mask expansion refers to how much the solder mask extends beyond the edge of a pad or via. Proper expansion helps to:

• Prevent solder bridges between adjacent pads
• Ensure adequate coverage of copper traces
• Improve the overall appearance of the board

Typical solder mask expansion values range from 1 to 3 mils.

Solder Mask Registration

Solder mask registration refers to the alignment of the solder mask layer with the underlying copper features. Poor registration can lead to:

• Exposed copper traces, increasing the risk of shorts
• Covered pads, making soldering difficult or impossible
• Aesthetic issues that may affect the perceived quality of the board

DFM checks verify that the solder mask is properly aligned within the manufacturer’s tolerances.

Solder Mask Relief or Solder Mask Web

Solder mask relief (also known as solder mask web) refers to the minimum width of solder mask between adjacent pads or other openings. Adequate relief is crucial for:

• Preventing solder bridges between adjacent pads
• Ensuring the structural integrity of the solder mask layer
• Facilitating proper component placement and soldering

Typical minimum solder mask web widths range from 3 to 5 mils.

Silkscreen Checks

Silkscreen provides important information on the PCB, such as component designators, polarity indicators, and warnings. DFM checks for silkscreen ensure that this information is legible and doesn’t interfere with other PCB features.

Silkscreen to Mask Spacing

Proper spacing between silkscreen and solder mask openings is crucial for:

• Ensuring silkscreen legibility
• Preventing silkscreen from interfering with soldering processes
• Maintaining a professional appearance

Typical minimum silkscreen to mask spacing is around 5 mils.

Silkscreen to Copper Spacing

Adequate spacing between silkscreen and exposed copper areas helps to:

• Prevent silkscreen from interfering with electrical connections
• Ensure proper adhesion of the silkscreen ink
• Maintain the integrity of both the silkscreen and copper features

A minimum spacing of 5 mils is often recommended.

Silkscreen to Hole Spacing and Route Spacing

Proper spacing between silkscreen and holes or routed areas is important for:

• Preventing silkscreen from falling into holes or routed areas
• Ensuring the legibility of silkscreen near board edges
• Maintaining a clean, professional appearance

Typical minimum spacing is around 10 mils for holes and 20 mils for routed edges.

Why Should You Perform DFM Checks?

Performing DFM checks offers numerous benefits:

1. Reduced manufacturing costs by catching issues early
2. Improved product quality and reliability
3. Faster time-to-market by minimizing design revisions
4. Better communication with manufacturers
5. Increased yield rates in production
6. Enhanced overall design efficiency

By integrating DFM checks into your design process, you can create more manufacturable PCBs and streamline the transition from design to production.

5 Common DFM Issues to Avoid in Your PCB Design

1. Floating Copper/Solder Mask Slivers Create Antennas

Floating copper areas or small slivers of solder mask can act as unintended antennas, potentially causing electromagnetic interference (EMI) issues. To avoid this:

• Remove isolated copper areas not connected to any nets
• Ensure proper copper pour connections
• Verify minimum solder mask sliver widths (typically 3-5 mils)

2. Starved Thermals Cause Soldering Issues

Starved thermals occur when there’s insufficient separation between a pad and the surrounding copper pour. This can lead to:

• Difficulty in soldering components
• Cold solder joints
• Increased risk of component damage during soldering

Ensure proper thermal relief design with adequate spoke width and air gap.

3. Absence of a Clearance Pad on the Pin Causes Short

When a through-hole component pin doesn’t have a clearance pad on non-component layers, it can cause shorts with copper features on those layers. To prevent this:

• Use proper pad stacks for through-hole components
• Ensure clearance pads on all layers for through-hole pins
• Verify that clearance pads are large enough to account for drilling tolerances

4. Insufficient Annular Ring Results in an Open Circuit

An annular ring is the copper surrounding a drilled hole. Insufficient annular ring can lead to:

• Open circuits if the hole misses the pad entirely
• Weak connections prone to failure
• Difficulties in plating the hole

Ensure that annular rings meet the manufacturer’s minimum requirements, typically 5-7 mils for outer layers and 3-5 mils for inner layers.

5. Copper Too Close to the Board Edge Causes Shorts in Adjacent Layers

Copper features too close to the board edge can cause problems during depanelization and increase the risk of shorts between layers. To avoid this:

• Maintain a copper-free zone near board edges (typically 10-20 mils)
• Use proper board edge clearance for components and traces
• Consider using edge plating techniques for designs requiring copper near edges

Checks for Controlling DFM Issues

1. Avoiding DFM Issues in Drilled Holes

To minimize DFM issues related to drilled holes:

• Use standard drill sizes whenever possible
• Maintain proper aspect ratios (typically 10:1 or less)
• Ensure adequate spacing between holes and other features
• Consider using buried or blind vias for high-density designs

2. Designing Annular Rings Without Any Breakouts

To create robust annular rings:

• Use larger pad sizes for critical connections
• Account for drill tolerances in pad size calculations
• Consider teardrop pads for improved reliability
• Verify annular ring sizes meet manufacturer specifications

3. Efficient Trace Routing to Limit DFM Issues

Proper trace routing is crucial for manufacturability:

• Maintain consistent trace widths for each net
• Use 45-degree angles instead of 90-degree turns
• Avoid running traces between pads of fine-pitch components
• Consider using differential pair routing for high-speed signals

4. DFM Checks for Solder Mask Clearance

Proper solder mask clearance is essential for reliable soldering:

• Ensure adequate clearance around pads and vias
• Verify solder mask dam widths meet manufacturer requirements
• Use consistent solder mask expansion values across the board

Design Tips for Solder Mask Clearance

• Use larger clearances for fine-pitch components
• Consider selective solder mask removal for sensitive areas
• Verify solder mask clearances with your manufacturer’s capabilities

5. DFM Checks for Silkscreen

Proper silkscreen design ensures clear and durable board markings:

• Verify minimum text sizes for legibility (typically 50 mils)
• Ensure adequate spacing between silkscreen and other features
• Use vector-based fonts for improved quality

Silkscreen Considerations During Circuit Designs

• Place component designators in consistent locations
• Avoid placing silkscreen on pads or vias
• Consider using both top and bottom silkscreen for dense designs

By implementing these DFM checks and design considerations, you can significantly improve the manufacturability of your PCB designs, reduce costs, and ensure higher quality end products.

Selecting the right surface mount technology (SMT) manufacturing partner is crucial for successfully producing electronic products. This article provides guidance on criteria to evaluate when choosing an electronics contract manufacturer with SMT capabilities for your assembly needs.

Overview of SMT Manufacturing

SMT is the predominant method of assembling printed circuit boards (PCBs) in electronics due to its speed, precision, and automation advantages over through hole assembly. In SMT:

• Components are mounted directly on surface of PCB
• High speed automated pick and place machines populate components
• Solder paste applied to pads through stencil
• Reflow oven melts solder to attach components

High mix SMT lines can place tens of thousands of components per hour on PCBs with precision less than 0.1mm.

Key advantages of SMT:

• Higher component density allowing miniaturization
• Lead-free processing
• Lower assembly costs at high volumes
• Improved reliability from process control
• Flexible component selection

Electronics OEMs rely on contract manufacturers for their expertise in SMT production.

Key SMT Manufacturing Capabilities

When evaluating contract manufacturers, consider their capabilities in these key SMT areas:

Equipment Technology

• High speed, high accuracy pick and place machines
• Advanced solder paste printing and dispensing
• Reflow ovens supporting lead-free profiles
• In-line inspection equipment – SPI, AOI, X-ray
• Automated test handlers
• Material handling automation – feeders, trolleys
• ESD control equipment

Newer equipment supports tighter tolerances for miniaturized PCBs. Look for regular tech refresh investments.

Manufacturing Processes

• Solder paste printing and inspection
• Pick and place program optimization
• Automated optical inspection
• X-ray inspection for BGAs/QFNs
• AXI for accepting and reworking defects
• Testing and burn-in
• Conformal coating
• Box build and product integration

Quality processes like SPI/AOI and testing should be standard practice.

Materials and Components

• Procurement systems with qualified suppliers
• Traceability systems for lot control and recalls
• Handling of moisture sensitive components
• Access to hard-to-find and long leadtime parts
• Management of component reels/tapes
• Shelf life control for solder paste

Look for disciplined material control and risk mitigation programs.

Certifications

• ISO 9001/13485 Quality Management
• IATF 16949 Automotive Quality
• AS9100 Aerospace Quality
• ISO 14001 Environmental
• OHSAS 18001 Health and Safety

Certifications validate disciplined management systems are in place. Make sure certs are current.

Assessing Technical Expertise

Look for expertise in:

• Design for Manufacturing (DFM) – Optimizing board designs for processing
• Process engineering – Programming machines, optimizing lines, troubleshooting
• New product introduction (NPI) – Managing ramp up of new assemblies
• Product and quality engineering – Applying robust quality practices
• Test engineering – Developing test coverage for functionality and reliability
• Process improvement – Applying LEAN, Six Sigma, SPC
• ESD control – Following standards for handling ESD-sensitive devices

Cross-trained technical teams indicate an environment focused on quality.

Evaluating Operational Capabilities

Consider range of operational capabilities:

• Volume Scalability – Ability to scale from prototypes to high volume production
• Mix Flexibility – Managing high mix, low to medium volume production
• Changeovers – Quickly switching between product variants
• Multi-line Management – Coordinating production across lines and sites
• Shortened Lead Times – Responding rapidly to priority orders
• Inventory & Materials Management – Avoiding part shortages that cause delays

Look for expertise in necessary operational models like high mix/low volume and short lead time.

Assessing Supply Chain Maturity

Mature supply chain practices minimize delays:

• Supplier Management – Qualification, audits, incoming inspection
• Inventory Control – Tracking shelf life and availability
• Logistics Partners – Negotiated rates, responsiveness
• Sales & Operation Planning – Aligning supply plan with demand
• Inventory Risk Management – Dual/alternate sources for key items
• Lead Time Reduction – Supplier agreements and procurement optimization

Choose a partner who helps de-risk the electronics component supply chain.

Evaluating Continuous Improvement Culture

• Use of PDCA cycles and structured problem solving
• Applying LEAN and Six Sigma principles
• Fostering feedback culture between teams
• Technology acceleration programs (e.g. AI, IoT)
• Employee training and advancement programs
• Established EHS and sustainability programs

Look for obsession with continuous improvement at all levels and functions.

Assessing Engineering Collaboration Capability

• Design for Manufacturing (DFM) expertise
• New Product Introduction (NPI) program structure
• Joint process capability assessment
• Dedicated engineering contacts
• Use of digital tools for collaboration
• Data transparency and analytics
• Managing product lifecycle and change management

Choose a partner who integrates with your engineering processes.

Considering Global Logistics Support

• Tax and duty optimization knowledge
• Consolidated ocean and air freight
• Well negotiated rates with carriers
• Automated customs forms and compliance
• Layer packing and crating capability
• Global order visibility and documentation
• Regional warehouse hubs and fulfillment

Global supply chain support provides flexibility in your fulfilment model.

Prioritizing Corporate Responsibility

• Employee health, safety and workplace practices
• Environmental sustainability initiatives
• Established ethics policies and controls
• Data security and IP protection regime
• Product safety and regulatory compliance
• Contributing back to communities

Shared commitment to social responsibility reduces supply chain risks.

Verifying Financial Stability

• Multi-year track record of revenue and growth
• Established customer base across industries
• Disciplined management of debt and cash flow
• Investment in facilities and technologies
• Global footprint with regional options
• Publicly traded or PE/VC backed companies

Choose an SMT partner on solid long-term financial footing.

Conclusion

Selecting the right SMT manufacturing partner requires thorough vetting across technical, operational, supply chain, quality, and financial considerations. Alignment between engineering teams is also key. Taking the time upfront to perform due diligence reduces program risks and sets the foundation for a lasting partnership driving electronic product success.

How to Choose SMT Manufacturing Partner – FAQ

Q: What volume production capabilities should be expected from an SMT CM?

A: A strong SMT partner should be able to scale efficiently from low volume prototypes to full mass production of tens or hundreds of thousands of boards per month.

Q: What is the optimal site visit process for evaluating an SMT factory?

A: Plan a site tour to inspect capabilities firsthand. Review machines, processes, and certifications. Meet engineering teams. Audit an SMT line in operation. Check factory organization and housekeeping.

Q: What types of electronics projects are best suited for SMT manufacturing?

A: Complex, miniaturized PCB assemblies requiring high density components are ideal for SMT production. Examples include consumer electronics, automotive electronics, medical devices, IoT products.

Q: How can an SMT CM help manage challenges like component shortages?

A: They can leverage industry buying power, alternate component recommendations, component substitutions, approved vendor lists, and inventory buffer stock.

Q: What questions help qualify an SMT factory’s quality commitment?

A: Ask about soldering certifications, repair/rework procedures, SPI/AOI/x-ray inspection, test coverage, quality culture, continuous improvement programs.

A printed circuit board, or PCB, is a nonconductive material with conductive lines etched or printed. Both PCB’s dry and wet film refers to those raw materials utilized for the PCBs circuit. The wet film can be described as a blue thick or silky liquid from a simpler substance formed through a chemical process from a resin, which is then included with the help of a filler, pigment, a solvent, and a sensitizer.

Dry films are a kind of high molecular compound. The function of both is quite the same. But, if the PCBs surface is not the flat type and a slim film is needed, the PCB producers can contemplate or decide to make use of a wet film. This is because wet films have a great filing ability. However, they lack protection, therefore the need for increased exposure energy. If the PCB is perforated, this dry film seems to be more applicable and easier in controlling the operations. This film type is easy to handle; however, the unit price of a wet film is lesser compared to the dry type.

More Information about Rogers Film

Rodgers Prepregs and Bondplys are created to be consistently reliable and perform the most demanding multilayer PWB application. Rogers film is an RF pcb board delivered by Rogers company’s crude material.

FR4 – Fire resistant level 4 is the material used in producing most PCBs which is a composite of glass fiber/epoxy, with copper foil overlaid on one of the two sides. Rogers PCB has astounding dielectric steady and temperature security, and its coefficient of warm extension of dielectric constant is predictable with that of copper foil, which can be utilized to improve the deficiency of PTFE substrate. It is truly reasonable for the plan of fast and high-recurrence circuits, just as the use of microwave and RF items.

In view of its low water assimilation, it may be utilized for high dampness applications. Rogers PCB is an exceptional PCB with a certain specialized edge. The overall PCB Plant is too inconvenient to even consider making it. Despite the modest number of requests from clients, they don’t have any desire to do it or rarely do it. Raypcb is an expert maker of Rogers PCB, which can address the issues of clients.

Rogers Metal Claddings

Different versions of metal claddings are available in the following foil type:

• Rolled
• Electrodeposited
• Electrodeposited Reverse Treated
• Resistive Foil

Advantages of Rogers PCB substrate

Materials termed FR-4 give the major norm to printed circuit board substratum or base. This ensures a broadly powerful harmony between costs, sturdiness, execution, and manufacturability. In any case, as execution and features of electronics assume a significant part in your plans, Rogers’s materials enjoy the benefits as follows:

• Low electrical loss
• Successful PCB creation
• Lower loss of dielectric
• Better warm administration
• Wide scope of Dk (dielectric constant) values (2.55 to 10.2)
• Low outgassing for application of space
• Improvement in the impedance handling

Substrates Used in PCB Manufacturing

On all electrical devices, you’ll find a printed circuit board. It is the carrier of all electronic devices. From domestic appliances to automotive electronic appliances, you’ll find PCB. PCB boards are very important. So what are the materials used in the PCB manufacturing process? Here are the materials used:

Base: PCB real material is a copper-clad substratum. The base is a resin plate that has copper on its two sides.

Copper Foil: This is the conductor which makes a wire at the top of the base. There are two major ways used in the manufacturing of copper foil – Electrolysis and calendaring.

PP: This is an extremely important material in its natural state, used in the manufacturing of the board. Also, it provides adhesion between the layers. It has a resin element as its central substance that has sensitivity to a specific spectrum and goes through a photochemical reaction.

Solder Resist ink: This is the resistance of the solder. It is a liquid photosensitive substance that has no relation to liquid solder. It hardens and changes under slight exposure to radiation of a particular spectrum. It can be referred to as ink. The color on the board we see is the color of the solder mask.

Film: This is material that makes use of photosensitive materials in recording images.

What Role Does Dry and Wet Films Play in Manufacturing PCB?

It is a fact that the circuit patterns need to be transposed to circuit boards from CAD files. To achieve this, it requires several materials and processes. The PCB manufacturer during the development and exposure process makes use of a kind of cleanable chemical protective films to convey the circuit patterns to CCL.

They are usually divided into two namely: wet film and dry film. Wet and dry films are materials that are photosensitive that react chemically under particular wavelengths of light. Dry Films can be categorized into two major types: photopolymerization and photodecomposition.

Wet films represent photosensitive liquid resist. Dry films are not hard to process, it doesn’t have any effect on the holes on the board, and it has benefits when dealing with a circuit of higher density. Dry films are quite expensive than wet films.

Wet films have high accuracy and suit an uneven surface, but demand accurate control of uniformity and thickness. Wet films are more difficult to control unlike dry films but there is price relativity. Additionally, the waste liquid produced is also not friendly to the environment.

Conclusion

By now, you should understand the difference between dry and wet films. PCB dry films are better than wet films. They are also convenient and stable. The only disadvantage it has is that it is expensive. With the advancement of electronic innovation, there are electronic items calling for an ever-increasing number of materials, like Rogers substrate, which is utilized for high recurrence circuits. This ensures that there is an improvement in electrical execution as utilized in protection, aviation, and versatile organization applications.

The manufacturing of PCB is a very complex task that requires using specialized equipment and engineering expertise. The advancement in technology has streamlined the major aspects of PCB manufacturing, with the introduction of lasers being one of the most recent developments.

The fabrication of PCBs requires various materials. These materials are selected based on their electrical performance to ensure mechanical and electrical reliability. PCB laser etching plays a significant role in the manufacturing of PCB.

Lasers Marking in PCBs

PCB  laser is used for marking circuit boards, an important step in PCB manufacturing. Since electronics manufacturing is becoming complex it is important to mark boards to determine major components and make sure that parts are placed in correct positions so that they can be well connected.

Identifying marks have become an important aspect in PCBs manufacturing. Traditionally, identifying marks are done alphanumerically, but there are restrictions due to the space available on the PCB surface. That is why lasers are used in marking PCBs since they can offer accurate marking.

Fiber laser PCB can help to include identifying codes to any PCB surface; they can use QR codes or bar codes to cram information into a smaller space.

Lasers are also very fast when it comes to marking PCBs. They can etch codes in a few seconds while preventing the material around the area of application from any damage or distortion. Laser marking also provides information in the manufacturing of integrated circuits. In this application, precision, efficiency, and precision are very important.

It is also important to know that using lasers to mark printed-board-circuits correspond with the marking of components by using the same procedure. This makes it easy to trace and replace parts while making sure that sensitive and fragile parts aren’t placed under undue pressure.

Lasers Cutting in PCBs

Cutting is an important aspect of PCB production since a circuit board requires to be designed using a stencil with apertures to connect and solder components. A fiber laser can be used to cut PCB stencils in large volumes within a few seconds. The beam of a laser cut pcb can punch through the circuit board material to leave the necessary apertures thereby ensuring that it doesn’t compromise the integrity of the material surrounding it.

In the case of mass production, this process has to be done repeatedly. Cnc laser pcb prevents damages from occurring and minimizes waste since they use a non-contact approach to cut materials.  Laser cut fr4 are an important aspect of PCB manufacturing.

Lasers Sintering in PCBs

Sintering is considered the perfect solution to affixing components of PCBs and this method can overcome the problems of soldering and enable more durable, stronger, and consistent bonds to form during the manufacturing of PCBs.

Laser sintering is giving opportunity for the development of cutting edge PCBs which are created without solder. High-density circuits are suitable for this technique, allowing improved stability. When sintering is done, a laser is applied to a powder that contains silver. The heat coming from the laser makes the powder reach a melting point and this is allowed to cool off to form a solid connection.

Laser Cutting and Routing Systems for the Depaneling of PCB

Laser depaneling in PCB is a great way for PCB producers to save time and money. Circuit boards contain sensitive parts that may get easily damaged and laser depaneling helps to reduce stress on these parts and their solder joints.

How to Select Laser Routing for PCB Depaneling

Laser routing is one of the popular approaches to depaneling. This procedure ensures that there is no physical contact with the board. Many producers consider laser routing to be ideal for sensitive and small PCBs used in the most recent wearable technologies.

UV (355 nm wavelength) and CO2 (10.6µm wavelength) are the two lasers for PCB depaneling. The relative importance of cycle time and the neatness of the cut edge are the most important factors to consider when determining the type of laser to use.

Choosing the Right Laser Source

It is important you determine the appropriate laser source for your depaneling needs. CO2 and UV lasers have their disadvantages and advantages.

UV lasers

Lasers that involve UV use “cold” cutting technology. UV lasers make it easy to control the thermal charring of the edge. Therefore, a UV laser is a better option if reducing char is more vital than speed.

Pros

• Delivers very clean cuts
• Low HAZ
• A narrow kerf width
• Ability to cut copper leads accurately

Cons

• Longer cut times
• More expensive

When utilizing a UV laser to get clean cuts, several repetitions of laser scanning are utilized to singulate the PCBs. To control the cut speed, software controls are utilized. These cuts cut through the whole panel that cingulate the board.

CO2 Lasers

A CO2 laser is a preferable option if cycle time is very important. CO2 laser PCB can help to make full cuts and are more commonly used to create perforated cuts. Making use of the perforation technique helps to reduce char and as well as allows for easier load and unload of panels and boards from the cutting machine.

The gap left between perforations is a vital factor in the perforation technique. A bigger gap will lead to less char on the edge, but more force will be required to separate boards. We can easily adjust perforation strength based on the specifications given.

Furthermore, the amount of charring and cycle time increases as material thickness increases. If V-grooves can be used to manufacture panels at cut locations, laser cuts can be faster and cleaner.

Pros

• Fast cut speeds
• Allows processing of aluminum panels
• Thicker substrates cut well
• Lower cost for each watt

Cons

• Larger HAZ
• More charring on cut edges
• More kerf width

How to Improve Cut Accuracy for PCB Depaneling

When depaneling PCBs, the accuracy of the cut plays a significant role in reducing waste and damage. You must ensure there is consistent cut placement and this can be achieved by ensuring accurate alignment of the laser with panel components and features.

A vision system identifies certain features on the panel and adjusts the cut path to ensure the cuts align accurately to the circuits.

Why Laser Depaneling is Better Than Other Methods

• Laser routing is a method that involves a no-contact process. This means that;
• No mechanical stress on components
• No sharpening or replacement of worn blades
• Can cut through any path even curves
• Software controls that enable simple and quick change between different cut patterns
• No switching of mechanical parts or realigning of blades

Lasers Drilling in PCBs

Laser drilling makes holes on a printed-circuit-board to create connections between several layers. The electronic appliances we have in our homes consist of HDI boards that make use of laser drills. Laser drilling procedures guarantee accuracy even when working with small sizes.

Laser drilling utilizes laser energy for drilling a hole. This is totally different from drilling holes with a machine. Holes are drilled on PCBs for placing components and bringing interconnection between various layers. Lasers are capable of drilling between 2.5 to 3-mil vias on flat reinforced glass. It can drill about 1-mil vias when it comes to an unreinforced dielectric.

Benefits of Drilling with a Laser

There are several benefits of using lasers to drill and they are discussed below;

Precise control: Lasers help you gain control over the heat output, beam intensity, and the period of the laser beam. This provides high accuracy and helps to make various hole shapes.

Multi-tasking: Lasers can be used in several manufacturing processes like cutting, welding, sintering, etc.

Non-contact process: Lasers ensure a no-contact process and as such, there is no damage caused by drilling vibration.

High aspect ratio: The aspect ratio is an important parameter of a drilled hole. The aspect ratio is the ratio between the diameter of the hole and the drilled depth. Lasers offer a high aspect ratio since they can make holes with small diameters.

Factors to Consider During Laser Drilling

Some factors need to be considered during laser drilling, these two major factors should be considered;

The copper thickness

The lowest thickness of the target copper layer should be twice as thick as the top copper layer to be drilled. Lasers are the most effective way to make microvias in PCBs. Laser-drilled microvias are important in the manufacturing of PCBs

Non-homogeneity of the stack-up

While using lasers to drill, the non-homogeneity of the stack-up is very important. Several materials get energy at various rates. For instance, FR4 resin takes up energy at the exact rate as the glass fibers. BT epoxy resin vaporizes at a much faster rate than glass and as such, leaves glass fibers in the hole.

Conclusion

Lasers are important and specialized equipment used in the manufacturing of PCBs. These equipment are used for several purposes, they are used for drilling, cutting, marking, and sintering PCBs. Since it offers precision, this equipment is a preferable option for PCB manufacturers. Lasers also utilize the no-contact approach making it easy to use in the production of PCBs. Laser engrave PCB is used in PCB production.