Have you ever experienced when you rub the comb on pull over, you can pick the small pieces of paper or when you rub the balloon, and it will stick to yourself. Another powerful example is the thunderbolt of lightning during heavy rainy season.

These all are the examples of static electricity.

What is Static Electricity..?

So what is static electricity actually..? The static electricity is basically the imbalance of charge produced by mechanical movement between two bodies’ surfaces.

One of the body is the bad conductor of charge called insulator when rubbed against a material surface it causes the resistance/friction that in turns creates “static charge”.

Science behind Static Electricity:

Actually all the matter exist in the universe is made of tiny particles called “atoms”. These atoms are further broken into 3 basic constituents called “electrons”, “protons” and “neutrons”. The matter is classified into elements in periodic table. There are 118 elements in periodic table till now. The atom is electrically neutral because of equal number of protons and electrons. The electrons are loosely bonded and can escape away the shell of atom upon small excitation energy or mechanical movement like friction.

The neutrons and protons are tightly bonded together in the nucleus of atom. The nucleus is the heaviest part of atom. The number of protons forms the identity of element. It is near impossible to extract / kick off proton from nucleus. Because if we can do this we could have changed the nature/identity of element. However neutron can be kicked off nucleus and as a side effect emits radioactive waves. Now when the electron from the valence shell is removed or electron added into the valence shell then it will become positive charged or negative charged respectively.

Benjamin Franklin’s Experiments Observations:

The fluid model of static electricity, was discovered by early scientist and pioneer researcher named Benjamin Franklin. He witnessed that upon rubbing glass rod with silk cloth will cause force of attraction between the two.

When the wax was rubbed against wool cloth this will also cause force of attraction between the two.

It was also observed that if two glass rods were rubbed with their respective silk cloths then these two glass rods repel each other. Hence generating force of repulsion.

Another observation was that when glass interacted/rubbed with silk and wax interacted/rubbed with wool then wax and glass would attract one another.

Hence it is was speculated by Franklin that some sort of invisible “Fluid” is transferred between two bodies during the process of rubbing. This transfer of fluid would render one body positively charged and another negatively charged. This positively charged and negatively charged were related to the deficiency and excess of that “fluid”. This hypothetical transfer of fluid then become “Charge”.

Hence it is was postulated that charge that is created by rubbing wax was negative and that charge created by rubbing wool is positive.

Charles Coulomb Measurement:

Charles Coulomb used the special device called “Torsional Balance” to measure exact value of charge. His experiment than came to following result

“If two point objects equally charged to 1 coulomb having no physical mass are placed at a distance of 1 meter apart, then there exist a force of 9 billion Newton either attractive force or repulsive force for opposite charges and similar charge types respectively. ”

The unit of measurement of charge was dedicated to the name of Scientist “Coulomb”.

1 Coulomb of charge is actually the excess or deficiency of  electrons. Or conversely speaking 1 electron charge is equal to  Coulomb (C)

Where F = Electrostatic Force

k = Coulomb’s Constant =

q1 and q2 are two point charges

r = distance between two point charges in meters

Static Electricity Phenomenon In terms of Electronic Charge:

When the two neutral bodies/materials are brought close together and rubbed with each other, this will create movement in electrons. The electrons will start to leave from one body and enter other body. The body that releases electrons is said to be positively charged due to scarcity of electrons and the body that receives electrons is said to be negatively charged due to excess of electrons.

Examples of Static Electricity:

Hat and Hair Example of Static Electricity:

In the context of all discussion above it is now clear that when we take off the hat our hairs stick to the hat because of transfer of charges/electrons from hair to hat. This will create negative (excess of electrons) static electricity on hat and positive (deficiency of electrons) static electricity on hair.

Static Electricity Balloon Example:

We can also say that a charged object will attract neutral object because of the same electrons flow from charged object to neutral. Example of this is a balloon that when rubbed on your hair will get negative charge, then it is brought near to the neutral wall but the balloon will stick to the wall because of electron flow from balloon to wall. This is also true for the case when we brush our hair with comb then the comb can pick up small pieces of paper.

Static Electricity of Clouds Friction:

The friction in the clouds in rainy season cause the generation of static electricity. This static electricity is stored in the clouds but is visible due to millions of volts created spark in sky. This static electricity converts into electrical current when some sort of current path is generated from clouds to the ground like a kite can bring the thunderbolt to the earth surface.

Ozone Cracking:

The ozone is created due to static discharge. This ozone is not good for elastomers. This ozone can make deep cracks in vehicle components like O-rings. The damaged fuel line from ozone can cause fire. To protect from this use elastomers that resist ozone.

Static Electricity vs Current:

The charged objects will hold these states of excess / scarce electrons until it is applied by external force to move it in a particular direction. These electromotive force (EMF) or “voltage applied across” will cause the electron to flow thus converting static electricity into “current”.

Current is always moving in a direction through a metallic wire. While static electricity remain stored in a body when applied to mechanical friction/movement.

Introduction

RoHS stands for Restriction of Hazardous Substances and is an important regulatory standard that impacts the electronics industry. RoHS compliance dictates restrictions on certain hazardous substances in electronic products and components. For printed circuit board (PCB) manufacturers, understanding and implementing RoHS compliance is crucial.

This guide will provide a comprehensive overview of RoHS, including:

• RoHS directive history and timeline
• Substances restricted under RoHS
• RoHS scope and exemptions
• Requirements for PCB manufacturing
• How to demonstrate RoHS compliance
• RoHS certification standards
• Cost impact of RoHS compliance
• Future outlook for RoHS

By the end of this article, you will have a deeper understanding of this critical set of regulations and how to ensure your PCB assembly process and supply chain upholds RoHS standards.

Overview and History of RoHS

RoHS stands for “Restriction of Hazardous Substances” and originated as a European Union directive known as “Directive 2002/95/EC” adopted in February 2003. The original RoHS directive focused on restricting certain hazardous substances in electrical and electronic equipment (EEE).

The motivation was to address health and environmental concerns around substances like lead, mercury, cadmium and other heavy metals found in electronics. RoHS regulations mandated stricter limits on these substances with a combined threshold percentage limit of 0.1% by weight per homogeneous material in applicable EEE.

The current version of the RoHS Directive is referred to as “RoHS 2” or “RoHS Recast.” It was published as Directive 2011/65/EU which updated and recast the original legislation. RoHS 2 expanded the scope of products covered while keeping the restricted substances largely the same.

Some key dates in the history of RoHS adoption include:

• February 2003 – Original RoHS Directive 2002/95/EC enters into force
• July 2006 – RoHS 1 takes effect and EEE in EU market must comply
• January 2009 – Commission exempts medical devices until 2014
• January 2011 – Commission exempts monitoring equipment until 2014
• July 2011 – RoHS 2 Directive 2011/65/EU is published
• January 2012 – RoHS 2 enters into force
• January 2013 – RoHS 2 compliance required

RoHS has gone through gradual expansion of its scope over the years since its inception while maintaining focused restrictions on some key hazardous substances.

Restricted Substances Under RoHS

The RoHS directives impose restrictions on the following main substances:

• Lead (Pb)
• Mercury (Hg)
• Cadmium (Cd)
• Hexavalent chromium (Cr6+)
• Polybrominated biphenyls (PBB)
• Polybrominated diphenyl ether (PBDE)

The maximum threshold level permissible for these restricted substances by weight in homogeneous materials is 0.1% (1000 ppm).

Additionally, RoHS 2 added four phthalates to the list of restricted substances:

• Bis(2-ethylhexyl) phthalate (DEHP)
• Butyl benzyl phthalate (BBP)
• Dibutyl phthalate (DBP)
• Diisobutyl phthalate (DIBP)

These hazardous substances were included in electronics primarily due to their properties in applications like lead solder, mercury switches, cadmium plating, and flame retardant plastics. However, the potential risks posed led to regulations limiting their use. Eliminating these from the supply chain required a major shift in materials and processes for the electronics industry.

RoHS Scope and Exemptions

RoHS 2 expanded the scope of applicable product categories versus RoHS 1. The legislation covers electronic equipment and devices that:

• Rely on electric/electromagnetic fields for functioning
• Generate, transmit, or measure such fields
• Use voltage not exceeding 1,000 volts AC and 1,500 volts DC

Within scope categories under RoHS 2 include:

• Large and small household appliances
• IT equipment like computers and servers
• Consumer electronics
• Lighting equipment including lamps and luminaires
• Monitoring instruments and control gear
• Automatic dispensers
• Power tools
• Toys and sports gear with electronic components
• Medical devices (from 2014)

Out of scope categories include military equipment, aerospace equipment, certain large-scale industrial tools, implantable medical devices, photovoltaic panels and some others.

Within the product categories covered under RoHS 2, the legislation allows for certain applications and materials to be exempt from the substance restrictions based on technical feasibility or reliability. Some current exemptions include lead in high melting temperature solders, lead in glass or ceramics, lead in server or storage system batteries, among others.

RoHS Requirements for PCB Manufacturing

Printed circuit board manufacturing and assembly is squarely within the scope of RoHS 2, since PCBs are core components of nearly all electronic equipment. This has major implications for PCB material sourcing, fabrication, assembly, and testing processes in order to comply. Here are key requirements for PCB manufacturing under RoHS:

Substrate and Laminate Materials

• Base substrate materials like FR-4 must not contain brominated flame retardants like PBB or PBDE exceeding the 0.1% threshold
• Prepreg bonding films also cannot contain these hazardous brominated compounds
• Ceramic or composite substrates need to avoid restricted phthalates

Solder

• Lead-free solder alloys like tin-silver-copper must be used instead of tin-lead solder
• Solder flux also should not contain prohibited substances

Plating

• Surface finishes need to eliminate hexavalent chromium and cadmium plating
• Alternatives like immersion tin, immersion silver, OSP or ENIG should be used

Components

• Parts need RoHS compliant termination finishes and lead-free soldering
• Must avoid lead, cadmium and other restricted substances

Marking and Documentation

• RoHS labels, markings should be present both on bare boards as well as assembled PCBs
• Certificate of Conformity and test documentation required

Adhering to these guidelines ensures PCB manufacturing avoids any use of restricted hazardous substances per RoHS 2 standards.

Demonstrating RoHS Compliance

Since RoHS regulations pertain to end products sold in the EU market, PCB manufacturers must be able to demonstrate RoHS compliance through documentation and traceability. Key ways to show compliance include:

Material Declarations

• Suppliers of substances, materials like laminates must provide material declaration forms listing any restricted substances and their concentrations.

Certificates of Conformity

• Certificate to declare RoHS compliance for the specific product being placed on EU market.

Test Reports

• Independent lab testing reports to validate concentrations of restricted substances in materials or components are below permissible levels. This can involve analytical testing like GC/MS.

Markings

• RoHS compliant labels, markings on PCBs and consumer end products. For example “RoHS” or “Lead-Free.”

Chain of Custody

• Documentation tracking materials through the entire supply chain to prove compliance at every step.

Maintaining this documentation provides evidence of RoHS conformance during any audits or regulatory inquiries.

RoHS Certification Standards

To ease the burden of compliance demonstration, industry standards have been developed that allow manufacturers to certify their products or materials are RoHS compliant once criteria are met. Two common standards include IPC and UL certification programs.

IPC-1752 Class D Materials Certification

• Standard published by IPC to certify materials as RoHS compliant with extensive testing requirements and stringent control levels.
• Allows materials suppliers to produce independent certification.
• Class 1-3 also exist for parts and components, PCBs, and electronics assemblies.

UL 1007 Standard

• Published by Underwriters Laboratories (UL) as a standard for RoHS materials verification
• Covers restricted materials testing methodology and acceptable concentration levels
• UL issues certificates for complying materials as recognized proof of RoHS conformance.

By having materials or boards be certified through these standards, manufacturers have recognized means to demonstrate RoHS compliance to customers and regulatory authorities.

Cost Impact of RoHS Compliance

Transitioning to RoHS compliant materials, components and processes did involve some cost increases for electronics manufacturers:

• Reformulation of laminates, prepregs, coatings to replace brominated FR additives
• New plating processes like immersion silver instead of hexavalent chromium
• More expensive solders like SAC alloys instead of tin-lead
• Component costs increased from lead-free terminations, marking, compliance testing
• New process controls around material handling, storage and traceability
• Increased documentation, certification, and record-keeping overhead

However, over time these costs diminished as compliant materials and processes matured and economies of scale optimized RoHS implementation. Substitutes like halogen-free FR materials eventually reached cost parity with older materials. Solder costs also declined.

For PCB manufacturers, careful supplier management and process controls enabled cost-effective RoHS compliance. The regulation is now well-integrated into electronics manufacturing.

Future Outlook for RoHS

As awareness around sustainability grows, expectations are for the scope and stringency of RoHS regulations to expand further:

• EU has stated intention to periodically review and add restricted substances to RoHS as needed.
• Exemptions may also be phased out over time if technically feasible substitutes emerge. This pushes industry to develop innovative solutions.
• More product categories and electronics could come under RoHS legislation as scope gaps get addressed.
• Tighter control limits on maximum permissible concentrations are also possible.
• Expect alignment and convergence between different global environmental regulations.

For PCB companies, retaining organizational agility and supply chain flexibility will be key to adapt to future RoHS changes. Staying abreast of emerging substitutes and sustainable materials will also allow companies to turn compliance into competitive advantage.

Conclusion

RoHS stands as one of the most influential environmental regulations shaping the electronics industry over the past two decades. Its restrictions on hazardous substances fundamentally changed materials, components and processes for PCB manufacturing.

While adapting to RoHS compliance did entail costs and process changes, manufacturers have largely integrated its ethos into operations. With proper material evaluation, process controls, certification and documentation, PCB assemblers can readily demonstrate RoHS conformance.

As the scope expands and companies focus more on sustainability, RoHS principles will continue guiding the industry’s responsible use of materials for benefit of human health and the environment.

Frequently Asked Questions

Here are some common questions around RoHS compliance for PCB manufacturing:

Q: Does RoHS apply to PCB manufacturers outside the EU?

RoHS applies to any PCBs that will end up in products sold or imported into the EU market, irrespective of where they are manufactured. So PCB assemblers globally must comply if boards will reach EU countries.

Q: How are RoHS regulations enforced for non-compliant products?

Within the EU, enforcement is handled at the national member state level through market surveillance. Customs agents or regulators can do sample procurement and testing to check for compliance, issuing penalties for violations. They can also force recall and disposal of non-compliant products.

Q: Can any deviations be allowed from the maximum substance concentration limits under RoHS?

In general, RoHS takes a strict interpretation of the 0.1% threshold substance limit in materials. However, the IPC-1752 standard does permit maximum levels of up to 0.2% for cadmium and mercury to account for measurement uncertainties and trace contaminants. Still, the main limit remains 0.1%.

Q: Does RoHS restrict only substances intentionally added or even trace contaminants?

RoHS covers both intentionally added restricted substances as well as contaminants arising from production of the material that may exceed permissible thresholds. Manufacturers are responsible for limiting both.

Q: Can normal FR-4 laminates still be used in RoHS compliant PCBs?

Yes, as long as the FR-4 laminate meets RoHS requirements. Usually this means replacing the brominated compounds previously used for flame retardancy with polymeric or reactive phosphorous-based FR additives that are RoHS compliant. RoHS-compatible FR-4 laminates are widely available.

Q: Does RoHS compliance also require lead-free component soldering?

Yes, for an assembled PCB to be fully RoHS compliant it requires lead-free soldering. So components must have lead-free terminations and lead-free solder alloy like SAC305 must be used to solder components to the board. Lead-free solder process controls are part of overall RoHS conformance.

What is RoHS and Why is Important

In 2003, the European Union (EU) created a legislation to restrict the use of hazardous substances in Electronics and Electrical industry for the sake of environmental and people safety and health issues. This legislation itself is known as RoHS (Restriction of Hazardous Substance)

We know that electronics and electrical industries have soared too much. People are buying electronics at unimaginable pace, from smart phones, to IoT products, computers, laptops, house hold equipment, auto industry, Wire, cables, connectors, components are widely available in the market from lowest grade quality to highest grade quality.

The low quality component and devices are cheap and high quality is expensive. So people tend to buy cheaper electronics to fit in their budget constraints. However they do not realize the dangers associated with cheap quality electronics, components and devices. Low quality products means products using Non-RoHS electronic components/materials in them.

ROHS Products are Expensive..!

The one biggest problem of RoHS is nothing more than “Expensive Products”. Why would a company choose components/materials for manufacturing their product that are expensive (RoHS compliant)..?

These expensive components or materials used to manufacture product will surely increase the price of end product thus reducing the profit margin of the company. This is the reason why many EE companies opt for Non-RoHS components.

This is the same case with individuals whose TV set if have some problem, that individual will use lead solder (that is cheap) for de-solder or repair purpose because lead free solder is little bit expensive so as to save money but in return inhaling solder fumes which is deadly for lungs.

So the question is “Should we use materials (as an EE company and individual working as hobbyist or repairman) that comply with RoHS standards while realizing that the end product or cost of service will increase thus possibly declining profit and reducing market. The answer as per the EU standards (CE Mark) is YES..!

This is because RoHS standards were designed not considering the financials or monetary implications of any individual or a company but to ensure welfare of people in terms of health and cleaner environment

Dangers Associated with Non-RoHS Materials:

As mentioned that RoHS legislation standards are important because to make sure that environmental pollution is reduced and people health care issues are resolved. Imagine a company that has a PCB assembly and PCB manufacturing facility where materials that are Non-RoHS compliant are used. Now you can imagine that people who are engaged in daily routine work on a conveyer belt handling those materials will suffer from different diseases of skin and lungs cancer, mesothelioma and asbestosis.

Those labor which are packaging these Non-RoHS PCB materials and products will also suffer because they handle materials with their bare hands. Thus everyone involved in handling these stuff manufacturing labor, packager, supplier, distributor will not be affected immediately or shortly but will be affected in longer run surely.

The dangers associated with Non-RoHS products/materials is not just limited to manufacturing and handling but during and after use, they are discarded and become part of Landfills. Because of longer life cycle of these Non-RoHS materials they do not decay soon, but take very long time to degrade/decay. Thus when thrown away in landfills (holes in the ground), their traces are mixed in underground water resources hence polluting environment, plants and fishes.

Why was ROHS introduced..?

Keeping in view above hazards, RoHS directives 2011/65/EU known as RoHS-2 was introduced in 2011 and directives 2015/863 known as RoHS-3 was introduced in 2015.

RoHS-2 directives 2011/65/EU introduced the restriction on the use of Bis (2-ethylhexyl) phthalate (DEHP) and Di-isobutyl phthalate (DIBP). The ROH-2 was specific for medical instruments for monitor and control and other EE equipment not covered. ROHS-2 also included the CE (Compliance Europe) Marking standard.

RoHS-3 added 4 new materials in the list of six Non-RoHS restricted materials under directive 2015/863. These are Bis (2-ethylhexyl) phthalate (DEHP), Butyl benzyl phthalate (BBP), Di-butyl phthalate (DBP) and Di-isobutyl phthalate (DIBP)

ELV Directive:

The End of Life Vehicle (ELV) is another directive of EU about the scrap cars and waste materials regarding wires, cables and electrical accessories. The ELV directive restricts the use of banned materials in the list given below in automobile industry.

WEEE Directive:

WEEE stands for Waste Electronic and Electrical Equipment. The Collection, treatment and recycling of waste electronics is the mandate of WEEE directive. It urges the electronic and electrical product manufacturers to comply with this standard otherwise legal action will be taken against those who do not comply in terms of thousands of dollar fine.

On the other side, awareness of WEEE and RoHS needs to be spread. The EE product designers and manufacturers need to make products such that they facilitates extraction of useful components and materials  like silver, gold, platinum, copper, aluminum, during recycling process.

RoHS Restricted Materials:

The RoHS standards have defined the admissible (minimum) amount of restricted materials that can be used in a product. This amount is measured in Parts per Million (ppm). So 1 ppm means out of every 1 million parts of RoHS compliant material, only 1 part of RoHS non compliant material is allowed.

The list of total 10 restricted materials along with their ppm (RoHS non compliant) is given below

1. Cadmium (Cd): < 100 ppm
2. Lead (Pb): < 1000 ppm
3. Mercury (Hg): < 1000 ppm
4. Hexavalent Chromium: (Cr VI) < 1000 ppm
5. Polybrominated Biphenyls (PBB): < 1000 ppm
6. Polybrominated Diphenyl Ethers (PBDE): < 1000 ppm
7. Bis(2-Ethylhexyl) phthalate (DEHP): < 1000 ppm
8. Benzyl butyl phthalate (BBP): < 1000 ppm
9. Dibutyl phthalate (DBP): < 1000 ppm
10. Diisobutyl phthalate (DIBP): < 1000 ppm

RoHS in Europe:

If you are still using one of the RoHS non complaint substances listed above and you are anywhere outside Europe then it is fine, but if you are in Europe then you may have to face consequences in terms of heavy penalty or even imprisonment. Any EE product that is sold in Europe it MUST be RoHS complaint and CE certified.

Introduction

The deployment of 5G networks is rapidly accelerating globally, with the new technology promising faster data speeds, lower latency, and the ability to connect massive numbers of devices. A key component that enables the functioning of 5G networks is the 5G printed circuit board (PCB). 5G PCBs facilitate the transmission of 5G signals and help achieve the high frequencies needed for 5G.

However, designing 5G PCBs comes with unique challenges compared to previous generations of wireless technology due to the higher frequencies used. New PCB materials and careful design considerations are required to account for signal loss, impedance control, thermal management, and more.

This comprehensive guide will provide electronics hardware designers and engineers with an overview of key considerations and best practices for designing 5G PCBs. Topics covered include:

• 5G frequency bands and data rate requirements
• Selection of PCB materials and properties to consider
• Layout techniques for improved signal integrity
• Strategies for thermal management
• EMI and signal loss mitigation techniques
• Testing and validation methods

By the end of this guide, you will have a solid understanding of how to design and optimize 5G PCBs to fully take advantage of 5G capabilities.

5G Frequency Bands and Data Rates

The frequencies used for 5G networks are a major difference compared to previous generations of wireless technology. 5G uses frequency bands in the high-frequency millimeter wave (mmWave) ranges between 24 GHz to 52 GHz, as well as some sub-6 GHz frequencies.

The advantage of mmWave frequencies is the availability of large amounts of contiguous spectrum which enables very high data rates. The mmWave bands currently defined for 5G use include:

• n257 (28 GHz)
• n258 (26 GHz)
• n261 (27.5 GHz – 28.35 GHz)

Some of the key 5G frequency bands and corresponding data rates include:

Frequency Band	Data Rate
600 MHz	100 Mbps
2.5 GHz	1 Gbps
4.7 GHz	1.3 Gbps
24 GHz	3 Gbps
28 GHz	5 Gbps
39 GHz	7 Gbps

However, the higher frequency mmWave signals also have much shorter wavelength and cannot penetrate obstacles as well. This leads to higher path loss and requires more advanced antenna technologies like massive MIMO and beamforming.

When designing a 5G PCB, the frequency bands and data rate requirements need to be carefully considered to ensure the board can support high frequency signals with adequate gain and minimal loss.

PCB Substrate Materials for 5G

The selection of the appropriate PCB substrate material is critical for 5G design. The dielectric substrate material separates copper layers in the PCB and impacts loss tangent, dielectric constant, thermal conductivity and other properties. Some key considerations for 5G PCB substrate selection include:

Dielectric Constant

A low dielectric constant (Dk) helps reduce signal loss and cross talk. Common low Dk substrates for 5G PCBs include fluoropolymers like PTFE (Dk of 2.1) and liquid crystal polymers (LCP) with Dk between 2.9-3.3.

Loss Tangent

The loss tangent indicates the material’s inherent signal loss due to dielectric absorption. Lower loss tangent values below 0.005 are desirable for mmWave 5G boards. Rogers RO3000 series laminates have loss tangents between 0.0021-0.0027.

Thermal Conductivity

The high power density of mmWave circuits leads to substantial heat generation. Using thermally conductive substrates like ceramic aluminum nitride (170 W/mK) and liquid crystal polymer (0.67 W/mK) helps dissipate heat.

Coefficient of Thermal Expansion (CTE)

Matching CTE between PCB and components prevents solder joint failure and pad cratering during thermal cycling. Glass reinforced hydrocarbon laminates offer CTE compatibility with common components.

Moisture Absorption

Materials like PTFE have very low moisture absorption, helping maintain stable electrical performance. High moisture absorption of substrates should be avoided.

Thickness

Thinner dielectrics help reduce loss at mmWave frequencies. While thickness depends on layer count, substrates between 0.1mm to 0.3mm thickness are typical for 5G.

Here is a comparison between some popular 5G PCB substrate materials and their properties:

Material	Dk	Loss Tangent	Thermal Conductivity	CTE	Moisture Absorption
Rogers RO3003	3.0	0.0013	0.31 W/mK	17 ppm/°C	0.06%
Rogers RO4835	3.33	0.0031	0.74 W/mK	11 ppm/°C	0.04%
Taconic RF-35A2	3.5	0.0018	0.69 W/mK	7 ppm/°C	0.02%
Polyimide	3.4-3.6	0.002-0.004	0.12 W/mK	20-70 ppm/°C	1-4%
PTFE	2.1	0.0002	0.25 W/mK	17 ppm/°C	0%
LCP	2.9	0.0025	0.67 W/mK	17 ppm/°C	0.04%
Aluminum Nitride	8.9	0.0001	170 W/mK	4.3 ppm/°C	0%

Layer Stackup Design

The layer stackup defines the number of copper and dielectric layers in a PCB. An optimal stackup is important for controlling impedance, minimizing loss and ensuring signal integrity at 5G frequencies. Here are some key guidelines for 5G PCB stackups:

• Use thicker copper layers (2oz/ft2 or more) to reduce conductive losses
• Minimize number of lamination cycles to limit signal loss
• Include ground planes close to signal layers for impedance control
• Keep layer count low, typically 4-8 layers for optimum 5G performance
• Use symmetric stripline configurations for differential pairs
• Manage layer transitions carefully using tapers/chamfers
• Adopt a split power plane approach to isolate noise-sensitive supplies
• Allow for thermal vias beneath hot components to dissipate heat

A sample 8 layer stackup for a high frequency 5G board could be:

Layer	Function	Thickness
1	Signal	2 oz Cu
2	Ground	1 oz Cu
3	Power	2 oz Cu
4	Signal	2 oz Cu
5	Ground	1 oz Cu
6	Power	2 oz Cu
7	Ground	1 oz Cu
8	Signal	2 oz Cu

The close proximity ground planes help control impedance, reduce EMI, and minimize crosstalk. The split power planes isolate digital and analog supplies. Thicker 2oz copper minimizes conduction losses.

5G PCB Layout Guidelines

Careful attention must be paid to the PCB layout to achieve design objectives for 5G performance, signal integrity and EMI control. Some key 5G layout techniques include:

Controlled Impedance

Maintain 100 Ohm differential impedance for interface traces by tuning trace width/spacing based on stackup. Minimize length differences between differential pairs.

Isolation Between RF and Digital

Separate RF and digital sections on layout using ground/shielding barriers. Prevent noise coupling by distance and orientation.

Minimize Trace Lengths

Keep trace lengths as short as possible on mmWave nets to reduce insertion loss. Use surface mount devices for shorter connections.

EMI Shielding

Incorporate shielding cans, guard traces, and ground/power moats to contain EMI emissions. Prevent slot antennas from forming.

Power Delivery Network

Use enough decoupling capacitors close to IC pins, and lower impedance power distribution for clean, stable supply rails.

Thermal Management

Allocate space under hot devices for thermal vias/metal slugs to conduct heat. Use internal cutouts/keepout zones for airflow.

Antenna Integration

Properly integrate antenna arrays within board or align edge mounts using cutouts and milling. Match impedance.

Test Points

Include test/probe points to validate performance over frequency, such as with network analyzers and TDR measurements.

With careful implementation of these guidelines, the PCB layout can be optimized for superior 5G signal integrity.

Mitigating Loss and Signal Integrity

Maintaining signal integrity and minimizing loss is critical for 5G PCBs due to the higher frequencies involved versus 4G or Wi-Fi. Some techniques to help mitigate loss and improve signal performance include:

Extensive Ground Stitches

Connecting all ground planes and areas with many via and microvia stitches reduces ground inductance.

Backdrilling (Via Stub Removal)

Backdrilling unused portions of plated through holes improves impedance matching and reduces reflections.

Buried/Blind Vias

Using vias that span only 2-3 layers controls coupling compared to full-depth drilled vias.

Smooth Layer Transitions

Tapered chamfers/rounded corner pads on layer transitions prevent abrupt impedance discontinuities.

Spacing from Ground

Maintaining adequate clearance from ground layers prevents energy loss through substrate radiation.

Matched Length Routing

Tuning trace lengths to match electrical lengths improves insertion loss in differential pairs.

Periodic Voiding

Introducing voids along a reference plane reduces eddy current losses at high frequencies.

Dielectric Coatings

Applying low-loss tangent coatings (e.g. paralene, PTFE) on traces cuts down on surface wave propagation loss.

With careful modeling and simulation, these techniques can be implemented to fine-tune 5G board performance.

Thermal Management Approaches

Thermal management is a significant concern for 5G PCBs due to increased power densities at mmWave frequencies. Here are some approaches to effectively dissipate heat:

• Metal core substrates – Base laminate itself is aluminum or copper for spreading heat
• Thermal vias – Drilled holes filled with metallization conduct heat to inner layers
• Heatsinks/heat-spreaders – Use machined aluminum heatsinks with thermal interface material
• Fans/air flow – Incorporate small fans or ventilation channels into enclosure
• Phase change materials – Substrates with materials that undergo phase change to absorb heat
• Vapor chambers – Hollow chamber with working fluid that evaporates and condenses, transferring heat

Ideally, thermal management techniques should be modeled during design to predict temperature gradients and optimize heat flow.

EMI Control Methods

EMI control is necessary in 5G designs to prevent interference with other devices and ensure conformance to EMI/EMC standards. Methods to control EMI include:

• Metal shielding cans over sensitive ICs
• Small aperture waveguide vents on enclosures
• Ground plane stitching through multiple layers -strategic placement of ground vias forming “walls”
• Filtering components like ferrite beads on I/O
• Additional shielding gaskets on enclosure seams
• Internal metal compartmentalization to prevent slot antennas
• Careful component placement to contain noise sources
• Sparse power plane fills with islands disconnected at DC

Prototyping and testing needs to validate EMI performance. It may be an iterative process as issues are found and fixes incorporated. Shielding, filtering and isolation are key principles to follow for managing EMI and EMC.

Testing and Validation

Throughout the PCB development process, testing and validation should be conducted using the following methods:

Simulation and Modeling

Perform 3D EM simulations of traces, stackup, PDN, thermal performance. Identify problem areas through modeling.

Frequency Sweeps

Use a network analyzer for insertion loss, return loss, and impedance measurements over frequency. Verify input to output magnitude and phase.

VSWR and Losses

Evaluate voltage standing wave ratio (VSWR), gain, and losses. Look for impedance discontinuities and unexpected resonances.

Eye Diagrams

Eye diagrams show signal integrity and jitter. A widely open clear eye is desired for clean signaling.

Time Domain Reflectometry

TDR plots will reveal impedance mismatches and discontinuities along a trace from reflections. Useful for controlled impedance validation.

Vibration/Shock

Assess mechanical robustness under vibration and shock conditions. Check for solder joint cracks or trace/via fractures.

Thermal Imaging

Use an IR thermal imaging camera to map board hot spots and temperature gradients. Identify cooling deficiencies.

EMI Diagnostics

Test for radiated and conducted EMI compliance. Sniff out specific noise sources.

With careful testing and validation, potential issues can be caught early and addressed to ensure optimal 5G board performance.

Conclusion

Designing printed circuit boards for 5G applications presents new challenges compared to previous wireless generations due to the use of mmWave frequencies and higher data rates. However, through careful planning and optimization across PCB materials selection, stackup design, layout considerations, thermal management, and EMI strategies, a high performance 5G board can be realized.

By following the guidelines and techniques outlined in this article, PCB designers can fully unlock the capabilities of 5G technology and facilitate the rollout of faster, lower latency 5G networks. With attention to signal integrity, thermal management and EMI control, the next generation of wireless connectivity can be achieved through optimal 5G PCB implementations.

Frequently Asked Questions

Q: What are some key differences between designing PCBs for 5G vs 4G?

A: Some key differences include:

• 5G uses higher mmWave frequencies between 24-52 GHz requiring attention to loss, impedance control and thermal issues. 4G uses lower frequency bands.
• Shorter mmWave signal wavelengths require smaller PCB features and tighter layout tolerances.
• 5G PCB materials favor low-loss, thermally conductive substrates whereas FR-4 was common for 4G.
• Beamforming antennas and higher power density ICs lead to greater thermal challenges.
• Shorter mmWave signal paths, isolation and EMI control are more critical in 5G design.

Q: How can signal loss issues be identified in 5G PCB design?

A: Methods to identify signal loss issues include:

• Performing insertion loss simulations on critical high speed nets
• Using TDR analysis to find impedance discontinuities causing reflections
• Evaluating S-parameter results from VNA tests for excessive loss at 5G frequencies
• Analyzing eye diagrams for signs of signal degradation from loss or distortion
• Measuring channel operating margin and link budgets to model expected vs actual loss
• Thermal imaging to check for excessive heating of traces causing resistive losses

Q: What are some methods to control EMI for 5G boards?

A: Techniques to control EMI in 5G PCB design include:

• Use of shielding enclosures and cans to contain emissions
• Careful component placement and orientation to avoid noise coupling
• Extensive ground plane stitching to reduce ground loop antennas
• Strategic use of ground/power moats around circuits
• Filter components like ferrites beads to suppress noise
• Limiting slot/aperture openings in enclosures
• Sparse fills and islands on power planes to reduce coupling
• Tight board-to-chassis grounding to shunt EMI away
• Prototyping and testing to identify issues and refine design

Q: How can signal integrity be maintained for sensitive 5G links?

A: Some best practices for maintaining signal integrity include:

• Matched length differential pairs to control skew and dispersion
• Cross-talk mitigation through distance and routing orientation
• Choosing low loss PCB materials and laminates
• Adding low loss coatings on traces when needed
• Proper backdrilling of unused via sections
• Careful design of transitions between layer changes
• Simulation and characterization of channel frequency response
• Managing noise through isolation and filtering
• Minimizing trace lengths whenever possible

Q: What kind of validation testing should be done on 5G PCB prototypes?

A: Recommended validation tests include:

• Frequency domain measurements using VNAs to characterize insertion loss, return loss, VSWR
• Time domain analysis with TDR to find impedance discontinuities
• Signal integrity checks using eye diagrams, jitter analysis
• EMI testing for radiated and conducted emissions
• Vibration and shock testing for mechanical integrity
• Thermal imaging and measurement of temperature gradients
• Functional testing to verify performance under use conditions
• Correlation to simulation models and results

5G PCB Technology – A Revolution in Telecommunication Industry

High Profile 5G 12 Layer PCB developed At Rayming PCB

If you want 5G PCB design suggestions or need 5G PCB Manufacturing service,Pls send email to sales@raypcb.com , You will get reply in short time.

5G technology

5G Pcb Board

The 5G (stands for 5^th Generation) technology is the whole new innovation in the field of telecommunication industry. It is the iteration of existing cellular 4G LTE (Long Term Evolution) technology. This 5G technology can break the records of high speed and reliable internet connection, cellular and satellite communication. It is estimated that average download speed of up-to 1GBps and the data rates as high as 20 GBps with latency less than 1mS is possible. This is astonishingly amazing to know that this high speed communication can open new doors to various applications in small

and large businesses, entertainment and multimedia, smart home, autonomous driving in automobile sector, Medical field in surgery, technology, mobile, and satellite communication and in IoT.

Latency: It is the time required by data to travel from source to destination.

The high speed 5G technology can enable the real time control and monitoring of machines and devices like robots, drones, automobiles, and other machines that will transmits feedback signal to the operator and receives command signals in response, this all done in high speed communication link.

4G Vs 5G Technology:

Parameters	4G	5G
Latency	10ms	1ms or less
Max Data Rate	1 Gbps	20Gbps
Transmitted Power	23dbm except for 2.5GHz TDD	26dbm at 2.5GHz and above
No of Mobile Connections	8 billion	11 billion
Frequency Range	600 MHz to 5.925 GHz	600 MHz to 28,39 and 80 GHz (mm wave technology)
Channel BW (Band Width)	20 MHz	100 MHz for 6 GHz400 MHz for above 6 GHz
Uplink Wave form	SC-FDMA	CP-OFDM
Download speed	100 Mbps	10,000 Mbps
Deployment Year	2006-2010	2020
User Data BW (Practical Analyses)	Mobile = 10-30MbpsFixed = 50-60 Mbps (cm wave)	Mobile = 80-100 MbpsFixed = 1-3 Gbps (mm wave)
Coverage per Antenna & Usage	Mobile = 50-150 Km (City, Rural area)Fixed = 1-2 Km (High Density Area)	Mobile = 50-80 Km (City, Rural area)Fixed = 250-300 meter (High Density Area)

How 5G Works:

The cellular networks are actually the cluster of small cells and these cells are further divided into sectors. In 4G LTE, the high power towers of cell are transmitting electromagnetic radiation to cover longer distances. However on the other hand 5G uses small towers mounted at every 1 Km on different types of high elevated places like rooftops and poles in large quantity. These many small cells transmit radiation of the wavelength of the order of few millimeter. These millimeter electromagnetic waves can travel smaller distances and travel in line of sight hence it is hindered by any physical objects like tall buildings and can be disturbed by weather conditions as a result degrading the signal strength.

The lower frequency spectrum of 5G can reach longer distance but data rates will be compromised while mm wave have smaller distance but higher data rates.

                                                                                                                            (Fig- 5G Cellular Network Base Station Types)

What is mm Wave..?

The millimeter (mm) wave spectrum falls in the frequency range of 30 GHz to 300 GHz. This phenomenal range of frequency has the wavelength of 1mm to 10mm. The mm wave are also known as VHF or EHF Very High Frequency or Extremely High Frequency respectively names given by ITU.

The mm waves are susceptible to heavy rainfall. The mm wave signal strength will drop when heavy droplets of rain interfere with mm wave i.e when the size of droplet or ice crystals reach the size of mm wave which is about few inches, then severe attenuation will be observed. This is also for snowy season with thick/dense blizzards are observed. This phenomenon is commonly known as “Rain Fade” or “Rain Loss”. This phenomenon can affect the satellite communication in LEO, MEO and GEO earth orbits. This phenomenon can also hinder GPS signals. Licensed bands from FCC are 71-76 GHz, 81-86 GHz and 92-95 GHz to operated point-point high BW. Unlicensed band for short range communication can be done on 60 GHz mm wave spectrum

5G Antenna:

Unlike passive antennas that are used in common RF communication which are made of metal rods, 5G antennas are active antennas having semiconductor devices embedded inside the antenna. High speed 5G dedicated PCB design and fabrication is utmost important for 5G antenna PCB and associated circuitry. At Rayming PCB we have developed state of the art 5G PCB. Please check out the snapshot of our 5G PCB.

The basic technique used is the beam forming which allows the 5G antenna to emit radiation in a particular direction or pattern instead of emitting equally in all directions. The 5G antenna is made of massive MIMO (Multiple Input Multiple Output) antennae. The massive / large number of antenna elements are used in phased array shape and different sizes are available. The individual antenna element size is small but are used in 100s to make dense array.

As a result the radio waves are directed to the targeted users with the help of advanced algorithms that determine the best route for radio waves to reach the end user. This phenomenon is known as beam steering. The beam steering is very effective and optimizes the power consumption and increase efficiency by eliminating the unwanted Omni directional radio transmission. As a result very high throughput thus allowing more people to connect simultaneously

5G Technology Applications:

• High Speed Cellular Network

As discussed above, the extremely high data rates enable the calling, messaging and multimedia services to speed up and faster communication is possible. So no worry about call dropping and undelivered text messages or slow internet. 5G technology will give you unstoppable high speed services

• Entertainment and Multimedia:

Now you can enjoy Netflix, Watch Live shows or download your favorite TV program, movies in the blink of an eye. Yes literally..! This is possible because of 5G high download speed up-to 10Gbps.

• Smart Home

The smart devices will be using 5G technology to connect to our mobile devices using wireless network for monitoring and control. High speed 5G connectivity can enable CCTV cameras to transmit live video streaming to our mobile devices

• Logistics

High speed communication 5G link will enable logistics tracking, management and delivery of shipment online on our cell phones

• 5G in Farming

Smart chips like RFID will be used in livestock to track position and activity. Smart agricultural machines can be controlled remotely through speedy 5G link.

• Medical Surgery

Live video streaming inside the patient’s body for transplant and operation is possible today due to 5G

• Autonomous Driving

In future, automatic cars will be on roads. Cars will interact with traffic signals and can communicate with other cars by means of 5G high speed link. This enable those to detect an obstacle in matter of milliseconds (latency of 5G) and to avoid collision.

An alternator is a crucial component in modern automobiles that is responsible for generating electricity to power the electrical system while the engine is running. The alternator charges the battery and powers the ignition system, lights, entertainment systems and other electrical components.

Understanding how an automotive alternator works helps drivers appreciate this vital engine component. This article will provide a comprehensive overview of alternator design, function and operation.

What is an Automotive Alternator?

An alternator is an electrical generator that converts mechanical energy from the engine into electrical energy through electromagnetic induction. Alternators generate alternating current (AC) electricity which is then converted to the direct current (DC) electricity needed to charge the battery and power vehicle electronics.

The key components of an automotive alternator include:

• Rotor – The rotating part consisting of a coil winding surrounding an iron core. It is mounted on the drive shaft and rotates within the stator.
• Stator – The stationary part consisting of three sets of windings surrounding an iron core. When the rotor rotates, it induces alternating current in the stator which is fed to the diodes.
• Diode Rectifier – Converts AC current generated in the stator to the DC current needed for the battery and vehicle system.
• Voltage Regulator – Controls the field current to maintain a constant voltage output as engine RPM varies.
• Brush Assembly – Contains slip rings and carbon brushes that conduct current to the rotor coil windings.
• Cooling Fan – Cools the alternator to prevent overheating.
• Front and Rear Housing – Contains the components and allows convenient mounting.

Diagram of the main components in a typical automotive alternator.

How Does an Automotive Alternator Produce Electricity?

Alternators generate electrical energy using the principles of electromagnetic induction discovered by Michael Faraday. Here are the key steps in the power generation process:

1. Mechanical Energy from the Engine

• The alternator is belt-driven by the engine’s crankshaft via a serpentine belt. This rotates the rotor at engine speed.

2. Magnetic Field Induced in the Rotor

• As the rotor spins, a small electric current is passed to the rotor windings through the slip rings and carbon brushes.
• This creates a magnetic field around the rotor coils.

3. Alternating Current Induced in the Stator

• As the rotor magnetic field rotates around the fixed stator windings, it induces an alternating current in the stator windings.
• This is caused by Faraday’s Law of electromagnetic induction. Faster rotor motion induces greater voltage.

4. Conversion to Direct Current

• The alternating current produced in the stator windings is converted into direct current by the diode rectifier bridge.
• The rectifier uses semiconductor diodes which allow current to flow in only one direction resulting in DC output.

5. Voltage Regulation

• The voltage regulator controls the rotor magnetic field strength to maintain a constant output voltage, typically around 14V, as engine rpm varies.
• It senses voltage at the battery terminal and adjusts current flow into the rotor.

6. Battery Charging

• The DC output current of the alternator recharges the vehicle’s battery. This provides electricity when the engine is off.
• The battery acts as a voltage stabilizer smoothing out transients in alternator output.

This alternating current (AC) to direct current (DC) conversion process takes place continuously while the engine is running. This provides the electricity needed for proper vehicle operation.

Main Types of Automotive Alternators

While alternator designs vary by manufacturer and application, they typically fall into two main configurations:

Claw Pole Alternator

This uses a claw-shaped pole piece in the rotor rather than windings. The claw pole rotor is pressed onto the shaft and surrounded by the stator. Benefits include simple design, low cost and high efficiency. Claw pole alternators are common in many late model vehicles.

Wound Field Alternator

This uses an electromagnetic coil winding in the rotor for the magnetic field like a traditional generator. It allows variable control of the rotor field current, enabling better voltage regulation. Wound field alternators are more expensive but commonly used on older vehicles.

The claw pole design is dominant today due to its simplicity, performance and cost-effectiveness for high output electronic charging systems. However, both provide the essential DC electricity generation function.

Major Components of an Automotive Alternator

Now let’s take a closer look at the major components that make up a typical modern high-output alternator.

Rotor

This is the rotating component that generates a moving magnetic field to induce current in the stator windings.

• On claw pole alternators, the rotor consists of a steel claw-shaped pole piece pressed and shrink-fitted onto an iron core which is mounted on the driveshaft.
• On wound field alternators, the rotor uses coil windings fed with DC current to generate the magnetic field.
• The rotor spins within the fixed stator, typically at up to 15,000 rpm on engine speeds. Faster rotor speed induces higher voltage in stator.

Stator

The stator is the stationary component containing electrical windings surrounding an iron core. The windings are composed of copper wire coils that are placed into slots in the laminated core.

• The stator core is made of many thin steel laminations for low hysteresis losses.
• The stator windings generate three-phase alternating current when rotating magnetic field of rotor sweeps past them.
• Each stator winding is connected to the rectifier diodes to convert AC to DC output current.

Diode Rectifier

The diode rectifier bridge converts the AC voltage generated in the stator windings into the DC voltage needed for the vehicle electrical system.

• It contains six diodes arranged as a bridge circuit. Each diode allows current flow in only one direction.
• The diodes only allow the half of the AC cycles where current flows towards the battery to pass, resulting in DC pulses.
• The rectifier is typically mounted on the alternator rear housing. Diodes are actively cooled to handle high current.

Voltage Regulator

The voltage regulator controls the field current entering the rotor to generate the required voltage output.

• It monitors battery voltage through a sensing wire connected to the battery terminal.
• When output voltage drops below the target level (e.g. 14V), the regulator increases field current which boosts induced voltage.
• This process keeps output voltage constant even as rotor speed varies with changing engine rpm.
• The regulator may be mounted internally or externally. Modern alternators have built-in regulators.

Brush Assembly

Brushes conduct electric current between the spinning rotor and the stationary contacts.

• Slip rings mounted on the rotor shaft are contacted by carbon brushes which have spring loading tension.
• Current is conducted through the brushes to excite the rotor magnetic field. Brushes wear over time and need periodic inspection.
• Brush assembly design aims to maximize contact surface area for high current and minimal friction.

Cooling Fans & Vents

Fans and vents provide critical cooling air circulation over and through the alternator.

• Cooling fans pull in outside air, improving heat dissipation from hot components.
• Vents allow air flow to reach internal components like diodes and windings.
• Proper cooling prevents alternator failure from overheating which reduces output.

Front & Rear Housings

• Sturdy front and rear die-cast aluminum housings enclose and protect the alternator components.
• They have mounting points to install the alternator on the engine securely.
• The housings allow easy access when disassembling the alternator for servicing.
• Vents, cooling fans and other attachments bolt on to the housings.

Alternator Design Variations

While the basic components described above make up the core of most automotive alternators, there can be variations in design:

• Single or Dual-Voltage – Some alternators have switchable voltage settings for 12V or 24V system applications.
• External or Internal Regulator – Older alternators had external regulators while modern ones have built-in regulators.
• Lundell and Salisbury Pole Rotors – Based on the shape and construction of the rotor pole pieces. Salisbury type has lower magnetic losses.
• Number of Stator Windings – Can be 12-pole or 24-pole stator designs. More poles typically means higher output current.
• Claw Pole or Wound Field – Fundamental rotor design difference as described earlier.
• Diode Bridge Design – Diode count, arrangement and cooling method can differ. Some use hybrid bridge regulators.
• Brush Configuration – Brush quantity, materials, tensioning and slip ring design affect performance.

So while basic working principle remains the same, alternators are engineered with variations to provide optimized performance for different vehicles and applications.

Alternator Drive Methods

Output current capacity is directly related to how fast the alternator spins. Therefore, proper drive design is critical. Here are the main alternator drive types:

Belt Drive

• Most common method using a serpentine v-belt running on pulleys connected to the crankshaft and alternator.
• Typically drive ratio of 2.5 to 3:1 relative to crank. Turning at engine idle speed generates sufficient voltage.
• Needs proper belt tension. Over or under-tightening reduces output and belt life.

Chain Drive

• Roller chain drive can be more durable and withstand higher loads than belt drive.
• Allows greater distance between crank and alternator mounting points.
• Requires periodic chain tensioning adjustment and lubrication.
• Noisy operation and cost make it less common than belt drive today.

Gear Drive

• Spur gearset provides constant meshing for robust drive and fixed ratio speed increase.
• Allows very high speed alternator shaft rotation up to 24,000rpm for max output.
• Needs precision gear machining and can be noisy in operation.
• Added cost limits use to high performance and racing applications.

Proper belt tensioning with idler pulleys is the most common and cost-effective drive today. But other drive options allow ultra-high output when needed.

How Voltage Output is Controlled

Maintaining steady charging system voltage as engine rpm varies is critical to avoid overcharging or undercharging the battery. Here’s how voltage regulation works:

Sensing Battery Voltage

• The voltage regulator monitors battery voltage through a sense wire connected to the positive terminal.
• If output voltage drops below the desired level, typically around 14 volts, the regulator activates.

Adjusting Field Current

• The regulator can electronically adjust current flow into the rotor field winding.
• Higher current strengthens rotor magnetic field which induces higher AC voltage in stator.
• Lower current weakens rotor field and decreases AC voltage generation.

Maintaining Constant Output Voltage

• By controlling rotor field current, the charging voltage can be held steady even as engine rpm changes.
• This prevents excessive or inadequate charging as driving conditions vary.
• If external power loads are added, the regulator further boosts field current to compensate load.

Limiting Maximum Voltage

• The regulator has overload protection if voltage spikes occur.
• It limits maximum field current input to prevent dangerously high voltage generation.
• This protection prevents damage to vehicle electronics from voltage surges.

Modern electronic regulators allow very precise and responsive voltage control tailored to match alternator design and output curves.

Alternator Charging Process Explained

Let’s walk through the key steps that take place as the alternator charges the battery:

1. Engine cranking rotates alternator rotor through drive belt. Rotor magnetic field is initially residual.
2. As rotor picks up speed, residual magnetism generates small AC voltage in stator windings.
3. Initial AC is converted to DC by rectifier diodes. This begins charging the battery which applies DC to rotor through brushes.
4. Rotor electromagnetism builds up from battery current flow through windings. Rotor field strengthens.
5. Stronger rotor magnetic field induces higher AC voltage in stator as it cuts across windings faster.
6. Higher AC voltage is rectified into stronger DC output. Battery charges faster and sends more current to rotor.
7. The cycle escalates until nominal voltage level is achieved, typically 14V. Regulator then holds it steady.
8. If battery state of charge decreases, regulator boosts rotor field current to increase output voltage to recharge.

This self-exciting process automatically builds charging voltage to the preset target level needed to keep the battery fully charged.

Troubleshooting Alternator Problems

Here are some common symptoms indicating alternator issues and likely causes:

Dead Battery

Fully discharged battery while driving points to the alternator not charging properly.

• Check for loose, broken or slipping drive belt. Tighten belt to spec.
• Inspect for poor wiring connections, damaged diodes or faulty voltage regulator.
• Test that rotor produces adequate magnetic field. Check brushes and slip rings.
• If battery keeps going dead, test alternator output voltage. Might need rebuild or replacement.

Dimming Headlights

If headlights and other lights dim noticeably at idle but brighten when revved, the alternator is weak.

• Belt may be loose or worn. Adjust belt tension.
• Faulty diodes, stator windings or regulator may need replacement.
• Check for high resistance on power output terminal causing voltage drop.

Whining Noise

High pitched whining or squealing noises usually come from drive belt or bearing issues.

• If noise varies with revs, belt is likely loose or misaligned on pulleys.
• Adjust belt tension or alignment. Replace belt if worn or glazed.
• Constant noise indicates worn bearings starting to fail. Alternator rebuild needed.

Smell or Smoke

Burning smell or visible smoke/sparks points to severe internal overheating failure.

• Immediately shut off engine to prevent greater damage.
• Check for jammed cooling fans, blocked ventilation and debris buildup causing overheating.
• Severe faults like grounded windings require complete alternator replacement.

Early detection of minor issues based on unusual noises, smells or operating changes can help prevent more extensive damage and avoid breakdowns.

Alternator Maintenance Tips

Routine prevention maintenance is key to maximize longevity of your vehicle’s alternator. Follow these alternator care tips:

• Check drive belt – Inspect belt periodically for cracks, glazing, fraying and tension. Replace belt if worn.
• Check belt alignment – Make sure belt runs straight on alternator, crank and idler pulleys. Misalignment causes excess wear.
• Check mounts – Ensure alternator mounting brackets are tight and free of cracks. Loose mounts cause misalignment.
• Check wiring – Clean and tighten electrical connections, especially positive and negative output terminals. Fix damaged wiring insulation.
• Check ventilation – Ensure cooling air ducts, fans and ventilation holes are not blocked by dirt or debris.
• Listen for noise – Take note of any unusual grinding, squealing or bearing rattle noises which indicate wear.
• Consider overhaul – For higher mileage vehicles, having the alternator rebuilt periodically will extend its life.
• Test output annually – Use a digital multimeter once a year to verify alternator is generating proper voltage.

Well-maintained alternators can last 150,000 miles or more. But neglecting basic component checks increases the chances of being left stranded when it fails.

Alternator Output Testing

If you suspect charging system issues, alternator output voltage and amperage should be tested. Here is one common testing method:

Test Equipment Needed

• Digital multimeter (DMM) with DC voltage and current capacity
• Jumper wires with alligator clips
• Load bank (such as a 12V headlamp)

Testing Procedure

1. Attach positive (red) DMM lead to alternator output terminal nut and negative (black) lead to battery negative terminal.
2. With engine off and keys out of ignition, check battery voltage. A well-charged battery will show 12.4 – 12.6V.
3. Start engine and turn on all loads (headlights, blower fan, rear defogger etc). Run engine at 1500 rpm.
4. Measure voltage at alternator output terminal again. Should show approx. 14V. If not, regulator may be faulty.
5. Turn off all loads. Then turn on load bank connected to battery positive terminal.
6. Gradually increase load resistance while observing amp output. Output should increase to meet demand.
7. Check for smooth voltage regulation back to 14V after load is removed. Erratic voltage indicates faulty diodes or bad rotor ground.
8. If output voltage or amperage is outside spec, the alternator may need overhaul or replacement. Consult a shop.

This test procedure checks key characteristics to determine if the alternator is performing properly or if repairs are needed.

Introduction

Industrial robots are transforming manufacturing and automation across industries ranging from automotive to healthcare. With their ability to precisely and tirelessly perform complex tasks, industrial robots provide huge efficiency and quality benefits.

There are hundreds of industrial robot models available from technology providers worldwide. In this guide, we will highlight the top 15 industrial robots that are driving innovation in manufacturing and reshaping industry. For each model, we’ll cover:

• Intended applications
• Key capabilities and specifications
• Unique strengths
• Manufacturer overview
• Example implementations

By the end, you’ll have a solid understanding of the leading industrial robots that are making an impact on manufacturing today. Let’s get started!

Top 15 Industrial Robots

1. FANUC LR Mate 200iD

The LR Mate 200iD from FANUC is one of their most popular table-top industrial robots suitable for lightweight material handling and assembly.

Applications: machine tending, pick and place, inspection, pharmaceuticals

Payload: 7 kg reach 600 mm

Key Features: Long-term precision, reliable Japanese quality, easy programming

Company: FANUC is one of the largest global industrial robot manufacturers. Over 25% of industrial robots worldwide are FANUC robots.

Example Use: Ford uses LR Mate robots for engine subassembly manufacturing.

2. ABB IRB 460

ABB IRB 460 is a fast and flexible palletizing robot ideal for packaging and stacking applications.

Applications: Palletizing, pick and place, stacking, packaging

Payload: 60 kg reach 2.55 m

Key Features: High speed, four-axis flexibility, robust for harsh environments, easy programming

Company: ABB is a global leader in industrial automation and robotics manufacturing.

Example Use: Picturehouse Cinemas uses an IRB 460 robot to automatically stack soft drink cups.

3. KUKA KR AGILUS

The KUKA KR AGILUS is an extremely versatile small industrial robot designed for assembly, packaging, and handling.

Applications: Assembly, pick and place, machine loading/unloading, welding

Payload: 6 or 10 kg reach 920 mm

Key Features: Compact size, fast cycle times, flexible installation, good value

Company: KUKA is a German industrial robot manufacturer with over 100,000 robots installed worldwide.

Example Use: The KR AGILUS precisely applies adhesive in automotive interior assembly.

4. Universal Robots UR10e

The UR10e collaborative robot from Universal Robots excels at flexible automation for small manufacturing.

Applications: Assembly, pick and place, packaging, testing, CNC tending

Payload: 12.5 kg reach 1300 mm

Key Features: Lightweight, collaborative operation, fast set up, flexible deployment

Company: Universal Robots pioneered the easy-to-use collaborative robot category.

Example Use: UR10e robots assist workers packaging merchandise at BigCommerce.

5. Mitsubishi Electric MELFA RV-7FRM-D

The RV-7FRM-D robot offers a 7kg payload in a compact footprint ideal for benchtop applications.

Applications: Assembly, pick and place, packaging, loading and unloading

Payload: 7 kg reach 892 mm

Key Features: Compact size, high speed, four arm options, reliable quality

Company: Mitsubishi Electric are a global diversified industrial automation provider.

Example Use: Assembling small motors at a Mitsubishi Electric factory.

6. Comau SMART5 NM

The Comau SMART5 NM is an ultra-flexible high speed modular robot for large payloads.

Applications: Material handling, machine tending, assembly, aerospace manufacturing

Payload: 60-270 kg reach 2.8 m

Key Features: Highly modular and customizable configurations, extremely rapid movement

Company: Comau specializes in industrial automation for vehicles, manufacturing, and other industries.

Example Use: Comau robots help assemble helicopters like the AW139.

7. Yaskawa Motoman GP7

The Motoman GP7 industrial robot provides a fast, compact solution for medium payloads.

Applications: Machine tending, material handling, assembly, packaging, palletizing

Payload: 7 kg reach 911 mm

Key Features: High speed, four-axis flexibility, durable construction

Company: Yaskawa Motoman specializes in industrial robotics and automation solutions.

Example Use: Palenight Story manufactures custom lamps with the help of a GP7 robot.

8. Stäubli TX2-60

The Staubli TX2-60 is an ultra-high speed 4-axis robot specialized for picking and packing applications.

Applications: Picking, packing, palletizing, kitting, machine tending

Payload: 60 kg reach 2300 mm

Key Features: Exceptionally fast cycles, high precision, robustness proven in industries

Company: Stäubli is a specialist in textile, robotics, and interconnect solutions.

Example Use: TX2-60 robots rapidly package Chobani yogurt cups after filling.

9. Omron TM Series

The Omron TM coloborative robot series features integrated machine vision and easy deployment.

Applications: Assembly, packaging, pick and place, quality inspection

Payload: 5 or 10 kg reach 1300 mm

Key Features: Integrated camera system, compact footprint, simple programming

Company: Omron specializes in automation, sensing, components, and robotics.

Example Use: TM5 assists workers gently handling baked goods for packaging and palletizing.

10. Epson C12XL

The Epson C12XL is a powerful 6-axis SCARA industrial robot capable of extremely fast cycle times.

Applications: Assembly, pick and place, packaging, loading and unloading, diagnostics

Payload: 6 kg reach 500 mm

Key Features: Ultra-fast 0.39 second cycles, compact footprint, reliable Japanese quality

Company: Epson specializes in advanced robotics, printers, and other technology.

Example Use: Automating insertion of bearings into drivetrain components.

11. Nachi SC1000F

The Nachi SC1000F delivers high performance, flexibility, and durability in a compact 6-axis package.

Applications: Machine tending, material handling, assembly, pick and place

Payload: 6 kg reach 1000 mm

Key Features: Long lifespan, high repeatability, advanced safety features, fast wrist joint

Company: Nachi manufactures versatile industrial robots globally.

Example Use: Nachi robots assist with quality control inspection on automotive assembly lines.

12. Doosan DR-5W

The DR-5W from Doosan is a durable 5-axis articulated arm robot suitable for welding, soldering, and dispensing.

Applications: Spot welding, dispensing, material handling, machine loading

Payload: 5 kg reach 1492 mm

Key Features: Precise path control, long reach, rugged IP67 construction, built-in dress out cabling

Company: Doosan produces over 11,000 robots annually for a wide range of industries.

Example Use: Aerospace component manufacturing and aircraft engine assembly.

13. Techman Robot TM Vision

The Techman TM Vision combines 2D and 3D machine vision with a 5kg 6-axis arm for smart applications.

Applications: Visual inspection, precision assembly, pick and place, packaging

Payload: 5 kg reach 911 mm

Key Features: Integrated camera with vision toolkit, simple programming, good value

Company: Techman Robot specializes in flexible industrial automation solutions.

Example Use: Automated candle inspection using machine vision.

14. Precise Automation SCARA

Precise SCARA robots offer ultra-high speed and precision pick-and-place for small parts assembly.

Applications: Electronics assembly, medical devices, pharmaceutical manufacturing

Payload: 1 or 3 kg reach 250-600 mm

Key Features: Exceptionally fast cycles under 0.5 seconds, high precision gearboxes, compact SCARA design

Company: Precise Automation provides customized automation equipment.

Example Use: High speed PCB loading and unloading for electronics manufacturing.

15. Franka Emika Panda

The Franka Emika Panda is a friendly trainable robot arm designed to be affordable and safe around humans.

Applications: Pick and place, assembly, packaging, machine tending

Payload: 3 kg reach 800 mm

Key Features: Low cost, lightweight, sensitive torque sensing, CSV based programming

Company: Franka Emika is focused on accessible and adaptable robotics.

Example Use: Light material handling and assisting machine operators in a safe manner.

Conclusion

This guide provided an overview of 15 advanced industrial robots that are pushing the boundaries of manufacturing automation in their unique ways. Whether it’s speed, precision, flexibility, vision or human collaboration, these robots represent the leading edge of innovation.

Industrial robot capabilities will only continue advancing. By keeping up with the latest developments, manufacturers can tap into their benefits – from increased efficiency to enhancing worker abilities and safety. The future of automation looks bright with advanced robots at the helm.

Hopefully this gave you a solid understanding of the diverse range of industrial robot models available and their typical applications. As your needs evolve, there is likely a specialized robot that can perform the tasks reliably and precisely.