What are Solder Paste Stencils?

Solder Paste Stencils

As the electronics technology is advancing, the use of through-hole components is getting out of fashion, and Surface Mount Devices have replaced them. The production of modern components is mostly Surface Mount Technology based.

 

Consequently, many manufacturers prefer using SMDs based products. When it comes to bulk production, manually soldering each board can be hectic and time-consuming. Besides the quality of each joint matters, even a poor joint can trigger malfunctioning in the product.

 

Surface Mount Technology Stencils offer convenience in depositing solder paste within perfect quantity and shape. All you need to do is to set up your board, put some solder paste and swipe it. In case of a single prototype to be developed, using an SMT stencil can be costly and, but for bulk production, SMT stencils can considerably reduce production time and cost.

 

Stencils are usually used in industry for bulk production, and a single stencil can serve thousands of PCBs. However, for few units production, metal stencils can be expensive. For small quantity of units to be produced, polyimide stencils are more suitable. These laser cut stencils works reliably if you are working on a few boards. Since these laser stencils are made of synthetic polymer, and the development cost is low, they are suitable for a limited quantity of boards to be developed.

 

How are Solder Paste Stencils Designed?

 

The solder paste stencil is designed using a soft version of the project. During the circuit is designed using any designer software such as Altium, Eagle, DipTrace or Kicad. The soft design includes a layer of solder paste and using this layer machine is instructed to cut holes in exact dimensions are precise locations.

 

The dimensions and location of each stencil hole determine its efficiency, designing a stencil using original design files of circuit ensure the locations are accurate and the solder paste is deposited in precise dimensions.

 

Since the solder paste needs to be deposited in a limited region and it can spread slightly out the hole boundaries. To cover up the excessive deposition, the stencil holes are designed a bit smaller the component pads.

 

How is a Solder Paste Stencil Used?

 

Using a solder paste stencil is simple and easy. The hardware must be set up properly before deposition, and the PCB needs to be in stationary position, in case of vibrations or movement, the solder paste might be deposited out the pads.

 

After setting up hardware, the stencil and PCB must be appropriately aligned. The alignment should ensure each solder pad is exposed through the holes of the stencil. Fix stencil on PCB. When aligning the stencil and PCB, look for IC pads, they are easy to track as they have multiple pads.

 

Carefully verify each pad is exposed through the hole and then put some solder paste on the stencil, using a card, slowly spread solder paste on holes. The paste needs to be spread in all direction to ensure the hole is appropriately covered with paste and the pad is not left uncovered partially.

 

Solder paste should be used within a few hours of pasting, in case of delay, its efficiency might reduce. Usually, solder paste deposited on stencil is more than needed and the extra paste is used for the next board. It is recommended to use a limited quantity of paste that can be served on a single board.

 

When the paste has been deposited entirely, remove tapes on the stencil and carefully remove the stencil from the PCB. Inspect each pad, check if the paste has been appropriately deposited. In case, the paste has spread more than needed, it must be removed, and if the paste is missing on any locations, it must be deposited manually.

 

After the paste is deposited on a PCB, often some paste is left in the stencil holes. This leftover paste is not harmful to the stencil and can be wiped later.

laser cut stencils

Carefully place all components using SMT pick and place machine, ensure the direction of the component is according to the design. Sometimes, during the placement of components, the component is misplaced or disoriented. Such misplacements can cause improper or no soldering of any legs. In such case, carefully move disoriented component and bring it in a proper place. A minute quantity of paste is often spread around the pad during the replacement. But during heating, this paste reaches back to the pad.

 

After a detailed examination of each component, the PCB is passed through an oven which heats the board from the top and the paste turns into molten solder. The paste is usually in flat formation before heating but as soon as it is heated, it takes the form of a proper solder joint, and the corresponding component’s leg is soldered with the pad.

 

Solder paste deposition demands patience and practice. The procedure is easy, but the process needs to be handled carefully.

 

Solder Paste Stencils manufacturing at RAYMING

 

RAYMING is a top notch seller of a variety of solder paste stencils. It doesn’t matter if you belong to a small or large industry with a few or several units order, RAYMING will come up with an affordable offer for you.

 

We offer various services related to PCB assembling. The modern technologies and state of the art machinery at RAYMING labs maintain superior quality of our services. So far, we have assisted industries belonging to different segments of the market, and we have developed a name for quality services.

 

We understand that the product reliability and durability are the core qualities that should not be compromised at any cost. Our automated systems enable us to focus even on microscopic level details of products.

 

Product development with proper testing makes it reliable and builds the confidence of consumer in using it. We, as a manufacturer of solder paste stencils, test each stencil on our advanced systems and our team ensures the product quality is maintained according to international standards.

 

RAYMING cares about small industries, and it has played a significant role in uplifting small industries. If you are looking for a solder paste stencil manufacturer, share your order details, and we will offer an appealing package.

 

We are always open to queries, if you need support, contact us at sales@raypcb.com and you will be responded in a short time.

 

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