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World Class Custom Laser Stencil Manufacturer in China

PCBMay is a Professional Custom Laser Stencil Manufacturer in China,Who Provides Many Different Kinds of Laser Stencils.

Laser Stencils or calls SMT Stencils are used to print solder paste on the PCBs for assembly components. They are often made of Stainless Steel and are manufactured by processes of laser cut or etching.Stencil Printing is the process of depositing solder paste on the PCB to establish electrical connections. it is to achieve through a single material namely solder paste which consists of solder metal and flux.The equipment and materials used in this stage are laser stencil,solder paste, and Paste printer.In order to meet a good solder joint,the right volume of solder paste needs to be printed,the component needs to be placed in the right solder PADs, the solder paste needs to wet well on the board and also must be clean enough for SMT stencil printing.

Main Advantages of Laser Stencil

Smooth internal pad walls(<= 3µm).

Aperture consistency reduces dpm’s.

High Pad positional accuracy.

Stencil to PCB registration (caused by film distortion).

No chemicals – Environmentally friendly process.

Drastic reduction in print rejects.

Clean and exact printing image of the solder paste.

Fine-pitch screen <= 250µM can be realized without problems.

Frequently Asked Questions (FAQ) About Our Laser Stencil Process and Capabilities

Here you will find many quick questions and answers about laser stencil,don’t hesitate to contact us,our email is sales@pcbmay.com.

It’s a solder-paste stencil that has been laser cut. … The paste is applied through the stencil, the thickness of the stencil determining the quantity of paste applied.

  1. Project Steps View All.
  2. Choose your vector art or make your own.
  3. Choose and measure your stencil material.
  4. Create a new Illustrator file.
  5. Insert and scale your vector art.
  6. Add outline colors and remove fill colors.
  7. Cut and stitch floating paths.
  8. Change your stroke thickness.

The most common material for stencils is Mylar – and for good reason. It is flexible, durable, easy to clean and long lasting. 10mil Mylar is our preferred thickness for its flexibility, durability and versatility. Other options include adhesive backed mylar, magnetic, acrylic or wood stencils.

A PCB Stencil is a sheet of stainless steel with laser-cut openings used to place solder paste on a PCB board for surface mount component placement. The PCB stencil is used to deposit solder paste on designated places on a bare PCB board so that components can be placed and perfectly aligned on the board.

Currently, as needed, our EMS contractor wipes the bottom side (board contact side) of each solder paste stencil using lint-free wipes saturated with IPA. Then once every 4 hours they remove each solder paste stencil from the screen printers and wipe both sides using IPA saturated lint-free wipes.

Additional flux is unnecessary for most applications, but using additional flux still may make the solder easier to work with for some tasks. When selecting flux core solder, it is important to use rosin core solder for electrical applications. Acid core solder should only be used for plumbing applications.

No,we can produce 1 to 10,000 pieces,what’s more,there is also no minimum order surcharge or additional fees

What is Laser Stencil Technology for PCB

With laser stencil technology, it is possible to create durable stencils in wood,Plexiglas, polypropylene or pressed cardboard for a few dozen sprays according to your needs.

laser Stencil 01

What are Metal Stencils

In order to be able to solder SMD components on the circuit board,a sufficient solder depot must be available.The end surfaces on the circuit board,such as HAL,are usually not sufficient for this. 

For this reason,a solder paste is applied to the pads for SMD components.The paste is applied with a laser-cut metal template.This is commonly referred to as an SMD stencil or stencil.

So that the SMD components cannot slip on the circuit board during the soldering process,they are fixed with an adhesive.The adhesive can also be applied using a laser-cut metal template.

Benefits of Laser Stencil

Sufficiently smooth walls and tapered apertures.This ensures that the solder paste easily passes through the apertures of the stencil when it is lifted from the print cycle.

  • High geometrical accuracy of apertures, allowing to apply precisely metered and repeatable amount of solder paste to the contact pads of the board.
  • High fidelity reproduction of the profiles of the contact pads on the stencil.It makes it easy and reliable to align the stencil with the PCB.
  • The production of a Laser Stencil is carried out directly from the data received from a computer.  It reduces to zero errors in the output of photomasks,the quality of their manufacture,as well as the quality of surface preparation.And the application of photoresist to foil,as is the case when making a stencil by chemical etching.
  • The stainless steel used for these stencils has little stretch.Therefore, the stencil does not change its shape and pattern of apertures,does not bend even after 10,000 printing cycles, which makes the stainless-steel stencil very durable in use.

Laser Processing of Stencils

The solution to the problem of making precision stencils was again proposed by laser processing of the material.After all,the necessary holes do not have to be made by chemical etching. 

They can also be made by direct laser processing of the material. In this case,on the one hand,it is possible to significantly increase the accuracy of maintaining the required hole shape.And on the other hand, the hole profile can be much closer to rectangular.

The dosage of the solder paste applied using such Laser Stencil will be much more accurate.It will drastically reduce the rejects during soldering.In addition, after laser processing,the holes have a slightly trapezoidal wall shape. 

The open portion of the aperture is usually slightly larger on the lower side.This shape of the hole provides better peeling of the solder paste from the walls of the hole when removing the stencil.

The second significant advantage of Laser Stencil is the material used for their manufacture.The absence of photochemical etching operations made it possible to abandon the use of special grades of bronze.

 For the manufacture of stencils by laser processing,tough grades of stainless steel are used.It resists wear significantly better than metals suitable for photochemical etching. 

Laser Stencil Process of Mounting Elements on PCB

When creating printed circuit boards of varying complexity, the methods of SMD and DIP mounting of elements are used.The first method of fixing components is applied after applying solder paste.Stencils for surface mounting are used for its distribution. Their use in the preparation process is characterized by many advantages:

  1. The solder paste is distributed as accurately as possible,since the created tracks are limited by the walls of the apertures
  2. The use of a Laser Stencil allows you to speed up the process of making a board;
  3. Due to automation,the cost of electronics production is reduced.

The clarity of the lines along which the solder paste is distributed and its dosage directly affect the quality of the installation.Since the pins of the surface components are at the same level,the track heights or contours of the pads are not allowed.

 It is not possible to achieve perfectly uniform distribution even in manual mode.Since squeezing the paste out of the syringe does not guarantee an accurate dosage.

What are the stencils for SMD mounting

Products for precise distribution and dosing of solder paste are:

  • Single-level
  • Multi-level.

Stencils of the first type are plates in which the apertures are at the same level.They are used for most printed circuit boards.Their use is relevant in cases when it is required to fix elements with leads of the same length on the plate.

More complex printed circuit boards are often created using chips of different sizes. In this case,the conclusions of some elements are shorter,others are longer.To solder them, it is required to apply the paste in layers of different thicknesses. 

In such cases,Laser Stencil are required. They are plates with protruding or recessed areas against the background of the main surface.

If the platform protrudes, then the walls of the apertures have a greater height.The paste is spread over them in thicker layers.If the platform is recessed,then the walls of the apertures have a lower height. Accordingly,the paste is distributed over them in thin layers.

Laser stencil 3

Here at PCBMay,we could provide custom stencils with different size and thickness,when you have this kind of laser stencil or SMT stencil,please send the inquiry to us.

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