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SMT Stencil / PCB Stencil Without Defects

At Millennium Circuits Limited (MCL), we’ve created a solid process for providing the best SMT Stencils on the market. As one of the most critical parts of the assembly process, we understand the importance of defect free SMT Stencils.

Why SMT Stencils Are Important

Before you can go into production, solder paste is printed onto the component pads of the PCB.

How can you make sure you apply the solder paste with precision exactly where it needs to go? SMT stencils, or surface mount technology stencils, are the answer. SMT stencils are the medium you use to transfer that solder paste onto the PCB.

Stencils consist of a foil made of stainless steel that is laser cut to match the places where surface mount devices will go on the board. This process creates the stencil that tells the solder paste where to go on the board. Once you have cut the stencil, you apply solder paste one time over the openings with a metal squeegee blade. You will then pull the stainless-steel foil away, leaving the solder paste perfectly placed on the board to receive your surface-mounted devices.

Can you apply soldering paste without an SMT stencil? Yes, but because of the precision required, trying to apply soldering paste everywhere it needs to go on the board by hand can be an extremely time-consuming, painstaking process. Furthermore, you cannot get the consistency when applying soldering paste by hand that you will get using a single SMT stencil. It’s important to consider that the chances of error are much greater when applying soldering paste by hand.

When applying soldering paste by hand, or trying to apply it without a perfect stencil you could face some very serious problems, like:

  • short circuits
  • voids in the soldering process
  • The desired printed result requires:
  • smooth and burr-free side walls of the apertures
  • flat, unstressed material
  • uniform tension distribution over the entire surface
  • precision in position and size of the apertures
SMT Stencil | PCB Stencil

SMT Stencil Printer

It’s imperative that the SMT Stencil be perfect to avoid the issues that could stop your assembly line in its tracks. MCL ensures perfection by utilizing the latest technology and highly trained technicians to deliver your SMT Stencil.

At MCL, we provide top of the line, 100% laser cut SMT Stencils at competitive prices. Stencils can be shipped same day from our east and west coast manufacturing locations. There are never additional charges for engineering changes.

SMT PCB Stencils Available From MCL

We offer the following SMT stencil products:

Framed SMT Stencils

Framed SMT stencils, also known as glue-in stencils, feature a permanent stencil frame. A mesh border keeps the stencil foil stretched taut for optimum accuracy. These stencils have benefits such as:

  • Double-bonding for high-wear applications: Sturdy engineering resists intense use.
  • Superior print performance: Smooth and taut aperture design creates accurate prints.
  • Non-fading fiducial (marking) results: Screen-printing process makes long-lasting fiducial layouts.
  • Ability to withstand numerous uses: Permanent mounting offers high levels of integrity.
  • Availability for immediate use with an SMT printer: Preassembled product works in a screen printer right away.

Because of its durable engineering, a framed SMT stencil suits high-volume printing applications. We recommend this product for production runs that require long-term use. Consider choosing a framed stencil when you plan to create a large number of PCBs over an extended period.

Unframed SMT Stencils

Unframed SMT stencils consist of a foil without a permanent frame. They fit into reusable frames and can unattach from them at any time. The benefits of using unframed stencils include:

  • Cost-effective price: Frameless design results in a significant price reduction from framed stencils.
  • Reduced storage space: Compact size saves on space needed for storage.
  • Lower environmental impact: Use of fewer materials suits eco-friendly production methods.
  • Excellent print performance: High-quality engineering promotes top performance throughout stencil’s lifespan.
  • Compatible with screenprinting and hand-printing: Versatile format allows for printing with a machine or squeegee.

Since unframed stencils last for a fair amount of time, they fit short-term applications. We recommend them for short production runs or prototype designs. Choose an unframed stencil for lower volumes of PCBs produced in a short period.

Prototype Stencils

A prototype stencil features the design you specify using a CAD or Gerber file. The user places it over their PCB and uses it to print the design by hand. Prototype stencils offer these benefits:

  • Precise hand-printing: Alternative to hand soldering reduces the potential for errors.
  • Reduced prototype assembly time: Quick alignment and printing increase efficiency.
  • Eliminated need to use a machine: Hand-printing application requires no machine setup.
  • Ultimate cost-effectiveness: Efficient design results in affordable price.
  • Ease of use: Alignment tools allow for an easy-to-understand printing process.

Prototype PCB stencils live up to their names — they suit prototype printing applications. We recommend using them to test out your PCB idea due to their affordability and ease of use. Add a prototype stencil to your order if you want to print a fast test product before creating a permanent design.

Prototype Stencil Kit

Our prototype SMT stencil kit comes with everything you need to print by hand. It includes:

  • Your custom prototype stencil
  • A squeegee blade that ensures precise application
  • Solder paste
  • Pick-and-place tool for careful handling
  • Temperature marker for accurate heating
  • A pair of gloves and alcohol wipes to prevent contamination

We suggest buying our prototype kit if you plan to print a board by hand for the first time. It uses simple tools that create precise results.

Below are pictures of Framed SMT Stencils, Unframed SMT Stencils, Prototype Stencils, and a Protoype Stencil Kit. Be sure to view our “Prototype Stencil Step-by-Step Tutorial“.

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