Nickel Electroformed Stencils:

To meet the most demanding requirements involved in consistently achieving the best results for fine pitched printing technology, Chepaume Industries, along with their parent company, Newcut Inc., have developed their nickel electroformed stencils.

The smooth, tapered aperture walls of electroformed stencils offer the best paste release characteristics available, which, when combined with the surface properties of Nickel, maximize both the solder paste deposit and its release, even from the finest of stencil apertures.

Our Electroformed stencils are processed to be stronger and harder than conventional stainless steel stencil, resulting in longer life and improved wear even when using hard urethane or stainless steel squeegee blades.

Squeegee side surface finish plays an important role in maintaining paste rheology. The unique pattern on Chepaume’s Electroformed stencils has been developed to ensure the solder paste will roll and not skid across the stencil with the progression of the squeegee blade. Thereby providing the ideal conditions for each and every print.

Electroformed stencils are typically available in any thickness up to 9 mils. Stencils are also produced for Flip Chip technology products in the range of 1.5 to 3 mils and are generally meshed into frames. Chepaume Industries can and has provided thicker as well as thinner products upon request.

Many electronics and surface mount specialist now recognize and agree that electroformed stencils offer the best solution available for solder paste deposition in fine and ultrafine pitch printing.

Advantages of Electroforming:

  • It is proven that smooth walls allow for better paste release and EF produces the smoothest of walls compared to Polished Laser or Etched stencils. The manufacturing process itself creates smooth trapezoidal sidewalls - no secondary process is needed.
  • EF stencils form a better seal to the board reducing bridging, shorts and bleeding. and the surface properties of Nickel enhance solder paste release.
  • With Electroformed stencils a wider range of thickness’ available - you are not limited to what the metal supplier can provide. (Standard stainless normally comes in 4, 5, 6,... mil standards with half mil increments becoming costly. with electroforming the possibilities are almost limitless - 3.8, 4.2, 5.5 ,5.7 mil)
  • The Superior printing characteristics of EF stencil lower defect rates and decreasing rework.
  • Electroformed stencils have a higher tensile strength and are harder than stainless, thus extend the life of the stencil and lowering overall mfg. costs.
  • The low surface tension of Nickel promotes maximized paste deposit and release
  • Low cost for Flip Chip bumping
  • Allows Reduction in device size 

Electroforming Technology Basics:

The electroforming process, which has been around for generations, consists of electrochemically growing metal shapes atom by atom.

The process begins when photoresist is polymerized by exposure to UV light through a phototool of the PCB image pattern.

After developing, a negative image is created on the mandrel where only pillars of resist, representing the apertures required, remain.

The stencil is then grown on the mandrel over time by Nickel Electroforming. Time and current determine the thickness of the finished stencil.

Any remaining photoresist is then removed from the apertures and the foil is then separated from the mandrel.

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