Kapton™ Prototype Stencils

When Appropriate?

Fewer than 10 prints 0.8mm pitch or greater geometries Enough distance between

apertures Smaller than 6 x 6” print area

Why Kapton™?

Excellent heat withstand properties to maintain dimensions

Ability to withstand local heat generated by laser machining to prevent “ridges” from forming and not being coplanar to the board

Type FPC used for stencils best cost/performance

Kapton™ Performance-Limitations Very similar to stainless to 0.8mm pitch 95-97% transfer efficiency if hand

printing and 0.8mm or greater For hand printing the “sccoping” effect

is more pronounced If distance between components is too

tight then “smearing” can become pronounced

Kapton™ Stencils at Ultrafine pitch-”smearing”

Why NOT Mylar?

Poor heat withstand properties Used because it is very cheap and

optically opaque for alignment Many different thicknesses “Ridges” near aperture walls

Why NOT Mylar?

Why NOT Mylar?

Kapton Performance-Limitations

“Scooping” of solder paste if too much pressure applied to squeegee

Kapton™ Stencil-More Research

Study of Kapton stencils transfer efficiency vs metal stencils

https://www.smtnet.com/library/files/upload/plastic-vs-metal-stencils.pdf

www.soldertools.net

Where to go?

www.soldertools.net www.stencilsunlimited.com

Professional companies-understand SMT assembly

Check plotsMultiple laser sources