Notes about OSH Stencils

A few notes from listening to Brent of OSH Stencils: on The Amp Hour:

  • Planning to offer 1.6mm jigs to eliminate the error vis a visa common PCB thickness (hurray)
  • For those that didn’t know:
    • Offering high quality Kester solder paste (in checkout cart, as with the jigs)
    • Offering stainless steel as well as kapton (stainless steel are common 4mil thickness).
  • 5x5mil smallest feature size possible with kapton stencils. Minimum feature size for steel stencils is ONE MIL!
  • They see 70/30% split between 3mil and 5mil thickness of kapton. The 3mil is best for ordinary work, while the 5mil is appropriate for high power devices with large thermal pads, etc. where a lot of solder is needed. I can vouch for the fact that 5mil is a total disaster for fine pitch parts like a QFN package. Kapton in 4mil is unobtanium, which is why they don’t offer that thickness.
  • Name is OSH Stencils because Brent was originally going to collaborate with Laen of OSH Park, but a change in Laen’s circumstances caused them to remain separate entities and Laen was totally OK with the similarity of names.
  • Can reduce kapton stencil curl by “counter-rolling” the material and this will give temporary relief.
  • Started with hobby laser: That “exploded” the first week after starting business. Switched to Epilog 24 (roughly $30k)
  • Stainless steel stencils made with approx $300k LPKF fiber-based “flagship model” laser cutter
  • Have maintained 24 hour turn time from the beginning. They went with high end laser to be able to make *the best* stainless steel stencils. They are competitive by avoiding framed stencils and using a proprietary material loading system into the LPKF. Basic cost of framed stencil material is 5X the cost of raw. Could use “pneumatic frame” to simulate real frame, but that didn’t allow sheet sizes that were large enough to be cost effective.
  • Brent said their charter as they began making steel stencils was to offer the top quality at reasonable prices. He invited people to compare their metal stencils to Chinese stencils under a microscope as they consider potential “cost savings” by going off shore. (OSH Stencils is in the Salt Lake City area of Utah). The metal makeup is different. Most offshore vendors use “inexpensive stainless steel”. Looking at the apertures (the cutouts) you often see grooves to do with the kerf (diameter of laser beam). With low quality metals the edges of apertures have grooves making them look like washboards.  Also see minor warping and ripples in the Chinese metal.
  • Look for “exciting announcements” to do with the stencil process to be offered by OSH Stencils in coming months.
  • OSH Stencils makes stencils for customers that have nothing to do with electronics. Art projects, special “plates” for mechanical components, etc. They’re open to queries about whether your creative application can be handled by their equipment.

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