We are planning to purchase a stencil for our LED boards. This will be my first stencil purchase so I don't have much idea about a good or bad one.

The inquiries I received typically suggest two materials: Phosphor Bronze or Steel. Steel ones are charged at 100$+VAT, while Phosphor bronze are about 65$+VAT.

The product is a high volume one, so the stencil will be used a lot. Also, per the info given to me, the holes on phosphor bronze are acid etched, while steel is laser cut, so there may be some roughness on phosphor one. We are not making a space shuttle PCB though, just some 2835 LEDs, so I guess this should be OK (again, just a guess)

Question is: what are the advantages of steel over phosphor bronze? Is the price worth the cons: durability and quality-wise, or is it just a trap? Should I have any concerns about end product quality if I buy the cheaper option?

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    \$\begingroup\$ You're probably mostly paying for shipping and handling. For fine (<0.5mm pitch) you may wish to specify electropolishing on the laser cut stainless stencils. Thickness is another variable, with several typical choices, such as 0.1, 0.12, 0.15, 0.2mm. \$\endgroup\$ – Spehro Pefhany Mar 18 '19 at 13:48

The assembly house I used to rely on once told me that the stainless steel ones are more durable, and that makes sense as steel is a tougher material compared to bronze.

I wouldn't worry too much about the laser cutting, as the stencils are polished, which will remore any sharp edges.

If in doubt ask the manufacturer for clarification, but in my opinion, saving $35+VAT is not worth the hassle of having to redo the stencil, and fix badly soldered boards at a later date, when the stencil it worn out.

  • \$\begingroup\$ Thank you. Did you ever try acid pierced stencils? \$\endgroup\$ – C K Mar 18 '19 at 13:54
  • \$\begingroup\$ I guess you mean etched stencils. Yes I have used them in the past, and worked just as well, but it was only on a small batch of boards. I have also used Kapton stencils, which can literally be used just a few times. They all have their merits in their area of use. \$\endgroup\$ – Elmesito Mar 18 '19 at 13:57

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