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Quick two part question on PCB manufacturing. I am looking to order a prototype PCB and all the manufactures I've gotten a quote from all offer to include a Laser stencil, some charge for the stencil some are given free with the board. After looking online to me it looks like the laser stencil just shows the outlines of the pads.

So 1. Why have a laser stencil? what advantages do you get from having one?

and 2. Why do some manufactures charge and some are free for what looks like the pad outline?

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    \$\begingroup\$ If you're not aware of how a stencil is used it's probably worth taking a look at a few YouTube videos like this: youtube.com/watch?v=QZmzuUqzPm8 - the "free" stencils is just a marketing thing. \$\endgroup\$ – PeterJ Aug 25 '17 at 10:11
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    \$\begingroup\$ If you're ordering a low quantity of boards to be assembled by hand, you may find a plastic stencil to be significantly cheaper than (and just as effective as) the steel ones typically provided by most PCB manufacturers. I've had great results with smtstencil.co.uk's polyester stencils for up to a dozen boards, although YMMV depending on feature size/spacing. \$\endgroup\$ – MTCoster Aug 25 '17 at 13:05
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  1. why have a laser stencil? what advantages do you get from having one?

That's probably the wrong name. It's a solder-paste stencil that has been laser cut.

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Figure 1. Application of surface-mount device solder paste to a PCB using a stencil. Source: SparkFun.

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Figure 2. The finished result. Note the well defined edges. These will make placement easy and reflow a high chance of success. Source: Zavax.

The paste is applied through the stencil, the thickness of the stencil determining the quantity of paste applied. The stencil is then lifted and components placed.

  1. Why do some manufactures charge and some are free ...?

Different business models.

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