You can always start out your SMT designs with DIY laser-cut stencils but eventually you’ll want to upgrade to a stenciling machine. Stencil machines hold the metal-cut stencil flat and taut so that you dont have any shifting or curling while you try to lay paste down. The good ones have a fixture so you can always get the same alignement every time – speeding up your stenciling time down to under a minute per PCB. They’re a little expensive, but if you ever plan to do over 100 of a PCB they are essential!
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Interesting, the stenciling ‘machine’ I use is a bit different:
It is made of 2 frames sitting on top of each other, at an adjustable offset;
The bottom frame contains an [x,y,angle] adjustable plate with magnetized standoffs (A real pain to get in the right place, but quite stable once set)
The top one is removable, and has one fixed clamp and one sliding clamp, for holding 2 edges of a ‘foil’ type stencil.
The top frame is set to a mm or so above the PCB, then a screw on the sliding clamp buckles the stencil down, forcing it hard against the PCB.
Springs pull the clamp back once the paste is applied and the screw undone, lifting the stencil clear of the PCB with no chance of smudging.
Question: what do you use as an applicator for the paste?
I use Stanley knife blades for their straight, rigid edge, although a very flexy steel spatula would probably be easier to handle.