Keeping solder masks rectangular?

I purchased a stencil cutter so I can make my own solder paste masks, and I’ll be using the software here:

From what I understand, cutting the stencils will go much faster if I can restrict myself to vertical and horizontal cuts. In Eagle you can set an option to disable rounded corners in the solder mask. Is there any option or script that would do this in KiCAD?

Don’t start by modifying PCB files on such assumptions.
Take some time to experiment with your new tool and get to know it’s capabilities.

And in the end, how important is the cutting speed of the stencil? You can go lunching, make a cup of coffee or etch a PCB in the time the machine is working.

Rounded corners in stencils also have advantages.

  • Sharp inner corners are “impossible” (which makes edge radius “undefined”)
  • A vinyl cutter can not make sharp corners anyway. Attempting to do so likely adds burrs to the material.
  • Sharp corners are more likely to retain a bit of paste.
  • Sharp corners are weak points in the stencil, it may start tearing there.

Thanks, I’ll take that advice. Since you seem familiar with what I’m doing, have I chosen the right software to get the Gerber to the Graphtec (Cameo) stencil cutter?

I’m on MacOS

I have no experience with making solder stencils myself, but do have some “background” knowledge.

Here’s a video from MikesElectricStuff and how he makes his stencils for low volume prototype boards:

I have the same stencil cutter and am on macOS. I don’t remember which conversion software i worked with, it was years ago when i tried it.

I could never get the cuts accurate rectangles, additionally they always had some overshoot (cutting a bit too far along one edge) or undercut (cutting not far enough so you have to remove the cut out manually).

Don’t expect to be able to cut 402 sizes.

Also, when you do manage to get a reasonable cut film, using that with a PCB and paste is not so much fun either. It is impossible imho to keep the film tight and flat on the PCB with no paste creep under the film.

A metal stencil from oshstencil (if you are in the usa) is cheap, lasts forever and very effective… just my thoughts.

Well, in the meantime I’ve got it all to work. There were some problems, I never got the gerbv UI to work on Mac, I had to do everything on the command line. But in the end I’m getting good results, and I absolutely can cut down to 0402 sizes. That is part of what the software does - all sorts of anti backlash techniques and so forth.

I just left the rounded corners - it will just take longer to cut.

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