I have, with the help of my daughter, made some progress on using a Cricut machine for model building activities. A Cricut is a computer numerical control cutting machine. Originally intended to cut vinyl sheet for decorations for scrapbookers, people have found it will cut many other thin materials. My original idea was to cut vinyl patterns to make painting masks, instead of the normal handwork cutting and masking with masking tape. Turns out it can also cut thin sheet styrene.
Pictures in a day or two. My current test project is a set of bridge supports for a scratch 1:144 WW1 German destroyer. The bridge has wings that stick out and these wings are one deck above the main deck and needs to be supported, so there is a deck support from the main deck holding up those wings. Originally I thought I could have the machine cut .020 sheet styrene. I was having a bit of problems with setting the depth of the cutting knife. While I was doing that, it dawned on me that the cut vinyl could act as a resist for etching to make PE parts from thin sheet brass. Monday my daughter was over for Christmas, and we took a few minutes to try both ideas. First, we cut vinyl to act as an etching mask (yes, vinyl is resistant to the ferric cloride etchant). That worked fine- I applied the mask to a piece of clear plastic to inspect it- it looks fine. I will be cutting two more masks to try etching the PE with actual brass.
We also got the sheet styrene cut, though the interior openings are sticking in and must be punched out- carefully since .020 styrene is pretty flimsy. I will be sanding the back of the piece to help punch out the openings. So far the piece looks pretty good.
The vinyl she is using (she makes etched custom designs on glassware- the vinyl is resistant to the flouride etching cream- is just regular adhesive backed Contact shelf liner. A transparent transfer sheet is also needed to move the design from the Cricut machine to the surface to be etched. She is using transparent Contact for that.
The idea is to design the part to be cut out or the mask by making a drawing (jpeg or png) and uploading the drawing to a Cricut web site. That site then runs a slicer program and downloads it back to your Cricut machine, which then does the cutting on the material you load into the machine. People are already using it to cut thin plywood (1/32 or so) for things like ship decks and such.
Again, pictures of the bridge support in a day or two.