I want to create two piece labels for storage containers. The main piece would be the “badge” which would have text cut out of it (e.g. “Paint”, “Electrical” etc.). The second piece would be a positive of the text which is would be in a different colour, and would fit inside the cut out on the badge. Because of the tolerance of 3D printers, I need to make the insert slightly smaller than the cut out. Initially, I thought I could just scale the insert but that would affect the letter spacing. Then I thought it would work if I could somehow taper the letters so they are slightly smaller at the top than the bottom. So my question is, how I do that. I did the original in OpenScad but I would try Fusion360 if that’s a better solution. Any and all suggestions are welcome. Thanks.
In OpenSCAD, apply the
offset transformation to inset the letter outlines before extruding them. However you may find it works better to fill the sunken letter shapes with nail polish then remove the overflow with acetone; see my question & answer https://3dprinting.stackexchange.com/a/10872/11157.
Fusion 360 can be easily used to alter the design. It has a button under
Construction > Edit > Push/Pull . Using this tool allows to select one or more surfaces and shift them all outside or inside as needed.
An alternative would be to include the size difference in design. By selecting a line or loop and then pressing
O opens a menu that easily creates an outline shifted by a specified ammount.
Tapering the extrusion is also easy: When extruding, one can choose to extrude with a -1°, resulting in a smaller size on the far side from the extrusion. positive angles make the far side larger.
You will need to run test prints to see how your printer behaves with your choice of filaments. Then you'll know how much narrower the letter-lines (not the letter dimensions) need to be to fit.
The problem with that is one of making letters with narrow solid parts but without "shrinking" the open parts so that they fit into the badge receptacle regions. You can't just reduce the dimensions of the letters themselves.
Other than what Trish's answer suggests, I'd recommend either using a very small nozzle diameter and setting a narrow linewidth to reduce the "over-dimensioning" effects. Even better would be to identify the letters separately from the badge but keep them as a single STL and use a two-color printer (twin extruders, etc) to make the badge in one run.