I would like to engrave simple label tags for machinery switches. I am not having any luck creating a usable workflow for this process. Because CC does not handle single-line fonts, I have not been able to come up with a tidy toolpath for engraving 1/4" tall letters in 1/16" two-tone HDPE. See this thread from 2020 Can a Shapeoko do this?
Is there a settled best practice for this process?
I would try a vcarve with a 60 degree v bit and not worry about a single line font. With text only 1/4 inch tall, depth of all but wide/bold fonts should be within the 1/16 inch thickness of the material. The completed tag in two tone HDPE may or may not look acceptable with a vcarve but I would definitely try.
What does this mean??
“single line fonts” is an oxymoron. It’s either single line, or a font. And CC can handle either one, you just need to know how to set up the toolpath.
1/4" letters are going to need a 1/16" or smaller (1mm) tool. (CNC Plastic Cutting Bit Amana Tool 51415-K Up-Cut Spiral O Flute) ??
or use a V-bit, but you have to be precise about depth to get the width of letters you want. You could end up going through 1/16" tag. And I don’t think it looks as nice.
For plastic you want the RPM (relatively) slow. Which could be 12000 - 15000 for a 1/16" tool.
And you’ll want the feedrate cranked up, 100 ipm or more. So you have to figure out depth of cut for those settings. How thick is the top layer of plastic you have to get through.
I might try 0.010" DOC to start.
I would try single lines, or a very skinny font, there are several places that will generate svg text in single lines.
And use a contour with no offset path.
Actually, there are two ways to represent letterforms:
One example which is actually usable (depending on one’s sense of aesthetics) are the “Hershey” fonts:
https://www.evilmadscientist.com/2011/hershey-text-an-inkscape-extension-for-engraving-fonts/
Or, for a utility which will set text thus so that it can be cut on the machines directly:
https://www.ncplot.com/stickfont/stickfont.htm
FWIW, I’ve actually been working on a single stroke font design:
which I hope to program as a METAFONT and use as a test bed for finally making the font design program/tool/system which I need to finish my version of Warren Chappell’s Trajanus and Eichenauer fonts.
I’m still patiently waiting for this very cool project 
Thank you for the reply. I have seen your post around while trying to figure this out, but I still don’t comprehend it. What does drawing “geometry at the narrowest point” do for this process? Do I need to do this for every set of text? I have many labels to make, and the font isn’t all the same size.
@HeuristicBishop The Warren Chappell font project has been on-going for a very long while, and as noted, is currently stalled on my having drawn outlines for all the characters which I have metal type examples of, but only having compleat size exemplars for N and n — and there not being a font editor which I like, so the current plan is to create a new one like to the METAFONT editor used in the Euler project at Stanford (and my life comes full circle since I missed that for want of a calculus class in high school).
@loudboy For each set of characters at each size.
Set the text:
nthen identify the narrowest region:
then inset by a bit less than that radius:
and if it turns out that one has misidentified the narrowest region:
try again:
Apply
Ah, now I get it. Thank you for spelling it out for me. I’l give that a shot with a V-bit.
If you’re going to use a V tool, might as well do V carving…
Wow, Will, that will be the perfect font for embedding text into FDM parts–constant stroke width and full-radius ends so it is easily strokable. The closest I’ve come so far with what we have available at work is Arial Rounded MT Bold, which is close but not perfect. The lettering comes out readable but inconsistent at the sizes I’m needing to use–.18-.22" letter height.
That is exactly why I’ve been developing it — one aspect I want to take into consideration is rounding angles so that it is possible to fill in around the letterforms with extruded material — the total inverse of ink and light traps.
I’ve been trying to, but it never resolves a cut plan. Just “Empty Toolpath”. My max depth is greater than my depth per pass, and my material thickness is greater than my max depth. I’ll keep playing with it.
You are using “No Offset” for the Contour toolpath?
Upload your file?
engine room labels.c2d (1.5 MB)
This is representative of what I will need to make. There are more than a dozen of these sets. I created the file in Lightburn for my laser engraver, exported it to .SVG, and imported it to CC. The laser works fine, but the fumes are terrible, which is why I would like to switch to the CNC. Thank you for your assistance with this.
Wow, 0.026" strokes. Cutting single line with a 1/32" would make them just a smidge bigger, but I think they would still look good
We start by organizing the file into layers:
Then, we measure the smallest/narrowest text region:
which probably is a no-go for any tool which will cut this in a reasonable period of time.
(this being the W in some Times variant)
For the balance, we have:
A #122 tool is quite a bit larger than this feature:
you would want to use a much smaller tool for versimilitude:
Fortunately, there are companies other than Carbide 3D which sell tooling, so if one were to patronize @TDA 's company’s wares:
then one could find a tool such as those listed on:
0.0200" (0.51mm) 0.0300" (0.76mm) 2 1/8" 1.42" (36.1mm) Available
MN208-0200-003F
(note the caution at the top of the page: “Use a good, water based cutting fluid to improve finish and reduce tool wear.”)
which if we then apply offset geometry expecting to use such a tool:
seems to have filled in everywhere except the more delicate/narrow regions at the ends of the parentheses and in the serifs/strokes of the afore-mentioned W.
Again, we make and move things to a new layer:
and then create the tool (this step will not be shown, you will need to work up your own settings for 0.02" diameter tooling and feeds and speeds suited to your material — hopefully John Torrez will chime in, or one of the other folks who does micro-machining) and assign a No Offset Contour toolpath, assigning by Layer:
which does generate a toolpath and previews as:
A bit of Node Editing w/ the parentheses and the intractable letter:
u (to make a cusp)
Repeat this at the other end and other instances and fill in the W to arrive at:
which previews as:
which arguably wants a bit of a touch-up on the serifs… hang on for that…
Re-creating this in Freehand (so as to get curves, not polylines, and using a slightly smaller offset), and also have to re-set some text:
c.f.,
which then allows using the Curve tool to edit things a bit more readily:
which previews as:
Attached as a v8 file, but note that the tool definition and feeds and speeds should be adjusted.
engine room labels_v8.c2d (3.5 MB)
