Engrave V-shaped Text

[DonStauffer99]

I use Inventor to make models to 3D print. In 3D printing, higher layers can actually overhang empty space, up to an angle of something greater than 45 degrees, without requiring support structures be printed. That's good, because supports mar the surfaces they support.

So I'd like to engrave text on a face that will be facing the build surface. To avoid supports, I need to make the engraving V-shaped (triangular). Rather than equilateral, I'd need it to be isosceles, because sharp angles between parts of a letter can steepen the slope when engraving at a particular angle. So I'd want to make the "trench" somewhat deeper than it is wide.

I've tried to do something with a sweep, but I can't find a font that will let me use a sweep. Even then, I'm not sure how easy it would be.

What's the best way to proceed?

[DonStauffer99]

This affects the STL file I export and use to print, so it's not a cosmetic simulation of a CNC milling or anything. It will actually print what the model contains.

[mcgyvr]

@DonStauffer99  What about just extruding text and using the "Taper" option to create the angle?

[DonStauffer99]

I can't get taper to work. It never likes the angle. It says it's too large , or "not meaningful", or doesn't produce "sweep geometry" .

[DonStauffer99]

I was able to achieve it on a SINGLE LETTER using the loft function. It took me all day, literally. Not practical.

[mcgyvr]

@DonStauffer99  Can you post your part or at the very least let us know what font, font height and how deep it needs to be in your part. 

[mcgyvr]

@DonStauffer99  Did you try "Draft"? or how about "Chamfer"

I would think thought that a typical FDM printer filament would just bridge the gap of typical fonts like that without issue.

[SBix26]

In my experience, most (all?) Windows & Inventor fonts are not a consistent stroke width, and contain lots of spline edges.  If you can find a font with fixed stroke width, and made up of lines and arcs, you should be able to use extrude with taper, or use the Draft tool after a straight extrusion.  I don't think I have ever found such a thing, though.

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Sam B
Inventor Pro 2022 | Windows 10 Home 2004
LinkedIn

[DonStauffer99]

As bridges go, it's not all that challenging, but I seldom see bridges looking great, and this is in a place which draws the eye. I've done slanted tricks like this before and they look great in comparison. Also, this print has supports in other places and I'd have to do lots of manual work to remove the supports under the text. This is also likely to be a common situation, so I want to find a workable solution.

The biggest problem with using lofts is that changing the text isn't as easy as editing the sketch, because complicated planes, axes & points as well as the lofts are dependent on the specific letter in a specific place. But yeah, I just did a lowercase t and it took about 2 hours, after a capital S that took about 6 hours. It's not conceptually that hard, but with Inventor, you have to do it exactly the way it wants you to or it gives arcane error messages.

[johnsonshiue]

Hi! Without seeing the file, I suspect Ruled Surface may help. It allows you to create surface from a given edge at an angle. With the surfaces, you can solidify them using Thicken or Stitch or Sculpt.

Many thanks!

[DonStauffer99]

So far, my best alternative has been to do the text sketch with the Simplex_IV50 font, which uses a consistent width to draw the characters, unlike some fancier fonts. I couldn't get Emboss/Engrave to do what I needed, so I went with Extrude. I set the taper to -30 degrees (it wanted negative to get smaller as it went down), which seemed safe since the printer can do overhangs up to about 55 degrees. Acute angles in the font accentuate the taper and so increase the overhang angle, so 30 degrees leaves plenty of room for that to happen.

I found that with the text at a size (height) of 14mm the deepest I could set it for without getting a "taper angle too large" error was 0.685mm. This produced text whose line width tapered from about 1.21mm to 0.42mm. My 3D printer with an 0.40mm nozzle is set for 0.44mm extrusion width, so that shouldn't even technically be a bridge. If I reduced the text size I had to reduce the depth too, to avoid the error (if I left the taper angle alone).

This lets me change the text for subsequent prints, and as long as I don't change the text size, no additional tweaking should be required.

The worst aspect seems to be that my slicer (Simplify3D) makes me click all the supports it generates for the text to get rid of them if I want to leave ANY supports on anything else. And at the support pillar resolution I use there are hundreds of them! My wrist hurts.

[DonStauffer99]

I found 3 fonts which would extrude: Simplex_IV50 worked but was too fine-lined to read easily.  TechnicLite worked but was no better (I liked the look of TechnicBold, but it had problems with the number 6 and a few letters I needed). I settled on one called BankGothic Md BT. I haven't looked at it 3D printed yet.

These 3 fonts didn't work if I selected the bold attribute, for some reason. I would have liked to. I found fonts didn't need to have perfectly invariant stoke widths; but what you don't want is the ones where the widths vary a lot. Serif fonts are worst (because of the serifs usually being so thin), but even sans serif fonts could be problematic if they were designed to be "dramatic".

I like Franklin Gothic Medium aesthetically, but the lowercase r is really narrow at one place. That kind of thing doesn't work, because with a given taper angle, the narrow parts determine how deep it will let you extrude, which leaves the wide parts wider at the extrusion depth, making for more difficult bridging when 3D printing.

[DonStauffer99]

Picture of results attached.

OK, I don't represent this as spectacular 3D printing. It's actually very bad! But the text came out about like I hoped. It's readable, and won't wear off, and it was printed without supports. The letters taper into the material. More of a trapezoid than a V, but that resulted in fairly easy bridging. So the lettering part was a resounding success. Thanks everyone for your help!

[gmwi]

Another way of doing what your asking for is extrude the distance you want. Then "daft" each letter separately. The program is calculating the total selection for taper and that leads to error. I've done this for casting / molding processes.

[DonStauffer99]

"Daft"? How?

[gmwi]

You emboss the letters and then daft the walls. Pay attention to which edge you select to pull because it is dependent.

[SBix26]

The tool you're describing is "Draft", not "daft".  Spell checkers are "daft", though...

In my experience, Draft runs into difficulties similar to the ones encountered with Extrude with taper.  It's rare (impossible?) to find a typeface where all characters will draft at 30 or 45°.  I'm still hoping to someday find a TrueType or OpenType typeface that is a completely uniform stroke width, straight lines and arcs wherever possible and has semi-circular stroke ends.  This typeface would look like machined text and would easily extrude with taper or draft to any reasonable angle.  Not sure such a thing exists, though.

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Sam B
Inventor Pro 2022 | Windows 10 Home 2004
LinkedIn

[gmwi]

The daft command is special, much like those people who are a bit daft.

I did a 45 degree draft on a text and if the auto-blend is on then it'll truncate the depth. If you want the "as machined" with tapered tool look then yes, it's a difficult find. This approach might save you some time on modifying.