Quick Laser Kerf Question


#1

Anybody got any idea what we are talking about here for 1/4" material? (Just order of magnitude.)

0.10 mm?
0.20 mm?

Or, if you have a moment for a test, if you cut out a 20 mm by 20 mm square, what are the actual final measurements of the hole, and of the cutout?

Muchas Gracias! :relaxed:


File preparation
#2

very roughly 0.01", plus or minus ~100%.


#3

Thank you very kindly! :relaxed:


#4

Ummmmm, can I ask one other question? Does your laser cut center on the vector line no matter how thick the visible line is, or does it place a vector around the outside of a thicker line? (Where the colors change?)


#5

When you do a vector cut or score, it runs down the vector itself - which is usually at the center of the visible area, although that’s a configurable option (you can create an illustrator “stroke” where the actual “path” is on one side or the other instead of in the middle).


#6

Totally freaking awesome! :grinning:

Thanks Dan!


#7

If using Illustrator, it’s probably really helpful to view outlines, which should be control-y (on PC, I think) or command-y. I don’t have a Glowforge yet, so I’m just surmising :wink:


#8

Yeah, i do use Illustrator, and it sounds like their program is going to have some of the same functionality, which is sweet.

If they didn’t have “cutline” placement on the outside of a wide stroke, we would have to place it there by Expanding the Appearance in Illustrator. So it saves a few steps and broadens our design capabilities.

What if we wanted to just include the kerf adjustment in the stroke width? It’s something to think about anyway…might not be able to figure out how to work it but that’s the part I like best.

:relaxed:

On second thought, after re-reading that, Dan might just be talking about using Illustrator to do it in the first place.

Either way, the answer is the laser follows the vector line exactly and ignores the stroke width.

Bah…it’s too late, my brain isn’t functioning…0.25 mm is practically invisible anyway. :smirk:


#9

I read it as following the vector line. You can apply a stroke of X points which helps you see things easier but the cut will be down the actual vector points. When you put it in outline mode, you see only the vector lines - no strokes for lines etc. Just a way to proof check a file before getting to a preview. Efficiency!


#10

So if your Illustrator design uses strokes, how do you cut the outside of the stroke instead of the center line?

How do you cut a stroke that so WYSIWYG?


#11

I guess I could interpret the question a couple of ways. You can offset the stroke +/- which would adjust the cut line. Or, I could interpret it as you have a line that you’ve applied a stroke to and you want to cut the outline, in which case you would expand appearance and it would be wysiwyg.

I don’t know best design practices for Glowforge - but just that their is sometimes a disconnect between what you see on the screen and what is going on with the actual vector. View outlines helps you see what the actual vector lines are in the file.


#12

I meant the second case. Unfortunately, the times I have tried to use Expand it did not give me easy WYSIWYG results. (I have a vinyl cutter which has some distant similarities to the GF… if I save an Illustrator file to a PDF, it wants to cut on the centerline of a stroked path, which is not WYSIWYG, so you have to Expand and do cleanup.)

This is the Illustrator workflow I really want for my vinyl and laser cutter–

  • Create b&w vector art in Illustrator
  • Issue some kind of “simplify” command that renders paths at the border of black & white, discarding the original path and stroke.

It would be kind of like saving the image to a high-res bitmap and then running an autotrace. The only lines in the resultant drawing would be cut lines.

If Expand Appearance is supposed to do that, then I haven’t been using it right.


#13

I know what you mean…

That’s exactly what Expand or Expand Appearance does in Illustrator, but if you have any enclosed areas, it tends to create a bunch of groups, Compound Paths and extra paths that you have to go in and delete if you don’t want duplications. Merging does the same thing depending on what your parts look like. It can take quite a while to clean up a file with a lot of very detailed interior cut paths. (I tend to just select the main Compound Path and lock it, turn off visibility for all the other garbage, and if the thing still looks like I want it to, I delete all the extras and turn off the Compound Path and set fill to zero.)

You can even have Compound Paths within Compound Paths, which makes it a challenge.

There are other programs for the vinyl cutters that do have a true WYSIWYG function (Funtime & Silhouette Studios are very nice) but you can’t get the results output in any kind of usable format for this.

You might want to check out CorelDraw…some of the other designers could tell you what it does - it might do a better job of it than Illustrator for a complex drawing, and I haven’t had a chance to play with it much yet.


#14

I’ve never used Corel, it’s worth a look. I’m not sufficiently skilled in Illustrator to lose a lot of ground switching.

Now that I think about it, saving to a giant bitmap and autotracing it is about the easiest way I can imagine to get the desired cut-friendly file from a vector doc loaded with complex paths. It just feels so wrong!


#15

That unfortunately depends on how good the Auto-trace function is too. It’s an option, but sometimes those are more error prone than not.


#16

Definitely–but the ones I have experience with have actually produced very good results, if the source artwork is sufficiently high resolution. And if you’re starting from a vector file, you should be able to produce an intermediate bitmap that’s enormous if needed.

Oops, I am threadjacking. :slight_smile:


#17

I’ve been known to do the same…chuckle! :blush:


#18

@GrooveStranger, what you’re describing sounds like it should be super easy, but I want to make sure I understand correctly. Is it possible you could throw an .AI file on here with an explanation of what you want to happen & what you’re afraid might happen? Then I can tell you the actual results in the software.


#19

@dan, I’ll do that in a day or two. I need to figure out a sample that I can post without copyright issues. Thanks!


#20

OK - if you can just demonstrate with a square or something that might be easiest.