To adjust for kerf or not to

Another point that popped in my mind:

I also use a lot of materials that glowforge will more than likely NEVER sell. Therefore I will be out of luck if Im not using a proofgrade analogue. Not to mention I either have tons of scrap or can run to the hardware or exotic woods store on a moments notice and get what I need instead of ordering something online and having to wait. While Im sure proofgrade will be cool, I cant see myself using it more than whats available locally. The formulations for most of these materials arent going to be any different.

Not only that, but even with certain materials I might want to change the kerf for the last piece. For example: EVA foam. When hit by heat it contracts. If I was building a multi-layer object out of EVA foam, I might want the top and bottom pieces to be hit with a heat gun to seal up the cells before coating it with plastidip. This will cause them to shrink and be a different size than the rest of the pieces. If I can manually adjust the kerf for these two pieces, or have a setting called ‘heatgun shrunk EVA’ ive saved in the menu, I can just select that and be on my way for the top and bottom pieces. No more bouncing between software EVERY TIME I have to cut multi-layer EVA.

A manual kerf just makes sense.


Good points. One humble suggestion – add a “Sample” or “Suggestion” watermark across your UI image. Sooner or later, it will get cross-posted as “look at this new feature!” I’m guessing sooner. :innocent:


I liked to think about it as “Kerf Wars”

As long as everyone goes home safe…


Agreed, all that those of us on the CNC-persuasion side are asking is that we be given the choice of selecting a kerf allowance and whether or not to use that option. We (or at least I) have no wish to force them to use a kerf allowance if they don’t want to. Come to think of it, make the default kerf allowance value “0.000” (inches or mm) and we can all be satisfied and GF only needs to add one input box to the UI.


Excellent point. If you want to sell the advantges of a cloud approach, you’d better have all the features that users want, especially if they are commonly available elsewhere.


Can you all who are interested in discussing the should or should nots on what SHOULD the Glowforge have in regards to options available currently with your CNC CAM stuff please create a new topic so its easier for those folks interested to find?
This post was originally created to explain what kerf is not how to do it. Thanks😀


Im all kerfed out anyways lol


I was so close posting similar pictures yesterday but decided I’d just keep my mouth shut :innocent:

Okay - been busy tutting (and losing this thread for some reason) but the problem with disconnected lines has nothing to do with the program that is receiving it, and everything to do with the program that exported the DXF.

That’s a problem that I’m very familiar with from the cutter world (and I’m sorry to have to keep referencing it, but we saw it there all the time.)

The bad news is - it might be how Solidworks or the HSM Processor, (whatever that is), is exporting the DXF file. (I’ve tested Rhino, and it exports connected paths. Similar for Fusion 360, Illustrator and Inkscape.)

My bet would be on the HSM thing…Solidworks is in too wide a use to do something like that unless it has to do with toolpath assignment.

If you can export your sketch as DXF directly from Solidworks - you can then, if necessary, convert it to SVG in Illustrator or Inkscape.

If you load up a DXF direct from Solidworks - i can test that in Illustrator to see if the paths come across as joined for you.

That workflow - jumping between that many programs, isn’t going to be necessary.

Mine is Fusion 360 export DXF> Illustrator (or Inkscape) convert to SVG > Glowforge cut

I’ll bet you can do that too.


I have imported .dfx files into Corel and sometimes they are connected but more times than not, they are all broken into segments. Easy fix with join nodes -non close curve which will close the shape by drawing an extra line between the first node and the last. Then export as .svg.

Otherwise and almost always…I design in Corel so its one conversion to .svg and then the Glowforge


Anything that gets created in the AutoDesk123 Make program gets exported as discrete segments in the DXF.

It’s annoying as hell - I have to circle everything and Join, circle and Join…so yeah, it can be a problem if you are trying to do something that is spaced too close together.

One of the reasons that I listed all of the programs that I used in the Shared Free files that I posted was so that if Tony and crew needed to know which programs were causing problems with unconnected segments, they would be able to pinpoint the problem. (And I’m not sure if I bothered to join everything in all of those…probably left a few unjoined so they could test with it.)

That one is nice for aligning tabs and slots, but almost not worth the trouble of cleaning up the results for cutting.


I have a feeling that a lot of my work will end up being run through Vcarve Pro as it will allow me to optimize vectors making sure they are closed and control start stop points.


The DXFs exported from SolidWorks aren’t joined either. I agree that the state of the exported file cannot possibly be attributed to the program opening the file.

I wasn’t speculating about the workflows, I was describing the only way to get from SolidWorks to SVG using the software I have and the following constraints…

  1. I’m not willing to enter “fake dimensions” into my designs to adjust for kerf
  2. I’m not willing to be driven mad by watching my cloud-optimized laser cutter bounce around the bed randomly
  3. I’m not willing to select all the lines I want to join individually and I’m also not willing to clean up the mess left by joining lines in Illustrator. I didn’t know how CorelDraw handles that operation, but it sounds like it mimics Illustrator (in other words, it sounds like it’s garbage).
  4. I’m not willing to clutter my SolidWorks parts or assemblies with additional sketches that serve no purpose other than to adjust for kerf

One of my worries initially was the conversion to different file formats. In my experience, converting from a native file format has almost always been a headache and things don’t export into other formats very cleanly a lot of the time.

I don’t use solidworks but google is littered with people having similar problems.

Do any of those solutions help the final DXF export?

What are you willing to do to get a final project ready to send to the Glowforge? Anything? It sounds like you already have a problem with just the DXF format from Solidworks, unless, hopefully, one of the solutions above work?


Yeah, switching formats can be problematic as well as being a hassle. SolidWorks’ being a bit of a POS when it comes to exporting doesn’t make it any better.

That first link you posted was actually extremely helpful. It’s actually one I’ve linked to before as well…

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Kerf is super important in inlay work.

Also, Kerfgate is my new favourite -gate.


Yes, I can see how even .008" could be significant in an inlay where you want it to push in snug.


Yep. I did some testing cutting text out of veneer, and you really do need that adjustment.


I just wanted to try and be the 200th in this thread… Kerfgate T-shirts anyone?


I’m surprised @jkopel’s description of “kerfuffle” hasn’t made it into this thread yet. It’s almost too perfect!