Kerf - odd problem

[Hank (Hank Morgan)]

@tnek

This has been like practicing self dentistry - specifically a root canal.

It’s hard to hold the mirror, flashlight, and drill all at the same time isn’t it?

@tnek

… If I combined both images on on 1 layer and set the kerf to 0.11 (1/2 of Kerf) would the result be the same as cutting on 2 separate layers with the setting at 0.11?

Yes. Same layer or separate layers are both fine as long as the kerf offset is the same on both layers.

@tnek

… Would the kerf work if I joined the two pieces as a single image with separation line/cut ending up with 2 pieces. The kerf setting would be set to 1/2 (0.11).

I’m not sure what you’re asking here. Can show example or explain differently?

@tnek

. Every rectangle I create has rounded corners when I preview the image.

That’s weird. I can’t think of any layer settings that would cause that. What’s the radius of the rounded corners? Are we talking a few mm or some tiny fraction of a mm, or?

[tnek (Kent Jager)]

@Hank

What’s the radius of the rounded corners? Are we talking a few mm or some tiny fraction of a mm, or?

"What’s the radius of the rounded corners? Are we talking a few mm or some tiny fraction of a mm, or?

On this one I don’t think the resolve is worth the effort on this one. Last night I had changed some cut settings and can not duplicate the issue this am. Nevertheless, the following is to answer your question.

These pieces are 1 1/8" tall x 1/2" wide. No shape properties applied and I don’t think any radius applied at least not on the tabs or slots.

Blue 2 cuts different kerf set. Left Red & black arrows= rounded/deformed tabs. Right red= deformed slots. Using the C01 layer the shapes seemed to change as the kerf changed.

@tnek

… Would the kerf work if I joined the two pieces as a single image with separation line/cut ending up with 2 pieces. The kerf setting would be set to 1/2 (0.11).

I’m not sure what you’re asking here."
![image|176x90](upload://pfhjOXGGQV8n2dfdzumvg81A3i7.png
Left two shapes are different layers & great fit. I cut these in sets of 6 resulting in a small waste between cuts. Right image - Layer C02 I removed the two vertical lines, joined the pieces and inserted a single line C01 layer in the center of the shape. Thus eliminating the small waste of materiel between the two right images. This test answered the two questions I asked. The left and right images can be put on 1 layer and cut successfully, the two images can be combined and cut successfully.

[jkwilborn (Jack Wilborn)]

I have the kerf at .166 for 4.6mm plywood. I can generally cut one side at .166 and the other at 0, and they mate up relatively well. This does tell me the outside kerf seems to be working.

However it’s an issue when you build a box and each part has to have a different kerf. Alternating kerf so the sides will fit, but the bottom has to mate with all of them.

Going to both parts, with a .083 kerf, leaves a relatively loose joint. However at .080, I get a snug fit

The difficulties seem to come with the negative kerf. I’m cutting out square holes for a shelf and the design is 4.6mm square, material thickness.

I’ve applied all kinds of variations and it isn’t functioning as expected. No matter what I did, it didn’t seem to change the size of the hole I did drop a line to tech support, they’ll get to when they can.

[Rick (Technical Evangelist)]

@jkwilborn

it isn’t functioning as expected.

I placed 2 - 100mm squares atop each other, only one has an inside kerf.

[tnek (Kent Jager)]

@jkwilborn

I’ve applied all kinds of variations and it isn’t functioning as expected. No matter what I did, it didn’t seem to change the size of the hole I did drop a line to tech support, they’ll get to when they can.

I would absolutely like to hear the response.

I have just mentally dumped all the kerf information I though I had under my belt before this post. I had done so many attempts some worked and some not. Now after getting the help from you and others I think my only problem was not using closed shapes. Mostly I will use boxes.py. I have modified some of the images manually in to fit my needs.

I have one more question regarding a response you made above regarding the “divide by 10”. But, I need to re-read it again to make sure I didn’t miss something.

[jkwilborn (Jack Wilborn)]

Then am I interpreting this incorrectly?

I have two 4.6mm squares. The one labeled -1 has a kerf set to -1, the 0 to 0 or no kerf. The preview:

?
lb-kerf.lbrn2 (7.9 KB)

[Rick (Technical Evangelist)]

These are not closed shapes.

[jkwilborn (Jack Wilborn)]

I used the ‘rectangle’ tool to draw them. Copied and pasted to duplicate them. What kind of operations would cause it to become unclosed?

Went back and fixed it. Any suggestion on how I ‘dis’ closed them?

Thanks

Jack Wilborn

[Rick (Technical Evangelist)]

‘Break Apart’ (Alt + B), by chance?

[jkwilborn (Jack Wilborn)]

Could have I guess… My keyboard needs replacement and it’s a bit sticky. This is the second time that issue has burnt me. First thing to check from now on.

I had this working… That’s what’s so frustrating…

Thanks, take care.

[Rick (Technical Evangelist)]

I’ll poke the team…

If you see it again, or find you can reproduce, we definitely want to know.

Thanks for all you do, Jack! Greatly appreciated.

[tnek (Kent Jager)]

I have the darnedest time with join/auto join/join with tolerance. I’m to the point where I set to fill. At times I can have some success with break then auto join.

[jkwilborn (Jack Wilborn)]

This has bit me before, I’ll be watching next time

Corrected and I reran my parts and they probably won’t need glue

Try this link to figuring out your lasers kerf.

It’s from ADA Fruit but that’s it in a nutshell.

[tnek (Kent Jager)]

@jkwilborn

Try this link to figuring out your lasers kerf .

Haven’t been to her site (if it is still hers) in a long time, had no idea she this kind of stuff now. Thanks for sharing.