Need Help Dogbone Issues on Rounded Corners

[Kyle H]

I have been having trouble with our Kongsberg XP CNC, cutting rounded edges or custom die-cuts. The blade seems to exit the corners in the wrong orientation or alignment and I end up with a wobbly cut.

I have been testing this with different radius corners and the smaller the corner the worse the problem but the problem remains no matter the radius. I am using Adobe Illustrator to create all of my cut files. the problem has not gotten any worse or better over the last year. I have cuts that are almost identical from a year ago with the same issues. I have had a technician come out looking for slop in the movement of the gantry or mis alignments but nothing was found. like I said the consistency of the issues is very confusing.

I am thinking that it must be a software issue because we didn't find any thing lose or "sloppy". Any help would be apreaciated. I don't know where to look next to fix the issues.

Thank you.

 

[jfiscus]

It isn't just your corners, your "straight lines" aren't straight either. Looks like something is wobbly/loose in the machine.

 

[White Haus]

Does it happen with multiple tools/blades?

Did the tech think this was acceptable output? (I don't)

Edited to add: If you performed multiple passes, would it follow the same lines every time or is it all over the place?

 

[MGB_LE]

When calling out the technician, don't suggest fixes. Let him know the problem and then expect a resolution. Sounds like you told him the gantry had play, so that's what he diagnosed. No slop in the gantry so he was on his way. "Hey, my cut quality is awful." is a great place to start him off. Just my two cents.

 

[Joseph44708]

Maybe Change your blade. It might not be sharp. Its dragging not cutting.

 

[AGCharlotte]

what are you cutting? if it's rigid you might be getting blade flex. On my Kongsberg, I don't use the single edge blades on anything other than vinyl, I use the thicker double edged blades (BLD-DR8160) on heavy banner, pvc and poly.

 

[Flatbed Tools]

Have you checked your lag settings? How is the pinion engagement with the X and Y motors?

 

[Adam Vreeke]

I agree with Jburton, usually when I get something like this, the pressure of the blade pushes the material up a little while cutting, creating an excess of material. When it gets to the corner and turns the excess dispels off and you get that shape. Try lightening the pressure of the blade, and a new starting point so the cut ends on a straight line and not right after a turn.

 

[Raum Divarco]

I have been having trouble with our Kongsberg XP CNC, cutting rounded edges or custom die-cuts. The blade seems to exit the corners in the wrong orientation or alignment and I end up with a wobbly cut.

I have been testing this with different radius corners and the smaller the corner the worse the problem but the problem remains no matter the radius. I am using Adobe Illustrator to create all of my cut files. the problem has not gotten any worse or better over the last year. I have cuts that are almost identical from a year ago with the same issues. I have had a technician come out looking for slop in the movement of the gantry or mis alignments but nothing was found. like I said the consistency of the issues is very confusing.

I am thinking that it must be a software issue because we didn't find any thing lose or "sloppy". Any help would be apreaciated. I don't know where to look next to fix the issues.

Thank you.

View attachment 154657 View attachment 154658 View attachment 154660 View attachment 154659 View attachment 154662

Is this Styrene?
Similar rigid materials provide a lot of deflection to the blade when cutting.
Blade deflection and material shifting will typically give you these results.
When possible you will want to assess the best starting position.
you may even consider adding a node to the side of a shape and step and repeat it.
the added node can be on a straight away which will be easier to trim if necessary.

To me this doesnt look like a software issue.
The XL-Guide or IPC adjustments are usually used when the corners aren't lining up or there are gaps or excessive overcuts.

In my experience, on single sided prints, i often raise the depth of cut some.
reduce a hair of depth so that the knife tip will just barely miss piercing the other side.
Most rigid materials are cleanly stripped from the sheet when done.
This minimizes deflection from the material and also increases machine production time as you can strip off the table.
Cycles times will be better and you will also have better results.