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Chipped ink when routing

DSC

New Member
OCE 250gt
Canon 256 Inks
Multicam Router

We are having issues with ink chipping post print when cutting to shape with an 1/8" or 1/16" router bit

Specifically with PVC

Looking for a solution that someone has tried and been successful at/with..

Thank you in advance..
 

BigPrintn

New Member
We were running into the same issues when printing on acrylic and then cutting. We had to start cutting out the pieces, then printing. Save your scrap cut as a template for your vacuum zones.

At least this was our solution for the time being.
 

DSC

New Member
We were running into the same issues when printing on acrylic and then cutting. We had to start cutting out the pieces, then printing. Save your scrap cut as a template for your vacuum zones.

At least this was our solution for the time being.

That is exactly what we are doing now..

Printing the outline on paper/coro/ scrap whatever, then taping the pieces to the outline, and printing..

Thank you.
 

Deano1

New Member
Not sure how relevant this will be for you but we print direct to acrylic blocks (mainly square shapes) and had similar issues, we managed to get around it with a bit of experimentation with a good adhesive promoter. we had to really smother the acrylic with the stuff and leave it for at least 20 minutes before printing, after that we found no problems with chipping. In all fairness we generally diamond plain the blocks rather then router but it might be worth a try.

The adhesion promoter is ZE680 by fujifilm.
 

artbot

New Member
I suggest pre-cutting the parts as well.

But that procedure has certain issues like possible over spray on the edge, cleaning the parts so they are flatbed ready, a lot of labor if there are many parts plus registration issues.

Before going this way, you may want to do a few tests with different points in the cure/post cure. Router bits prefer good adhesion and a bit of stretch to the ink during cutting. If the
pieces are sitting around a long time before routing the ink may become more brittle and chip vs cut cleanly. you wouldn't even need to use the router for testing this. ...print a piece of
pvc, then push pieces through a table saw from "just printed" to 5, 10, 15, 60, 120 minutes, a day later. you may see a change in ink chipping becoming gradually better or worse as the time progresses.
 

tjwilton

New Member
I agree with earlier post. If the image is upward facing on your CNC you need to cut with a downward spiral bit. Works for us - Vutek QS print and AXYZ CNC.
 

DSC

New Member
Thank you!

Thank for all the input MUCH appreciated

here are some responses


"I suggest pre-cutting the parts as well.

But that procedure has certain issues like possible over spray on the edge, cleaning the parts so they are flatbed ready, a lot of labor if there are many parts plus registration issues. "

Over spray and registration set up time more than issues are what I am trying to avoid to be better/more competitive with our pricing.. The point really is to print, then cut.. But Thank you! Seems we are on the same page..

"If the image is upward facing on your CNC you need to cut with a downward spiral bit. Works for us - Vutek QS print and AXYZ CNC."

actually not sure if our production person has tried this, I will connect with him and see.. Thank you!!!

"You might try increasing the RPMs as well."

Done, but not with the downward spiral as far as I know .. Great suggestion for the next step..

Thanks to all!



 

artbot

New Member
one thing i forgot to mention. delamination at the edge during cut can have a lot to do with heat. the ink's bond is weaker when the ink is hot. blade sharpness and dwell time as well as bit cooling may be part of your
solution.


so if you aren't running a proper bit (a proper plastic bit that costs $$$) you will get a hot edge that weakens the ink's bond.
 

DougWestwood

New Member
OCE / FUJI guy here

Hi There,

I have run several OCE and FUJI UV flatbeds. The ink type can help you here.
I think it is the K1 inks which are more "rubbery" and flexible. Would help stay put when cutting.
I have tested this ink by printing on coroplast, then putting a sample cut in the freezer for three days.
Took it out, and FOLDED it twice. No cracks or flakes. Nice.

Also, there is an adhesion promoter liquid available. You wipe it on, let it dry a few minutes, then print.
It might change the color of your print (slightly yellower) and it smells up the whole shop, but it works.
It helps the ink "melt" into the material.

Good Luck!
- Doug
Vancouver
 

Andy D

Active Member
one thing i forgot to mention. delamination at the edge during cut can have a lot to do with heat. the ink's bond is weaker when the ink is hot. blade sharpness and dwell time as well as bit cooling may be part of your
solution.
so if you aren't running a proper bit (a proper plastic bit that costs $$$) you will get a hot edge that weakens the ink's bond.

Good point. I wonder if doing the cut in multiple passes, and having the first pass "score" the surface at around 1/16" deep & at a fast cut rate
would eliminate the chipping. We used to have a lot of chipping issues in other type of applications, like cutting coroplast or shearing aluminum & composite aluminium,
we finally had to change our ink to a more flexible type.. If nothing else works, this may be your only option.
 

Andy D

Active Member
Also, when we were having chipping issues with the old ink, it was always
with darker colors where the printer put a lot more ink down, adjusting the lamps
did help, and in worst case scenarios, I would print at 50% density and then print again at
50%.. one more option is to mount optically clear vinyl to the acrylic and print to that, our ink adhered much better
to vinyl than substrates...
 

Jester1167

Premium Subscriber
We used to rout a lot of PVC and had problems with the top edge being fuzzy with and Onsurd upcut single flutted bit. We solved the problem by masking the PVC before we routed it. Masking it may help in you situation as well.
 

rossmosh

New Member
We used to rout a lot of PVC and had problems with the top edge being fuzzy with and Onsurd upcut single flutted bit. We solved the problem by masking the PVC before we routed it. Masking it may help in you situation as well.

Fuzzy tops of PVC is down to your bits not being very sharp. You can cut a lot of PVC with pretty sharp bits but the top edge will fuzz up. This problem shows up way more on interior grade stuff. Exterior grade PVC doesn't fuzz the same way.

Instead of masking, look into buying less expensive bits and swap them out more regularly. You can get good o-flute bits for $15 which is about half what Onsrud's bits go for.
 

Jester1167

Premium Subscriber
When your cutting a whole 6mm sheet of 3" characters, it doesn't matter how new your bit is. eventually they start fuzzing. Faster and cheaper to mask it than a couple of bit changes.
 
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