Cutting PETG - Laser pulse settings

[Parry Palmer]

Been trying to cut some 1mm PETG skins for electric car chargers for one of my customers, but the edge either melts (if too much power is applied), or cuts with a pulsing effect (if sped up).
I have gone through the whole manual again (I did last year when it was released), but cannot remember and find how to increase the frequency of the laser pulse (ie. shorter spacing between each pulse).
The settings are perfect for everything else (so ideally I would only like to change them for a specified job) but, reading on a plastics forum I have found that increasing laser pulse frequency should help.

Thank you in advance,


Parry

[Pete Cyr]

I don’t believe you can adjust the pulse freq with a glass tube co2 laser. Physically you can by going into the vendor setting, but l think 20k the freq it orates and is not variable.

[Mike Tuppen]

There is a dot mode selectable. dot length, dot time, dot power are selectable in rdworks. This is not the laser frequency.

If you set the dot length to less than 0.1 mm (the usual kerf width of a cut) and adjust the power and pulse time you may be able to get a cut.
I have not tried this!

[sebastien laforet]

dot mode is very useful for tricky cuts, especially when applying too much power is a problem.

setting a very short "pulse/skip" interval in dot mode allows to effectively reduce burning and charring. i have successfully cut leather when the lowest power that would effectively cut was also burning the edge. using more power and dot mode was ok.

it has to be tested on PETG, but i believe it can reduce melting.

[Gene Uselman]

I cut a lot of PETG for painting stencils [think Real Fire flames on autos] and .060 and .125 styrene for paint stencils and always get a burr on the bottom surface which I remove with a card scraper easily. I always cut at full military power and as much speed as is possible.

[Parry Palmer]

Well, job done and pretty happy with the results. I have tried several settings, using both cut and dot mode.
Finally settled for 2 passes at 75% power (15mA on my 60 tube) and as fast as possible. The first pass cut almost through but second pass polished the edge quite nicely. I also used a card scraper, as Gene suggested, to remove any burr. Leaving the protective plastic during processing also helped in avoid cleaning any yellowing residue.

PETG.jpg

PETG with print.jpg

[Doug Fisher]

Looks nice. Do you print directly on the PETG or print to an adhesive and then apply that to the PETG?

[Parry Palmer]

Looks nice. Do you print directly on the PETG or print to an adhesive and then apply that to the PETG?

Vinyl with matte laminate. In the sample above there is a bit of silvering due to cold laminating, but in the production run I will use a heat assisted laminator

[Gene Uselman]

Good job- we have pvc free vinyl and laminate but I have not seen matte pvc free lam.