Plastic Residue in engraving on Chinese laser

[Dan Ashlin]

So, I've had my Chinese laser from Legacy lasers for about 3 months now and everything is great. Aside from a few technical hiccups which are easily worked around, the laser performs at the same quality and consistency as my slowly dying trotec speedy 1. Except in the area of rowmark plastic. I cannot for the life of me get it to engrave without the debris making the engraving absolutely unacceptable. I've tried everything, new exhaust, multiple passes, you name it and still the engraving on black/white rowmark comes out debris filled and grey. There has to be a way to fix this. I know there are a ton of Chinese laser users here and some of you have to use rowmark, ipi or similar materials, its a HUGE part of our business. I've scoured these forums and the Chinese laser support forums to no avail and I'm about ready to throw in the towel and send the thing back. How do i fix this?

[George M. Perzel]

Hi Dan;
What kind of air assist system do you have? Does the air enter the laser head just below the lens or is it directed down at the work?
Best Regards,
George
Laserarts

[Rodne Gold]

I engrave that material a lot with my laser , check you are indeed using laserable material. Do you have coaxial air assist , ie it blows thru the same nozzle the laser fire outa? If so , we have found it to not work as well as an obliquely directed air flow via a dedicated nozzle does.

MOST importantly , buy a 10x loupe (camera shops, stamp shops etc) and inspect the engraving to see EXACTLY whats going on , for any laser owner , this is an indispensible tool to tune the machine , tune settings and to diagnose issues , you will be amazed at what you see.

Check you are running at 250-300+ dpi , check your speed and power settings are right - experiment with this and use the loupe to inspect , turn up air assist to a "strong blast" , check you backlash compensation to make sure forward and backward scan firing lines up. You can try scrubbing the plate after its engraved with a toothbrush and a mild abraisive household cleaner , or you could fill the engraving with white gilders wax.

[Uros Sovilj]

Hi

I had same problems with rowmark. I my case foult was on crap airassist that came with machine. After plugin new compressor problem was solved.

[Gary Hair]

Engrave it from the bottom up and your problems will likely go away.

[Brian Stezowski]

I had the same problem with my 60W from Legacy. It was a mixture of my settings and the air assist. I'm still using the compressor that came with it but I have since re-routed the air nozzle to point right at the surface of the material that is being lasered.

Not ideal, but it works. One of these days I'll pony up and get a better compressor, until then...

[John Noell]

As Gary said, bottom up is usually best and the Mr. Clean Magic Scubbers are very good at a quick clean up of embedded debris.

[Ernie Balch]

I have a new Rabbit Laser and while selecting materials I got a number of Rowmark and IPI materials to test from Johnson Plastics, Inspecting with a low power microscope I found that the IPI materials performed significantly better than Rowmark . The IPI Laser Tuff really looked great compared to all the other materials I tried. I am going to try the blow off modifications recommended above to improve the performance with Rowmark.

My best results are with 300 speed, single direction, 0.065 scan gap, and 15% power. Bi-directional looks ok at 300 speed but not as good at 600 speed. I see occasional dots under the microscope where the laser has fired in error on the trailing ends of engraving lines.

edit_____ I just modified my air blowoff to be at an angle rather than straight down and it makes a big difference! Now the Rowmark material looks fine as well. Apparently redeposition was causing the problem.

ernie

[Stephen Hooper]

Not restricted to Chinese machines, I had the same issue initially with my Epilog util I found the air assist was actually missing the point of cut. Fixed this and then no problem.