Need Help!- Problem with laser engraving

[sakismor]

Hello,
I have a laser Co2 from china and I use the lasercut 5.3 software. My big problem is that when I am engraving plexiglass(acrylic) it leaves me lines. I make much tests with different power,speed and step (from 0.1 to 0.02). But please check the photo the problem is the some.
I have the some problem with rubber check the second photo.

Please help me...I have to make an order.

[zax15uk]

You may be able to reduce the lines by de-focusing the laser slightly, and if necessary increasing power to compensate (to get the same depth).

The lines are normal, and would also be present with CNC machining. All you can do is minimize the effect.

Better results may be obtained by using a lighter multipass or you could use a flame polisher on the Plexi (although this takes some skill).

Zax.

[sakismor]

Thank you very much for your quick answer.
Anyone that is having an other idea?

[bpoulin]

For starters turn down your speed on #5, that was the cause of that problem. Also you didn't give us the power of your laser. Here are the settings I use for my 80w, in Lasercut 5.3 for 2mm acrylic. Engraving should stay the same, but cutting will change with different thicknesses.

Engrave:
Speed: 600
Power: 20
Scan Gap: 0.025

Cut:
Speed: 10
Power: 25

[sakismor]

Thank you very much. I will make a test tomorrow. You use the some settings and for rubbers?
And one more problem is that sometimes after plexi engraving when I cut it leaves a white powder that it sticks on the material. How can I clean it or a solution not to make it this when cuts?
Thank-you for your help...

[bpoulin]

For me that white powder brushes off, sometimes it needs a little coaxing with water. Or if you mean the etched surface looks white after you clean it, I use a little 220grit sand paper on the edges to make it match.

[sakismor]

Hello bpoulin,

I have to tell that my laser is 60w. I would like to know if you used "bidir" and about PWM frequency for engraving, I use 20000.
And do you have any experience with rubbers?

Thank you a lot.

[bpoulin]

Try your etching at speed 600 power 25, I did the math, with me doing it at 20 it's approx 15w and if you etch at 25 it will be 16w. That's a good place to start. And no I don't etch rubber so I can't help you there. I use bidir if I'm in a hurry, it burns in both directions of the pass, however it will slightly cut down on quality. Hardly noticeable in my opinion, and if you un-check bidir it takes twice as long to etch. and my pwm is also 20000, although I haven't played with the pwm setting to see how it effects the etch.

[Rodney Gold]

That perspex engraving is shockingly bad , I would check focus depth and tube alignment before you go further.

[sakismor]

Thank you very much for your help, bpoulin!!!

Hello Rodney Gold,

You are thinking that I have a problem and that why I have problem with acrylic engraving? I would check focus depth and tube alignment... Anything else that I have to check? Any other advice.

Thank you for your time.
Anastasios

[bpoulin]

Have you tried engraving again with the new settings? Also I don't know if you calibrated it or just trusted the red-dot from the factory, but I had to calibrate mine, it was WAY off.