LaserUser.com Forum (formerly RDWorksLab)

Hi there,

I'm going mental on cutting a B/BB 9mm birch plywood to make some big round key chains.

I have cleaned all mirrors and lens, have realigned all of them and have tried with 50.8mm and 101.6mm lenses all the way to 70% (which equals 24mA) using a RECI W4. I specifically bought this tube to not run into this problem but I guess I was just being naive...

At the end managed to cut through at max power with the 101.6mm lens and about 6mm/sec doing it with two passes. Obviously it was pure charcoal the result...



Any suggestion would be much appreciated!

Thank you very much in advance

The only advice I have is to verify your focal distance for the lens you use.
Your system should be able to cut that material with a 50.8 or the 101.6mm lens.

If your tube is older than 5 years it may be time to replace the tube.

Hi Pete,

Thank you for your reply. I have done a focal distance test on both lenses with the ramp test.

The tube has less than half a year and I've been very cautious on not over run it, that's why I can't understand what's going on...

I'll keep testing however I'm running out of ideas...

Cheers

Where is your focal point? On the surface, or are you adjusting so the focal point is 1/2 way through the thickness of the material?

What about your air assist? Is it blowing at full strength? If it's just the stock air pump, you might consider the "ultimate air assist" upgrade.

I second the air assist- when cutting thru you cannot have too much air to clear out the cut debris. And I agree you should be able to cut this fairly easily- if your beam alignment is good- also the beam centered in the nozzle. If all else fails you could try a GaAs 2.5 lens- they cut like crazy.

Your laser is a Shenhui- I bought a similar machine for my daughter and granddaughter and I have been very happy with it.

Do you have issues cutting any other materials of that thickness? For example, can you cut solid wood (instead of plywood)? Sometimes the glue in plywood is very resistant to the laser.

Thanks a lot for all the replies.

I've got the ultimate air assist and used it with a lot of pressure, I will try with less pressure just in case.

I've also tried to put the focal point at the middle of the thickness but doesn't help.

I've also aligned all the mirrors and the 3rd mirror goes dead center. I wonder if the nozzle hole is perhaps not big enough (a standard 2mm or 2.5mm, can't remember)

Unfortunately I haven't tried any other material this thickness yet.
I'll look into the GaAs 2.5 lenses, thanks!