Cutting thicker items......

[donald bugansky]

Fellow Creeker's...Happy Holidays to all.

Relative to cutting 1/2 inch mdf (but my question would apply to hardwood and acrylic as well). Is there a special technique to cutting thinker items?

My mother-in-law wants me to cut the word "Believe" out of 1/2 inch mdf so she can glitter them for Christmas.

Naturally I said, "I've got a new laser...no problem". When I attempt to cut at 100% power (thinking I'll need the power to cut through), it cuts partially through but burns like crazy. I assumed 75w could cut 1/2 inch??????

Do you use less power, cut through part way and then after multiple passes it's done? If so, do I adjust the focus after a few passes since the area being cut is in a sense "out of focus" since it's farther from the lens?

I've tried a number of things and I seem to end up with charcoal.

Thanks for any assistance.

[Martin Boekers]

I'm not sure about Trotec Lasers, but with my Epilog If I cut the frequency down it really cuts the charring down.

You might give that a shot.


Marty

[Steve Clarkson]

Definitely lower the frequency (you didn't give us your speed or freq) and also try mirroring the image in Corel and then flipping the piece over to cut from the back.

[Dan Hintz]

You're going to find 1/2" wood challenging...

[James Stokes]

With 75 watts you should be able to cut 1/2 mdf. I have a 100 watt that has lost a lot of power and still cut it. I use a speed of 15 100 power. I generally do not change frequency. There are differant qualitys of mdf. The larger the chip the easier to cut.

[Frank Corker]

It should be able to cut it but the frequency or pulses per inch (ppi) is the a big factor in the burning you are getting. On an epilog to cut acrylic the frequency (ppi) is 5000 but on wood 500. Big difference. Try cutting the wood at 5000 and you will end up with a burning log.

You need to have air assist on, this will reduce your charring, two or three passes at a reduced power instead of trying to hit it with the full 100% might also stop/reduce it. Don't be afraid to alter the ppi taking it lower than what you have it now and using the epilog as a guidance will give you a percentage reduction idea.

[Sergio Arze]

Fellow Creeker's...Happy Holidays to all.

Relative to cutting 1/2 inch mdf (but my question would apply to hardwood and acrylic as well). Is there a special technique to cutting thinker items?

My mother-in-law wants me to cut the word "Believe" out of 1/2 inch mdf so she can glitter them for Christmas.

Naturally I said, "I've got a new laser...no problem". When I attempt to cut at 100% power (thinking I'll need the power to cut through), it cuts partially through but burns like crazy. I assumed 75w could cut 1/2 inch??????

Do you use less power, cut through part way and then after multiple passes it's done? If so, do I adjust the focus after a few passes since the area being cut is in a sense "out of focus" since it's farther from the lens?

I've tried a number of things and I seem to end up with charcoal.

Thanks for any assistance.

what is your air psi?, if you are using a small air compressor it may be difficult to cut in one pass. We use 45PSI on our 70watt to cut trough 1/2 MDF .

[Joe Pelonio]

I did a fairly big job for a cutomer asking for 1/2" MDF. I just cut a double set with 1/4" and glued them together. If you do one face up and the other in mirror, the edges meet to give a tight fit and the angle of the cut edge is barely noticeable.

[James Jaragosky]

This looks like another laser head fell into "If the only tool that you have is a hammer, Everything looks like a nail" syndrome.
This might be better done with a cnc router.

Regards
Jim J.

[donald bugansky]

Thanks for the input. I'll try your suggestions tomorrow evening.

Regards - Bugs

[Rob Bosworth]

Don, try moving the focus point about 1/3 of the way into your material. That will help, because it will actually give you a thinner kerf.

Lower your PPI (pulse per inch for the linear movement of your machine). The lower PPI allows the laser pulse to have a much higher peak pulse at the beginning of the pulse, then drop off towards the end of the pulse. This will "allow" the cut area to cool between pulses. (Don't worry, we are talking a very high frequency rate, so you should not get just a series of holes in your material, if your PPI is set correctly.)

A fairly good flow of assist air also should reduce the charring of the MDF.

Good luck.

Oh yea, don't forget to ask your sales rep for advice.

[donald bugansky]

Thanks Rob,

I'll give it a try this evening.

Hope all is well.