Cutting 1" polylam (polyethylene) foam

[Richard Rumancik]

Does anybody have any suggestions as to cutting 1" thick polylam foam (used for packing electronics in shipping)? I have tried various focus positions and cutting strategies (eg cut twice) but am not pleased with the results so far. Any ideas would be appreciated.

[Joe Pelonio]

Regardless of your power cutting a foam 1" thick is not likely to have great results, it's not very dense so set to cut all the way through tends to melt the top part. One suggestion is two or more passes at a low frequency.

[Richard Rumancik]

You are correct, Joe. The best I was able to do is to get 98% through but there are still some "strings" holding the dropouts and parts together. I have to finish them off with a utility knife or X-acto knife. To laser those last few strings would not be cost effective time-wise.

I am feeding long 6.5" wide strips into the laser. Index to stop, cut 2 parts, cutoff, remove parts, and repeat.

I experimented with double pass but the problem is that the material wants to close up after the first pass as the stresses relax etc and the gap closes up. Not always, but enough to make it two passes unpredicable.

But I have a question for you. You suggest "low frequency". Does your machine allow you to set the frequency at all cutting speeds? The Mercury as I understand it goes into "continuous" mode when you set a speed below 3%. So it will accept the ppi setting but ignore it (if I am understanding this correctly.) I was wondering if other lasers do something similar.

[Joe Pelonio]

Yes, on my Epilog the power, speed and frequency are independent controls.
Running slow with low power and low freq on some materials perforates it like a tear-off. With plastics lower freq helps reduce the melting. With acrylic it's the opposite, high freq makes it nice and glossy and smooth.

Did you try refocusing after the first pass, to about 1/2" lower?

[Mike Null]

What about using 1/2" material and laminating it?

[Pete Simmons]

You may not want to do it this way but,


Freeze it and cut it with a knife. Once frozen it cuts clean and easily.

[Robert Murray]

Have you tried different lens. Not that I have one myself but I would think with foam a 4" lens might help. Anyone with more experience have thought on a differ lens?

[Peck Sidara]

Richard,

I've cut 2" thick electronic packaging foam so I know it's doable. The application was submitted from a firm that packages custom electronics for meetings/shows etc. Testing was completed on a Legend 36EXT 120W.

speed setting was 10-23% depending on the foam density.
Power was 100%
Frequency was 1K
a 4" cone lens was used with air-assist.

The 4" cone lens with air-assist is the key factor, it's not likely you have the same set-up but if you could get a longer focal length lens and blow lots of air over the foam, it'll probably work.

GL

[Leonard Clark]

Go into your kitchen at get the eletric knife. I cut alsorts of foam with mine. But then again I redid the foam in my chairs.

[Warren Eames]

Richard,

I've cut 2" thick electronic packaging foam so I know it's doable. The application was submitted from a firm that packages custom electronics for meetings/shows etc. Testing was completed on a Legend 36EXT 120W.

speed setting was 10-23% depending on the foam density.
Power was 100%
Frequency was 1K
a 4" cone lens was used with air-assist.

The 4" cone lens with air-assist is the key factor, it's not likely you have the same set-up but if you could get a longer focal length lens and blow lots of air over the foam, it'll probably work.

GL
Peck,
I am looking at a 120w-150w Laser. Could you tell me how your machine is with 120w power on Engraving ?
Regards
Warren

[Peck Sidara]

Warren,

Engraving quality on the Legend 36EXT will be the equivalent as the quality on our Mini/Helix systems, excellent. Would you have expected a different answer?

If you'd like to discuss certain applications, have specific questions or would like to have something processed thru our applications lab on the EXT, feel free to contact me at 888.437.4564 ext 236 or pecks at epiloglaser dot com.