Laser cutting foam board

[hamishn]

I'm looking for advice or experience with the laser cutting of foam board.

I am a school teacher running a after school activity to build the tiny trainer and have found that the younger kids find it very difficult to cut out the patterns from the foam board, so I wanted to get it laser cut to help speed up the build process.
I live in Dubai so we don't have the DTFB available here, I am not sure exactly how our board differs from the DTFB but it is not the same.

When the board is cut with the laser it causes the foam to melt/burn? and is recessed below the paper.

Does anybody have experience with laser cutting this type of foam and how did you get on.

Attached are a couple of photos so you can understand what I mean.

Thanks

 

[pccharlie]

i have no experience with laser cutters so i know nothing about them but i do know that this is caused by heat can you turn down the power output on the laser ?

 

[Spitfire222]

While I have not personally built one of the Flite Test Speed-Build Kits, I do know that they also feature small "scallops" in the edge due to the foam melting from the laser. In that sense, what you experienced is normal and expected. However, your pieces seems to have it even more pronounced, along with singed paper edges. I can only deduce that the laser or setting you used is too strong/high. You'll likely need to experiment with different laser power settings to find the lowest one that cuts the foam completely through. Good luck!

 

[rockyboy]

I've had the same challenge using DTFB on a laser cutter here in the states. Turning the power down till it just barely cut through the bottom paper layer helped a little bit, but the slight melting effect will still be there. However, the FliteTest kits have the same effect, so I haven't worried about it too much.

For anything where I do want a really square edge, I cut the power back to just make it about half way through the foam with the laser and finish the cut by hand.

 

[hamishn]

Thanks for the suggestions I think you are right, the laser power is to high causing the melting.
The cutting is being done by a company that makes advertising signage and i think their experience with foam board is limited.
Will try with the laser power turned down and see how we go, if some hand finishing is required shouldn't be a problem.

 

[AkimboGlueGuns]

I'm not sure if this is a possibility for you, but have you tried cutting the water proof board? The white paper reflects a lot of light and requires a higher power setting to cut (hence the under cut edges) but the brown paper absorbs heat and can be cut at a much lower temperature which reduces under cuts.

 

[Mostly Harmless]

The white paper reflects a lot of light ....

This is true at visible wavelengths. However, at the wavelength that CO2 lasers operate (in the mid-IR range, or about 10.6 microns), pretty much every material (non-metallic) appears "black." White foamboard -- and even clear plexiglass are only appear that way in the visible spectrum our eyes detect. In the mid IR, they will absorb just as much of the laser's power as the darker foamboard.

 

[localfiend]

Another thing to try would be to increase the power of the laser and try to cut faster. If the place you're getting stuff cut at has the power, cuts might end up a lot cleaner with more power and higher feed rate.

 

[kevparang]

You need to experiment with the light intensity, the speed and the power. It really depends on the exact settings, the foam, and the machine. Try using different foams to figure out what fits your setting and needs.

 

[Maingear]

I'm looking for advice or experience with the laser cutting of foam board.



Thanks

Your laser appears to be cutting properly. Wrong material. That is exactly what Elmer's foam board does in all laser cutters. Try Adams foam board instead. I get exactly the same results with 60 watts as the FT Store when I use Adams foam board.

-just remember that over time the tube will dim and need to be replaced. They are pretty cheap.

Good luck!

Justin

 

[mungral]

i have had a bit success with cutting with low power (15%) but fast speed (100 mm/sec) and doing 2 passes.
(i have a 50 Watt c02 laser)

but it would be nice if someone from FliteTest who knows about their laser setup could comment.

 

[GremlinRC]

Hey Hamishn. I just wonder if you did it in two or three passes? Mybe one to cut just through the paper, then a really fast pass for the foam followed by cutting the bottom paper?

A question, how many watts to you need to cut foamboard? How many watts did you use cutting the piece shown in your pic? I have a cnc machine which I'd love to retrofit with a laser cutter, but I know very little about the power required.

 

[MotoPilot]

Dallas makerspace has a couple of laser cutters and has some published settings for the 100Watt laser. I'm trying to find the right settings for the 130watts unit. (unfortunately, both are overpowered for cutting foamcore)

The settings for the 100W laser are: Etch - 6% power; Score - 12% power; Cut - 25% power. All 1500mm/s feed rate. For even higher speed cutting: Etch - 16% @ 6000mm/s; Score - 40% @ 6000mm/s; Cut - 100% @ 3500mm/s.

For the 130W laser, settings are still being developed - but try: Etch - 5% @ 500mm/s, Score - 5% @ 300mm/s, Cut - 50% @ 200mm/s.

I'd also love to know what FliteTest uses on their laser cutters.