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Messages - RobOlsen3

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Cutting / Re: Cutting foam board
« on: October 01, 2018, 02:53:45 PM »
Yes, pink Foamular styrofoam from HD, both 3/4" and 1".

Perhaps my standards for acceptable cuts are less exacting? 

Let's see here - looks like this file has a lot of F800 in it, probably cutting feed rate, and some F2000 which I imagine is rapid movement feed rate.I also appear to have baked 10 passes in, but I don't think it needed that many.

Looks like 6-8 passes at 800mm/min should do it.  I've cut with the peel-off "skin" in place and removed, doesn't seem to care.  Passes through, doesn't seem to stop the cut.

I set the laser focus to be fairly far from the lens, for a shallower angle and greater depth of field - this keeps the beam narrow over a longer cut depth. I then set the focus for about halfway through the material; setting the focus on top means it is pretty diffuse by the time it gets to the bottom of the cut.  I am not adjusting work height or focus distance between passes.  I think air assist is critical here, the combustion gasses from the cutting process expand within the kerf but the foam is so low-mass that the gasses eat into the edges of the cut, hence the scalloping.  So strong airflow really helps here, I think.

I have some videos somewhere. I should post some closeups of the fingerjointing so you can see the edge quality.

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Cutting / Re: Cutting foam board
« on: October 01, 2018, 09:37:15 AM »
I cut the pink styrofoam from Home Depot (outdoors - fumes) to throw together quick cheap boxes and speaker enclosures with NO sawdust. I need several passes at high speed to get a relatively clean cut; the hot combustion gases tend to further erode and scallop the cut edges.  I use Fusion360 to make the cut patterns, including tab-and-slot features to interlock the panels, and generate the gcode. Assembly uses either Glidden Gripper primer or expanding polyurethane foam (Great Stuff) as adhesive; the Gripper is neater but takes forever to cure, the Great Stuff cures quicker but gets EVERYWHERE.  I usually clamp with either packing tape or cling wrap film. Gorilla Glue would probably work really well, too.

I also cut foam core with my 2.5W; I bought a 10 pack of Elmer's 20" x 30" black on black from Amazon, but I've seen B on B at Michael's around here when I was picking up slate coasters.  I also bought a large piece of black-on-black at Office Depot or Staples or some such, and it all cuts really easily.  Nothing with white inner foam cuts worth a <bad word>.

3/4" pink styro tabbed and glued like this is unexpectedly strong, especially for the weight.
--Rob

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