paulororke
New member
Well I could just possibly be the world's worse pilot, there are regualry many pieces of foam to pick up at the park... so this is proving a tonne of fun as I crank out replacement air frames.
I have had this pic for years, who knows where I picked it up at.
[PIC]
Is the laser vented to the outside or internally (I assume with a filter box)?
If internal, it might not be about toxicity as much as smell.
Smoke (from wood/paper) will be mostly particulates where as acrylic and polystyrene (foamboard) will stink if they don't have carbon filters.
Here's a pretty good link (quick google search) again, NOT hazardous gases, but a risk of fire...
http://www.atxhackerspace.org/wiki/Laser_Cutter_Materials
And yes, I HAVE had FB torch on my laser... (mostly in complex curves... inkscape creates Many (sometimes thousands) of lines to represent a b-spline curve...) if I don't catch those sometimes the laser slows WAY down in those corners and starts a burn.
Do they have an airpump to force air out the nozzle?
Well yes im not saying it is impossible or dangerous, the makerspace is saying they dont allow it (with their cutter). im looking for experience and possibly proof i can useOr more probably they use a polystyrene compatible cutter with adequate vent/filtering.
That looks like a pretty amazing bit of kit! Mine is a chepo Chinese laser...
I guess what I was saying is I've never seen it on a list of Don't cut for fumes reason. And I concede there is a fire risk (but there is with most things you laser cut... Just the nature of the beast.) I was trying to say I have torched a sheet or two of foamboard in my time.
One thing you might try is just working with them, acknowledge the risk and ask their lead laser guy to help you dial in the power levels. You said it was 100 Watt?... It might be hard to get that laser tube to fire and JUST mark the foamboard... I run mine pretty close to the bottom end when marking.
Also, Set the values low enough so it takes two passes to cut through. First reason is you will see less undercutting of the foam and second it should reduce the fire risk quite a bit.
I think if the guys see how it cuts foamboard (and you show genuine respect for the equipment) they might relax a bit.
I might sound like cpt obvious, but check the 2nd thread of this subforum if you haven’t alreadyI'm thinking of replacing my laser with a spin saw, which is basically a tiny router. Not because of the fumes, just the time it takes me to cut anything out. I realized my cheapo Chinese laser gives me a good basis to start, its software, basic as it is can handle 3 axis control and I'm thinking I can make something with a brushless RC motor to give me fester less "smelly" cuts. it would also mean i can use the water proof papered foam from here.
I second that! Do you have a 3D printer to make the parts for a mpcnc?I might sound like cpt obvious, but check the 2nd thread of this subforum if you haven’t already
Try running two passes, works pretty good here (you'll always get some undercutting, just the nature of the beast.)I do get a bit more cutback then I wan
I use three passes and the undercut is just enough to make a good glue pocket.Try running two passes, works pretty good here (you'll always get some undercutting, just the nature of the beast.)
I have a cheap Chinese 15W visible light engraver/cutter and while it won't cut the white foam board with the water proof brown paper from Flight Test (sadness) I found it does cut black board from Staples.
It's not fast, and trial and error and more than a few fires later I find that 2 passes at 150mm/min will cut the paper then U must speed it up to >200mm/min on the foam itself to avoid melting. 3 to 5 passes gets through the black foam to the second lower sheet of paper then it gets problematic. If I run slower than 200mm/min I risk getting large melted areas but even though it cuts the top sheet at that speed the bottom sheet seems more resistant. maybe because of the residual melted foam being a bit too reflective. I'm not sure. I'm still experimenting. Maybe again because of the melted foam on the bottom sheet even cutting it out with an Olfa blade seems to rip the paper and result in a messy finish. The top looks great though.
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I tweak the downloaded PDF files using the PDF-XChange Editor and use InkScape with the JTech Photonics free plugin.
I second that! Do you have a 3D printer to make the parts for a mpcnc?
The problem with the router idea is first you aren’t going to get clean cuts. Second the z height is going to be tricky (for 50% cuts for example.
The needle cutter is really the way to go!!
(If your driving your current setup with a ramps board, that should be fine for the mpcnc. )
I like the needle cutter but not the constant needle failures that I read so much of. The laser will have it's own issues but would most likely cut black foam board without an issue.
To be fair...I probably had more needle failures than everyone else combined with my first needle cutter. But with my latest design (the one you printed based on your post in the needle thread) I've only had a two failures in over a year. The first wasn't really even a failure - the needle just came off the bearing while trying to cut cardboard and push the limits. The other failure was an actual failure and came after cutting probably close to 2 or 3 cases of foam over a year....and probably could have been avoided if I had listened to my intuition and sharpened the needle since I noticed it was getting dull.
The big key was getting a tach and dialing in my needle speed. Before I had been trying to calculate the speed based on voltage and motor kv - but that only works if you're going 100% full throttle since ESC's aren't always linear in their throttle response. So I was running almost twice as fast as I thought I was - once I slowed the needle down my failures all but went away.