When I was looking at cutting CF, My plan was to grab a high-sided cookie sheet just big enough for the CF to fit in and fill it with water. What I never figured out was an easy way to stick the CF to the cookie sheet. I was afraid double-sided mounting tape would come loose in the water.
I never ordered the materials to give it a try. I still have a dozen other projects I need to finish before I start a new one.
I’ve broken a fair share of motors aswell. Bent the shafts, bells, messed up the bearings, etc. I just meant as far as carbon goes I haven’t damaged too much. I mean it’s pretty impressive that a material like CF, can outlive metals like aluminum sometimes in crashes.
Cookie sheet is a decent idea, would just need a new one so it wouldn’t be bent up or anything to stay square to the endmill. I was thinking of having some kind of mounting like with bosses or something that have a washer and a screw on each corner to hold it in place, and I shouldn’t need any spoil material assuming I go nice and smoothly on a Z plunge. The only thing then is I am limited to a certain CF sheet size. I haven’t figured out how I would move the clamps around. Magnets maybe, but I don’t think they would be strong enough, even neodymium.
I gave it a bit of a go a little while ago, using a deep cooking tray that was a few dollars at walmart. I held it down with some printed hooks screwed into the spoilboard and put drawer mat stuff to act as the spoilboard. Tried using a crap ton of neodymium magnets to hold a sheet down, but it would shift eventually. It flung a spray of water all over the place, misting the whole machine and worse. I ended up just putting a ring of packing tape around the end of the spindle with enough clearance to not drag on the part significantly when it went through the material. It was cutting nicely (1/8" PCD carbide burr) and I’d like to revisit it at some point when I bother to work a better hold down method out. Are there any double sided tapes that would stick well enough if you bonded the board to your spoilboard dry, then had an easily operable hold down system to clamp down a specific size spoilboard? Then you’d have to find something cheap but waterproof and easy to cut. Maybe corrugated plastic?
Woodworkers often use “carpet tape”. It is very strong and it comes off in boogers like rubber cement. It is strong enough to do pattern routing. You might also try spray adhesive. I saw Jimmy Diresta use it in one of his videos on his cnc for MDF. I tried spray once, and I must not have the right stuff because it made a big mess.
All the aluminum cutting I’ve done recently has been with the painter’s tape and superglue method. Tape your part and the spoilboard, then glue the two pieces of tape together. Glue kicker helps. Once you’re done the parts come off with a paint scraper fairly well. Then the tape just peels right off. I think if you use a dust shoe with a hepa filter on a shop vac you’d probably be alright for dust.
Do you have a picture of what you’re talking about with the painters’ tape and glue? I sort of get what you’re saying but not completely. Somebody else also told me double sided tape was popular but I’m surprised it holds aluminum well enough. You must be making pretty shallow cuts at a slow speed, right?
On the carbon fiber note, I actually cut some last weekend. Attempted to cut some rather. I ended up building a water bed that screwed into the holes I cut into my spoilboard using aluminum angle and galvanized sheet metal. The sheet metal was the size of the square of my workable cutting area, then on top of that sat the angle (facing inwards so that I could screw it down from the outside) then I had 3 or so holes on each of the 4 sides to hold it down then 1 hole in the middle I sealed with a rubber washer. I then siliconed the edges to try and seal it. I 3D printed some spacers with a slot for a magnet to fit in, so I pressed that in place to offset my CF sheet from the bottom so I didn’t cut through. To hold it in place, I made some clamps (I wish I had a picture but I don’t) with a 3D printed part and some M8 screws with nuts I epoxied onto the side of the angle after drilling holes for them, then sealed those. It seemed like a good idea, since I saw a video of somebody cutting CF in a bath with hardly any support whatsoever with no problem.
What ended up happening though was that 1 - With 2mm thick CF, it must’ve been flexing downwards too much when cutting because I had to go back and rerun the program to get it to cut completely through, multiple times. 2 - The clamps must not have been good enough because not only did it somehow crash once (and rip the bit out of my router instead of breaking it. Surely I can’t be the only one who has this happen with the DeWalt 660?) but the tolerances were also terrible. Holes were way small, slots looked like they weren’t parallel to the OD of the part, etc. 3 - The seals only held up for so long. As I was cutting some small parts started to break loose. I doubt it had anything to do with the carbon and it was more of my own incompetence, but it was still frustrating.
Needless to say, the next thing that I’m going to try is lightly misting the parts as they cut so the dust isn’t necessarily dust and it clumps up so it can be vacuumed up. But first I’m switching from parallel wiring to series, then making a riser so I can cut higher up closer to the gantry to get maximum performance before I do any more upgrades. I knew that with parallel wiring my drivers were getting hot (I measured them at 150F once day) but didn’t think it was too big of a deal. When I rewired it in series yesterday, the pins to the board were melted. Sooo now I’m printing an enclosure and wiring a 5v fan to hopefully cool down the drivers…
Not everything is bad though. When it was cutting in the bed, it only splashed on rapids as the tool was near the top of the water. The deeper you have the water, the less splashing you get in my experience. Also no dust was nice. The carbon-water wasn’t clean by any means but was still better than having ANY kind of dust floating around, carbon or wood.
This is where I got the idea.
Aluminum on my mpcnc 1mm depth of cut 15mm/s x/y 10% trochoidal length 50%width .05mm oscillation
5v fan? Don’t drive it from the Ramps 5V pins, you will overload your arduino. best to use a 12v fan from the power supply power rails.
I’m using a CNC shield/grbl shield, does the same apply? If so I’ll sacrifice an old USB cord. My workbench has 2 USB outs so I can power it from there if need be. Don’t think I have any 12v fans from old computers laying around 
I’m not sure I haven’t used that arduino. Better safe than sorry.
I actually ended up having a 12v fan, I hooked it up though and I figured it wasn’t worth it. Drew 300mAh (not that it’s a big deal but still) and I couldn’t feel any difference between it (140mm) and a 40mm 5v fan so I just wired the 5v one to a USB hookup, powers on when I power on the strip to my machine and DW660.
Was also rewiring to series, completed that, and since I was having bad luck with aluminum as well I decided to make myself some kind of spacer out of a wooden plate from Lowe’s. I’m sure it being soft wood compared to the MDF I surfaced before, it surfaced like butter. 1/4" 4 flute endmill (since I’m too impatient to wait for a proper surfacing tool :P) and it was taking between 2-3.5mm off in one DoC at the low-high points, 1200mm/min. Once it got to the high point it BARELY started to sound like it was putting some real work in, so I’m sure I could’ve got away with 1500mm/min no problem. The real star though is that having it wired in series vs parallel was a game changer on driver temps (also I’m sure the fan helped lol). Anyway, the heatsinks were only 2 degrees warmer than the ambient temp for something else in the garage. Very happy with that.
Hopefully the easy cutting trend continues
Tell me, did you ever get carbon fibre cutting working nicely?
Have you considered cutting the fabric before you heat it up? Are you using the laser MPCNC with a laser to cut material or just the 660?