I don't know where, or who, but you could have it punched out. It would not fray the edges if the die were made to very tight tolerances, and it would be fast once the die was made such that you could have quite a few punched out and possibly make a few bucks. :wink: :wink: :yes:

:yes:Yes, that's an idea I could look into... I do know a few print houses that employ die makers. I'll get on the phone tomorrow.

Thanks Man.

Alien

:surprised: Hey, no problem!

DO NOT USE A WATERJET!!!!

I actually posted a thread some time back with sample pics of very clean cuts on CF by a waterjet. I have completely changed my opinion. I got lots of delaminating at the corners when they actually cut my chassis, and am out nearly $100 in material.

I don't have any experience with laser on CF, but it seems to me I remember reading that it doesn't work well. At least do a trial cut, and be prepared that it may do worse on the final cut than the sample.

I have quite a few years in amateur CF, including laying-up custom bent pieces. The BEST way to cut it accurately on a budget is to use a router table. Yes, a woodworking router table. Get a fiberglass router bit (available from online tool stores if not local) and cut away with your fence guides. Be sure to be wearing a mask and have the vacuum running! If you are having internal cut-outs (as your drawing shows), you can make yourself a pattern first from wood. Mount a pin the same diameter as your bit immediately above your bit in a v-notched piece of wood secured by clamps or the like to the table, and drill a pilot hole in the CF, and run the pattern using the pin against the wood as a guide. This will work just as well as a pattern-cutting router bit (which for some reason aren't available in the fiberglass variety) does on wood.

Otherwise, full cnc is the way to go.

Here's the earlier thread I mentioned: http://www.rc-monster.com/forum/showthread.php?t=17697

I also use a router-table & router, drill-press with 3-axis milling vice, my trusty Dremel, some stationary grinders & sanders, and a couple files...you can get very professional results if you take your time.

I am buying a CNC Masters CNC Jr. ($5,000), or maybe the CNC Baron ($7,500), so that I can start manufacturing custom Carbon-Fiber, ALuminum, Titanium, Delrin, & Nylon parts for RC, 1:1 vehicles, and other things as well...I can't wait to get started!

Wow, I'm learning every day... To be honest a friend who I fly models with, told me something similar before (he's a mechanical engineer). He said because of the velocity and force of the water jet, it may be possible to delaminate the carbon.

The router option sounds like another cool idea. Do you have any photos of your setup? I am still hopeful one of the CNC owners will accommodate me and help out with the cut.

Alien

Did the place that cut your chassis use just water or did they use any abrasive material? Here is a video that shows a nice piece of CF being cut using a water jet: http://www.youtube.com/watch?v=zI4QnWOwAys.

I do agree that cnc is the way to go.

An option for you - use the laser but with a 3mm gap around the whole chassis and then sand in the rest.

For the holes just burn a tiny guide hole and then drill it out...

:yes:Yep, CNC is looking like the 'easier' way to get this done right. I also like the router option too... I really want to get this chassis done... It's my first real 'design'.

An idea, but the heat made the fibers/epoxy flash area so big (even with a mask), the frayed fibers were longer than 5mm.:whip:

Yes they used an abrasive slurry. It would be better without on the CF, but it is rare to find a shop that will jet a piece anymore without the slurry.

I don't have any pics since I haven't had it set up for the last couple years. If you're really brave (and steady handed) you can just use the fiberglass router bit in a router or even Dremel freehand.

Cool... I'll make an attempt with a small part first when I get some time.


Alien

I understand Laser/CNC are the options being discussed but I can add a little to water cutting problems

Watercutting CF will work BUT and it's a big but...delamination will occur at the point of entry (first cut) & can be up to a diameter of 20-30mm - no good for holes! and the operator should have a map & enough material to cut into the final shape from 30mm plus of the final cut

Watercutting CF can be improved by sandwiching the CF between alloy plate, this may be advantageous if you want alloy bits the same?? adds some cost though

CNC is best but destroys most tools & again the operator needs a good understanding of CF to get the best outcome

Wow, 4.3 mm carbon, are you sure you need that? Quasi-isotropic carbon has about the same stiffness as aluminium, with 40% weight reduction. I would use 2 mm or 3 mm carbon and make less cut-outs. Of course you need some for servos etc., but the others don't do much for weight saving and might hurt stiffness a lot (if you haven't done FEM on them).

Laser cutting of carbon: Yes, it does work, but you need the right machine and the right settings. Of course it doesn't work with a 120 W engraving laser, you want something in the kW range to evaporate the material instead of slowly melting it. A big problem might be emissions, which can pollute the mirrors (which results in overheating) or contaminate the environment.

Water jet cutting of carbon: Yes, it does work. We have cut 10 mm solid carbon and 5 mm sandwich consisting of 3 mm wood core and 1 mm carbon coverings. Last year, the parts were done in wet lay-up and showed minor delamination after cutting. This year, prepreg material was used with autoclave curing and the cuts are very neat.

Machining of carbon: Yes, it does work, and again, you need the right tools and settings. Carbide tools are not suitable for this, as they're very brittle. The best tools for carbon are CBN, but expensive as well. Steel tools are not suitable because carbon diffuses into the tool, changing the chemical composition.
For drilling holes, HSS tools don't last long, but are cheap. HSCO works last longer, but are more expensive.
For straight cuts, a diamond equipped circular saw is working well.

If you get a lot of fraying, I'd say you're not using the right machine or settings.

For any RC project with small quantities and a budget, I would recommend using a dremel with the cheap cutting blades and some cylindrical sandpaper grinders.

That's all off the top of my head, but it should be correct.

Regards,
Thomas