RunRyder - Mill Cutting Carbon Fiber

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CAD - Engineering - Technical > Mill Cutting Carbon Fiber

JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

I've cut one carbon sideframe out of my balsa/carbon layup. The cutting went fine, but the carbon weave started to fray along the edges. It was removable with a razor blade and a little bit of sanding.

I was running a 1/4" HSS tool bit about 4000 RPM, feeding at 4 IPM or so. Changing feed speed up to 250% in either direction didn't make much difference.

I'm looking at going to a diamond or carbide burr, or with any suggestions.

Thanks, John Cadwell

01-23-2004 Over year old.

JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

BTW, for carbon holddown to run the initial drill routine I used Super 77 sprayed onto the alumium mold outline, and stuck the carbon to it.

In the future I'm going to cover both sides of the carbon with some kind of clear tape or laminate, to keep from scratching the plate with swarf, then mount to the plate with Super 77. After I run the drill routine I run screws into the perimeter to hold the piece down for the routing steps.

Do you guys cutting regularly use a roughing pass for carbon ever?

Thanks, John Cadwell

01-23-2004 Over year old.

Raptorm@n
Senior Heliman
Location: Habo, Sweden

When I cut the carbonplates I let a local company to watercut it. Turned out real good.

Fredrik

01-23-2004 Over year old.

Ozzy Pilot
Senior Heliman
Location: Victoria, Australia

I have often wondered how laser cutting would work as like water jet cutting it is used to profile all types of material and there are plenty of local contractors around. I have found that if you can give them the CAD files then the service becomes quite affordable.

Must try some carbon and see if it can be done.

Member of Good Guy list (seller) Pg. 23. Turbines - Audile pleasuring

01-23-2004 Over year old.

HOMEPAGE

CK_
Senior Heliman
Location: Redondo Beach, CA

Use carbide cutters. HSS dulls too quickly. Even the carbide ones dull pretty quickly. Go here and search for "8181kac". You'll find a PDF that explains it all.

I mount a piece of particle board on the bed for sacrificial stock and use a hot glue gun to tack the laminate down on the edges. Works pretty well. Just make sure you control the dust somehow.

Chris

01-23-2004 Over year old.

Peefor
Veteran
Location: St Albans UK

I have just cut some 2mm carbon sheet. Used a 1.60mm dia cutter running at 24,000rpm feed rate of 1m/min.

Results were quite good, with no breaking out of the fibres.

Pete

01-24-2004 Over year old.

Wally
Veteran
Location: San Diego, CA

Waterjet is the way to go.

I can lay up 5, even 10 sheets at a time, and accuracy actually increases with multiple sheets.

The Big Wally

01-24-2004 Over year old.

sbalder
Senior Heliman
Location: Westland, Michigan

I don't have a cnc setup, but I have had good luck making CF parts (see my gallery) using a conventional milling machine with a dremel flex shaft running in the milling head. I run a straight 3/32" (1/8" shank) at full speed. The edges come out super smooth.

-Steven Balder

01-24-2004 Over year old.

HOMEPAGE

TMoore
rrProfessor
Location: Cookeville, TN

The problem with using a laser on CF is the toxic fumes and the heat affected edge. You would have to use a pretty solid exhaust system and most shops that I've sold lasers to won't touch the stuff. WJ's are more applicable to this sort of work. IMHO, unless you have a real CNC and not a table top machine, cutting CF is in most cases a waste of your time. Most TT machines don't have the spindle RPM or a decent enough motion controller to do a more than a passable job on CF. Even a real solid CNC vertical machining center needs a 10K spindle, decent CNC for motion contol and an exhaust system with air blast unless you want to run coolant and clean the coolant after every shift.

WJ's are the ticket for flat CF work. Most places are going to charge you $100.00/hour for the work because it costs them $30.00 hour an hour to run the machine not counting their facility overhead and emplyee cost. If a Fab shop with WJ capacity is any good they are busy on high paying work. If they are slow you might get some of their time.

Terry

01-24-2004 Over year old.

nap_tan
Senior Heliman
Location: Santa Clara CA, USA

JCadwell,

Try using a 1/8 or smaller dia brand new carbide endmill to bring the shearing force down. I havent had any experience milling CF but normally with brittle plastics, you would want to take multiple light depth cuts (.02-.04" / pass). You would also want to get the tool in and out fast to prevent material melting and sticking into your chip space. Run high rpm as well as high feedrate (i.e. 8,000-10000rpm, 15-25 ipm). Keep us updated.

01-25-2004 Over year old.

tauscnc
Veteran
Location: IL : www.cuttingedgecnc.c om

Hey guys,

I cut my first carbon fiber parts and it was much eaiser then I thought it would be! I used a "fishtail router" instead of an endmill, worked wonders! I also use Scotch Double Side tape to hold the CF down. If you have not tired that yet, get some of the thin Scotch Double Side tape, its excellent! I drowned the part in 3 in1 oil as it cut to keep the dust from getting airborne

It was black slug when the part was done.

The bits can be found at from Harbor Freight Tools: http://www.harborfreight.com/cpi/ct...temnumber=34640 and they work great!

Pics of the CF fins can be found here https://home.insightbb.com/~kristaus/raptorv2.htm as well as a pic of the fishtail router.

For more pics please check out my main site www.cuttingedgecnc.com
thanks
taus

01-25-2004 Over year old.

HOMEPAGE

JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

I'm having problems keeping the edges from fraying. I'm running 13 IPM, 10K on the spindle, tried both a 1/8" solid carbide fishtail router, and a 1/8" 2 flute endmill. I put skotch tape on both sides, and used Super 77 to stick it to the sacrificial mill table. No movement at all, but the edges still fray. Aluminum cuts brilliantly with the same setup and a slightly slower feed rate. Any thoughts?

Thanks, John Cadwell

01-25-2004 Over year old.

tauscnc
Veteran
Location: IL : www.cuttingedgecnc.c om

Hey JCadwell,

Hummmmm, The cutter I used is 1.58mm and running around 5-6K on the Sherline. I don't think the oil really did the trick as I also tried it dry with and it came out just as smooth. I did have a a few splinters but they where easily sanded off under running water.

I did 2 passes, how many are you doing? I did not run mine that fast. Try it at the speed the AL comes out well at. I would think the fishtail router would work well.

What type of carbon fiber are you using? There are so many kinds and how they are put together. The one I used is very shiny and seems to have a protective coating on it. Maybe that helped.....but then you said you did try scotch tape on it too.

Try a slower speed.

Hope any of this helps

taus
www.cuttingedgecnc.com

01-25-2004 Over year old.

HOMEPAGE

JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

I'm using a composite flat plate that I laid up. It had two layers of carbon fiber on each side of a 3/32" basswood plate. There are 2 layers on each side of 282 style carbon weave in 5.7 per layer, one diagonal and one parallel with the wood, with an Aeropoxy 2032 epoxy matrix with one hour hardener.

I'm doing one pass. Would a finishing pass be useful? I tried all several feeds, spindle speeds, and cutting tools. I'm thinking I either have heat problems, or that using a wood core causes the resin to be able to shake out of the weave, allowing the fibers to flutter. It cleans up with sandpaper, but it is ugly when it comes off the table, and it isn't easy to clean up nicely. Both the top and the bottom of the plate had fraying.

Perhaps I just need to lay up a flat plate and try to cut that and see if the results are any better.

Thanks, John Cadwell

01-25-2004 Over year old.

nap_tan
Senior Heliman
Location: Santa Clara CA, USA

are you cutting the sheet with one shot or multiple passes?

01-25-2004 Over year old.

nap_tan
Senior Heliman
Location: Santa Clara CA, USA

try several light passes

01-25-2004 Over year old.

tauscnc
Veteran
Location: IL : www.cuttingedgecnc.c om

The carbon I am uisng is also woven but is ALL carbon, no wood. I also wonder if the basswood inbetween is causing it to shake and fray as you say. The 1 pass maybe to much for the router/machine/speed. I assume the sheet I used is either vaccume bagged under high pressure as the carbon layers are very tight. Did you vaccum bag yours or just lay it up and let it dry?

I say, do 2 passes and a little slower.

keep us posted!
taus
www.cuttingedgecnc.com

01-25-2004 Over year old.

HOMEPAGE

TMoore
rrProfessor
Location: Cookeville, TN

JCadwell,

If you are milling CF, drop the cutter down to the full depth and run. What you are seeing is called "splaying" or delaminating. After you get the material off you can try a finish pass but the chances are that your endmill will be too dull. Try a new one for the finish pass. Don't make the finish pass too light. You will need to leave some material to finish off, otherwise all the cutter will do is rub.

Terry

01-25-2004 Over year old.

JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

I've been cutting at full depth. How much stock should I leave for a finish pass? Thanks for the help.

Thanks, John Cadwell

01-25-2004 Over year old.

Rotary Flyer
Senior Heliman
Location: North UK

Carbide tools, as fast as you can get (within reason obviously) Full cut. I double-sided tape the 2 sheets together before cutting so they turn out identical (if that is what you need) and then everything lines up, including the bolt holes for bearing blocks etc. If you do get a bit of a ragged edge once the cutter dulls, a sanding drum soon cleans up the edges.

Watch the dust.

01-27-2004 Over year old.

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