Tools and techniques for cutting Carbon/Kevlar composites?

General Composites Discussions Equipment Talk
#1

Untill recently most of my projects have been quite small and almost exclusively made of carbon. However I have been creating something a bit different over the last few weeks and the final piece has many more layers in the composition and is over 50% Kevlar.

Now on a material test sample I made before this piece I found that the Kevlar was unsurprisingly much harder to cut than the carbon once cured. I have been using a Dremel with Tungsten Carbide cutting wheels from http://www.permagrit.com/ which works fine on pure carbon pieces/

I am reasonably certain my current tools will not be able to cut through my new layup. Does any one have any recommendations as to the best way to cut a piece which has a large amount of Kevlar (6 x 175 GSM plain weave layers)?

#2

Don’t layup the aramid where you need to cut. Aramid has nothing to do there, except being a pain in the ass. Basically cut your aramid smaller then your part is going to be. That way you don’t have to cut trough it while trimming, and don’t have any fluffy fibres exposed :slight_smile:

#3

Doh, that is so sensible. Wish I had done that before making the part. Any advise if I do have to cut through it ?

#4

sharp tools, lot’s of patience, and don’t try to burn the part :wink: (wet) sand with a very fine grit (1000-1500) afterwards to get rid of most loose fibres.
Good luck!

#5

What Susho said! These are rough cut bike dropouts cut from solid plate containing 4 layers of aramid. It took over 20 blades on a scrol saw to cut that pair.

#6

For scroll saws, use tiles saw blades, and go slow.

Because a picture says more:

#7

I certainly agree with Susho on this. In my roof panels I make, I use a la thick 20 oz. layer of Kevlar and under cut it just inside where my final trim line will be later. Your parts may not always be build-able that way, but when possible…do it. Huge frustration eliminated !

#8

Affordable bandsaw blade recommendations for cutting carbon?

#9

I’d looking into a water jetting service, personally. It might cost a few bucks, but you’ll get a perfectly clean cut every time.

#10

One of the 5 machine that I am using is Kress 1050

with flexible

Very strong machine and you can use it for cutting carbon fibers or router for CNC.

#11

Send it to a water jet cutting bloke, works perfectly.

#12

Your options for band saw blades that will last any amount of time are carbide tipped or carbide grit, neither of which are particularly cheap. For a medium sized band saw you can expect to pay $120-150 per blade. If you want to cut lots of G10 or fiberglass the grit blade is the way to go. The carbide tipped blades cut carbon well and are also nice because you can still cruise through wood and aluminum on them. If you run the grit blade you are much more limited in what you can cut with out ruining the blade

#13

Those grit blades, and diamond blades, can be cleaned by cutting some concrete. They are like new after that. (it burns away resin residue)

#14

+1 for the water jet…

Maybe you can find a shop that has slow business and is interested into working with composites that could give you a good deal? It’s definitely the preferred method to cut composites if possible. Flat shapes should be no problems but some one might have a 5 axis as well?