Cutting Carbon Fiber

I thought they could be sheared using a guillotine (or similar), but have not actually tried myself. Laser and waterjet seem to be options.

I have heard from a boat builder that breaking them over ones knee is a very bad idea.

A google search of "cutting carbon fibers" produced some useful results that should help.

You might consider using rotary shear blades if your just looking at cutting the fibre cloth itself. Using a top rotary cutting blade with a bottom anvil blade they are somewhat self sharpening. You can find them at graphic print suppliers typically and it would be something similar to what is on a Stahl folder.

The blade and the anvil interlock on a parallel plane, as the material runs through it it is cut basically like a pair of hand shears would cut it. The systems themselves are designed for rapid changing of the blades and on normal paper material that is typically .008 thick they will last about 2-3 weeks worth of continuous duty 120 hours per week.

If you have them manufactured to a better hardness rating then you can get more life out of them. you just have to make sure the anvil is harder than the shear blade by a few degrees so the shear sees the wear and not the anvil.

Just not terribly sure how well they will work or last with carbon fibre material. I have seen beople cut CF cloth with the same scissors that my wife has at home.

Hi, that is interesting, where exactly did you see these "beople" and how did they get your wife`s scissors? - I tried the spell check, it cought the "beople" thing before these creatures got out of hand.

No, really,

Getting tooling coated with a carbide coating may be a good direction, it won`t be cheap but is a great alternative for the kitchen tools. Current tools may also be coated. When using bypass type tooling, select different types of steel and harden to max. and temper to around 59 RC hardness, this works well on thick steel sheet cutting applications however it may react differently on CF, speak to a CF manufacturer if you can.

Sorry, couldn't`t resist the pun.

LOL sorry forgot the spell check on that last post.

I think it was on the discovery channel on How Its Made. They were cutting a carbon fibre cloth to make a Kayak's hull. And they were using scissors that looked like a pair of Fiskars like my wife uses.

jack of all trades is correct - a guillotine is the best and most commonly used option. If you're worried about wearing out blades, laser cutting is an option too, but likely just as expensive.

Have some blades made out of carbide.

We are selling circular knifes with 100 mm diameter, that are also used in cutting carbon fibres.

If this is something you want to try please e-mail me at:

hitex@charterinternet.com

The fibre that I'm wanting to cut is just the fibre. It comes out of a machine that at about 2m/s. It is this fibre that I am wanting to cut. Lasers are very tricky in that they want the fibre to be at a very accurate place in space due to focussing of the laser. The circular knives and scissors require that the fibre be stopped(Difficult).

Rotary knives are specifically for a continuous operation, but are going to run inline with the material path. Ideal for slitting probably not so good for a cross cut.

I understand your dilemma a bit better. In which case I would have to go with the recommendation of others and suggest using a high carbon steel shear cutting system. Using a driven Nip roller system that works off a looped infeed you can maintain a continuous process and only stop the material being fed into the shear.

The nip starts and stops the material for cutting and the process continues because it feeds the material into the loop when waiting for the shear to cut it. Look at Rolt for something that they manufacture for the printing industry. I am sure it would be no trouble to modify it to work with your system.

Hi W.

Three things come to mind:

A flying cut off blade assembly that travels with the feed speed, however 2m/s may cause a timing issue.

Water Jet - expensive, but may not require the exact focus you are concerned about with the laser, can be oscillated.

Ultrasonic Cutting - I am almost certain that it can be applied to cut CF, check with companies like Branson or Dukane.

Let us know what finally worked.

Dear Sirs

The most up-to-date technology to cut carbon fibers is by laser cutting beam. The equipment can be supplied by several manufacturers in the States, EC and I beleive it is now available in Japan and China. Regards.

Prof.Dr. Mahmoud Rabah

Cryogenic treating of the cutting blades can increase the useful life of the blades making them more resistant to wear without hardening the steel. Works with good higher carbon steels and alloys. dkimmel@300below.com

I was going to copy the thread info and send to Kyocera (see https://secure.kyoceraadvancedceramics.com/products/custom/), but had a connection failure. You may wish to try contacting them directly. They make knives, scissors, and other blade-type products of advanced ceramics, far harder than steel. They are also much lighter in weight. Instead of using a loop to intermittently stop the fiber tow while cutting (a valid suggestion made by another repsonder), you could consider moving the cutting tool along with the tow; lighter weight translates into less force to accelerate/decelerate to match speeds and to return to resting position. So-called flying cutters are used in some industries where product is produced in continuous form, but needs to be cut into shorter lengths for shipping, use, or other reasons.

Why not try diamond blades like they use to cut concrete.

Some excellent suggestions from contributers. "Flying shears" appears to be a good solution but may require automation. We have coated rotary and flying shears with tungsten carbide to prolong the life of the shears used in stainless steel sheet cutting. Please contact me at technovationsintl@gmail.com if you need more information