Anyone from ohio / midwest with helical carbide planer to test cut gnarly composite?

[John Blazy]

I'm looking into buying a 26" helical carbide planer to surface the carbon fiber composite that I make prior to running through abrasive drum / wide belt sander, and I have a real strong hunch that it will do the job great, but don't want to drop over $10K without testing first.

If I buy a new planer, all warranties will be void due to the abrasive nature of the CF near bearings so am planning to get a used planer and installing a helical head on it, if this works, then shielding the bearings coupled with powerful dust collection. If anyone is interested in running a small pc for me, I will pay what you want to charge, plus cover the cost of the dull carbide. I will know if it tears out badly just from a 3" x 3" pc, so I was planning to cut a 3 x 3 x 1/4" deep mortice into a pc of 8" x 18" hardwood then epoxying a couple 3 x 3's of the chatoyant carbon fiber into it, flush with the surface. One pc will have the grain direction going longways with the wood grain like normal, and one pc will have the grain going across grain, perpendicular to feed direction. The CF has wavy "wood" figure to it, like curly maple, so I am expecting bad tearout on the long grain pc, but expecting the cross grain pc to cut fairly clean, so I can follow that surface with 60 grit.

BTW, this material is used in knife handles and gun grips but recently got interest from a well known supercar company for interiors and need to ramp up production quick.

If anyone is interested, I can ship out the test panel, and you can keep it, just send pics of results.

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[Peter Christensen]

I have no direct experience but think it would be brutal in a planer. Have you considered a CNC router? It’ll give you more options in the future and while it is running the operator can be changing or rotating inserts in other tool holders so there is very little downtime. You can also get ceramic and diamond inserts that may be better suited to the abrasive material.

[Carl Beckett]

I have worked with various carbon composites as engineering materials. They can often be machined. But you will not get the same surface finish as if 'molded'. When machining you are shearing the ends of the fibers which go all the way to the surface. If coming out of a mold (or even injection molding), the fibers will lay parallel to the surface and a thin film build over them allowing a smooth surface.

None of this may matter for what you are doing, but if cosmetics matter definitely try a test piece (the cosmetic finish will be the hardest part to achieve). Just chuck it up to a regular metal working lathe or mill and take some passes, this will give you an idea of how it machines.

(btw there are many specialty contract manufacturers that machine composites regularly so know it can be done, just depends on the specs of the finished product)

[John Blazy]

I have no direct experience but think it would be brutal in a planer. Have you considered a CNC router?

You are kindof correct in both points - thanks for your input! When I first made test panels, all I had was a carbide dado set, and the dado teeth would stay sharp enough to surface 1/8" off of a 24" panel before I had to resharpen the teeth. It also cut cross grain real well, no chip outs in the valleys of the curly grain. CNC with diamond burrs is what the gun grip guys are testing now with my CCF, but I need high production surfacing to take .030" off in one pass and plan to go though a $200.00 set of square carbide (turning the chippers 4X) every 50 feet of CCF stock. It just has to remove stock better than the 40 grit abrasive drum I am currently using.




I have worked with various carbon composites as engineering materials. They can often be machined. But you will not get the same surface finish as if 'molded'. When machining you are shearing the ends of the fibers which go all the way to the surface. If coming out of a mold (or even injection molding), the fibers will lay parallel to the surface and a thin film build over them allowing a smooth surface.

None of this may matter for what you are doing, but if cosmetics matter definitely try a test piece (the cosmetic finish will be the hardest part to achieve). Just chuck it up to a regular metal working lathe or mill and take some passes, this will give you an idea of how it machines.

(btw there are many specialty contract manufacturers that machine composites regularly so know it can be done, just depends on the specs of the finished product)

I have machined this through my drum from 40 through 100, then 220, then ROS to 600 grit, and even through 3000 Trizact then buff, so is machines fine. There is no way to mold this material flat into the effect that I get. The chatoyance only comes from shearing through the bent fibers.

Here is a pic of the surface of a flat panel 12 x 18 in the pic

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[Peter Christensen]

I'm not thinking of burrs for machining but a lot bigger, more like face mills. They come in all kinds of sizes to suit the router/milling machine's power. Some of the ones in the aerospace machining plant I QC inspected in were 8" or more across but we also had them under an inch (end mills). If you can drive a 2" or 3" face mill you run it until experience tell you it's time to change it (machine counts the spindle time and warns you), drop the cutter and change to another in less than a minute if it doesn't have an automatic tool changer. While it runs you rotate the inserts and ready it to go back in. Some inserts have 8 sides or more. You won't really know the possibilities until you talk to manufacturing reps from the machine makers and the cutter makers. If your production ever warranted it one operator could run and feed more than one CNC at the same time.

https://www.sandvik.coromant.com/en-gb/knowledge/milling/application_overview/face_milling/general_face_milling/pages/default.aspx

https://www.secotools.com/#article/m_6898?language=en

https://www.kennametal.com/en/products/20478624/57493250/556247/46610642/46708769.html

[John Blazy]

I'm not thinking of burrs for machining but a lot bigger, more like face mills. They come in all kinds of sizes to suit the router/milling machine's power. Some of the ones in the aerospace machining plant I QC inspected in were 8" or more across but we also had them under an inch (end mills). If you can drive a 2" or 3" face mill you run it until experience tell you it's time to change it (machine counts the spindle time and warns you), drop the cutter and change to another in less than a minute if it doesn't have an automatic tool changer. While it runs you rotate the inserts and ready it to go back in. Some inserts have 8 sides or more. You won't really know the possibilities until you talk to manufacturing reps from the machine makers and the cutter makers. If your production ever warranted it one operator could run and feed more than one CNC at the same time.

https://www.sandvik.coromant.com/en-gb/knowledge/milling/application_overview/face_milling/general_face_milling/pages/default.aspx

https://www.secotools.com/#article/m_6898?language=en

https://www.kennametal.com/en/products/20478624/57493250/556247/46610642/46708769.html
Thanks for this info, Peter. My original milling process was side shear milling like this but need larger system. I might still look into this because the side shear will cut without tearout. Bummer is that I need a huge milling machine for many times the cost of the planer, and need to hold down the panel somehow. I've seen a "swingblade" sawmill system that is similar - huge 10" DIA 3/8" thick teeth that is similar too, but again need to hold down the panel which kills time savings. Planer is best route, if it works.

[Peter Christensen]

Usually on a mill they hold the plate down with vacuum. If both sides of your casting is wavy that becomes difficult or impossible. You're left with clamping around the edges and moving clamps to new locations and completing the cuts. Once one side was flat flip out over and use vacuum for that side. If the material is thick enough it could be held with toe clamps that just bit into the edges and then you can mill right over top. Here is one kind to give you the idea. https://www.miteebite.com/products/pitbull-clamps/

[John Blazy]

Both sides wavy prior to planing, so no vac hold down. Those Miteebites are awesome - need some on my other machines, but I need the efficiency of running board after board without the time consuming fixturing required. I never photographed a raw panel fresh out of the mold prior to surfacing, but I found a cutoff from squaring these panels that shows the radical waviness prior to surfacing to give you all an idea of why I need to hog off a ton of material face and back. I have to laminate 5/16" of solid CF which yields a 3/8" thick raw molded panel in order to get a target thickness of .190" for knife handles. I laminate 5/8" to get 3/8" material for fixed blade knives etc, and 3/16" to get .040" veneer for luxury vehicle interior trim.

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