machining ”Peek” …and ”Carbon fibre”

[lancelotParticipant @lancelot]

Peek Carbon fibre.

[lancelotParticipant @lancelot]

Hi all, will be machining some of this in due time and will be using very small but precision machines to do the work…if any one has machined this material , what toolng cutters gave you the best result…[the carbon fibre will be in sheet form no more than1/4'' thick… Peek …will be up to 1/2'' rod].

John.

[Anonymous]

I've never machined carbon fibre, but have machined a lot of PEEK on a manual lathe and CNC mill. PEEK turns beautifully using polished carbide inserts with high positive rake, designed for aluminium. For milling I used uncoated carbide end mills, slowish speed and high chip loads, as with all plastics.

Regards,

Andrew

[lancelotParticipant @lancelot]

polished carbide inserts with high positive rake, designed for aluminium. For milling I used uncoated carbide end mills, slowish speed and high chip loads, as with all plastics.

Hi Andrew, the turning inserts I can get for the Glanze tools…I think I may be able to get the carbide end mills in the short series ok. I know about wearing a mask with carbon fibre …any problems with Peek, fumes ?

John.

[Michael GilliganParticipant @michaelgilligan61133]

John,

Andrew is spot-on regarding PEEK … it's lovely material.

Carbon Fibre sheet is more of an unknown: Mainly because the quality is so variable.

[unfortunately it's become trendy, so much of it is more decorative than functional]

Good material cuts well with small carbide cutters running at high speed.

… it's probably worth looking at what the RC car guys are doing; they use CF sheet for the chassis.

MichaelG.

.

Edit: Check out this video on YouTube

Edited By Michael Gilligan on 13/10/2013 12:39:53

[lancelotParticipant @lancelot]

Hi Michael and Andrew, I thank you for the information …I will follow up on that.

Cheers, John.

[John Stevenson 1Participant @johnstevenson1]

Carbon fibre is insanely abrasive even for carbide cutters.

i have had decent success with the rotary rasp type tooth form in carbide but you do have to factor in tooling costs at about x4 or x6 of normal machining.

[jason udallParticipant @jasonudall57142]

A la “ten year’s time”…just wonder what graphine machines like?

[Michael GilliganParticipant @michaelgilligan61133]

Posted by jason udall on 13/10/2013 15:45:14:
A la "ten year's time"…just wonder what graphine machines like?

.

Hopefully, costs will come down; but for now it looks to be outside our budget.

MichaelG.

[lancelotParticipant @lancelot]

Hi Michael, had a look..wayyy over my head, what is it used for? seems to be really cutting edge material…

John.

[Anonymous]

Posted by lancelot on 13/10/2013 11:50:53:

Hi Andrew, the turning inserts I can get for the Glanze tools…I think I may be able to get the carbide end mills in the short series ok. I know about wearing a mask with carbon fibre …any problems with Peek, fumes ?

John.

I didn't bother with a mask for machining PEEK; there was no smell that I could detect. If there are fumes then the plastic is getting too hot and cutting speeds should be reduced.

Regards,

Andrew

[Michael GilliganParticipant @michaelgilligan61133]

Posted by lancelot on 13/10/2013 16:56:21:

Hi Michael, had a look..wayyy over my head, what is it used for? seems to be really cutting edge material…

John.

.

Way beyond me too, John … but the gist of it seems to be that clever people are investigating potential uses for Graphene. But, most of the things they would need to make would ultimately be created by techniques like photo-etching. These processes are only really suited to mass production techniques [compare the production of silicon wafers for ICs].

The Zeiss contraption allows then to directly machine Graphine, at the nanometere scales required.

… a bit like machining a prototype circuit board, which would [in production] ultimately be printed.

MichaelG..

[David Clark 13Participant @davidclark13]

Carbon fibre is horrible. Splinters like mad.

I have only machined carbon fibre tube, not sheet.

Drilling it was awful. I would probably drill a tiny pilot hole then open up with various sizes of slot drill with a support underneath like MDF or plywood.

Better still, sub contract it out to somone that specialises in it.

If doing it now, I would research it on the Internet.

regards David

Edited By David Clark 1 on 14/10/2013 08:28:06

[Michael GilliganParticipant @michaelgilligan61133]

Posted by lancelot on 13/10/2013 16:56:21:

… what is it used for? seems to be really cutting edge material…

John.

.

John,

I forgot to paste the link to this Wikipedia page about Graphene.

… Probably more info. than any of us here will ever need.

MichaelG.

[Trevor WrightParticipant @trevorwright62541]

Machining peek is wonderful, just one thing to watch for, if machining tight tolerances the chuck will squash the material and expand when released, leaving you with a triangular diameter.

Carbon fibre is very abrasive and will grind the tool away like a grinding wheel. If you keep the revs down you can reduce the number of passes with the cutting edge and make it last longer. Put a new cutter in for the finishing op.

Trevor

[lancelotParticipant @lancelot]

Hi guys, worked in r/e in learfan 4 yrs, they had their own cutting room for machining the finished product,I rarely had to cut the material I drilled lots of holes drills were tungsten or diamond tipped cutters were mainly diamond rather pricey unless some of your mates are in the trade…this was obviously some time ago and I had never heard of Peek…having watched the video of the race car frames being cut out was amazing…

thank you all for your input,

John…

[mike mcdermidParticipant @mikemcdermid41977]

Carbon only splinters with incorrect tools

118 degree point derills splinter 90 degree points do not for bigger holes orbital drilling is used ,think of it like a circular pocket cycle on a cnc ising a flat bottom boring bit

Are you trying to profile mill drill or pocket the carbon the only cutter which looks familiar in proffesional composites machining is the humble ball mill and then we use CVD or PCD to make those last the rest look more like Burrs

All will have a different cutter geometry than a trditional carbide mill bit as the top and bottom face of the sheet will want to delaminate these are called (google) compression geometry milling tools 15 and 25 degree helix are normal here

if your machining a few bits and bobs you will get by with DLC coated carbide, this is not for production use though they wont last

Easiest way to cut carbon sheet is high pressure water ,we use a 5 axis water jet in aerospace for this

[lancelotParticipant @lancelot]

Hi Mike, I managed to find/pick up some suitable tooling for my purposes…< Are you trying to profile mill drill or pocket the carbon > I will be doing all of that. I will be sandwiching the part in 1mm. perspex sheet to try stop delam, cutting dim, not critical.Will have to watch the dust and run the vacuum.

Cheers, John.

[jason udallParticipant @jasonudall57142]

If carbon fibre is any thing like photocopier toner…watch out for vacuuming up the dust….it conducts even as dust in air..enough to get shocks…so take care…

[VersabossParticipant @versaboss]

Posted by John Stevenson on 13/10/2013 15:35:09:

Carbon fibre is insanely abrasive even for carbide cutters.

i have had decent success with the rotary rasp type tooth form in carbide but you do have to factor in tooling costs at about x4 or x6 of normal machining.

Hello John,

I hope you are still around…

I am very much interested what form of rotary rasp cutter you used for carbon fibre. I have to do a couple of hundred holes of 12 mm diameter, in 2 mm CF. The holes should be as clean as possible, with no splintering or delaminating. I used before a 12 mm carbide endmill, but had to feed down extremely slooow…

Maybe your usage was for side cutting only with these rasps?

Greetings, Hansrudolf

[Ian S CParticipant @iansc]

Hansrudolf, would it maybe better if you could punch the holes? I have not worked with CF, so only an idea.

Ian S C

[VersabossParticipant @versaboss]

Ian, I don't think punching is possible. Firstly I have not the equipment, and secondly the holes go through Aluminium also.

That's what I want to make (now follows that terrible picture-inserting-horror):

Not ok; camera symbol did nothing. Again:

Strange, second try seems to be successful. oh yeah…

Greetings, Hansrudolf

[lancelotParticipant @lancelot]

Hi Hansrudolf, ……try here…**LINK**

hope this has done the trick, you will have to cut the holes with a diamond faced tool, no way would you punch it ,if at all it would delaminate…

[VersabossParticipant @versaboss]

Lancelot, thank you very very much for the advice above. I was at first not very sure if that works, but took the plunge and got a 12 mm diamond core drill (from ARC, satisfied customer etc etc.). Quite cheap they are also…

Yes it works a treat. I put the rings in a jig (top and bottom plate with the 6 holes), so the drill had a bit of guidance and I could cut from both sides. Result; a clean hole, not the slightest delamination or splintering. Happy!!!

I put this here just in case someone faces the same problem.

Greetings, Hansrudolf

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

I know that carbon fibre products are available in sheet and rod form for machining but bear in mind that the whole reason for the existance of carbon fibre originally was as a long fibre high strength material which could be moulded into purpose made near finished shapes with almost ideal lay of fibres and with strength that was both high and purpose optimised .

Anyone wishing to utilise carbon fibre at its most effective would be well advised to look at moulding components and not machining from solid .

MikeW

[Author]

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