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Garolite G7 some questions

mochinist

Aluminum
Joined
Apr 9, 2004
Location
Mesa, AZ
I have machined plenty of G10, but have never touched this G7 grade garolite. The parts a relatively simple basically .5" x 1" x 3.75" with two 11/32 holes and two slots(.75 x .25 deep) running in the 1" direction. Anyways I have to quote 24 of them and I am looking in Mcmaster Carr and it says that I need diamond coating tooling :confused: so am I going to have to get a diamond coated bandsaw blade to cut this stuff up(do they even make those?) or can I just sacrifice a regular bandsaw blade to cut this up. Secondly diamond coated tooling doesn't seem to be cheap, I grabbed a random catalogs(harvey tool and J@L) and a diamond coated 1/2 inch end mill list for around $220 :eek: .

Other than the expensive tools needed does it machine relatively easy if I am using the diamond tools, I will be doing it in the HAAS cnc, should flood coolant be used, I use it for G10 with no problems.

I think I covered everything but if I missed anything be sure to ask

Thanks
Don
 
I don't think diamond tooling is necessary. I am quoting a job right now that is made of garolite. I am guessing that the material is abrasive and you will go through tooling faster. I suppose daimond tooling will not dull as fast as regular tooling.
 
Well there is different variety's of garolite, I know for G10 I use carbide for the most part, but I have used HSS and it is fine as long as you aren't on a production run or hoping to use the HSS endmill again without resharpening. G7 and G9 both recomend the diamond tooling though.
 
Mochinist-I posted on the G-7 on the HSM board. It's in the thread about this site being down. I couldn't get on here until just now.
 
Mochinist-I posted on the G-7 on the HSM board. It's in the thread about this site being down. I couldn't get on here until just now.
 
by reading your posts here and the HSM board, it really sounds like you just want to by a diamond endmill for the hell of it. mcmaster carr does not say it can't machined with carbide. the problem with the stuff is that it's abrasive and it will make your tooling wear out faster. you can buy a few regular 1/2" endmills for the same price as one of those.
 
Use a carbide-grit coated bandsaw blade.

For milling or turning, don't used the PVD
coated diamond tooling, don't buy PCD end mills.

Instead go with PCD (polycrystaline diamond)
*inserts* like the ones sold by valenite.

They're not that expensive and will fit into
the smaller insert endmills like those sold
by ceratip. I use the TPG221 size, with the
full length edge, in the insert mills.

Jim
 
by reading your posts here and the HSM board, it really sounds like you just want to by a diamond endmill for the hell of it. mcmaster carr does not say it can't machined with carbide. the problem with the stuff is that it's abrasive and it will make your tooling wear out faster. you can buy a few regular 1/2" endmills for the same price as one of those.
It really sounds like your reading comprehension is low, but thanks for the help :rolleyes:
Mochinist-I posted on the G-7 on the HSM board. It's in the thread about this site being down. I couldn't get on here until just now.
Thanks I will look as soon as I can, apparently that site is down now. Damn intraweb


Jim R, thanks for the tips.
 
RE: I milled 100 holes, 1.133" dia x .27dp. 1 carbide 3/8 endmill without any adjustments. all +/-.001

I don't think you need diamond tooling.
 
You don't *need* PCD tooling to do glass
composite machining.

YOu can use HSS if you want. You won't
get 100 holes out of an end mill that way.

The carbide is better, sure. You'll be able
to do the 100. Then try to do the next 100.
The trouble with carbide is, it's not all
carbide. Carbide tooling is "cemented carbide."
This means it is a sintered mixture of silicon
carbide in a binder metal, typically cobalt.

The SiC is highly resistant to wear - but the
glass whiskers pick out the softer cobalt metal
between the hard grains of SiC. They lose their
support and fall out of the matrix. That's
the wear mechanism.

The PCD is also diamond sintered in cobalt - but
the diamond is harder and there's less cobalt
I think. All I do know is you can mill 1000
holes with PCD inserts in an endmill, and the
things feel every bit as sharp when you're done.

Jim
 
I have done a lot of this in a previous life (I keep reminding myself it could always be worse), as well as machining G-10/G-11 and G-9/G-5 materials. G-7 is somewhat prone to delamination if the cutting tools get dull, and the use of flood coolant may complicate your life if that occurs. G-10 is typically a more "solid" material as far as delamination goes. That being said, carbide tooling is used commonly for cutting and machining operations on these types of fiberglass-resin composites. In the work and plastic fab operations I saw, typically the sawing was always done with diamond blades and flood or heavy spray-mist coolant, but the subsequent ops (holes, slots, profiling) were generally performed with solid carbide or carbide-tipped tools. Forget about HSS for this application, it will be about as sharp as a marble after the first 30 seconds, and you'll run the risk of wrecking the material. There may be a lot of benefit to trying those circuit-board router bit type cutters. Those are very commonly used for this type of material, with high spindle speeds and dry conditions, lots of good vacuum to pull the dust away. If I had a choice of doing this on a knee-mill machine, that's probably what I would do, no coolant, cover everything, and a couple of shopvacs or a good drum-type dust collector on the setup.

I wouldn't dream of doing this on a machine I really cared about. The fiberglass particles will go everywhere you don't want them, especially with flood coolant. If this is a rare occasion for you, do everything you can to control the stuff coming from the cutting. If you plan to do a lot of this type of material, plan your machinery replacement/rebuilding well ahead of time. It has it's uses as a material, but machining it sucks pretty hard.
 








 
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