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CAD - Engineering - Technical > Cutting G10/Carbon fibre
 
 
genexis
Senior Heliman
Location: SG

Hi, i'm planning to cut some G10 and carbon fibre, both 2 mm thick. Can anybody suggest the bits to use? I'm thinking of using 3mm Carbide Endmills, cuttin 2mm in one pass, will i go wrong with that?
06-27-2007 Over year old.
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jester4
Veteran
Location: Brampton, Ontario (Flyin' outta Mississauga)

No problem using carbide on the G10 or carbon fibre. You could also use HSS for that matter.......
06-27-2007 Over year old.
 
 
Dave22
Heliman
Location: Phoenix AZ

Anything that has geometry for plastic or aluminum will work well.



http://www.american-carbide.com/Woo...lection=1&Cat=4



HSS will wear in CF very fast. Put a vaccume hose up to the cut to get the dust collected.
06-27-2007 Over year old.
 
 
jester4
Veteran
Location: Brampton, Ontario (Flyin' outta Mississauga)

correct, a high rake end mill in prefferably 2 flute is best for machining plastics, aluminum and soft steel. HSS is fine for wear, not a big problem there.
06-27-2007 Over year old.
 
 
TMoore
rrProfessor
Location: Cookeville, TN

4 flute solid carbide races through G10 like a hot weiner in a mustard bath.

TM

"If you can do it, it ain’t bragging." - Will Rogers
06-27-2007 Over year old.
HOMEPAGE  
 
 
genexis
Senior Heliman
Location: SG

Hi thanks for all the replies. I did my first CNC cutting of G10 last night. Check out the pictures on my blog: http://simplewords.genexis.net

Do input some comments and shout me some messages
06-28-2007 Over year old.
HOMEPAGE  
 
 
Dave22
Heliman
Location: Phoenix AZ

You got the CNC bug.

Man don't fight it.

Check out http://www.kdcapital.com/ (CNC vertical mills)and look in the CNC mill section. Real mills come up all the time for 12k and under. I bought my first Mill a Fadal VMC 15 for 10k at this place. I had a little Taig CNC many years back, and there is no comparison. Move a little Fadal or Haas into that garage and go nuts.

Be aware prices fluctuate a lot, I bought for 10k and sold for over 20, depends on the market. Keep watching that site and wait 6 months, a year or more you will see the prices drop, and drop. We are on an upswing right now with all of the new airliner contracts, wait it out and pick up a VMC for a song if you need to.

Dave
06-28-2007 Over year old.
 
 
genexis
Senior Heliman
Location: SG

thanks for the advice. I'm just starting out, still trying to figure how to do 2.5D pocketing, its a real headache when you are new.
06-29-2007 Over year old.
HOMEPAGE  
 
 
Portblock
Veteran
Location: Van Nuys, CA

What CAM software are you using? Pocketing from a Solid model is rather easy, although may apear hard if comming from a basic background like I did, I use to use Mastercam 10 years ago, and now I re-think machining to break my old habbits.

.....
06-29-2007 Over year old.
HOMEPAGE  
 
 
genexis
Senior Heliman
Location: SG

Hi, currently using MastercamX, i just manage to figure out the how to do it. The solution to my problem is to use island facing pocketing.

I have more details of my problems here: http://www.cnczone.com/forums/showthread.php?t=39709

Hope you will be able to help out also.
06-29-2007 Over year old.
HOMEPAGE  
 
 
jester4
Veteran
Location: Brampton, Ontario (Flyin' outta Mississauga)

Nice looking project. I noticed that you had problems with the HSS. I am surprised that it didn't make the grade for you. I have used HSS end mill to cut everything from titanium to monel to 316 stainless and more on a production scale here at work with no issues. Quite honestly, carbide is better obviously because it is more forgiving to incorrect feeds and speeds than HSS, and this is probably where the problem lies. The sherline you have (I think that's what it is, sorry I didn't pay close attention), is not capable of running at the elevated feed rates that you need to run in accordance with the RPM you were probably using. This likely caused lots of "rubbing" instead of cutting and gummed up the cutting edges, and HSS is not quite as tolerant as carbide in that respect. I hope you did not think that I was giving you bad advise, but HSS is better than what a lot of people give them credit. Remember, carbide is relatively new to the machining world, what do you think people used before that. Carbide is fantastic because it is harder than HSS, tougher, and can run at much, much, much higher cutting SFM than HSS, but in general is not needed for the average hobbyist, and the machines that they use at home. I program/run a big CNC mill here at work, and I exclusively only buy carbide drills and end mills, but my taig cnc at home I will usually only buy HSS for most of my machining projects. Good luck with your future projects, and welcome to the wonderful world of CNC.....

Tony
06-29-2007 Over year old.
 
 
TMoore
rrProfessor
Location: Cookeville, TN

Quote 
Remember, carbide is relatively new to the machining world, what do you think people used before that. Carbide is fantastic because it is harder than HSS, tougher, and can run at much, much, much higher cutting SFM than HSS, but in general is not needed for the average hobbyist, and the machines that they use at home


Are you kidding? Carbide has been around since the turn of the century, the 20th century that is. The biggest reason for using carbide on G10/CF is because it's abrasion resistant. Composites eat tools but not due to cutting pressures or unduly high feed rates and breakage.

Composites don't take heat away in the chip so it helps to run air or vacuum to get the chips out of the cutting zone. All the heat from the cutting action will manifest itself in the cutter, holder and spindle.

HSS is great for cutting aluminum and some steels depending on the amount of spindle HP and torque available. Cutter/holder rigidity is a factor as well, especially on the toy machines.

TM

"If you can do it, it ain’t bragging." - Will Rogers
06-29-2007 Over year old.
HOMEPAGE  
 
 
jester4
Veteran
Location: Brampton, Ontario (Flyin' outta Mississauga)

Quote 
Both the rotation speed of the spindle and the "feed rate" or the speed at which the tool moves through or across the part are important for a precise cut that penetrates the material without overheating. "A high chip feed rate is how heat is dissipated and the ideal chip form in composites is dry and powdery like confectioner's sugar," says Mackey. "If the spindle rotation speed is too high, and the chips aren't shoveled away fast enough, too much heat will be generated and you run the risk of melting the resin and damaging the tool as well as the part."

This quote is from compositesworld on machining if you don't like my theory.

Like I said, carbide is better, but not neccessary.

I may have spoken too fast on how long carbide has been around. I didn't realize it has been around much longer than I thought, but not in the capacity of today's cutting tools. Mostly the carbide available has been cemented type. I give you that....my mistake
06-29-2007 Over year old.
 
 
TMoore
rrProfessor
Location: Cookeville, TN

Theory is great but reality is more telling.

Facts are facts. Call Tim down at Miniature and ask him what his budget is for cutters and what wears them out, or better yet try the folks at Boeing or Raytheon and ask them. Nobody uses HSS for cutting composites.

I've been cutting this stuff since the mid 70's and my experience is what I'm going on.

TM

"If you can do it, it ain’t bragging." - Will Rogers
06-29-2007 Over year old.
HOMEPAGE  
 
 
jester4
Veteran
Location: Brampton, Ontario (Flyin' outta Mississauga)

I think you may be confusing production with hobby type of machining. You can NEVER run a hobby cnc to the capacity of a carbide end mill, it's just not possible with these machines. No theory here. I've been a machinist for quite some time. Please understand, nowhere have I said that HSS is better than carbide, but I have said not necessary for hobby type of machining. If you run the HSS mill at the proper SFM and feed rate, you should NEVER have any issues.
06-29-2007 Over year old.
 
 
genexis
Senior Heliman
Location: SG

Hey guys, thanks for the input. I've decided to use the 3mm 2 flute solid carbide. I've already manage to cut it with 1 depth pass, 2mm at a go.

I've pictures up @ http://simplewords.genexis.net/, do check them out and leave me some comments

The next thing i will try is my 4 flute 3mm carbide coated carbide endmill, wonder how will 4 flute perform against the 2 flute one
06-29-2007 Over year old.
HOMEPAGE  
 
 
jester4
Veteran
Location: Brampton, Ontario (Flyin' outta Mississauga)

Your passes are not too deep, so you should be fine, but in general 4 flute end mills are used in side milling and contouring. If you slot something use 2 or 3 flutes. This is not a "rule" but just a common practice.

The reason that 4 flutes is not commonly used in slotting operations is that the 4 flutes present a problem with chip evacuation in deep slots (usually 1 to 1-1/2 times diameter of mill). Your slot is not deep so non issue...
06-29-2007 Over year old.
 
 
Havoc
Key Veteran
Location: Ky.

Quote 
The reason that 4 flutes is not commonly used in slotting operations is that the 4 flutes present a problem with chip evacuation in deep slots (usually 1 to 1-1/2 times diameter of mill). Your slot is not deep so non issue...

It's because they are not typically center cutting and so you would need to drill or use a center cutting endmill to start it anyway.
07-07-2007 Over year old.
 
 
jester4
Veteran
Location: Brampton, Ontario (Flyin' outta Mississauga)

Actually a large majority of todays end mills in the smaller diameters ( about 1/2" and under ) in 4 flutes are center cutting. I buy about 50 end mills every month or two from all the largest manufacturers of high performance mills, and you are pretty hard-pressed to find a non center cutting mill. Once you start getting into 6 flutes and over, the opposite is true.
07-08-2007 Over year old.
 
 
Havoc
Key Veteran
Location: Ky.

We have center cutting four flute endmills as well but the two flute plunge much easier. But that's also why I said "typically". We rarely machine soft materials like aluminum or plastics.
07-08-2007 Over year old.
 
 
1 page897 viewsPOST REPLY
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CAD - Engineering - Technical > Cutting G10/Carbon fibre
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