How to cut Block of Fiberglass material ?

[Calico]

I have 2 inch thick Fiberglass material and I wonder how to cut with best finishing ?
I have a router CNC with up to 20000RPM spindle speed.

my questions:
1. what is the feedrate, cutdepth etc to cut the material and at what RPM ?
2. should I use Metal bit cutter like 4 flute endmill ? or I should use the wood router bit to cut the fiberglas material ?
3. how to findout the best cut depth/feedrate etc for fiberglass ? try and error ?

thank you
cal

[Boots]

What type of fiberglass are you going to cut? Does it have a name or number like G10. G10 is a vacumed, layered fiberglass that is very tough and needs a diamond edge cutter. So the type and density of fiberglass varies a great deal and all have their problems. Are you cutting all the way through? Fiberglass causes heat that will destroy your tooling so a low rpm and high feed rate are necessary and you have a good strong hold on the part or it can move

[Calico]

diamond ? oh no ... cost me big deal.
I have no idea what kind of fiberglass, but I will take a picture tomorrow and post it here.
I think it's very hard fiberglass, it's a plywood size with 35mm thick.
the color is greenish...

I don't think the seller know what grade is... but it's very dry and hard.
I though this can be cut much easier than alumunium ?

so low RPM and deep cut.

I'll post the picture later on

trhanks
cal

[Boots]

Sounds like the material here is G10. It's very Hard and light greenish in color. 35mm is about an inch and 3/8. The G10 that I cut was only 12mm thick. (about 1/2 inch) and I did it with a diamond bit. They are not that expensive. Onsrud Tool #67-254 $137.00 . This tool will only go 32mm deep so you will need a longer tool. The problem with this fiberglass is that it is vacumed layers of fiber and resin and it is dense. You have to turn it to powder it will not make chips. So I got the Diamond bit and it cuts like butter. Well, not really but it sure beats carbide or powderd steel Tooling. You can experiment like I did and get no where or just get the Diamond bit and you won't have the same problems I had. I ran this tool at 4000 RPM and 20 IPM feed at .25 deep on each pass. And it didn't get too hot and made powder of the material. Have a good system to take away the dust and do not breath it. Good luck....

[High Seas]

Calico -
You didn't mention the shape of the cuts you'll be making. I just finished cutting some G10. Because my cuts were simple - straight lines - straight through the G10, I used a tile wetsaw.

I put a diamond 4 inch blade -on it - like the ones you can find for an angle grinder (Slotted/type -- like these - but lots cheaper http://compassdiamondblades.com/index.php?cPath=1_2). Worked great! The edges were Smooth As -- and no dust. The fiberglass dust/bits formed a paste like mess that was easy to clean up.

Maybe that will help some - but it will depend on the shapes/product you are cutting. I suppose you might be able to adapt a water flush to a scroll saw too - but again it would only work on through cuts.

Good Luck, and
Jim

[Calico]

boots,
thank yoiu for sharing youe experience...
what do you meant by .25 deep ? is it in Inch ?
I think it's G10


see my attachmewnt photo of the 3dmodel i want to cut.
it's 12cm wide, 7cm deep and 3,5cm high.
I need apair /mirror to cut.

high seas,
maybe after I send the 3dmodel attached you can suggest me more exact tool I need.
i wonder if this bit available on ebay ? wait ....nope no diamond bit available at ebay.

is there another brand beside onsrud ?

cal

[High Seas]

Calico -
I know you have the Block of Fiberglass - but looking at the model - I wouldn't mill that from a solid block. I guess the 3 pegs maybe support something? Or are used to position the rectangular cup for attachment? Either way there won't be much strength in the piece once machined to the shape of the model.

If fiberglass is the preferred material for the product - I would make a mold and lay up the fiberglass. That way the pegs and cup could be reinforced and the fiberglass weave/pattern/grain could be better aligned with the forces you'd anticipate.

If the product is ornamental (no strength required) - again I would make a mold and just cast it in resin/plastic.

Best of Luck!
Jim

[Calico]

Jim,
here is the second top mirror part (attached).
I don't really need strong Pegs, it's just for a protection for the Tubes amplifier.

I've been thinking molding using fiberglass but that will take sometime since I have no expert on fiberglass.

since I have CNC machine and I love CNC, maybe I just replace the material to Ebonite, (don't know what to called in english) it's a block material use for PCB.

I thought I need stronger than ebonite.

Now I'm curious about making the Mold for fiberglass.
Jim .. if you have the tutorial/how to make this mold please please I love it, I might use Carbon Fiber caouse it looks cool !

but I think making the mold is not easy, because this part is komplex for a mold to be make, specially for fiber. I hope I'm Wrong !
what's the material for the mold? machinable Wax block ?

Best regards
Cal

[High Seas]

Calico -
here are a couple of quick pointers on moldmaking for fiberglass projects:

www.cstsales.com/tutorials/fiberglass_mold.pdf

http://www.fiberglasswarehouse.com/f...old_making.asp

http://www.fibreglast.com/contentpag...enter-286.html

BTW, if you don't need the stiffness and the high strength of Carbon Fiber - there is a Black Fiberglass - that looks as cool - but is 1/3 the cost. I got some very tight weave (satin finish) at: Fiberglasssite.com there are other places too.

For the pegs/rails - I'd use rods Could be wood dowell - or fiberglass tent poles then maybe pull a sleeve/sock over them and then insert in pockets with some epoxy. Saaembly required - but easier than molding and/or milling them.
SO; First I'd make a female mold mdf milled, seal it - shelac, then tooling gel coat it 3 times, then wax it - 3 to 5 times then spray PVA - let it dry, then start the layup with vacuum (bagging) assist.

Sorry can't give more detail - traveling for the next few days - and gotta go catch a plane! Hope that is helpful - Looks like a neat project. Maybe you could make a thread of the entire build and its progress with pictures.
Jim