[cmmphish]

im looking to make some molds out of wood and graphite. i need to be able to cut about 3" deep in some molds. biggest mold would be about 12"x12" and 3" deep. can anyone give me a starting point of type machine to start researching?

[bostosh]

Foe 3" deep i would seek something with a 1/2 dia spindle to accept the long tapered cutters used in "die sinking" and enough z travel to clear the top with those long cutters.

[jahnj0584]

300$ - Sienci Mill 1
500$ OB mini Mill
500-1000 Chinese 3020/6040
1-2000 -Cbeam (Xlarge)
2.5-4k -Probotix Premades
4500+ -CNCRP

[wizard]

If the max mold size is 12 x 12 you have a lot of options and frankly which way you go is up to you. You could very easily fit this into the work envelope of a CNC mill with a high speed spindke attached. Or you could build your own router like machine.

More into on the graphite is in order though. Is this material a compound that is hard , well harder to machine than wood or is it relatively soft. There is little information for us to act on here.

Given the lack of information im going to make some off the wall suggestions.
1.
Build a machine with at least a 18" square work area and at least six inches of clearance under the gantry. If the molds are 3" deep im assuming they are formed out of stock at least an inch or mire thicker than that.
2.
To go deep requires long cutters or extensions thus you will want more than six inches of travel on your Z. This especially if you do a lot of bulk material removal with large cutters or drill bits.
3.
Go with a moving table design. This will give you a stiff easy to align machine that can do very high quality work. This asunes a strong frame build.
4.
Build out of steel for cost and strength advantages. Enlist a machine shop if required but DIY in steel isnt as bad as some imagine.
5.
Design in a large spindle. Not so much for power but ratger stiffness and a large collet. The large collet due to the need for large cutters to minimize deflection and other issues.

Just 5 points of opinion to consider.

[awerby]

Graphite is a difficult material to work with. It makes a big mess, coating everything in the vicinity with black dust. The dust is not only abrasive, so that it gets into any unprotected sliding parts and ruins them, but it's conductive as well, so if it gets into your electronics it will short them out. If possible, work it under flood coolant to avoid filling the atmosphere with the dust, but unfortunately some applications forbid that and require it be worked dry.