Newbie- Cutting Aluminum vs Wood

[TMc]

I just found this site and this is my first post. What a wonderful resource! I have been doing woodworking for years and now am interested in going to the next level by building my own CNC.

I am interested in building a CNC which can do wood, and also some aluminum parts. I haven't seen anything on the site that discribes the design requirements and differences you need to consider if you want to build a CNC which can mill both wood and aluminum.

I am interested in building a machine that has about a 2'X3' cutting area, what do I need to consider so I can cut both materials on it?

[abomb55076]

You need to make sure the machine is rigid. You dont want any torque. Also, making sure everything is aligned properly is a main factor you must consider when your building your machine. Finally, as for the materials you can cut, that mostly depends on your router or spindle. You just need to find the right feed rate and spindle speed for the material. Good Luck!

[Eurisko]

I love aluminum. It's cheap, strong and easily machined. There are times, though, when it tends to weld itself to your cutters. Excessive heat and friction is a no-no.

Try tapping aluminum dry and you'll see what I mean. Add a lubricant (WD-40 or mineral oil, spray or mist) to keep the aluminum from "loading up" on the cutter. Aluminum buildup on a cutter leads to very ugly surface finishes and tool breakage.

Some CNCZoners use compressed air to keep the chips clear and to dissipate excess heat. Spindle speed has to be controlled. You can't run every tool at 25,000 rpms in aluminum.

[ahren]

A key for cutting aluminum with a router is to keep the spindle speed down -- a decent rough formula is 2000 RPM / cutter diameter. So for a 1/4" tool, you really want to be around 8000 RPM. The Hitachi M12VC is variable speed, and actually goes this low.

For a good (free) set of 2 x 3 plans, Nate Lowrie of www.finelineautomation.com and I have just released some in the open source plans section. They are also available on both of our websites.

Best of luck!

Ahren
www.cncrouterparts.com

[TMc]

Thank you for the great information. As mentioned I do a lot of woodworking and have a number of woodworking router bits. Do you use the same bits on aluminum or do you need to have special bits?

Thanks again,

TMc

[jsheerin]

You'll want an endmill. You can find them at MSC among many other places. There are specific ones for aluminum, but I find regular ones (typically for steel) work as well. Somewhat like router bits, there are all different kinds.