[dvirb]

Hi guys,

I am thinking about the option of building a 3 axis CNC using parts (after I have been told that any of the budget "chinese" frames are not rigit enough to machine small steel parts)

I was thinking about assembling my axis from parts.
I know where to get an x and y axis that are solid steel (from a manual milling machine for an example - I guess these could be converted to CNC ?)

but I was unable to find a z axis that is steel, most of them are made of thick 6061T6 aluminum.

I have heard that 6061T6 aluminum is almost as strong as steel, but I can not confirm this with relating this to a CNC machine.

x + y axis solid steel (converted to CNC from a manual mill) and the z axis made of 6061T6 aluminum - Is that any good ?

I am interested in building a machine that will be able to machine small steel (and possibly stainless) parts.


Any input will be appreciated

thanks!

[twoartistic]

You can build your CNC out of steel or aluminum, or steel and aluminum. You could even make the case that you could build it out of plastic or wood for the frame. Will it still work, yes, but you would have to adjust how you program your parts. The reason an all steel heavy machine is superior, is mass. Lots of heavy steel castings keep things rigid, and reduce chatter. In general, the heavier the machine, the more rigid the machine is, the more stable the machine will be. That results in the ability to use bigger tools, bigger cuts, shorter run times.

Depending on how large the parts that you want to cut are, you may want to consider finding a used knee mill. I helped a friend do a conversion. We built all the parts on my CNC, used a Mach controller with servos. He also had an old school machinist go through his table and tighten and align it all up. All said and done he was into his system for under $7K and he runs parts on it everyday. Getting the z-axis set up was the most challenging part, as it required considerable thought to be able to make it function both as a CNC, and manually for things like simple hole drilling.

When I built my CNC I was in a location that didn't have any machine shops with a table motion large enough to machine my biggest plates. So I built my machine with temporary MDF, plywood and oak parts, then used my machine to make my own aluminum plates. I had to take very shallow slow passes to cut the 1/2" thick plates, but it did the job, and now my machine is all aluminum (I use mine for wood and plastic).

Good luck on your machine.