Thread: 3-axis cnc for cutting aluminium.

**george_grat** · 07-23-2013, 07:40 PM

Hello guys,

I am new in this hobby and after many readings I diside to create one CNC for cutting aluminium.
The dimension of cnc will be 1200χ1100χ400. I have already buy (on his way) the below equipments:

3pcs ballscrew RM1605-1150/850/450mm with ballnuts3pcs end machined.
3pcs support linear rail SBR16-1100/800/400mm(6pcs linear rail+12pcs SBR16UU blocks)
3sets of BK/BF12 end support.
3pcs couplers*6.35*10mm

Do you thing the above equipments to create one strong cnc? I am thinking to buy stepper motor nema 32 3χ 1600οz?

Please advice

**awerby** · 07-23-2013, 09:56 PM

Those components might work if you attach them to a frame that's heavy-duty enough. But the typical moving-gantry routers framed in MDF or light aluminum extrusions that you see people making here, while okay for foam, plastics or wood, are less than adequate for milling aluminum. When designing your frame, rigidity is the key factor you'll need to maximize. Have you settled on a design yet?

Andrew Werby
www.computersculpture.com

**george_grat** · 07-23-2013, 10:19 PM

First of all I would like to thank you for your reply.
Honestly not yet but I thinking to create something like the picture below:
Attachment 193168

Just only the frame not the others. I am thinking to make bigger base for the rails apprx. 120x60 square cubes around the base.

**awerby** · 07-24-2013, 10:35 PM

That design might work to some extent, but it's pretty minimal if you're serious about cutting aluminum. I'd say making it about twice as heavy-duty - larger steel members with greater wall-thickness for the parts that don't move, and some X-bracing wherever you can fit it. For the gantry, you might consider using aluminum rather than steel, to cut down on the weight you're pushing around. Try to figure out how much torque you need to reverse direction on the gantry at top speed, before buying the motors. That frame looks like it was set up for rack-and-pinion drive, so you'll need to do things a little differently to make room for your ballscrews.

Andrew Werby
www.computersculpture.com

**george_grat** · 07-25-2013, 07:40 AM

Do I have to buy 2 motors for the x one for the z and one for the y? Because I am thinking to buy 3 motors instead of 4.

**awerby** · 07-25-2013, 10:13 PM

Using two motors on the X axis is good, because it avoids the "stuck drawer effect" you get from trying to push from one side or the middle. It also gives you a way to square the axis, which can be a problem, and gives extra power to the heaviest axis. It's optional, not mandatory, but the expense of an extra motor and drive might be insignificant in contrast with the problems they help you avoid.

Andrew Werby
www.computersculpture.com