New Machine Build- small DIY CNC

[jan4321]

I made a theard before but i posted it into the FAQ.
I am new at chczone and i want to build a small cnc.
here are some pictures:




The green things are rails. the blue things are NEMA17 steppers controlled by a tb6560.
The onerthings are made of wood and metal. The z Axis is not finished jet.
What do you think about this cnc? Do you have any suggestions?

[bobsch]

If you drive your x axis only from one side you will have a serious racking problem. Either move the x drive to the middle or drive it from both sides.

[jan4321]

yes, i think i can put the x axis to the bottom of the box and make a moving table. (the table is about the sice of an A4 paper)
like this:

[awerby]

If you're switching from a moving gantry to a fixed bridge design, you don't need those high walls to support your Y axis. Make your bridge more rigid with triangulated bracing; if it doesn't have to move it can be as heavy as needed. You'll need more length in the X rails to give yourself the ability to reach the far edges of your workpiece. I don't understand how the Z axis is supposed to work; are you planning to move it manually? NEMA 17 motors are too small; get NEMA 23s instead. In a machine as small as this, material costs won't be a big factor; I'd use metal instead of wood, except perhaps as a spoilboard on top of the table.

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[RCaffin]

Either way the X and Y axes are OK, but the Z-axis has a real problem. The two rails on the y-axis are far to close together, and the tip of the Z-axis will deflect in the X direction.

Cheers