Fixed Gantry CNC Router

I am building a fixed gantry style CNC router. This router will have 15mm linear rails and 16mm ball-screws on the X and Y axis, the Z axis will be a unit I adapt from another machine. I should have a cutting area of 380mm X 500mm. I will use openbuilds motors, electronics and software for the control.

I have modeled most of this build in fusion 360, however I am still making decisions and reworking things as I go.


With lots of plates to cut out I have worked out the following technique. I hold down stock with clamps and bore my holes with an 1/8" single flute endmill. Once I have holes I use screws to attach the plate to the waste-board so I can do any contour operations with a 1/4 endmill. Once I am done with the contour cuts I add a chamfer and do any 2-sided work using a shallow pocket in the waste-board if necessary.


The motor for the Y axis will sit under the moving bed, I have mounted it with a pulley and belt to reduce the footprint of the machine.


The gantry is made from 3 25x75mm al extrusions these are bolted together and supported with endplates.


The x axis ball screw is mounted to the gantry with custom spacers.




Here are a few photos from milling the ball screw spacers.



I am reusing a z-axis from another machine, it does not mount directly on rails so I have made an adaptor plate to make it work. I started out by 3d printing a few test pieces to get the hole spacing and mounting height correct. The adaptor plate is made from 5/16 or 8mm plate.


For the bed I have a piece of 3/8 cast plate. So far all I have done with it is to cut it to the rough size. I will be cutting some mounting holes in it soon...