Custom CNC machine Gantry with 240mm Z-Axis stroke

grabcad

This is a design I decided to model up so people could have a good place to start when designing a solid hobby CNC machine. Keep in mind the main gantry beam uses an 80 x 160mm aluminum extrusion along with 20mm linear rails and bearing blocks. I used what I own which is NSK but even the HiWin and HiWin knock-offs will fit as long as they are flanged 4 hole blocks. The ballscrew is also an NSK and is a 20mm with a 16mm lead as it's also what I own so I cross checked my measurements with those of a model I found on NSK's website to make sure they were the same. The Teknic Clearpath servo is a NEMA34 but can be substituted for any NEMA34 you'd like to use as the bolt pattern is the same. Also, I reused my CNC Depot FM30 ATC spindle model as it's what I had handy and looks great with the red anodizing on the aluminum parts. However, this can also be substituted for any spindle you'd like to use you will just have to add in mounting holes for your spindle mount. This will take 25mm (or 1inch) thick aluminum plate to get the clearance needed for the ballscrew nut. I also use 10mm aluminum plate for some other smaller parts. These parts will have double side machining so if you don't think you can pull double sided ops off I'd just spot drill the holes for the bearing block bolts and then use a drill press to finish the job as well as tapping the holes for the M5, M6 and M8 bolts. I have modeled all threads for every hole if that helps any of you out. I just use my pitch and offset measurements for threaded holes and use a thread mill. To each their own. This should be a very rigid gantry and Z-axis if done correctly. The extra bracing down each side of the spindle reduces the flex that can occur with longer spindle mount plates even if they are thick (18mm+). So i wouldn't forgo these if you are serious about rigidity and good surface finish. As usual, if you have any questions just drop me a comment and I'll get back to you as soon as I canYou will also need to design your X-Axis motion system as I left this out of the model intentionally. Everyone seems to do things differently and some put the ballscrew on the back of the gantry beam and some put it on the top. Myself, I usually put it on the top as it's further from the debris and gets less dust and stuff on it than it does at the back or front. But that's your call, put it wherever you like just add the necessary components to facilitate how you plan to mount it. Good luck!!