New to DIY CNC. Do these parts make sense?
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I know I'm still missing a PSU, but I wasn't really sure how to pick them out. I'll make most of the body out of some thick mdf I have lying around and the 2x4's I included. Are those motors sufficient to power a large CNC machine that will only be cutting things wood and softer? Any help and any advice would be greatly appreciated.
I'll have all of the screw stuff reinforced with laser cut delrin, and additional inserts made out of either acrylic or plywood.
Thanks in advance.
azb_
Re: New to DIY CNC. Do these parts make sense?
Not most of them. The smooth rods you're specifying are too thin, and lack support, which is essential if you want a machine that won't vibrate too much. The hardware-store threaded rods lack precision, and will tend to hang up due to their irregularity. 2x4s will work to build a table to mount a router, but they move around too much to use for critical parts. The motors want 50vDC but the drivers max out at 42vDC - it should still work, but you won't get the full performance the motor can deliver.
Re: New to DIY CNC. Do these parts make sense?
It hard to say with out a design to look at.
I used these bearing 608ZZ VXB Bearing Search Results | Search for Bearings Today little cheaper but they are 8mm ID.
Re: New to DIY CNC. Do these parts make sense?
Thanks for the advice. Where/what kind of threaded rods would you suggest instead and where would I buy them? Also, roughly how thick should the support metal beams be? Also, where did you see that 50V number, and how should that influence my PSU choice?
Re: New to DIY CNC. Do these parts make sense?
As Steve said, it's hard to say what's going to work for a design you haven't shared with us. Acme screws with trapezoidal thread profiles work better than screws with sharp thread profiles. Here's one place to buy them: Kerk 1/2" (13mm) Lead Screw . Support beams need to be proportional to the distances they span. The 50v number is calculated from the 2.5mH inductance of those motors. The formula (square root of the inductance times 32) gives the optimum voltage a stepper should be supplied with to perform at maximum speed. But the drivers you use have to be able to handle it too. It's advisable to build your frame first, and shop for motors and electronics last, once you've settled on a final design, since things are liable to change in the course of a build.
Re: New to DIY CNC. Do these parts make sense?
So you need a 50 v power supply and different driver or you need different stepper.
Now I am going to go against the wisdom of the board but I have found the threaded 1/2 x13 rod workable for a first build on a budget. It what I am using on my wood / aluminium / plastic DIY CNC.
As awerby said design the machine first, If you have not used a CAD program before. It will give a place to learn, look at fusion 360 it free for hobby user and you can use it as you CAM program later.
Re: New to DIY CNC. Do these parts make sense?
What are you planning for travels, and what are you planning on using for your linear bearings?
Using plain threaded rod for your lead screws has 3 major downsides. Efficiency is terrible, normal 60 degree threads are for holding, not for moving. They're designed to bind when tightened. Threaded rod doesn't tend to be all that straight, so it tends to cause vibration. Backlash will probably tend to be worse as well.
