Welded DIY just because.
First, I have a multicam and a axyz machine in my shop, so this is not a real "need". I have rebuilt, repaired, bought and sold several machines. I ran across a set of round linear shafts and bearings along with a leadscrew with delrin nut for the z for a very cheap price. My neighbor has a steel rack pretty well stocked and he always told me to take anything I wanted. So with inexpensive rails and free steel, I figured what the heck.
I have a background in welding, mechanics, and electronic's.
I am at the point of having all axis moving smoothly and the Z working with a drill on the shaft. I have a set of nema 34 motors and leadshine drivers. The electrical end is easy for me, so I am leaving that for last.
Cutting size is working out to be 25"x37" with a 7 inch Z stroke.
I am doing this a little odd, because I had no real plan or drawings going into it. Welding and dealing with steel moving was interesting. I did some welding on the opposite sides of parts to pull things back and was selective about where to weld and where not to weld.
I am unshure if I want to buy more lead screws (5 start 1/2" is what I'm looking at), rack and pinion, or ball screws. At this time I have about $300 dollars in this build. My thought was to keep it cheap, but it's solid and smooth. I am looking for thoughts on placement and choices of drive systems.
Ken
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Re: Welded DIY just because.
Oh WOW is that frame rusty! You are going to treat it with some rust converter & paint it, right?
As for the axis drives, I think I'd probably go for a rack&pinion setup; so you don't have to worry about screws whipping during rapids.
I have no personal experience with their products, so I can't recommend for or against them, but... this is the sort of setup I was thinking about:
Standard Rack and Pinion Drive, NEMA 23 | Avid CNC | CNC Router Parts
Re: Welded DIY just because.
It's not a big enough machine to be worrying about screws whipping if he has a Ballscrew of 20mm dia or bigger would be fineOriginally Posted by __Britt
Oh WOW is that frame rusty! You are going to treat it with some rust converter & paint it, right?
As for the axis drives, I think I'd probably go for a rack&pinion setup; so you don't have to worry about screws whipping during rapids.
I have no personal experience with their products, so I can't recommend for or against them, but... this is the sort of setup I was thinking about:
Standard Rack and Pinion Drive, NEMA 23 | Avid CNC | CNC Router Parts
The leadscrews would be a waste of time installing them, with what you have for this machine
Mactec54
Re: Welded DIY just because.
Rack and pinion are cheaper but you can get some cheap Ballscrews as well which are still better than a Rack and pinion
Mactec54
Re: Welded DIY just because.
Eh... yeah; I suppose. Just had a quick look on eBay; this is the first thing that popped up (not a recommendation - it's literally just the first link I found):
https://www.ebay.com/itm/Antibacklas...g/263897799531
I would tend to think that a stepper big enough to be a NEMA 34 would probably have enough torque to handle the 10mm/turn of that ballscrew; and with the ballscrew being so steep you'd get good rapids out of it. Assuming the motor is 200 steps per rev; and the drive is set to 16 microsteps; doing the math on that 10mm/turn ballscrew yields 0.003125mm/step, or 0.000123031496063in/step.
Re: Welded DIY just because.
The motors are in the 900 in oz range so I have plenty. The little thing is very solid, strong, and straight. I guess I'll pony up for some ball screws. Maybe replace the lead screw on the z that came with the slides. The surface rust doesn't bother me and I'll fix that. I am still welding a little here and there, so clean up and paint will be later.
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