Missing Steps?

[drxlcarfreak]

If you were going to switch to Nema 34, I'd recommend going with the CNC Router Parts motors. While they cost more, you know that they'll work, as they've been used on hundreds of machines. I don't think you want to buy something cheaper, and hope that they'll work.

Ugh, that makes too much sense! Haha. Unfortunately swapping to the the CNCRP motors, it looks like I would need new drives and a bigger power supply to keep up! The other ones just barely squeaked by with my PS and drives. That will take some more self convincing to buy that and redo the wiring for the machine, but I did graph it out vs the ones I linked above, whew they have substantially more torque across the range, at least 50% higher through 1000IPM, not that I would go there. I did notice that the Nema 23 graph stops at 400IPM. I wonder why they didn't wind it out farther, I wonder if the torque starts dropping off significantly after that.

This morning I got a response back from the manufacturer and said something that confused me, but also confirmed that the driver should be set that the RMS rating matches the torque of the motor, which is the very highest setting I mentioned above. He also noted that the driver does not match the motor because it is a Nema 34 motor and it may cause poor driving. That didn't really make sense to me. I thought that the driver just puts out pulses and it is a universal pulse no matter the nema configuration. Regardless of that confusion, I did up the amperages this morning, the Z didn't seem to like it so much as it skipped for the first time ever so I will drop that one back down, but I upped the velocity and speed of the X&Y and ran two operations back to back and it performed very well! They were very hot towards the end, but I could hold my hand on all of the motors. It seems as if I may have been under driving the motors? I will test this quite a bit more before I reach a final conclusion though. That was all the time I had before work this morning. I do also plan to still replace all of the bearings tonight as well and try to get the gantry perfectly true before tightening down the bolts. Hopefully I can report back with a couple finished pieces!

[wmgeorge]

I agree with Gerry 100%, get your parts from cncrouterparts. a good NEMA 23 motor complete setup should work however. I would contact them and buy what they suggest, if they say 34 go that route. Your Chinese vender does not even know what he sold you!!

[drxlcarfreak]

I agree with Gerry 100%, get your parts from cncrouterparts. a good NEMA 23 motor complete setup should work however. I would contact them and buy what they suggest, if they say 34 go that route. Your Chinese vender does not even know what he sold you!!

Yeah, I agree too. Kind of bit off more than I can chew my first time out. Kind of hard to learn CNCing and programming etc when I'm not sure what's an issue with me or an issue with the machine. I have a quote I am waiting for back from them, hope to get it tomorrow. A 23 setup should definitely do it, but after getting frustrated the upgrade bug got to me, I would probably never fully use the 34 but I am justifying it to myself because I plan to use these motors for a plasma cutter. Yeah, I was under the impression that they are a reputable company, not an eBay style company, but I may have been wrong.

So. I apparently work slower than I thought, but I did get all of the bearings replaced on the Y axis tonight and ran a program moving it back and forth between G0 and G1. I ran it for 20 minutes with the spindle on and off. I dropped it back down to zero location and it was off maybe 1/64", the rapids were back up to 400/30 and I had the cutting motion accelerated to about 300 because I was getting bored. I am not saying it's fixed, but at this point I am cautiously optimistic. The gantry also runs a lot smoother on the rails now and all of the bearings are making contact to the rails. Tomorrow I'll replace the bearings in the X and see if there is an improvement there as well.

[drxlcarfreak]

So, a little update. I replaced the X axis bearings last night as well. Ran two test cuts again with the rapids at 400/30, which ran perfectly, so I decided to try out an actual first test piece. Other than the board moving a tiny bit on me because I didn't have it clamped down tight enough, it performed great! So, knock on wood replacing the bearings as well as changing the amperage settings on the drive really seemed to make the machine start working.

I am not sure if a bunch of bearings were bad from me initially cranking on it, or repeatedly hitting the bumpers broke them or pulled the machine out of square or what it was, but it really seems to be working much better now. Thanks for all of your help guys!

Now to get the idea of upgrading to Nema34 out of my head...

[wmgeorge]

Yes for the size of your machine 23's should work with the right settings. On my table I am going to use two layers of board. First on a 1/2 inch multi ply sheet of plywood, top sheet 1/2 inch good MDF. I am installing tracks and will use clamps and I have the option of course to use screws.

[ger21]

So, a little update. I replaced the X axis bearings last night as well. Ran two test cuts again with the rapids at 400/30, which ran perfectly, so I decided to try out an actual first test piece. Other than the board moving a tiny bit on me because I didn't have it clamped down tight enough, it performed great! So, knock on wood replacing the bearings as well as changing the amperage settings on the drive really seemed to make the machine start working.

This shows two things.
1) If you are running near the edge of the systems capabilities, then it doesn't take much binding,or friction, to cause lost steps.
2) You are running near the edge of your systems capabilities.

as well as changing the amperage settings on the drive

I thought that everything I had ever read said to use the Peak setting on the drives. I just googled to confirm what I thought, and just about everything I read seemed to confirm that.
Then I found a post here from Leadshine themselves, which states that the RMS value is the correct one to use. So, you definitely were not getting the full power out of your motors.

I would do some more testing, slowly increasing velocity until you see stalling or missed steps. Then back it off by about 20%. This should help to find a reliable speed to run the machine at.

[automationtechinc]

This shows two things.
1) If you are running near the edge of the systems capabilities, then it doesn't take much binding,or friction, to cause lost steps.
2) You are running near the edge of your systems capabilities.

I thought that everything I had ever read said to use the Peak setting on the drives. I just googled to confirm what I thought, and just about everything I read seemed to confirm that.
Then I found a post here from Leadshine themselves, which states that the RMS value is the correct one to use. So, you definitely were not getting the full power out of your motors.

I would do some more testing, slowly increasing velocity until you see stalling or missed steps. Then back it off by about 20%. This should help to find a reliable speed to run the machine at.

Pls email me or call me on Monday

I will help you to check step by step

https://www.automationtechnologiesinc.com/

[drxlcarfreak]

Yes for the size of your machine 23's should work with the right settings. On my table I am going to use two layers of board. First on a 1/2 inch multi ply sheet of plywood, top sheet 1/2 inch good MDF. I am installing tracks and will use clamps and I have the option of course to use screws.

I agree, I need to start playing with it now that it seems like I am running more stable. I started cutting the spoil board mounts last night. I probably ran the machine for a solid 2-3 hours and she seemed fine sticking with my normal rapids. I plan on doing something similar, with 2 sheets of 3/4" MDF. I plan to use dogholes and friction clamps, but those tracks are really starting to grow on me. I may add those to the outside perimeter for the larger pieces I cant squeeze in the footprint of the machine. I really need to start playing with my feeds/speeds for cutting mdf, my cuts need quite a bit of sanding to get them looking smooth.

This shows two things.
1) If you are running near the edge of the systems capabilities, then it doesn't take much binding,or friction, to cause lost steps.
2) You are running near the edge of your systems capabilities.

I thought that everything I had ever read said to use the Peak setting on the drives. I just googled to confirm what I thought, and just about everything I read seemed to confirm that.
Then I found a post here from Leadshine themselves, which states that the RMS value is the correct one to use. So, you definitely were not getting the full power out of your motors.

I would do some more testing, slowly increasing velocity until you see stalling or missed steps. Then back it off by about 20%. This should help to find a reliable speed to run the machine at.

Yep, I agree. I want to get sweeps on the rails asap to keep any dust down so it is less of an issue long term. They run a boat load better now than they did giving them more amperage! I bumped it up quite a bit, I think to 750 or so and it started stalling on me, around 600 it actually seemed fine. Right now, I am running it at 400, to make sure that it cuts reliably. After I get the spoil boards cut out, I will start testing the rapids again.. After looking at the torque curve of the motors again they stop really low, so I am guessing there is a rapid drop off of torque after 400rpm which is why they didn't plot it.

Pls email me or call me on Monday

I will help you to check step by step

https://www.automationtechnologiesinc.com/

Hey, I actually am not running your steppers or drives, but I do like your offerings. I will send you a message!