[Stnq]

Hello,

First off, sorry if that was already covered, I have searched for the serial number of my motor and stuff, didn't come up with anything. Before I start, I want to say I have read a lot about setting up steps per [...], but I don't believe I fully understand it.

I have recently purchased this: CNC Bausatz 5 Achse Interface-Platine TB6600HG Nema23 Schrittmotor Und Endstufe | eBay

I have wired it up correctly, but the motors did not want to turn. Y axis and Z axis moved just fine, but the X axis had heavier job, it just made noise and didn't move at all. I have set them up differently in terms of micro stepping and output current from here: https://gyazo.com/b714eab779e3ae278c2fb64875fec51c and it simply didn't work.

Do you perhaps have any suggestions as to why it doesn't work?

After I didn't have any more ideas, I remembered I had older drivers (don't know the specifications, as I'm not in the workshop right now and didn't think about writing it down, sorry) - that I connected for the X axis and Y axis and surprise, surprise, it works flawlessly. That would mean that everything is wired correctly and I recall the current output for the old driver is 5.6A I think, not 5A - is that the issue here? If yes, why would they sell drivers not capable of moving stuff with their motors?

That's question number one.

Question number two is a tad more complicated. I'm obviously stuck on steps per mm, as I have always been. I have read a lot about how I should actually do it, as in, with my motor that has 1.8 degree, would be 200 * (microstepping setting) * lead screw/pinch. That last part I don't understand. Where do I check that? How do I find it?

I have them set up at 1/16 microsteps, that would mean 200 * 16 * something else, right? I should also take into consideration that it's belt driven, but *how* exactly should I account for that? Because everywhere I Found, they just wrote "you have to take into consideration that it's belt driven". Well, I do, but I don't know how I should apply it. Please guide me, explain to me how should I accomplish this, I have PTSD whenever I think about this machine.

Question number three would be a lot more complicated to explain - I have previously used the automatic steps setting feature in mach 3 - it has unfortunately failed me and I don't know why.
Let' say I have made a cambam project to cut a 50mm x 50mm square. I have then gcoded it, checked if it actually has the X=50 and what not, loaded it up to mach3 with the automatic steps done and instead of getting a 50x50mm square, I got let's say 83mmx83mm square. I have no idea why. What did I do wrong? Where could the error be?

How do I set it up so that one unit in mach 3 corresponds to actual one centimeter? Is it done through steps per mm? I think so, since changing that changes the distance traveled.

I am truly lost. I keep reading more and more, but without someone to bounce questions off I just...fail. I'm sorry to bother you guys here, but this is four months that I have done it on my own. I can't do it on my own, clearly.

I need your help, thank you for your time.

EDIT: I didn't include the motor name, that would be : Nema23 2.5Nm/354 Oz-in 57BYGH112-401A

EDIT2: To clarify, I have dismantled and reconnected the machine twice, I have swapped the working Y and Z drivers to X axis and it still didn't work. The X driver worked both on Z and Y, but Z and Y had the same issues on X axis.

[James Newton]

If you is working, try swapping X and Y drivers and then put the step and direction signals for you on the X driver.

[Stnq]

Oh, yes, sorry, I forgot to write this - I have swapped each and every driver, cable and whatever there is from working Y and Z to X. The X driver worked everywhere else, the Y and Z didn't work on X much the same. I'll edit the post to clarify this.

Do you perhaps have any thoughts about the rest of the questions?

[James Newton]

Try swapping the step and direction signals from the X axis to the Y axis driver. It may be that the signals from your motion controller aren't working. If the size is wrong, just correct your settings by the percentage error in the size. Easy. Don't overthink things.

[Stnq]

I actually did get that working, so everything is moving. I'm just curious as to *why* did it not work - but I swapped the drivers and everything is ok now (with the older ones, I think 5.6A instead of 5).

Right now the biggest struggle is with the steps per mm, I can't grasp it.

[awerby]

You need to set the steps per unit so that a certain number of them advance the stage one mm. You get there by starting with the number of steps your motor takes to rotate a full turn, which is 200, multiplied by the microstepping factor, which is 16. So now you're at 320 microsteps to rotate once around. Depending on the pitch of your screw, this figure will need to be multiplied again to take that into account. So if your screw takes 2 turns to advance one mm, then it's a two-pitch screw and you're at 640. But if it's a faster screw, which advances 2mm per turn, then you need to multiply by .5, which gets you to 160. The same principle applies to your belt drive; if you're reducing the speed to get more torque, using a 2-to-1 ratio for example, then it takes twice as many steps to go the same distance, so you double the steps per unit. But if you're trading torque for speed, using a 1-to-2 ratio, then you'd halve it. (In general, though, steppers are rarely run with belt reduction, since their torque falls off with speed, so driving it twice as fast doesn't really give you double the torque. It would make more sense to run them slower and use the belts to increase the speed.}

[Stnq]

Thank you for your insight.

I'm guessing it's 3200 microsteps and that's a typo, right? 200*16? But what's the "pitch of the screw"? I'm not a native english speaker, that's why I don't know these terms. Once I get a rough idea of what it is, I'll find it in my machine.

Which screw rotates? Something inside the motor, or maybe the thingie that sticks out of the motor? And how exactly do I establish what "one turn" is? Just jog the motor and check how much the screw has turned?

Again, thanks for your insight, it's very helpful to actually be able to ask the questions, I have read everything you wrote here in bits and pieces, but I can't put it together alone.

[awerby]

Thank you for your insight.

I'm guessing it's 3200 microsteps and that's a typo, right? 200*16?

Right; I dropped a zero.

But what's the "pitch of the screw"? I'm not a native english speaker, that's why I don't know these terms. Once I get a rough idea of what it is, I'll find it in my machine.

[It's the number of threads per unit (mm). You can measure along the screw and count them.]

Which screw rotates? Something inside the motor, or maybe the thingie that sticks out of the motor? And how exactly do I establish what "one turn" is? Just jog the motor and check how much the screw has turned?

The shaft of the motor rotates; it's usually connected to the leadscrew with a coupler so they both rotate. You don't have to establish what one turn is; that's the 200 steps marked on your motor. What you need to measure is the distance traveled when a certain distance is commanded; fortunately on a CNC system the digital readout should tell you that.

Again, thanks for your insight, it's very helpful to actually be able to ask the questions, I have read everything you wrote here in bits and pieces, but I can't put it together alone.

It's not really that hard...

[Stnq]

Huh you quoted your entire post, and I was thinking you just quoted me and said "it's not that hard", heh.

Ok, got the pitch. So you're saying the shaft is connected to the screw, to the coupler? I'm sorry I think I lost it. I assume the screw is *outside* of the motor, pardon my dumb question? From memory I can't figure out what screw you're talking about. Could you please show me on some sort of example machine? I'll then tie it to where my screw is.

Yeah, I know it's 'not that hard', but I have a lot of trouble with getting the proper literature in my native language, and then translating it to german - getting english names everywhere I go on the internet doesn't help either.

Mainly I'm just lost when we go from the point of 200*16 to the "pitch of the screw'. I just don't know which screw. I don't know about any screw near my motor shaft.

If you can show it, I'll probably facepalm and say "obviously". Thanks!

[vakeiros]

hello there, well your problem it's a bit odd since you swapped the working Y and Z to the X axis and still didn't work, my first thought was your driver was bad but you did swapped it so this idea is gone. so did you test disconnecting the motor from the machine and test if it turns with no load? did you tested swapping the X motor for one of the working ones on Y or Z? I'm asking that because it can be a faulty motor instead of a faulty driver. If it's not a faulty driver or motor it should be a bad connection... also check your settings on the driver, and try to increase the micro stepping to 1/4, for your motor and this microsteps you should have the switches like this, from 1 to 6: off on off on on off (3.3Amps and 1/4 stepping).

the second question it's a bit obvious, do you know which ballcrews you have? 1204? 1205? 1605? 1610?... etc... this number means the first 2 digits are the diameter, the second 2 are the pitch, so 1204 is 12mm diameter and 4mm pitch (means 4mm per turn), so your steps per turn with 1/4 microstepping are: 200*4 (since the motor has 200 steps and you are 1/4 microstepping means you need 4 impulses to make an actual step of the motor)

in steps per unit (per mm in your case) you need to divide the previous number by the pitch, if one turn it's, for example 5mm, so to move 1 mm it's 1/5 of one turn, so it's 800/5 so your step per mm it's 160.

now the belt driven, here you need to know the ratio, let's say it's 1:3 meaning it one turn of the motor will turn the axis 3 turns (don't know if this is 1:3 oir 3:1 but it's the same logic), this means you'll need 1/3 of the steps to move the machine the same distance if you had direct driven axis.

so according to the previous calculations you'll have 160/3 = 53.33333333 step per mm

if it's a 3:1 ratio (1turn of the motor turns the axis 1/3 turns) you'll need 3 times the steps of a direct driven axis, so 160*3=480 steps per unit

you have an option on mach3 to caalibrate the steps where you can say the machine to move X mm on the selected axis and you measure the actual distance traveled and insert on mach3 and it will determine the actual steps per mmm, search for mach 3 calibrate steps per mm or calibrate axis.

hope I'h answer your questions

[Stnq]

It turns with no load without issues. The moment it gets a shred of load it stops and starts...buzzing, I guess. I also swapped the entire motor, since I had a kit for 4 axis. The same with new motor. I'm still thinking that the driver wasn't strong enough (since it has 5A and the old one that's working has 5.6A) if that's even possible.

I also did mix up the microsteps, but in some options it just didn't work at all, it was just a high pitched noise and no movement - no idea why.

As for the ballscrews - I'm not sure I even have them. I have a belt driven machine that connects to the belt in I think 1:1 scale, here are some pictures of how it is connected:

https://gyazo.com/eb9f2b6bca74a55bf81eede86cfcd7b9
https://gyazo.com/4f9c3ed695c1baa0c6c2485b01874f67
https://gyazo.com/a8127cb08ea06dfe09212ec97617a62a
https://gyazo.com/86e8faf89c6fe79672775fa9d5686efd

So is it possible I just don't have the ballscrew? Because I know how it looks like, as I'm using one in my car lifter, and I can't locate anything in this machine. I did not built her though, it was shipped to me in pieces and not functioning, and in the assembly process I did not see anything looking like a ballscrew.

I also assume that it's 1 to 1, because ever so slightly moving the ratchet will instantly move the whole axis. I don't think there's any reduction/increase. I might be wrong though, but I don't know how to test it otherwise. I'm not a CNC professional, I'm a ads designer by trade.

So if we can determine whether or not it's possible to not have ballscrews and just belt driven only, it would be awesome.
Thank you so much for the explanation here, I think I actually grasped how it works.

As for the mach3 calibration - I wrote about it in my OP, I don't know why but when I set it, so I pick X axis, tell it to move 5cm, it moves like 6mm, I will then input the 6mm to the prompt window, then I'll do it again to test it and it actually moves 5cm when I tell it 5cm, it's awesome.

But then I run into a problem when I load the Gcode from cambam, done in cambam, where a square is made in 5cmx5cm dimensions, and the gcode is X=50 or whatever, it won't travel 50mm, it'll travel far more - it has happened every time I tried to calibrate each axis with automated mach3 calibration - it just overshoots the scale or something. That's what I don't understand. What am I doing wrong here?

Because I'd love for it to set up the steps through automated system, but then I run into these problems.

I have one more question though - is the distance moved by the axis directly tied to the number of steps per unit? Because that's how I originally did it, with old motors that I already replaced - I had I think 13.2 steps per mm on Y axis and when I ran Y=10 it actually went 10mm. Mach3 calibrated it at like thousands of steps and instead of Y=10 and going 10mm, it moved like 50+. So is the distance traveled tied to steps per mm?

I hope I make sense huh.

[vakeiros]

yes, from the photos your machine don't have lead/ball screws, it's just a belt driven, usually when we talk in belt driven it's either to use on servos so it reduces the speed increasing the torque or on steppers increasing the speed and making use of the high torque, anyway your system it's not like this.
so in few words, first your drivers have to be set according to the motor, if you're using the motors shown on the link, they are 3A per fase so you have to set the drivers to 3A (3.3 it's the best option on those drivers for that motor). about microstepping the lees you can use the better (closest to 1/1, usually I use 1/2 or 1/4).

about the steps and travel connection, yes they are directly connected because there's no ratio changing I mean, one turn of the motor will always make the machine travel the same distance because there are no gears changing the ratio so that's it it has to be linear, just can't be other way. so if you tell the machine to move 5mm and it moves exactly 5mm, if you tell it to move 50mm it has to move 50mm plain and simple, if it moves less it means either you lost steps or it didn't move the exact 5mm on calibration. if it moves more the only thing that occurs to my head is that it also moved more than 5mm on calibration... these are linear systems so step pulses directly proportional to travel. now there's also the pulse length option, that means that the pulse might not be long enough for the driver "understand them" you may try to increase the value on motor tunning to 10 or 15us... also check the enhanced pulses on mach3 options I think it's called like that, I'm not on my shop right now so I can't be sure about that.... CNC are great machines when working right but when it comes to problems they can braze our heads into pieces....

keep us posted on developments

[Stnq]

So I'm thinking is the cambam post processing in any way responsible for changing the size or something? Is it even possible?

Because I might have worded it wrong, but it's like this - if I calibrate it correctly using mach3 calibration, using that window again and calibrating it again - when I say 5cm, it will move 5 cm.

But when I load Gcode that orders it to make a 5cmx5cm square, it will make it bigger. And that's what I don't understand. Postprocess isues? Calibration issues?

Another problem I have which is probably tied to motor tuning is that my motors don't immidiately stop moving after I stop pressing the button. They travel a bit after that. Is there a set motor tuning set up for my motors that will make it travel ideally? Or do I have to find it myself? If the latter, how do I actually do that?

So no ballscrews involved! Awesome. So the step calculation would be simply 200 * microstepping? That's it?

[vakeiros]

one other thing, please don't mess up with mm and cm, mach ALWAYS talks in mm so let's talk just like it, just mm. the impulse per mm are also tied to microstepping, so let's say, first you can start by doing one thing, it won't be accurate at all but you can test manually, assemble the motor on your machine like everything it's ok than you rotate by hand exactly one full turn (as exact as you can be) and check how far the machine traveled (these will be very rough values but this way you'll have an idea of what you have in hands).

let's say it moved roughly 20mm. now you know one turn moves 20mm, so 200 steps equals 20mm, now what's your microstepping? lets say 1/4, so you'll need 800 pulses for a full turn (200 steps of the motor * 4 from microstepping), 800pulses for 20mm equals 40pulses per mm. this is your base value, than if you calibrate the axis using mach you'll know it has to be a value close to this, maybe a bit more, maybe a bit less but it has to be close...

[Stnq]

Ah so 40 pulses per mm = 40 steps per mm? Got it. I was wondering because everyone here have astronomical numbers like 3200 or 6400 or even more steps per mm, and will the 40 steps per mm not be rough, yanky and what not? I really need a fluid movement, it's why I bought the microstepping motors so I can get the really fluid cut on my plasma cutter.

How do I rotate motor by hand? I mean it's directly connected to the ratchet, I have no way of grabbing it sadly. I guess I could fitget up an extension to the shaft and rotate it that way. One turn of the shaft you say?

I think we might be actually getting somewhere.

Oh! I have another question, since you're so kind to help out. With my old motors and old setup, when I finally got the steps per mm right, it was choppy, yanky and it wasn't fluid at all. Is this related to low amount of steps? If I increase steps, will it go easier? Also, with my old setup when I wanted it to make a circle, it actually did an elipse, bending always in the same direction. Straight cuts were fine, but circles were more elipses, meaning I would cut a 26,5mm hole, it would have 26,5mm on one diagonal, but 27+mm on the other diagonal. I have since picked apart and replaced most of the gear and rods that were there in fear of them not being straight, and have not yet tested how the cirlcles cut yet (due to steps per mm issue), but I want to know if it's possible that the choppy movement would produce such results? It kinda makes sense to me that straight cuts were fine with the choppy movement, but angles and elipses were not.

Also, if I have 1/16 microstepping, will it not be even more fluid? Isn't that the point of microsteps? Because I really need to be precise when I cut 5mm circles and stuff.

[vakeiros]

So I'm thinking is the cambam post processing in any way responsible for changing the size or something? Is it even possible?

Because I might have worded it wrong, but it's like this - if I calibrate it correctly using mach3 calibration, using that window again and calibrating it again - when I say 5cm, it will move 5 cm.

But when I load Gcode that orders it to make a 5cmx5cm square, it will make it bigger. And that's what I don't understand. Postprocess isues? Calibration issues?

Another problem I have which is probably tied to motor tuning is that my motors don't immidiately stop moving after I stop pressing the button. They travel a bit after that. Is there a set motor tuning set up for my motors that will make it travel ideally? Or do I have to find it myself? If the latter, how do I actually do that?

So no ballscrews involved! Awesome. So the step calculation would be simply 200 * microstepping? That's it?

theres a simple way to test this. after calibrate, you can zero your axis the one you want to test make some kind of marking of the position of that axis (I don't even know what kind of machine we are talking about... router? mill? plasma? laser?...) if it's a mill or router you can make like 4 holes on a scrap piece of wood like a square 50mm ou 70mm or whatever but moving the machine manually, like zero X and Y on mach3, make one small hole like with a 3mm drill or so, move x to 50mm make another, move Y to 50mm amke another, move x back to 0 make another and move y back to 0 and it should be on your starting point. report on that. if it's not a mill or router think one other way to check.

one other thing I didn't ask, what about acceleration?? what's your values? they might be too low or too high...

[Stnq]

Oh right. It's a plasma cutter.

As I said, I don't know what to set up in motor tuning with acceleration/speed - is there an universal value for these motors? Because as I said, they're not stopping immidiately when I stop pushing the button - they instead slide a bit further and then stop.

[vakeiros]

those number really depends on the microstepping and the travel of the machine with 1 turn on the motor shaft.

usually elipses coming out instead of circles it's related to backlash, don't know if you're familiar with this term. backlash means that there's a gap between the movement of the motor and the movement of the axis. I've absolutely no experience on plasmas just mills and routers so I don't really know about the accuracy of the cuts. about the linear motion it's all the same basics...

take a look on the motor tuning settings to see the value of the acceleration, steppers don't like a very high acceleration it's a bit of trial and error...

about the hand rotation of the motor shaft, you can move your machine with the keyboard, just make a mark on the pulley with a sharpie and move the axis until it makes a full turn and check how far the machine travelled so you can have an idea on what value of steps per mm you should get.

tunning a cnc machine it's a pain I know... I'd already built 2 machines from scratch and the first one was a pain, but once you get it it's really not that hard you just to have an idea of what you're doing... understand the concepts and that's all.

can I ask why did you changed the motors/drivers?

[Stnq]

Huh backlash is something new for me. How does it actually work, I mean the gap means lost steps or what exactly? Right not it's just an axis, I have dismantled the plasma so we can just discuss in this term.

I will do that with the keyboard after I make the 200 * 16 steps per mm and check if they actually work like that. I will then calibrate it automatically nad check if that works too, so I'll get some proof that it actually goes the desired length.

I changed the motors and the drivers because I *thought* they did not have microstepping option and I believed they didn't have one because they were choppy and not fluid at all. I came to that conclusion when I saw people having 3000+ steps per mm and I had only 13,2 for it to work, so I assumed they didn't have. Turns out they did have, but weren't set up in any way. I didn't know that you physically move switches to set up microstepping and each article I read about it was very vague as to *how* exactly you set up microsteps, assuming everyone reading that already knew how to do so. I also didn't have any instruction manual as that was not a prebuilt machine, so between the choppy and yanky movement and the elipses I just thought that both are related to lack of microstepping and in order to get microstepping I bought a stepper motor with the function.

Lack of knowledge costs money, man, heh.

[vakeiros]

backlash can be related to a number of things, like in ballscrews it's the gap between the rod grooves and the balls, on leadscrews it's the gap between threads but it also can be due to loose pulleys or motor couplers, also a loose motor can induce backlash...anything that make the movement of the motor not pass to the machine instantaneously induce backlash...