@George_Allen you are entering a confusing phase of DIY CNC. Or the more you understand the more sense you can make out of an opaque process. Getting stepper motors running good is a bit of a trick. But your controller is giving you information. You have to pay attention to what your senses are telling you too. One thing I’d try if I was you would be turning your drive current setting down and seeing how your motors run. Also if you are using an adjustable SMPS turn the voltage up some on it. TB6600 drives can handle at least 32V input. Stepper motors are going to run a lot better at 32V than 24V. I know it sounds trivial it did to me but I’ve seen the difference. Night and day would be one way of putting it. Then you’re going to have to time trial your machine a lot. Run it back and forth at different feed rates. The faster it can go the better. There’s two signs of stepper motor over current. One is when you’re holding (the machine is powered on but not actually moving) the motors get really hot. They should get warm. But they should not be like wholly crap they’re burning up hot. The other sign is when they’re moving they run rough. It is often called cogging. Each step seems to hang up a bit. This is due to coil flux (magnetic force) just being too high. You want the Jamaican bobsled team effect. Smooth and cool runnings. Stepper motors are basically ass backwards to the way one would intuitively think a motor should work. Less current can make them go faster and stronger. Stupid, I know. But stepper motors trip up over too much current. So give turning your current settings down a try. You’re not going to burn anything up by using less current. If you have Wang Hung Lo brand Chinese stepper motors the specs are probably a complete fabrication. So you’re going to have to play it by ear to dial them in. All you can do is keep testing and adjusting and seeing what works best.
@George_Allen there’s one other spec that is critical that I don’t think anyone mentioned. That is setup and hold times. Motor drives need timing signals a certain width in order to trigger on them. You’re better off erring on too wide than too narrow. Though the wider you go the less data changes you can make. If you’re right on your setup timing lines your drives will run stupid. They’ll trigger sometimes and not trigger others. That’s bad. So you might have to bump that up a bit. Though a lot of controllers (Mach 3 is a controller) the default is a very conservative value. Wasting too much time setting up isn’t good either. One big difference between good and bad drives is setup time though. Better drives need less setup time. The time spent setting up is time not spent running. So it is a value you’re going to have to pay attention to. Your drives probably have a spec which may or may not be right. You find out how off it is by increasing the setup time and seeing if that helps things. If it does then your specs are crock. The spec is given as a minimum and not everything can run right on the line. You might have to add a bit of setup is what I’m saying. But the less you have to add the better.
@Paul_Frederick It doesn’t seem like I clear one hurdle and two more pop up. Yes, when I ran my Ox, there was always a challenge to get my Steppers the right current for them to work optimally. With my reprap 3D printer too, although that included not burning them up.
I do intend to learn Linux CNC. How much I get into it depends on whether it will work with my machines and how well.
@George_Allen LinuxCNC has a GUI setup wizard now so there’s not a lot of learning required. You install the image, run the wizard which presents you with a few windows of parameters you need to fill out and you’re done. Then you have an icon on your desktop called launch my mill. Easy peasy lemon squeezy.
You can see the wizard here http://linuxcnc.org/docs/html/config/stepconf.html
@Paul_Frederick Thanks. Maybe that’s the problem. I’ve actually seen that type of parameter in Mach, but not in others. I guess that’s listed on the others when you do a gcode system analysis of your setup, but I didn’t always look deeply at everything. Since using Mach I see more and more adjustments that you can make that I really don’t understand. The one thing in all of them that is a bit Greek to me is the buffer. Most of the time with TinyG I would just close the program and reopen between runs.
The smooth Stepper plugin has a default of one thing at 1 kHz and then defaults for each axis for something I think at 256 kHz each. I could be wrong on those, but one of those sounds maybe like what you are talking about. It has to do with processing the data from the computer. As others have stated, Windows PC isn’t great about prioritizing the data being sent to the machine, thus they discourage going above 1khz, especially with older types of machines. I thought I had a relatively fast PC, but I may not. I will have to check the processor
I’m more of a tinkerer than an engineer. My educational background was in Chemistry & Psychology. I did have a fair amount of instrumentation in Chemistry & statistical analysis in psychology, but that was as close as it comes. I actually did poorly in drafting & many “hands-on” types of things because it would take me longer to complete than others in the class. I found out later, I would usually have the correct answer more often than most, it just took me longer to process the question and give an answer. Anyways, all that to say, I’m more like a “jack of this trade” than “a master,” but I’m picking much of it up faster than I thought I would.
@George_Allen you are using a smoothstepper hardware pulse generator board?
Another thing I’m having difficulty with are the switches & multiple names/kinds for each: I have several (a surplus) NPN proximity sensors that I bought from China and decided I might use them for limit switches and thought it wouldn’t be too complicated wiring them up. Initially, I thought NPN & PNP were technical designations for normally open and normally closed. But, not so, you can have an NPN-normally open or normally closed as well as having a PNP Normally open or normally closed. I was, however, able to surmise that my sensors were NPN (stated on label) normally closed (concluded due to the fact that the light was on in its normal state and went off when an object came within about an inch of the sensor). But, even knowing what kind of sensor it is hasn’t shown me exactly how it should be wired to the BOB. I’m pretty sure I can figure it out if I wire them up independently, but I haven’t had success experimenting with putting them on, either in series or parallel. Also, it is required to have a pull-up resistor to lower the voltages to about 5v to allow the input signal to go to the BOB. Then, after I figure that out, I have to insure that my estop, a Single Pole Double Throw SPDT, (I think) switch needs to be wired. Couple all that with trying to wire a water flow meter to the estop as well as trying to figure out, 1) if I can wire the other limit switches that I currently have to the machine (because I just saw the writing on them that they were 250 VAC, if the proximity sensors don’t work, and I’m now about to pull my hair out. I didn’t think limit switches would be a specific voltage & type of current, I thought they would just open or close a circuit. So, I don’t know if they will work for 24v DC.
Oh yes, I need to connect a vacuum and tool coolant. Ah, “so much time and so little to do…oh, strike that, reverse it.”
- Willie Wonka@Jim_Fong Yes, Ethernet Smooth Stepper.
@Jim_Fong It took me forever to get it to move my Steppers, but I finally got it. But, I still can’t get my axes tuned. I put in the values you gave, but, either my dip switches are wrong or my velocities and accelerations are wrong because I keep getting various types of stammers & stutters.
@George_Allen I do not know about a buffer either in CNC. I have never run into it myself. Whatever buffering LinuxCNC does is not made visible to the user. That’s something it just does on its own. Setup time is a hardware limitation of motor drives. It varies from model to model. So Mach 3 needs to know what your drives setup time is so it can make the signals it sends to your motor drives correctly. Being a time the value is usually expressed in nanoseconds, not frequency.
machine controller latency is another of those catch 22 scenarios. “Fast” PCs are made to perform software tasks quickly. Real time control is not usually a particularly challenging software task though. What matters is how fast a bit of information can travel through the whole system. So a simpler system can push the bit through faster. Then it has a lower latency. Even if it is not as “Powerful”. When you don’t need power it doesn’t help you any to have it. And in this case it actually hurts.
@Paul_Frederick Oh yes, I saw that in motor tuning. You think I should try increasing that slightly? The problems I am currently experiencing have been on my X-axis, which has my DM542T Driver running the motor (ironically one of my more expensive drivers). It is a digital driver, that doesn’t have to be setup differently than the TB6600s, do they? I’m having more troubles with my more expensive equipment…crazy. The TB6600s seem to be working okay. The DM542T is set for the lowest microstepping it can be: 400 pulses per revolution. It can go up to the several thousands.
@George_Allen what you need to do is go from slow to fast. If you detune everything you should run smooth, but slow. Then you keep turning everything up to go faster. As soon as you turn something up too much and you run rough again back off. Then keep turning everything else up to go faster. Eventually you’ll hit your peak performance plateau. So you turn down your current and turn up your setup times. Then you test. And turn up your current and lower your setup times incrementally. You should have your acceleration low too. Eventually you should find the balance where your machine works best. But there’s always going to be a speed breakover point. You can’t confuse that with having something else set wrong. Then you’re just going too fast for your present settings. There’s always going to be a too fast. Your goal is to push too fast as far up as you can get it. But it is going to be a combination of current, setup time, and acceleration. That’s probably the order you should tackle them in too. Find your current level then find your right setup time, then see how fast you can accelerate and how fast you can go. But initially run a low current, a high setup time, and a slow acceleration. First bump up the current until you see it is too high. When you hold the motors get too hot, and it runs crappy. So back that off. Then keep reducing the setup time until the drives are not running right anymore, then increase that some. Then finally keep increasing your acceleration until your machine can’t get going anymore. Although really high acceleration can be kind of herkey jerky. Like if your machine starts hopping around you might want to back off some and call it a day. There are physical limits. Use common sense. Not that I always have. It is easy to start playing we’re at the track with all of this. Faster faster! At one point I had my lead screws going 2,000 RPM. Let 'er rip!
@Paul_Frederick What I cannot figure though, is initially, when the speeds and steps per unit were up, it would at least move when I did a g0 move. Now that everything has been lowered so much, sometimes, I only get a chirp from the motor, if that.
@Paul_Frederick I should add that running my leads at 2K RPM burnt out my X axis lead nut. It took me a while to figure out I’d done it too. With the nut stripped it caused jobs to run funny. I thought it was an electrical problem. Then I thought it was a problem with my linear guides. Then I finally figured it out. But this is what I saw the plot on the left is distorted http://i.imgur.com/vVdcSLx.jpg
@George_Allen OH SHIT! did not know that. You have one of the better hardware pulse generation systems available. I don’t even have one. This is way better than Linuxcnc, in my opinion.
You don’t need a particularly fast PC since the smoothstepper handles all the hard work externally. From pulse generation to limit switching etc. This board does Megahertz stepper pulsing with very low latency.
First of all looks like your running Mach3 in Demo mode. I believe none of the external hardware plugins will correctly work without a licensed copy of Mach3.
Second I can’t help with configuration of the smoothstepper. I just don’t know it. There is a few parameters that need to be configured right. They have a user forum that have well versed Mach3 and smoothstepper users. You will get much better help then here. Smoothstepper has been around a long time with many many users with real cnc experience. There is to much “wrong and silly info” given to you here, much doesn’t pertain to setup of smoothstepper.
@Paul_Frederick Are you running an acme screw, and a metal nut or Delrin?
@Jim_Fong Yes, I got a pretty good deal off of eBay, I think. The controller wasn’t much more than that single gecko driver I bought. It was “pre-owned” and I bought it for $125. Seems to work okay, after I finally got it configured. There was one step in the configuration of it I had trouble with. And, I finally ditched Mach4. I couldn’t get it to work.