Due to problems with the z axis skipping steps I have decided to test out a larger stepper motor. I have tried different thread pitch and adjusted on max amp and torque settings but still having trouble with skipping steps during jobs. This only occurs on the up step and only on z axis so the gantry might be too heavy for the original motor on my setup. I made a simple modification to the print to accept a Nema 17 Stepper Motor Bipolar 1.8deg 65Ncm 2.1A 42x60mm this motor is 12 mm longer.
Made a some long tests and added two kg weights on the gantry to see if it still holds up to the set height and it did.
Ill chime in as well. For sure not the motors. Your rails and or lead screw need to be lubed. And did you check to make sure the XZ plate fell naturally after assembly on the YZ plate? I bet you have a filament “hump” from putting the screws in putting your rails in a bind. And just so happens you didn’t get that on the new set.
As others have noted, it’s not the stepper torque, which amplified through the mechanical advantage of the lead screw and lead nut can easily lift way more than the machine needs.
You have a mechanical issue most likely, or perhaps a very poorly set drive current.
Let’s troubleshoot what’s wrong before you go nuts chasing a problem that isn’t.
IThanks for all reply and solutions. When power is off it plummets smoothly to the bottom and I did lube threads regularly. I decided to rewire the machine anyway because I suspected poor cable and connectors. The print and motor swap was the easy part. To be fair it was not all all jobs it skipped a step but when it did it kind of ruined my job, mostly cutting copper and alloy. My gantry is made of 1.5mm 300mm SS tubing and is fitted wit a led strip so weight wise it should be fine. What the culprit was is unclear but whatever it was it solved the problem.
im a fan of that steppers for the z axis, in fact was thinking about it but decided to build the stock route first. NO you dont need those motors for the z axis to be usable, you had another issue that now is going to stay hidden. (i would look at what your config.yaml and the amps your z axis were run at + speed for the z axis rapids)
It is hard to reconsile skipped steps with some of the weight we’ve put on the gantry and still lifted.
It is also very hard to diagnose exactly where the issues are. An intermittent wiring problem is very tricky. But the fact that it happened more on the way up is a good sign of a wiring issue. If one coil fails, the gantry can “fall” through to the other winding. But it won’t “jump” up to the right one.
Still, having the option for larger nema17s isn’t a terrible choice. Much better than having to use nema23s because a machine shop enthusiast said it was required. I applaud your effort and I’m glad it is working for you.
