Quotethe_digital_dentist "Tight, but not too tight"- if they can slip on a drive pulley, the belts are definitely too loose. Usually, in a corexy printer, if the belts are so loose they slip on the drive pulleys, there's a problem with the belt positioning relative to the X and Y axis guide rails or linear guides. Be sure the pulleys are positioned so that the belts are parallel to the guide raiby dlc60 - CoreXY Machines
Quotethe_digital_dentist What does it mean that "overpowers the belt" and it slips? Is the belt slipping on the drive pulley or is the motor slipping - i.e. missing steps? Neither of those should happen, especially not at such a low speed. Are the motor and pulley mounts solid? Adequate tension on the belts? Excessive jerk speed or acceleration? High voltage (12V) motors? Low power supply voltageby dlc60 - CoreXY Machines
Well, weeks of effort on fixing this problem has gotten me, pretty much nowhere: Swapped ports for both X and Y - no effect Swapped X and Y steppers (changed the direction of the shift, and found one stepper that was weak and replaced it - didn't fix the problem) Raised the current to 1.2 Amp (no effect), dropped it to .4 Amp(too low to run at all) Changed acceleration, Jerk and even Stealth chopby dlc60 - CoreXY Machines
Quotedc42 If you think the issue may be that the Z axis isn't moving enough, have you tried reducing Z axis acceleration? That is one thing that I am going to try. However, while watching the hot end bang on things as it moved I noticed that my Z carriage was not "flat". The bed was adjusted to be flat but there was a 2mm difference in the carriage from left to right. I balanced the carriageby dlc60 - CoreXY Machines
Quotethe_digital_dentist I think there's something wrong with the Z axis if the nozzle is banging into the print hard enough to cause layers to shift. Indeed. The two lead screws are linked by a belt loop to a single stepper, the same type as the X/Y steppers, so plenty of power and the bed is not heavy. But the thought that plagues me is, why? Why did everything work great for two weeks, and tby dlc60 - CoreXY Machines
I was actually able to be right there when the problem happened this time. The hot end was striking plastic, like the Z had not dropped to the next level. This is a completely different kind of problem. I wonder why it always shifts the same direction? Maybe that belt is looser or that stepper is just a little weaker... This is why my exercise program showed no issue, it drops the Z about 5mmby dlc60 - CoreXY Machines
Quotedlc60 Oh for pity sake. I moved the wrong stepper wire. :| I am running a print now to see if this fixes or changes things. Thanks for the reminder, DLC Using the E2 port acted the same as using the X or the Y port, moved each of them to check. That wasn't it. DLCby dlc60 - CoreXY Machines
Quotethe_digital_dentist What kind of steppers do you have now? Basic specs.... 17HD48002H-22B Nema 17 Stepper Motor 1.7 A, 0.59 Nm I am driving them at 1.0 Amp, I tried driving at 1.3A but the motors got pretty hot, pretty fast, seems like they shouldn't have though since they are rated at 1.7Amp. These seem plenty strong enough. I let the pulleys free-wheel on the stepper shafts and moved theby dlc60 - CoreXY Machines
Quotedlc60 Oh for pity sake. I moved the wrong stepper wire. :| I am running a print now to see if this fixes or changes things. Thanks for the reminder, DLC Moving to another motor port did not help. Time to consider new steppers. DLCby dlc60 - CoreXY Machines
Oh for pity sake. I moved the wrong stepper wire. :| I am running a print now to see if this fixes or changes things. Thanks for the reminder, DLCby dlc60 - CoreXY Machines
Quotedlc60 Quotedc42 Have you tried connecting the Y motor to the E1 motor output yet, to rule out a problem with the driver? I do not see a way to do that in the configurator. How do I reassign Y to E1? EDIT Never mind, I found it. DLC But, no matter how I set P4, the stepper goes the wrong way. The configurator doesn't do anything different. How should I set this then? EDIT What happens isby dlc60 - CoreXY Machines
Quotedc42 Have you tried connecting the Y motor to the E1 motor output yet, to rule out a problem with the driver? I do not see a way to do that in the configurator. How do I reassign Y to E1? EDIT Never mind, I found it. DLCby dlc60 - CoreXY Machines
Quoteruggb Interesting EDIT Well, predictably, the "smoothers" did nothing but make the system louder. I am now out of ideas. is the noise coming from the motors? On mine, they quieted the motors significantly. Overall system. I saw no change in anything with these. I didn't really expect to, but it was worth a try. DLCby dlc60 - CoreXY Machines
QuoteJoergS5 The reason why I ask for M122 and hiccups so many times is the thread But you have a very differect firmware version and no hiccups, so it seems not to be a similar reason. He had write errors at the drivers also, however. My biggest bet would be on the supply voltage min 0.0 volt, but I'm not sure why (and when) this happened. But there is no undervoltage event, so this maybe a vby dlc60 - CoreXY Machines
No dice. Got a layer shift. And, as always seems to happen, Y did not fully home but X did. M122 gives me this, which I don't really know how to read. 6/17/2020, 11:17:10 PM M122 === Diagnostics === RepRapFirmware for Duet 2 Maestro version 3.1.1 running on Duet Maestro 1.0 Board ID: 08DAM-9F9GA-J24TD-6J1DJ-3SS6K-KR1AV Used output buffers: 3 of 24 (20 max) === RTOS === Static ram: 21924 Dynby dlc60 - CoreXY Machines
Quoteruggb OK, let's assume it is getting stuck. It should make some strange noise when it does. Either the pulley is slipping on the motor shaft or the motor is overpowering the belt and skipping over some grooves. If it isn't making a different sound, then the motor is just stopping - which would be even harder to explain. Have you tried slicing it in a different position or at an angle? Thatby dlc60 - CoreXY Machines
Quoteruggb The movement to Y after motors are disabled might be indicating an interaction between motors, or maybe a mechanical issue. Try this, it may help to isolate it. If it homes X and Y independently, both motors need to run for each home. If one motor stops b4 it gets to Y0, the other will gronk. If you enable quick_home and place the carriage at X=100, Y=100, then home it, what happens?by dlc60 - CoreXY Machines
Well, pulling everything apart and having it open worked, for a while, longer than the last several runs. I did the M122. No hiccups, didn't see anything that said errors, two of the stepper drivers said they had 1 timeout. I canceled the print 2hours and 17 minutes in (which is where the large layer shift occurred), would that reset all of the diagnostics about the print? When I canceled theby dlc60 - CoreXY Machines
QuoteJoergS5 The config.g looks ok IMHO. The motor currents are a bit low, but should be ok. An M122 when the problem appears again would be the next I recommend. I will do that. Right now I have removed the board from its enclosure, unbound all of the cables and spread them out, like I had them before I dressed the cables in a spiral wrap and put everything in the enclosure. So far I am 3.1mby dlc60 - CoreXY Machines
Quotemcdanlj Quoteruggb This is what I used; This is even simpler; but I didn't find it till after I installed the above. It mounts under the driver if you have one of these, TMC2100 A4988 Drv8825 I can't vouch for this as I did not order any. Those "smoothers" are not flyback diodes, as used to protect against back-emf from a relay or solenoid coil, and are a workaround for a weakness in soby dlc60 - CoreXY Machines
QuotePDBeal If it only happens on large prints, you could be experiencing temp issues on the driver chip for a particular motor? Section_M305_Set_temperature_sensor_parameters QuoteSection_M305_Set_temperature_sensor_parameters - Channel 1000 is the on-chip microcontroller temperature sensor - Channel 1001 represents the temperature warning and overheat flags on the TMC2660, TMC2224 or other smby dlc60 - Duet
Quotemcdanlj Like ruggb, I can't come up for a mental model by which noise would account for precisely this symptom. Quotedlc60 I will consider that. In looking back, I think that my problems started when I dressed the cables and mounted the Maestro in this enclosure. ... I wonder if some of you have been correct and the problem might be electrical interference since cables go every which way iby dlc60 - CoreXY Machines
Quoteruggb the solution is simpler now than it was when I implemented it. It is also very cheap. For reference when DC is applied or removed from a coil a significant reverse voltage spike is prduced. That spike can fry components, produce extra steps in stepper motors or cause them to miss steps, as it did on my printer. Look at any commercial product driving a relay or other type of coil. Thereby dlc60 - CoreXY Machines
Quoteruggb noise is going to produce random results. It is going to affect higher Z circuits like thermistors and endstops not stepper motors. It will come from stepper motors and fans. Stepper motor noise can be reduced using flyback diodes, which in my case stopped the layer shift I was having. Most all boards have filter caps on higher Z circuits, but that didn't help my thermistors when the wby dlc60 - CoreXY Machines
Quotemcdanlj Quotedlc60 This isn't a big printer, so the 37oz-in steppers _seemed_ to be adequate... The size of the printer isn't highly relevant to how much torque is needed for XY/AB steppers in your corexy. One more thought: Have you tried swapping stepper motors between stations and see if the problem follows the stepper or the station? If you swapped X and Y (or A and and the problem chaby dlc60 - CoreXY Machines
I have a scratch built CoreXY that I recently completed. For a couple of weeks it has worked flawlessly, but now I am getting intermittent diagonal layer shifts toward the "X" stepper (the right one looking from the front). I know this is the direction traveled when the X stepper is running and the Y stepper is not. It seems to happen "mostly" on larger models, more compact models 90% of the timeby dlc60 - Duet
Quotethe_digital_dentist You might try posting a message to the Duet3d forums... Worth a shot. I am out of ideas. Thanks, DLCby dlc60 - CoreXY Machines
Quoteruggb does it have mechanical endstops? do you have pullup or pulldowns? Possibility of noise if the stop point is random But not homing can't be the same issue that is causing the missing steps. If it missed steps on a home it should continue till it hit the endstop. Or do you have some other form of endstop? Mechanical endstops. The end stops are fully powered, and give a digital signal,by dlc60 - CoreXY Machines
Quotethe_digital_dentist The behavior that occurs when you hit "pause" depends on the contents of the pause.g configuration file. Likewise if you then hit "cancel", the next behavior will depend on what's in the cancel.g file (if it exists- it might not). If there's no cancel.g, the tools are deselected and heaters turned off. Thanks for the hint. There is no pause.g, there is a cancel, and itby dlc60 - CoreXY Machines
Well, That binding idler may not have been it, because I still have the problem. I can't find anything clearly wrong with the printer, other than it does this layer shift thing. Does anyone know, on a Duet 2, when you cancel a printer, does it try to home X/Y or does it just try to home X? DLCby dlc60 - CoreXY Machines