Ormerod 2 commissioning issue: vibrating stepper motors

Dear 3D-printing enthousiasts,

I recently bought and assembled an Ormerod 2. Everything went fine up until the commissioning phase.
Out of the 4 stepper motors only the one for the Y-axis/carriage is working as it should. The other 3 (X-, Z-axis and extruder) are all shaking/vibrating and making lots of noise. (kind of like a woodpecker I guess)

At first I thought there was too much resistance on the carriage or gears, or maybe that the belt tension was too high, but the motors show exactly the same behavior when they aren't under any load, so that can't be the problem.

Then I swapped out the motors, in order to find out if they might be at fault. All the motors worked fine when they were connected to the Y-axis loom, and whatever stepper was connected to the X-, Z-axis or extruder-loom started vibrating as soon as I sent the move command. Thus the stepper-motors are definitely not broken.

I looked up the problem online and found that vibrating steppers are usually caused by broken stepperdrivers, bad wiring or lack of current.
On the first startup I made sure the drivers didn't heat up, as is stated in the commissioning part of the user guide. So unless they were broken "out of the box" I don't really think they are at fault. The wiring looms are correctly plugged into the Duet board, so unless they also came broken or miss-wired "out of the box", that is rather unlikely to be the problem...
In the standard config.g file the maximum motor currents are limited to 800 milliamps, except for the Y-axis which has a maximum of 1000 milliamps. I thought I found the problem, but changing all of the to a maximum of 1000 milliamps didn't change a single thing.

I get exactly the same shaking stepper behavior when I sent commands through Pronterface as through the web interface...

All the other electronics work flawlessly: fans, hot-end, heated bed, endstop switch, LEDs and the temperature sensors.

I also reinstalled the (latest) firmware (0.78C) and tried using a different SD-card both without any luck.

Has anybody any idea what the problem might be, and especially, how to solve it? Cause my limited knowledge of assembling 3D-printers (and steppermotors/electronics) has left me clueless...

Greetings,

DidierDeluxe

I'm Hi Didier

You need to make sure you only change 1 item at a time when debugging, as you did with the stepper motors, so you know they are working.

Before disconnecting or re-connecting any of the stepper motors at either end of the wiring loom make sure to power OFF the Duet,
I am paranoid and turn off the PSU and disconnect the USB when I do this.
You may damage the stepper driver chips if you leave power connected when moving the connector.

You have proved that the Y-axis works, so the Y-axis wiring loom, and stepper motor are OK.
You can use these working parts to continue your invetigations of the Duet stepper driver chips and check if they are OK.

First check the stepper and wiring again using pronterface so that you know every thing moves OK for the Y-axis and then note which way round the connector is placed,

Then to check the Duet board and driver chips I suggest moving the connector at the Duet end from the Y axis connector on the Duet to the Z-axis connector on the Duet.
Make sure you select the correct 4 pins and that the connector is oriented the same way round, after turning power on again, use Pronterface to see if the Z axis is moving correctly.

You can check the other axis driver chips by repeating this procedure and connecting the working stepper and wiring to the X and extruder connectors as well.

This will identify if the Duet/software is causing the fault or a wiring problem/orientation in the other looms.
If all the drivers are working then you can move onto checking the wiring looms and their orientation by replace just the wiring loom for each of the axis making sure to orientate the connectors to the same way as the Y-axis. Dont forget to power of the PSU when making changes.

If the working Y-axis stepper/wiring loom does not work when connected the same way to the other axis connectors you need to email RRP for support with this board and I expect they will suggest additional steps to take.

Also, what settings do you have for the following in the config.g file on the SD card? I am assuming you have it pushed in correctly.

M201 X800 Y800 Z15 E1000 ; Accelerations (mm/s^2)
M203 X15000 Y15000 Z100 E3600 ; Maximum speeds (mm/min)
M566 X600 Y600 Z30 E20 ; Minimum speeds mm/minute

If you have changed any settings maybe you are trying to accelerate the motors too quickly.
Have you used the correct SD card files for this sofware version?.
If you have made changes have you put the files back to the defaults which should work.

There maybe suggestions from other forum members as well, so look out for them too.

Lloyd

Edited 2 time(s). Last edit at 11/06/2014 02:03PM by ezwul.

For testing the motors, here's our usual motor movement troubleshooting advice:

NOTE: If you are connecting/disconnecting motors from the Duet, make sure the motors have NO POWER. Disconnecting a motor with the power on may destroy the stepper driver on the Duet.

If there is a particular motor moving randomly, vibrating, or not moving at all, there are three areas to check:
1. The motor. These are generally very reliable - we have sent out over 10,000 of them, and had about 10 faulty ones.
2. The wiring. This is also generally very reliable, but it's possible it has been put together incorrectly, or there is a break in the wiring.
3. The electronics. The Duet may have suffered damage to the stepper driver.

To test, turn off the power to the printer, and swap the wiring at the Duet between two axes, eg X and Y, or Z and extruder. Make VERY sure you have connected the wiring correctly; check the wiring diagram. Turn on power, connect, and test BOTH axes. If the problem stays with the same motor as before, the issue is with the motor or wiring; if it swaps to the other motor, the problem is with the Duet.

If the problem follows the motor, turn off the printer, and replace the motor wiring on the correct pins. Then:

1. Check the motor wiring loom. We have had a few cases (in nearly 2000 kits!) where the motor loom is incorrectly wired. Compare the wiring loom, at both ends, with another, known-working motor loom; check that the colour order is the same, check that the wires are connected to the right pins of the plug into the motor. The crimps are quite easy to release from the housing, and put in the correct order.

2. It is possible there is a problem with motor, but this is rare. Connect the motor to a known-working wiring loom, and test it. Also, with the motor removed from the printer, rotate the motor shaft in your fingers. Does it feel notchy? We'll replace any motor that is faulty, under warranty.

If the problem appears to be with the Duet, most likely the stepper driver has failed. The main reason for this is a poor connection, or disconnecting the motor wiring when the motor has power going to it; for the technical explanation, see: [reprap.org]
If the axis has never worked, we'll replace the board under warranty; email me on support@reprappro.com

Ian
RepRapPro tech support

Additionally, check that your motor wiring looms are connected to the correct pins on the Duet.

Also, If you have a Duet with no keyed headers (a little plastic part around the pins that aligns the wiring connection) the crimp in the loom housing can easily get distorted. The crimps in the housings are standard Molex KK 2.54mm crimps (eg [uk.rs-online.com] ), and are a ramp-style connector. If the housing is not put on the pins straight, the ramp (the 'curly' part of the crimp) can get bent back, and a poor connection can result. You can remove the crimp from the housing quite easily, and bend them back so they have better contact. You can also bend the pins on the Duet a little, to improve contact. You can, of course, replace the crimps and housings with anything you deem better, such is the nature of a kit build.

Ian
RepRapPro tech support

I had also issues with the z-axis motor and the y-endswitch. Replaced the y-endswitch but then i realized that the connector
problems can be fixed rather easy. Use a thin metal piece to push against the metal hook holding the pin inside of the
female connector. When pushed right you can remove the metal piece which should do the contact. Bend this metal piece
open so that it fills out the whole hole, push it back in until it sits again in its place. Repeat with every pin.

Quote
tstone
I had also issues with the z-axis motor and the y-endswitch. Replaced the y-endswitch but then i realized that the connector
problems can be fixed rather easy. Use a thin metal piece to push against the metal hook holding the pin inside of the
female connector. When pushed right you can remove the metal piece which should do the contact. Bend this metal piece
open so that it fills out the whole hole, push it back in until it sits again in its place. Repeat with every pin.

I think that's pretty much what I said in my message above! ie remove the crimp from the housing, bend the crimp for better contact, replace in housing.

Ian
RepRapPro tech support

Thanks for the quick responses!

The wiring looms and connectors were indeed the problem. The stepper drivers all seem to work fine, so luckily the duet isn't toast.

Sorry for my late response by the way, but I'm putting it together for a local fablab and someone else will fix the loom connections. I'll let you know if everything works fine when the looms are repaired...