Step motors missing steps in large print

I tried to do a large flat print some days ago - roughly 17 x 12 x 2 cm.

It basically went smooth (except for some minor z-axis calibration issue) up to 1 cm height - then the X- and Y-motors started skipping steps.

I'm using Slic3r with the standard settings in the Ormerod ini file.
I would like to experiment with some lower settings for jerk, acceleration and maybe speed.

Could anyone point me in the right direction, what parameters to tweak and a rough idea about what values to put in?

If someone knows a small test-file that will provoke steps-skipping, I would be very glad to know.
The part in the pictures took almost 12 hours to print, and it started skipping at about 5 - 6 hours into the print - way to time-consuming for experimentation and problem-hunting.

Thank you very much.

Best regards,

Carsten Olsen

Hi Carsten!

Is your firmware up-to-date?

Older firmware versions did not correctly calculate direction changes,
this results in moves that the stepper cannot make, so it misses steps.

You can check your firmware version with the M115 command.
This problem has been fixed by dc42's 0.57n firmware update

The currently advised firmware is dc42's RepRapFirmware-057p

Edited 1 time(s). Last edit at 02/25/2014 02:47AM by 3D-ES.

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RS-Online Ormerod #263, Kossel mini with Minitronics, Prusa i3 MK2

Hi 3D-ES,

Thanks for your reply.

The firmware lying on my laptop is 0.57a from 16-01-2014....the printer is at home, but I'll check in evening
The printer is about one month old, and I updated the firmware as one of the first things.

Actually I have got very great results by doing a ton of z-axis and filament-settings calibration and testing.
So right now steps-skipping is the only issue preventing larger prints.

Best regards,

Carsten

The Y motor in particular may need its current increased to e.g. 1000mA to make sure it steps reliably as the weight on the bed increases. There is normally a command in config.g to set the motor currents.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Another thing to check that we found after exploring every other possibility is that the small grub screw has not fallen out of the drive pulley. We were getting similar print issues until we noticed this.

So, now its humming and summing - Firmware is updated, grub screws checked (nothing loose) and all motor currents are increased to 1000mA.

I just have to wait and see what happens.

Thank you very much for your inputs.

Best regards,

Carsten

PS @dc42. I have been following your post on the z-sensor with great interest. Looking very much forward to hear the results.