(Video) Shuddering/Skipping Steps at high feedrate

Hey Guys, I have this problem on my Mini Kossel as well as my full size Kossel Pro.
It didn't start doing this until I modified/removed my bed probe retract sequence (switched to FSR on the mini and manual retraction on the kossel).
I have not messed with the microstepping jumpers and I've only turned down the acceleration settings in the EEPROM ( Max Feedrate is 200.00 for all axis, max acceleration is 500 for all axis)
It seems like it's going too fast and skipping steps.

If i send a

G1 X-1.823 Y-8.683 F12000.000

It will not shudder but if I increase the feedrate to 13000 or above it will shudder like in the video below.

I only ever see it do this once it has finished probing, as it moves to the first spot to start printing. Looking at the gcode, the feedrate for this move is F15000. Often times it skips enough steps along the way that by the time it gets to the print surface it will float above the bed on one side of the print, and try to drive the head into the glass on the other side. But this is not always the case, sometimes it shudders a lot but ends up printing fine.

So, what is the best/ most correct way to resolve this issue? Let me know if I should post anything from the firmware.

Thanks for the help! Here's a link to the video >>> Video of Kossel Pro skipping steps

The first thing you should do is tell us what electronics and firmware you are using.

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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].

The Setup:
OpenBeam Kossel Pro with Brainwave Pro control board on Marlin and a Poly Stroooder Tri Hotend currently installed. I have all thermistors, heaters, and extruder motors working. I use Slic3r and Repetier Host.

The Brainwave pro is an old 8-bit 16MHz board, so asking it to do 250mm/sec travel moves when running Marlin is almost certainly more than it can handle. Some users claim that Repetier firmware does a better job of running a delta printer on slow electronics than Marlin. However, if you want really fast travel speeds, you'll probably need to upgrade to 32-bit electronics.

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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].

Thanks for the tips! I was able to remedy this problem by reducing my 'Speed for non-print moves' in Slic3r from 250 to 175mm/s

Repetier can do 250 mm/s travel speed on 8-bit Arduino without LCD and with delta segments per second of 90.

On my stock Kossel Pro/Brainwave Pro I'm doing 250mm/s travel and 160 delta segments, problem free! Not sure if I modified anything else that's causing my other machines to shudder but it's manageable. I'll probably go 32-bit this winter when I have more time to fiddle with it.

It worked fine until the auto bed probing was done: meaning there is more CPU load now to calculate the steps for the virtual plane.

Quote
NFrank89
On my stock Kossel Pro/Brainwave Pro I'm doing 250mm/s travel and 160 delta segments, problem free! Not sure if I modified anything else that's causing my other machines to shudder but it's manageable. I'll probably go 32-bit this winter when I have more time to fiddle with it.

With which firmware?

The step generation rate needed also depends on the ratio of rod length to delta radius, so changes in the geometry will affect the maximum speed achievable.

Edited 1 time(s). Last edit at 08/02/2016 02:16PM by dc42.

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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].