Smooth movement problem

Hello,
I have built a Kossel XL and having a problem with smooth movement when moving X and Y directions.
When I send all axis down to Z 0, movement is nice and smooth.
But when I send it sideways there are some imperfections in moves. Arms are moving but every lets say 5cm there is very short stop of the movement and then it continues again, then it travels for another couple of cm and then again.That causes small lumps on the surface (photo in the link below).
I dont know what causes this problem.
Already changed all motors, nothing has changed.
I measured also motors current and its all same 1.06. Iam using MiniRambo board.
Any idea what it can be?


Imperfections caused by very short stops during the moves

Try to lower DELTA_SEGMENTS_PER_SECOND in configuration.h

Oh, that worked!!
Thank you very much!! I owe you a pint
I will have finally some sleep today. I already spent 3 days looking for mechanical faults

Quote
bolec
Oh, that worked!!
Thank you very much!! I owe you a pint
I will have finally some sleep today. I already spent 3 days looking for mechanical faults

What did you change your settings from and to?

Original setting was 100. I tried 90 and it was almost smooth exept one stop. I lowered it to 80 and now its nice and smooth. Might try to go somewhere betwen 80-90 and will see, whats the highest number I can get before it starts doing again.

Well...
I think i was happy too early.
Just started a print and it does it again. It doesnt do it when moving the axis in Ponterface, but when I started the print from SD card, it does it again.

Quote
bolec
Well...
I think i was happy too early.
Just started a print and it does it again. It doesnt do it when moving the axis in Ponterface, but when I started the print from SD card, it does it again.

Try setting it higher. Plug in 200. Let us know what that does.

Edited 1 time(s). Last edit at 03/27/2016 06:40PM by MrBaz.

I set it to 200 but it was even worse. Set it to 70 now, will see, if that gonna be any better.

Hi Bolec,

Lowering Delta segments per second cuts down on the calculations. You may not notice much difference in quality with a lower value, to a point.

So, you have a Mini Rambo - that's an 8-Bit Arduino. Are you using a Full Graphics display?

Depending on your configuration (steps per mm, printing speed, move speed) there may not be enough processing power to calculate the delta math and output the steps fast enough, and and run a graphics controller. The same issue occurs with RAMPS and Graphic controllers on Deltas.

If you are running one, you could comment it out in firmware and try the test.

I started with an 8-bit controller (Rumba) and had the exact same issue due to high step rates caused by .9 degree motors and smaller drive pulleys - I was running non-graphic display. (Using a Smoothie now, not looking back).

That's all I can think of at the moment. Hope that helps.

---

My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!

Quote
Paul Wanamaker
Hi Bolec,

Lowering Delta segments per second cuts down on the calculations. You may not notice much difference in quality with a lower value, to a point.

So, you have a Mini Rambo - that's an 8-Bit Arduino. Are you using a Full Graphics display?

Depending on your configuration (steps per mm, printing speed, move speed) there may not be enough processing power to calculate the delta math and output the steps fast enough, and and run a graphics controller. The same issue occurs with RAMPS and Graphic controllers on Deltas.

If you are running one, you could comment it out in firmware and try the test.

I started with an 8-bit controller (Rumba) and had the exact same issue due to high step rates caused by .9 degree motors and smaller drive pulleys - I was running non-graphic display. (Using a Smoothie now, not looking back).

That's all I can think of at the moment. Hope that helps.

That is interesting. I am currently using a RUMBA with 1.8* motors at 1/32 microstepping, 16 tooth pulleys, and I also have a reprapdiscount LCD attached. I'm not having any issues like the OP is having. I even have printing segments at 200. I haven't run into any issues so far. I really am looking forward to upgrading to a 32bit controller, though.

Hi again.
Yes, Iam using full graphic Reprap controller. I managed to achieve smooth movement at value 65. Will try your suggestion and uncomment the LCD controller if there is any difference.
Thanks for advice.