Delta slow speed - DEFAULT_MAX_FEEDRATE <= 65.0 mm/s

Hello.
I finished building my first delta printer.

I have problems with proper calibration (jerk, acceleration, speed).

Printer can print with acceleration = 20000 and jerk = 60 (I haven't checked higher values).
But when DEFAULT_MAX_FEEDRATE is higher than 65mm/s effector randomly starts to slows down and stalling, but motors don't lose any step (there is no layer shifting).
Movie while printing:
[www.youtube.com]

This is configuration from movie print:

#define DEFAULT_AXIS_STEPS_PER_UNIT   {376.47, 376.47, 376.47, 191.72}
#define DEFAULT_MAX_FEEDRATE          {100.0, 100.0, 100.0, 100.0}    // (mm/sec)
#define DEFAULT_MAX_ACCELERATION      {9000,9000,9000,9000}    // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION          3000    // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION  3000   // X, Y, Z and E max acceleration in mm/s^2 for retracts
// The speed change that does not require acceleration (i.e. the software might assume it can be done instantaneously)
#define DEFAULT_XYJERK                20.0    // (mm/sec)
#define DEFAULT_ZJERK                 20.0    // (mm/sec)
#define DEFAULT_EJERK                 20.0    // (mm/sec)

Printer Hardware:
- Smart LCD Controller (4x20) with SD [ gcode files served by SDcard ]
- Arduino Mega R3 [ powered by voltage stepper down ]
- RAMPS 1.4 [ 1/32 micro-step - all jumpers inserted ]
- DRV8825 Stepper Motor Driver [ 0.60 Vref ]
- 42byghm809 [ 1.7A(U) 0.9deg/step - Wantai Stepper Motor ]
- 24V 17A Power supply

Software:
- Marlin 1.0

Edited 2 time(s). Last edit at 05/16/2017 07:11AM by asrt.

Maybe segment buffer underflow. Try to lower segments per second to 90. Also if it is possible to lower LCD refresh rate then try that too.

he is also doing 4 times the microstepping than is normal so that won't help either CPU is probably bogging down under the strain

Thanks for quick response.
I found line in ultralcd.h

#define LCD_UPDATE_INTERVAL 100

and changed to 5000 ms (5s).
I also:
- left only jumpers at MS3 pinouts (1/16 micro-stepping).
- recalculate steps/mm
- changed max feedrate to 200.00
Manual movements G1 with F12000 seams to work fine.

Edited 2 time(s). Last edit at 05/17/2017 03:10AM by asrt.

Now I have problem with homing all (G28 command).
Its way to fast than maximum feedrate 200mm/s (12000mm/min).
So when I manually go from Z0 to Z307 (G1Z307F12000) everything works fine.
But when I type G28 then speed is much faster, and sometimes one motor stall.
I almost destroy my effector because it went too far from center while G28
Is there any way to adjust max homing speed ?

---edit---
I found #define HOMING_FEEDRATE in Configuration.h.
For safety i cheange this to {9000, 9000, 9000, 0}.

Thank you all for helping me with troubleshooting.

Edited 5 time(s). Last edit at 05/17/2017 05:42AM by asrt.

It seems as though a lot of values you have quoted here are very high. 20000 acceleration? That's astronomically high! Try 3000. Homing feedrate 9000? I use 2500, and I have a large, rigid, fast delta. Ramps can go reasonably fast using repetier but marlin struggles on delta with 1/32 microstepping.

It's nice to have high travel speed when printing I. E. 150mm/s but you won't be able to lay filament down accurately much above 100 mm/s and as for other movements what do you gain from going that fast?

Start slow and gradually increase speed as your machine proves itself. You wouldn't build a fast car and go for a top speed run as its first outing.

Edited 3 time(s). Last edit at 05/20/2017 02:14AM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions