Duet 2 Wifi performance for laser raster printing

spw

Is there any benchmark that shows how many gcode/second can Duet 2 process?

I have a Duet in my 3D printer and love it, used it with a blue laser and did well. Now I'm planning to use it with K40 CO2 laser cutter, but it looks like everyone is using Cohesion3D https://forum.cohesion3d.com/t/improved-raster-speed-firmware-update-for-cohesion3d-boards/850 .
The CO2 laser raster printing can be done much faster than blue laser which makes me worry that Duet won't be able to support it.

Veti

hmm
looking at the processor.

32 bit LPC1769 Microcontroller running at 120Mhz,
vs
Powerful 32 Bit Processor: Atmel SAM4E8E: 120MHz ARM Cortex-M4

upcomming duet3
Powerful 32 Bit Processor (ARM Cortex M7 @300Mhz)

the performance is explained here
https://reprap.org/wiki/Step_rates#Achievable_step_rates

Smoothie on Smoothieboard with 120MHz ARM Cortex-M3 (no FPU): 120 kHz (configurable, 120k is default, rates up to 200 are

RepRapFirmware on Duet WiFi (120MHz ARM Cortex-M4, firmware 1.17d) using up to octal stepping at high speeds: 360kHz with one motor moving, and 180KHz simultaneously on 3 motors

However do take into account that the board is specialised for laser cutting. so i would expect a lot more optimization in the firmware of the cohesion compared to the duet for laser operation. I have just read a few post about people using the duet laser mode (https://duet3d.dozuki.com/Wiki/Gcode#Section_M452_Select_Laser_Printer_Mode)

spw

I did some testing and while the hardware and implementation would point that Duet should be faster the tests show otherwise.
My results:
Firmware 2.0.2
300 DPI raster @ 200mm/s UI was showing max top speed 30mm/s out off requested 200mm/s
100 DPI raster @ 200mm/s UI was showing max top speed 67mm/s movement was visibly faster
Firmware 2.0.4
100 DPI raster @ 200mm/s UI was showing max top speed 81mm/s

The last job had 16k G1 moves and completed in 60 seconds which means Duet can process about 267 gCodes/second which is 10 times less than Cohesion3D.

Can anyone familiar with the firmware ( @dc42 ) confirm that my results make sense or I should be looking into configuration/gCode problems?

My setup is Ender-3 theoretically able to deliver movements of 220mm/s and configured like that (M203 X12000 Y12000 Z900 E3000 ).
The test was executed using web UI to upload and start the job.
My files:
config.g
duet.gcode
LASER MODE macro.g

Phaedrux

M566 X600 Y600 Z24 E300                   ; Set maximum instantaneous speed changes (mm/min) MARLIN
;M203 X9000 Y9000 Z900 E3000               ; Set maximum speeds (mm/min) MARLIN
M203 X12000 Y12000 Z900 E3000             ; Set maximum speeds (mm/min) MARLIN
M201 X500 Y500 Z100 E5000                 ; Set accelerations (mm/s^2)

With your low acceleration and jerk values I'm not sure you'd be able to hit 200mm/s on the small bed of the ender 3 anyway.

With 500mm/s^2 it would take nearly 50mm to reach 200mm/s and with a jerk value of 600mm/min you'd have to slow down to 10mm/s at every hard segment.

Try increasing your acceleration to 2000 and your jerk to 1200 and see if that helps your top speed.

spw

Thanks @Phaedrux it was my mistake I didn't think about bumping acceleration and jerk.

It did help with the performance I can hit 136mm/s and the job is completed in 36 seconds which increased the throughput to 444 gcode/sec, but there was a side effect.
The gCode instructs the machine to move a laser along x-axis for 120mm and then proceed with next line. The movement is a very uneven entire machine is jerking but not on direction change but during the long movement. I tried both 2000 and 1200 jerk as well as some very high values like 20000 and 12000 with the same result.

I think it is because there is some delay between executing the commands and the x-axis motor constantly decelerates and accelerates instead of doing long streaks.
I'll play with the config and remove the laser/extruder to see if it is a mechanical limitation or a firmware problem.

Video showing jerk during long movements: https://youtu.be/ePAcdSWWiTc

spw

I played a bit with the speed and it looks like the limit is 140mm/s for 100 dpi at this speed the movements are smooth anything higher makes "Top speed" value to fluctuate and printer jerk during the long moves.

The limit of Duet is:
3.94 px / mm x 140mm/s = 551.6 gcode/s

It is about 5 times slower than Cohesion3D and 2 times slower than default Smoothieware.
I'll create a new topic in wishlist category to find out if there is any desire or even if it is possible to improve the firmware to support higher speeds.

dc42

We looked into high speed laser rastering earlier this year and came up with a proposed GCode extension to better support it. See https://docs.google.com/document/d/1SMWFJUXfRSxe-p-veWEP-NU3A9ESKU_TVGB1Y1ADAV8/edit?usp=sharing.

Phaedrux

@spw said in Duet 2 Wifi performance for laser raster printing:

Video showing jerk during long movements: https://youtu.be/ePAcdSWWiTc

I think that may have more to do with the motors of the Ender 3 than the Duet.

The belts also look loose?