Printing speed problem



  • Hello. I have recently bought a duet3.
    Im still fighting a little to get my desired config, but the main things are running now.
    My setup is: duet board, connected through USB to a raspberry pi 3 B+.
    And Im using octoprint. I have chosen this because octoprint offers me a lot of exta functionality through the use of plugins. I have this setup in my older printer and I was not suffering from the problem I will describe.
    I have tried a couple of print tests, And 1 in particular called my atention. Is a simple vase mode print. I try to print it at 100 mm/s. My printer (corexy, hbot config) is more than capable of holding such speed. But I was watching the print and I notied that there was not smooth and conntinuous movement. The print shape is basically circular, so movement should be continuous and smooth?
    Instead of that I can see that movements is not continous, in perfectly semicircular paths the printhead makes like movements in chunks.
    Any ideas why this is happening? Gcode is not being transferred quicly enough to duet?
    Ideas about how to test and solve this? The same board + raspi setup using USB was my previous setup, and the board was a very simple 2540 ramps board and could stand that speed without this chunk movements, so duet is way way far more powerful than that and so I dont understand why is this happening.
    Thanks in advance for the help.


  • Moderator

    It's not recommended to print over USB. One of the biggest benefits of the duet is that it allows for a web interface to ease control and uploading of gcode (which gets printed locally via the SD card).

    https://duet3d.dozuki.com/Wiki/Firmware_Overview#Section_Printing_over_USB_connection_Octoprint_Cura_Simplify3D_Etc

    The Duet 3 allows for a connection to the pi to run the duet. Have you tried that yet? It's true that currently octoprint has many plugins that aren't available for the duet yet, but a plugin framework is coming soon.



  • Thanks for the reply. Im aware of the possible limitations of printing through USB, but it is strange that it is happening with this print. I would expect the limitations to happen on something more complex, but this is a simple vase mode print, and I already print it this using a mega 2560 board, and this problem did not happen.
    Is there any way to increase buffers size in duet maybe to do some test?


  • Moderator

    I think based on your other thread about the stuttering the issue is related partially to the fact you're running x256 microstepping and an outdated release candidate firmware in combination with running over USB. Once you resolve the issues from your other thread you may find the USB streaming performs better.


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