Dual extruder used for different nozzle sizes

I would like to use a dual extruder (Replicator1 clone) with two different nozzle sizes but it must be an unusual thing to consider since there is no way to set different sizes for each extruder in Octoprint as it assumes both nozzles must be the same size. Failing that I have tried to make two separate printer profiles in Octoprint but the GPX plugin does not change nozzle size to reflect the change of profile. Sometimes we have the need to print fast models that don't have details and other times we like a nice fine detailed print so having two nozzle sizes ready at any one time offers that ability. I would like move on to investigate the viability of using this set up to combine both extruders into one print in a similar way to how multi colour prints work. This would have the advantage of increasing speed for fine detail printing because in most cases it is not necessary to print the whole model in a fine nozzle like 0.2 things like infill and walls could be done in a larger diameter nozzle and this might be possible using a Cura profile.ini

Just testing the water, any input appreciated.

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I think thats a wonderful idea. perhaps looking for another dual extruder machine and using that profile?

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OctoPrint really doesn't care what size the nozzles are. Other parameters in the Printer Profile are only used to configure the controls. What is important is that the slicer that generated the GCode you uploaded and the firmware in the printer have intimate knowledge of the configuration.

In the OctoPrint Printer Profile creation, tell OctoPrint that there are two nozzles and don't worry that one of the nozzles is the wrong size. See the "fine print" at the bottom of each page.

This information is used for the temperature tab, the bounding box check, the GCODE Viewer and/or when slicing from OctoPrint. It does NOT influence already sliced files that you upload to OctoPrint!
This information is used for manual control via the "Control" tab. It does NOT influence already sliced files that you upload to OctoPrint!
This information is used for the graph and controls available in the "Temperature" tab, the GCODE viewer and when slicing from within OctoPrint. It does NOT influence already sliced files that you upload to OctoPrint!

I read your original post again and saw:

possible using a Cura profile.ini

You should not be using the (now unbundled) Cura plugin to slice your prints on the RPi. I'm afraid it isn't up to the task you describe. You should be slicing on a more suitable computer with a graphical interface and uploading the generated GCode through the OctoPrint web interface.


Its a pity Cura is being unbundled because I thought it was one of the strongest features. I have been slicing with it using a raspberry pi zero for two years and although its a bit slow I found it indispensable for quick parts.

A zero has a single core. Pretty much the requirement for OctoPrint is the four-cored Raspberry Pi 3B, for what it's worth. You might consider the upgrade.

fwiw this is a much better solution and achieves the best of both worlds.

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Yes but I thought the quad core requirement was for the people who wanted live web streaming, I can live without that. My pi zero doesn't struggle with Octopi unless I give it an insanely large CAD file and that's understandable.

I program to the OctoPrint image five days per week, it's what I do. My rig is optimized to show me how much processing power is required for any given activity as well as the general or graphics-related RAM.

  • bringing up the web interface on a new browser or pressing the reload/refresh button will consume 100% of one core for about two minutes on a Raspberry Pi 3B
  • anything that writes to the microSD card seems to also chew up some extra processing time and effort as well as increase the power needs

It's not just the webcam stuff. Visiting the gcode viewer tab has all that canvas-rendered data that has to be pushed to the browser. Visiting the temperature tab has all those data points that have to be pushed to the browser. Just sitting there idle in the web browser watching the job print is an entire orchestration of data that's flowing from OctoPrint to the browser so that you have up-to-date information. And all this processing is really superficial to the actual job of serializing the gcode to the printer board.

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