Change flow rate / extrusion multiplier between objects?
I want to setup a flow calibration test and was wondering how to create this in PrusaSlicer. Ideally I would like to have 4-5 boxes and would like to change the extrusion multiplier by 2% between the boxes. Box 1 = 100% / 1.0... Box 2 = 98% / 0.98... etc.
Is there a simple way to do this in the custom gcode, possibly with some type of expression? Maybe with sequential printing?
Thanks in advance!
RE: Change flow rate / extrusion multiplier between objects?
The 'easiest' way I know to do this is to use Super Slicer. SuSi is a fork of Prusa slicer and based on the same code base (but with way more options made visible to the user). It has several built in calibration functions on the top menu under Calibrate. One of them being flow. It can do 2% spreads. One of those is because there are a lot more of the settings available as modifiers, including flows so it uises that to generate automatic test prints for you.
Once you have the values you need you can then also use them in your Prusa Slicer configurations.
https://github.com/supermerill/SuperSlicer/releases/tag/2.4.58.4
RE: Change flow rate / extrusion multiplier between objects?
I have the latest of SuperSlicer and have messed with the calibration features. They seem to do a decent job. I have my own calibration methods used for my production prints and was looking to build my own tests with specific models and processes. I am sure PrusaSlicer can do this, but I just dont know enough about expressions.
RE: Change flow rate / extrusion multiplier between objects?
You can generate the plate is SuSi, load your own models and then use control+c and control+v to copy and paste the modifier stack from the generated ones to your specific models.
The problem is PS is that it only has a limited set of modifiers that can be applied. I’m not sure you can do it will gcode conditionals.
RE: Change flow rate / extrusion multiplier between objects?
Hmmm I might give that a try. Currently I just edit the PrusaSlicer generated gcode file at the beginning of each object ID during a sequential print with M221 S100... M221 S98... etc. Seems to do the job, but would figure there would have to be a way to do this simple edit within PrusaSlicer via expressions. Thanks for the help, I will keep digging.
RE: Change flow rate / extrusion multiplier between objects?
This is a while old. I searched for exactly the same and did not find anything but this posting.
To get my rusty rust knowledge a little better I coded a pre-processor to change flow rate or extrusion multiplier per object.
It's done. It works for me but you never know. Feel free to try and please report back and in case of error file an issue on the project.
RE: Change flow rate / extrusion multiplier between objects?
I have to tried to use your post-processing script but have the following error when I try to export from PrusaSlicer. Probably not a useful error msg but if you could help please? 
RE: Change flow rate / extrusion multiplier between objects?
My guess it's related to the binary gcode. Either disable binary gcode, or export as ASCII gcode and pass in the path to the ASCII gcode file as an argument to prusaslicer_m221_per_object.