Changing the string sequence
Hello, I would like to change the string sequence in the slicing process.
In the appending picture on the left side you see, how prusa slicer is slicing. On the right side you see, how I wish that it should be.
It is important to me that the outer contour is printed without settling so that the transition at the top from the left radius to the straight line to the right radius is as smooth as possible. I would therefore like to change the print sequence. Is there a way to manually change the seqence in the Prusa Slicer? Is there a setting that can help me with this? (I have already tested avoiding crossing the perimeters). But I don't wand to edit the gcode manually, because there are many parts to print.
Best regards
Have you experimented with: Print Settings > Layers and perimeters > External perimeters first ?
(It's an Expert mode setting)
Not quite what you're asking for but it might go some of the way.
Cheerio,
RE: Changing the string sequence
Thank you for the hint.
The setting "External perimeters first" makes no difference.
If 'External perimeters first' doesn't smooth the outer transition (yes, it will still step to the interior afterwards) then there may be something you can do with your part.
Slice your part, save your project as a .3mf file
Files > Save Project as
Zip the .3mf and post it here. It will contain both your part and your settings for us to diagnose.
Cheerio,
RE: Changing the string sequence
Hier is the project as .3mf file and also the part as .obj file.
As set, with your 0.8mm nozzle and such narrow walls you have only a single extrusion width wall between the two 'D' shapes. When the straight vertical of each 'D' contracts as it cools it naturally drags the single extrusion slightly out of line causing the irregularity.
The simplest route to a smooth transition is to ensure there are at least three extrusions with 'External perimeters first ' set so that the inner one can be dragged aside without diverting the outer.
So: Either make the walls thicker, or revert to a 0.4mm nozzle and use one of the default settings.
Cheerio,
RE: Changing the string sequence
Hello Diem,
I increased the number of extrusions of the "D" to 3 and 5 strings. Booth don't lead to the wished solution (see picture). The thickness of the bridge of 0,8mm I cannot increase, because I need this thickness.
RE: Changing the string sequence
Thank you very much Diem, 0,4mm nozzle works fine (see picture). But it takes 18 minutes, compared with 5 minutes with 0,8mm nozzle. I want to print many parts. Therefore it would be very usefull, if there would be another solution for 0,8mm nozzle and a bridge, made of only one extrusion.
RE: Changing the string sequence
Does anyone know a software, capable of changing the sequence of extrusion sections?
Changing the sequence will not prevent thermal contraction. You are hitting the limits of FDM printing. Essentially you have to trade accuracy for speed.
If you want to increase output without comprimising accuracy the standard answer is to add more printers to the production line.
Cheerio,
RE: Changing the string sequence
I would find the following option for Prusa Slicer useful:
Option: “Specify print order of outer surface”
Before slicing, I click on the surfaces of the part in the order in which I want them to be printed. Then these surfaces are printed in that order and the inner volume is printed afterwards.
Those two curved perimeters are made up from hundreds of short straight lines - you are going to be clicking for hours...
and that wouldn't affect the thermal contraction issue.
Cheerio,
RE: Changing the string sequence
I don't care about thermal contraction. In my opinion having control over the order of extrusion is more important. I would like to decide for myself.
OK, the proper place to make such a suggestion is Prusa's GitHub.
Cheeriuo,
RE: Changing the string sequence
I'd rate the chances of that being implemented oh, sometime maybe in the next 5 years. If you are lucky. You currently have the option of preferring clockwise or counter clockwise extrusion. That is it.
As Diem points out , to let the user control it you would need some form of interface to let the user select the order of the faces to be printed. With most geometries thats going to be a tall order as there could be thousands of segments on each layer. And each layer is likely to also be different. So not a trivial undertaking. Even your example has many more faces than you would think.
Good luck with your feature request.
You may be better off exploring https://fullcontrolgcode.com/