Comment on Retraction Test
papalonian@lemmy.world 4 months ago
Extrusion works by the motor pushing the filament forward, causing pressure behind the nozzle, and the filament melting and extruding out the end. When your printer wants to stop extruding ( ie moving to a new part or section to print without printing anything in the middle), it makes a retraction to pull the filament back, releasing the pressure behind the nozzle, and stopping the filament from extruding out.
In a perfect world, a full retraction would not be necessary; not pushing the filament forward should stop the pressure buildup, and stop the filament from flowing. However, we don’t live in a perfect world, and so backing the filament up a small amount is necessary to stop it from flowing.
Finding out exactly how much you need to back the filament up is the purpose of this test. Back the filament up too much, and you can create clogging issues, extrusion issues caused by the filament not being at the end of the nozzle at the beginning of the extrusion, and (slightly) increased print time; don’t back the filament up far enough, and filament will continue extruding out the nozzle, causing stringing.
The test works by having you lower your retraction distance to a very small number ( a lot of tests will have you disable retraction altogether, ie 0 mm), and slowly increase it from there. The idea is that the bottom of the tower will look like hot garbage, and slowly improve as the retraction increases; what’s the quality stops improving, you know that that is your ideal retraction distance.
If you have a Bowden tube setup, a good retraction Tower would have values ranging from 0 mm to around 10 mm. Direct drive extruders need far less retraction; 0 to 2 mm in 0.2 mm increments should be good. Again, you’re looking for the first setting that gets rid of stringing.
JoShmoe@lemmy.world 4 months ago
I must have done something wrong because the whole tower looks pretty much the same except for a clear overextrusion around the middle on one side. The rest have really thin barely visible strings that don’t go very far.
papalonian@lemmy.world 4 months ago
I don’t use orca slicer so I’m not familiar with how it works specifically, but are you sure that the retraction settings are actually changing between different sections? I made the mistake when I first started it just loading the model and letting it print with default settings from my slicer. If the GitHub doesn’t specify exactly how to enable the retraction tower settings, I would look up a guide on YouTube. If you’ve done temp towers, it’ll likely be set up in a similar fashion.
If your test starts at 0 and you don’t see any difference, it definitely it not working as intended; 0 retraction with result in a huge stringy mess, and going to the next step will be a significant change.
JoShmoe@lemmy.world 4 months ago
The way the test is implemented through orca slicer is actually a bit confusing. The forks of bambulab and orca slicer are likely intermingled. I used the default settings given in the drop menu then it imported a model. I then started the test as is without modifying anything.
I honestly have no idea which the correct values were for the p1p. Now that you mentioned it, I suppose I should have checked with bambulabs online manual. I hadn’t thought about that.
papalonian@lemmy.world 4 months ago
Do some poking around for your printer and slicer - for your printer, you need to know if you have a direct drive or Bowden tube setup, and for your slicer, you need to figure out how to modify the standard gcode.
Looking at some pictures online I’m pretty sure your printer is a direct drive. Again I’m not familiar with your slicer so I don’t know what your model looks like, but typically retraction tests will be a tower with different values printed on the side indicating how far the retraction distance is. For a direct drive, these values should be pretty small, likely topping out at just a couple mm at most.
A search for " <slicer name> retraction tower setup" should get you numerous tutorials for your slicer, just follow those guides and input a range appropriate to your setup and should be good to go
BOFH666@lemmy.world 4 months ago
Maybe you don’t need to ‘fix’ your retraction settings?
If it looks good enough, why bother?
papalonian@lemmy.world 4 months ago
You do understand what community you’re in, right? ;)
GrayBackgroundMusic@lemm.ee 4 months ago
Perfect is the enemy of good. Screw good. I wanna be perfect.
JoShmoe@lemmy.world 4 months ago
I’m currently trying to solve some seam artifacts. I assumed retraction has something to do with it.
UnH1ng3d@lemmy.world 4 months ago
I’ve had the same thing. I think orca’s retraction test is just too ‘easy’. I think the towers are too far apart.