What are the visual cues you use to get idler tension just right?
Hi all, I would like to learn some new ways to dial my idler tension in. I am looking for as many answers as possible: What do YOU look for to get your idler tension just right? I'm not looking for Prusa manual references (I am aware of the usual method for tuning idler tension), I am looking for unique techniques that others use tune their printer.
If there are visual cues you use that relate to other parts of the printer, I would also love to hear them!
Here's an example pertaining to z-offset:
I own the satin sheet from PRUSA which has dashed grid lines on it. It so happens that, when I run the first layer calibration, the parts of the "zig zag" it prints which lie along the y-axis are perfectly on top of these dashed lines. When I am running the calibration, I use a slightly clear or transparent filament and I have noticed that the ideal height is when the printed line is the same thickness as the dashed line on the bed. I find this visual method is most fast and consistent for getting my z offset right.
RE: What are the visual cues you use to get idler tension just right?
@karalt
I use TPU\TPE to set my idler tension, here's what I do for a 0.4mm nozzle:
So what I do is preheat the hot end for FLEX then I loosen the idler, to the point that it won't quite pull/push the filament in and I manually feed some through the hot end, then with Alan-wrench in hand, I select the load filament from the menu. The extruder will turn but not feed because it's to loose. use the Alan-wrench to very slowly turn the idler screw until it just barely grabs and starts to feed filament out of the end, then stop and print a test square 100X100 or whatever size you use, with a layer height of 0.2, to see how it's flowing and don't make adjustments of more then an 1/8 turn at a time If any farther adjustment is needed.
Notes:
It's important to use the flex preheat for this because the loading feed rate is set for it.
The 100 X 100 is the best test for this to be sure your getting what you need from the extruder ( an even consistent flow)
I use these settings for almost every filament once I have it where I want it, now a days it takes me about 5 min to set.
The only times I change the adjustment to the idler is if I using something really hard with Carbon Fiber or Fiber Glass in it, then I just count the turns I added to the screw and reverse when done with the harder filament.
Hope this helps,
Swiss_Cheese
The Filament Whisperer
RE: What are the visual cues you use to get idler tension just right?
@swiss_cheese
Thanks for your reply. What is the reason for using a flex-type material for this? I don't currently have filament of that type but I will try this once I do get some. Also, I appreciate the detail of not making more than 1/8th turn at a time. I wasn't sure how much I should adjust my extruder which is currently grabbing filament but not consistently extruding, so thanks for including that tip.
RE: What are the visual cues you use to get idler tension just right?
@karalt
I use Flex because its the softest and most sensitive filament to idler tension. I have found that If I'm adjusted properly to extrude flexible materials than I'm good to go with most others.
Note: It is still possible to make the extruder skip by attempting to print to quickly for any filament type, and tightening the extruder in an attempt to get this to stop is not always the right answer. other causes can be, partially clogged nozzles, nozzle temps to low, misaligned filament path, and poor tolerances of cheap filament just to name a few.
Aside from the aforementioned fiber impregnated filaments you may also find it necessary to tighten a bit for some of the harder PC (poly carbonates) filaments.
Once the tension is set for Flex you'll notice a very nice even tension when using PLA, PETG, ASA, ABS, and normal (non fiber impregnated) PA's and PC blends
I use Ninjaflex to set my tension it's durometer 85A, however a more common 95A should also do the trick.
Regards
Swiss_Cheese
The Filament Whisperer
RE: What are the visual cues you use to get idler tension just right?
I just eyeball it so the head of the screw is just slightly below the surface of the left side of the extruder body.
