Everything about Extruder Pre-Tension!

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We are a very small 3d printer manufacturer. What we advice to our customers is: loosen the tension screw, while holding the filament firmly not letting the extruder pull, run the extruder and tighten the screw slowly until the extruder stops grinding the filament and starts loosing steps with tick sound. This works for pla and enables the user to find the best grip tension.

suggestion: for future videos with graphs where each line is a progression, could you color code them in a way with a clear progression? example: 0 turns - green, 2 turns - yellow, 4 turns - orange, 6 turns - red, 8 turns - violet it would make the graph so much easier to read at first glance

"Is your Bowden tube okay? Are your extruder gears clean and not worn down? Is the nozzle not blocked?" Rhythm in my head, "do your ears hang low, do they toggle to the floor, can you tie them in a knot, can you tie them in a bow." Ha ha. Keep up the great work. I always have your videos in the background.

I removed the nozzle from my hot end, blocked the z axis so it could not move, then placed a postal scale under the hot end. This way I could directly measure extrusion force (at stall) and perfectly dial in my tension spring to maximize force. I found a 3x variation in force across the range of adjustment. And on one extruder I found the included spring was outside of the optimal range, swapping in a softer spring made a big improvement.

This guy manages to do research on things I didn't even think you could do this much research on. Great video Stefan, this has been very informative!

I learned this the hard way and took allot of time to actually discover this by myself two years ago when starting to print ABS and grinding like crazy... This video should be mandatory to every noob. Thank you Stefan for making all this content!

Always strange to see how old technology comes back. Early makerbot extruders use to have "fixed" idlers, and they were pretty common with reprap projects in that time period as well. The spring loaded idlers quickly overtook them as they dealt with the deviations in the filament diameter better, and the inconsistent hardness of the mostly ABS filament that was used in that time.

Very detailed video! We too have commonly found other factors like printing speed and nozzle temperature are to blame for failed prints. But it's good to see a more comprehensive view so extrusion problems can be better diagnosed.

Congratulations on the video Stefan. Interesting and informative as usual. Great to see the Bondtech LGX is the most consistent and delivered less than 5% under-extrusion up to 22mm^3/s with your setup, outperforming the remaining runner-up extruders in the comparison by almost 50%, and confirming our findings and the reason why we released it. Thank you.

This has been really helpful. I have had lots of problems with underextrusion and this has helped to refine a few things. I'm now watching a flow tower print successfully for the first time after adjusting the tension screw and pretension on my E3v2. Previously it would break apart after just a few layers due to underextrusion

Stefan, i have been trying to setup my Ender 3 Neo for months, your 15 minute video helped solve a 6 month long dilemma for me. Thank you from Australia!!!🙌

I love your scientific approach to 3D printing things in such detail... Keep ut the great work Stephan!

"Plow ferformance" knocked me out, nice job, waiting for your next videos in impatience.

Thanks a lot. Similar to you, I never cared much to try different settings and followed the extruder manufacturer's guideline. Glad to learn it was correct, overall.

Extruder tension is definitely one of those misunderstood things. I discovered it on my Prusa Mini running the bondtech extruder. After setting it up per bondtech's instructions, I had very inconsistent extrusions very underextruded on parts with lots of retractions, with some overextrusion in random other parts. After many parts checks and disassemblies, I tried lowering the extruder tension until prints were consistent, then continued to lower it until filament would grind, and used the halfway mark between the two. Also learned that making a mark on the tension thumbscrew makes it much easier to count turns.

I really needed this video about six months ago. Lol. I took apart my Prusa Mini's hot end twice before realizing my tension was off. Sigh. Keep up the great work!

Mate, that was ridiculously well made and presented. Thanks a million!

This confirms what I've been experiencing on my work printers where the petg filament was buckling. In my case it was a combination of the capricorn tubing causing too much resistance and tension settings. Replaced the Capricorn tubing with standard and I tighten the bondtech gears all the way down and then back it off 5-7 half twists.

Thanks for this investigation! The only time I've really needed to adjust it was when I stupidly printed with CF Nylon and wore down the knurled gear on my feeder. It took me awhile to diagnose the resulting under-extrusion, thankfully a little more tension made the feeder grip properly again.