Changing E steps

Hi,

I am experimenting to see the effect of changing E steps on my prints. I lowered the E steps value form 745 (the calibrated value) to 685 and interestingly I only see very minor differences in the amount of extrusion. I expected to see gaps between filament lines when I was underextruding but I didn't. I'll upload some pictures when I have access to my printer but I was wondering if there is something overriding my e step values (I have enabled eprom changes, so any change I make on the LCD menu is saved).

Thanks

What is your aim here?

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

Good question What I do might seem illogical, but I have problems with my estep calibration. I measure it exactly how it is described in the calibration guide, I get a value, but when I measure it again another day, I get a different value and those values change between 715-755. This is a very large spectrum so I was wondering if something is overriding my measurements.. To check this, I am applying values well out of range (like 680) to see if there is any visible change in the extrusion.

I don't know what method you use to calibrate the extruder. When i calibrate i try to use a long piece of filament (1-2m) and measure the difference between what the extruder should and did transport.
The longer the measured distance the smaller the error you get. Don't use the same filament multiple times, the pitting from the bolt can throw off measurements.

Problems with unde ror over extrusion don't have to be visible. Underextrusion can result in a perfect looking print that is brittle as hell, since the layers don't connect correctly.
Don't try to push the extremes, try to perfect your measurements.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

My e-step problem has not been solved yet. Whenever I do the calibration test by measuring 120 mm filament and extruding 100 mm, I always get a different result. Mostly there is underextrusion (8-9 mm), so I increase e-steps, but I then can get overextrusion. I suspect there might be problems with the extruder (Wade's geared extruder), the motor or the hobbed bolt.

I am able to prevent the filament from advancing by holding it firmly at the entrance. The tensioning lid is at maximum strength and even at that level, I only have slight markings on the filament caused by the hobbed bolt. I'd expect the hobbed bolt to break chunks of filament at that pressure level but it doesn't, so I suspect the bolt might not be sharp enough. However there is also the possibility that I might be missing steps on the extruder. Is there a way to test this? I don't hear any abnormal sounds or irregularity of motion when the gears turn, but if the problem is there, no matter what I do on the hobbed bolt front, I won'T be able to correct the problem.

Any ideas?

If you post a sharp closeup of the bolt we can see if it is sharp enough or not.
Regarding calibration, i usually use a meter of filament for calibration, that makes it easy to get precise values.
When extruding just watch the filament coming out and see if it moves smoothly, if it doesn't sometghing is seriously wrong with your extruder.
Before calibration make sure that all gears are realy tight on the axis. Hold the filament with some pliers so it can't move into the exturder, then turn the big gear by hand. How hard is it? A well built Wade will shred the filament (if it isn't tough elastic stuff but ABS or PLA). If you don't use pliers but your hand you should not be able to hold on to it.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

Here's the picture of my hobbed bolts:



As you can see I have 2 different bolts. The black one is from Aliexpress (China) and it is worse than the other one. It practically has no teeth. The white one is the original hobbed bold which came with my machine.

I can definitely stop the filament manually (and quite easily). When I leave it, it continues to run, so I assume the bolt doesn't tear any chunks, otherwise it would stop completely.

The silver bolt looks unevenly cut, but useable, the black one is crap.
If you can stop the filament so easily i would start looking at the idler pressure and again check for any mechanical slip from the gears.
What kind of filament are you trying this with? PLA and ABS are usefull, but nylon or any elastic stuff less so.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

Right now I am printing with Colorfabb nGen. The problem is that the idler is already at maximum pressure and normally I'd expect it to shred the filament however it doesn't. I am waiting for better hobbed bolts to arrive by post.