Preload tuning

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sinned6915
Posts: 55
Joined: 28 Nov 2017, 10:06

Preload tuning

Post by sinned6915 »

Greetings all-

I am trying to tune a new printer build. Its using a Bowden extruder, ~900mm from drive wheel to nozzle (length surprised me too but its a 300x300x300 build envelope). I am using the same filaments I use on my Di3, so I have some starting points.

I read the threads here about Preload tuning and I thought I understood that I should expect for results, but I am totally confused by what I am seeing.

I varied my values per the instructions from 2x the initial material wizard preload or 0.75, so 1.5 at the bottom. No shells and 0.8mm wall thickness and 20% infill. This is what I got.
preload_VE_Tuning.png
This is eSun PLA+ printed at 210. Things on this printer run a little hotter than I am used to. I have this stairstepped pattern of missing or unbonded filament. I have no idea what the adhesion issue is, I have never seen it like this before. Seam is at 6 o'clock position. Any tips for taking better pictures to avoid the Moire patterns?

The left side of the seam feels like there is a ridge, the right side where the new path started feels low. There is a low region between the start and end of the path.
cube-crop.jpg
Thanks in advance

sinneD
Attachments
Eust_25mm_PLA_210_PreloadVE.zip
(348.09 KiB) Downloaded 111 times
sinned6915
Posts: 55
Joined: 28 Nov 2017, 10:06

Re: Preload tuning

Post by sinned6915 »

I am trying again to do PreloadVE Tuning- here are my settings. I am doing this on my 'known-good' printer for now.

I would really appreciate it if someone could review and confirm that the settings and style are appropriate. The printer is a Wanhao i3 clone.I am also including the gcode in case.

I will post pics of the resulting cube next.

Thanks

Dennis

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this filament does not photograph well. but the results of the second look way better than the first. Preload VE=0 on the right end, 1.0 on the left. The undercut is the same all the way up. I need to try another colored filament. I think that its around 3/4 the way up that it looks best.

IMG_20180425_121444.jpg
Attachments
PETG_PreloadVE0-1.7z
(99.36 KiB) Downloaded 102 times
sinned6915
Posts: 55
Joined: 28 Nov 2017, 10:06

Re: Preload tuning

Post by sinned6915 »

What are we looking for to evaluate to optimize the setting? IIRC, its where the surface is as 'flat & even' as best can.

I tried doing the Experimental Method to get a PreloadVE- my result was 5.38. I could not weigh the drool crumbs accurately, so I used a piece of tape and laid the filament out to measure the drool and used the calculator.

Then I tried Wizard tuning using a range of 5.0-6.0, the results were not good. The extruder ended up ejecting the filament about 1/3 the way up. Its like it retracted so far it lost grip. Then I tried 0-5, and then the filament jammed.

So I decided to redo 0-1 and then try 1-2. The prisms are much nicer to view. The 0-1 looks almost the same all the way up. If I had to judge, the lower levels look best.

The 0-1 prism looks the same all the way up. The 1-2 has a small band at the bottom ~20% up that is the finest of seam edges.
The attachment PreloadVE_0-2.jpg is no longer available
So I am interpreting that almost any value under 1.25 yields the same result. I think I will try the wizard again with the range of 1.0 - 1.25 and see what I get.
Attachments
PreloadVE_0-2.jpg
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