Understanding the visual encoder calibration results

[NeverDie]

@T_guttata

How did you compensate for shrinkage?

Here’s the method I’m using:

Did the high precision calibrations make a difference?

@APEX86 OK, thanks, that gives me an idea then. I need to look into it, but there may be an asymmetry in the infill pattern I’m using on the webbing. If I switch that infill from rectilinear to concentric, then I expect that should make it the 100% symmetric. I retained the beveling of the original makerworld model, which was a brilliant idea by the original author, but I added half circles directly into the print as further prevention against possible warping in the final print, on the theor…

You can iterate, and the shrinkage compensation gets better with each iteration. You multiply the proposed new shrinkage compensation factor by the old one to yield the new shrinkage compensation factor to plug into your filament profile. For the first iteration, you simply start with the default 100%.

[T_guttata]

Problem is: if it would be a constant; it should be very easy to correct in the Bambulab profile by default?

By the way: my H2D has firmware 01.00.01.05 installed. With this firmware, no compensation values are shown after calibration!

[NeverDie]

I think it’s likely moisture content plays a role. It may only be accurate to how well you dried it, if that’s what you calibrated it at.

[T_guttata]

Ok, might be. That’s why I’m currently working on a dry cabinet to ensure, that all my filament (50 rolls) will be stored @ <15%RH.

[NeverDie]

@T_guttata

01.00.01.05 installed.

That’s maybe the factory installed version. time to upgrade.

[T_guttata]

Yes, i will. But I wanted to do some heatbed measurements before to find out, if Bambu did any improvements regarding temperature uniformity.

[NeverDie]

@T_guttata

it should be very easy to correct in the Bambulab profile by default?

The funny part is that even the default Bambu filament profiles lack any kind of shrinkage compensation. They’re all set at 100%. i.e. no shrinkage compensation. Apparently Bambu never bothered to measure it, even for their own filament!

[hotellonely]

they did measure it and it’s very inconsistent that’s why they didn’t include it. beside the filament itself, dampness also significantly changes the result

[T_guttata]

Yes, this is what I currently encounter myself.

After motion calibration, measurements were consistent for X and Y axis, but were off roughly 0.3mm @ 150mm. So I did correct it for PLA, reprinted and the result was very accurate (150.05mm).

So I did the same for PLA-CF, but the correction made it significantly worse.
I measured roughly 150.15mm, and tried to correct it with a factor of 100.091%.
I reprinted the Test part (Alex Shrinking Test 4.1) and the result was 149.7mm???

[NeverDie]

Even a small amount of warpage can throw off the number. So be extra careful to look for that. That’s why I went out of my way to make my fork of the model warp resistant.