Layer thickness problems

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

Layer thickness problems

Post by sinned6915 »

I went to print a bench today and I got warnings for "Possible Layer Thickness Problems" popup.

https://drive.google.com/open?id=1tFqhN ... z4slJM13w3

I have been using this EXACT profile for weeks with the same material. I cant get my head around what the error is telling me.

50% of 0.4 = 0.2mm for layer thickness
75% of 0.4 = 0.3mm for Max

So why is it reporting 0.15 and 0.302 for mins and maxes if I already gave it the threshold values?

Thanks

Dennis
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MatejEU
Posts: 6
Joined: 24 Jan 2018, 14:04

Re: Layer thickness problems

Post by MatejEU »

Hi Dennis,
I think that you should check your Z-step value in Printer->Hardware.

It is a value specific to your printer and slicer will use it for its layer height calculations. In my case that value is 0.04mm and I could use something like 0.12mm for min and 0.2mm for max layer thickness. If you don't want to use dynamic layer transitions, simply put the same value for min and max, e.g. 0.2.

Check with your printer's manufacturer for the z-step height or in some facebook "support group" for your printer. Also, you can use this calculator to verify your Z-step size, check under "Optimal layer height for your Z axis": https://www.prusaprinters.org/calculator/

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

Re: Layer thickness problems

Post by sinned6915 »

Matej-

Thanks for the suggestions. I understand what you are saying, and agree its a math thing with the number of max/min layers and Z steps.

On my printer, Z steps are 400steps/mm, or a resolution of 0.0025mm/step for TR8X8 leadscrew and 1/16 stepping, 1.8deg motor. I see the same numbers for the Prusa i3 profile that Peter posted. So I am pretty sure its a combination of the model height and the results of the slicing increments.

I am trying to understand why KS is coming up with these odd increments. I can not find out how it computes the layer heights for variable settings.

Can anyone describe the algorithm behind the math?

Thanks

Dennis
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pjr
Posts: 692
Joined: 05 May 2015, 10:27
Location: Kamnik, Slovenia

Re: Layer thickness problems

Post by pjr »

Dennis

Can you please upload the model and project file (when the error occurs)?

Thanks

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

Re: Layer thickness problems

Post by sinned6915 »

There is an appearent bug in the Prusa calculator- https://www.prusaprinters.org/calculator/

The gear input fields in the optimal layer height one are reversed to the convention above for the steps/mm ones. I did the math by hand and but Triffid's page as well.

I will see if I have the model still- i may have deleted it. But I will post the next if it happens again
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pjr
Posts: 692
Joined: 05 May 2015, 10:27
Location: Kamnik, Slovenia

Re: Layer thickness problems

Post by pjr »

Just one more thought... I think that many Benchy models do have errors which are not a problem for most slicers.

I did have a 4C version, again with many errors, which I had fixed by MakePrintable.com and which retained the individual meshes. Unfortunately, that model was stored on my old PC which broke over Christmas :-(

Peter
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