Why is the 4-layer per 1mm on the z setting of 0.2mm

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jspark
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Why is the 4-layer per 1mm on the z setting of 0.2mm

Post by jspark » Mon Sep 03, 2012 12:25 pm

0.2mm z-resolution setting is just fake?
There are only 4-layers per 1mm on the 0.2mm resolution printing.
It has to be 5-layers, but there are only 4-layers in order to make 1mm.
Although I've setted the resolution to 0.2mm, It was 0.25mm printing!
Is there a any reason?

jspark
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Re: Why is the 4-layer per 1mm on the z setting of 0.2mm

Post by jspark » Mon Sep 03, 2012 12:52 pm

The total layer number is reasonable.
the model(24mm)+raft(2mm) = 26mm
the total layer number = 129
26/129 = 0.20155mm

But there was just 4-layer in some part of model as following photo.
I wonder why are the layer number mismatched with z-resolution value.
_DSC5976_600.jpg
_DSC5976_600.jpg (179.21 KiB) Viewed 4609 times

eyUP
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Re: Why is the 4-layer per 1mm on the z setting of 0.2mm

Post by eyUP » Mon Sep 03, 2012 1:57 pm

Just to be sure what's going on, put a ruler against the model and take a close-up photo in macro mode.
It's easy to count number of layers per mm against the ruler divisions when zoomed up on screen.

jspark
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Re: Why is the 4-layer per 1mm on the z setting of 0.2mm

Post by jspark » Mon Sep 03, 2012 2:23 pm

Yep!
I got the macro photos as follows.
It is weird!
Please check the photos.
_DSC5987_600.jpg
_DSC5987_600.jpg (225.33 KiB) Viewed 4593 times
_DSC5993_600.jpg
_DSC5993_600.jpg (165.97 KiB) Viewed 4593 times

eyUP
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Re: Why is the 4-layer per 1mm on the z setting of 0.2mm

Post by eyUP » Mon Sep 03, 2012 3:07 pm

Weird - the other part of the model look to be finer though, unless it's an optical illusion, there look to be 5 layers in the width of that lug you are measuring.

Maybe this is related to the Surface setting ? (default of 3 layers IIRC) It could be trying to create the best solid surface by altering layer thickness ?

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DrewPetitclerc
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Re: Why is the 4-layer per 1mm on the z setting of 0.2mm

Post by DrewPetitclerc » Tue Sep 04, 2012 4:52 am

The answer is pretty simple, from the bottom (Zero build plate contact) of your part to the first surface (underside) of the "Tab" could be at a "midpoint" of a 0.2mm measurement from "Zero" so that the layer slice could be less than half (0.09mm), the software would then need to decide whether to attempt to build that layer or not, depending on the algorithm it decides it is less than what meets its requirements and instead starts the next layer of the "Tab" giving you only 4 layers.
If your tab was the only part being built then the first slice would be from "Zero" and you should see a complete 5 layers at 0.2mm slice in your part if your system is properly calibrated.

Hope you can understand my ramblings. :ugeek:
Drew Petitclerc
Petitclerc Designs
Owner/Senior Principal Designer, prototype, tooling and test equipment design and 3D printing
http://flash-graphics.deviantart.com/
http://www.thingiverse.com/DrewPetitclerc

eyUP
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Re: Why is the 4-layer per 1mm on the z setting of 0.2mm

Post by eyUP » Tue Sep 04, 2012 3:01 pm

Hope you can understand my ramblings.
I understand what your saying but it's still strange why it would switch to 0.25mm layers in some parts of the model (which it appears to be doing)
The 4 layers shown in the mic are exactly on size and I can't see why it wouldn't have just built it in 5 x 0.2mm layers ? I would have thought using the smallest allowable layer thickness would make it easier to hit the dimensions needed ?
Anyway, there are only a few people who know the answer and they probably aren't reading this ;)

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