puzzling first layer height issue

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Raddiver
Posts: 39
Joined: Fri May 13, 2016 6:27 am

puzzling first layer height issue

Post by Raddiver » Sun Jul 03, 2016 5:35 pm

So here is my dilemma,
Everything i've been reading here says i should set my first layer height to 100%. But when i do that, there are gaps between the shells and the infill. These go away by later 3 or so.
I also have adhesion issues when its set to 100%. Mostly because the infill is not properly bonding to the shells.
If i reduce it to 90%, the gaps aren't present even at layer 1, and adhesion seems better.
So im left asking... "What kind of sorcery is this?!" Isn't this counter intuitive?
I really want to understand the mechanics of what's going on here.

I've printed tons of calibration cubes and thin walled cubes setting each of the layer height percentages i get them to 2.00 +/- .01 and the same with the .4 thinwall.
Any help is appreciated.

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Jules
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Re: puzzling first layer height issue

Post by Jules » Sun Jul 03, 2016 5:47 pm

I think S3D has something written into the software for that extrusion rate fudge factor to compensate for less than 100% first layer height. Might move the nozzle just a little bit closer or something. (If you want to know more about how it works though, you need to do some research on the S3D site - I only noted some comments about it once.) :)

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jimc
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Re: puzzling first layer height issue

Post by jimc » Mon Jul 04, 2016 3:09 am

yes your bed gap is just a hair too big. if your moving the bed closer by setting that to 90 then what you are doing is compensating for your bed to nozzle gap being too big.

Raddiver
Posts: 39
Joined: Fri May 13, 2016 6:27 am

Re: puzzling first layer height issue

Post by Raddiver » Mon Jul 04, 2016 6:13 am

if your moving the bed closer by setting that to 90
And that is the missing piece of the puzzle. I didn't realize that is what was happening.
So, if my layer height is set to .2 the 90% would raise the bed by .02? So let's say that my global offset is -.05 (arbitrary number because i cant remember what it is), if i change that to -.07 and reset the layer height percentage to 100% that should be equivalent right?

It also doesn't help that I'm a bit squeamish about going too low, i just installed buildtak on the plate and don't want it bonding to the point i cant get things off of it.

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