"Erode First Layer" Feature Request

[etotheipi]

I posted this on the Makergear forums yesterday thinking this might already exist. I'm convinced it doesn't. Please tell me if there's a way to do this already. Here's a link to that post though I will rehash much of it here:

http://forum.makergear.com/viewtopic.php?f=3&t=3569

In a nutshell, I use a tighter printer calibration to improve adhesion, but I get a lot of "squish-out" that makes that first layer larger than the other layers. This creates a sharp edge, and impacts the potential to join parts together. This is an effective "dilation" of the first layer. What I want to do is "erode" the first layer by 0.5mm to offset the dilation, and it makes the most sense for the slicing engine to do it for me.

I use the terms "erosion" and "dilation" to mean what they do in image morphology: http://www.inf.u-szeged.hu/ssip/1996/mo ... ology.html

In Simplify3D, all I can find is "First Layer Width: 100%", which is scalar instead of constant, and I'm not even clear if it does both X and Y. Further, if I do multiple objects in one print, a global X/Y rescaling of the first layer as single object is going to be super wrong. Instead I want to treat the first layer as a 2D binary image, perform a user-specified erosion on it, then use that for generating g-code paths.

I have been hacking it with my SolidPython/OpenSCAD model, by chopping off the bottom 0.3mm of the box to be printed, and replacing it with a layer that is 0.5mm smaller on each side. It does do exactly what I want, but this is an ugly hack/workaround that won't work with more complex models. It really needs to be a feature of the slicing engine.

I'm an experienced programmer -- if there was a mechanism to achieve this through plugin or script, I would get on that right away.

[CompoundCarl]

Typically, this means that you are squishing the first layer a bit too much if there is a lot of extra plastic sticking out on the first layer, so first of all, I would make sure you definitely have the nozzle position in the best place for your printer. Try to move it a bit further from the bed using the global Z-axis offset and see if it still sticks okay.

Now if you have the Z-position the best you can get and you are still seeing this, then they already have a nice "Horizontal size compensation" feature that will offset the model outline by a specific distance. So if you go to the Other tab and you enter -0.1mm for the size compensation, then it will shrink all your outlines by that value.

If you only want that to happen for the very first layer, then just make 2 processes, one for the first layer only, and another for everything after that. This link explains how to do that if you haven't before: https://www.simplify3d.com/support/tuto ... f-a-model/

[tonyno]

I second this. The first layer is inherently bigger by design.

I have achieved similar results by "shrinking" (Horizontal Size Compensation) the first layer by -0.4mm (pain due to having to specify height in mm instead of layers), or, beveling the bottom of objects by 0.040".

[bray.christopher]

+1

I also like a bit of squish on the first layer. This creates a small lip around the base of the part. Sometimes we call it "elephant foot", I don't know why.

Anyway, if this is going to annoy me, I add a small chamfer around the base of the part in the CAD model.

I like the idea of being able to do effectively the same thing in the slicer.

[BaronWilliams]

+1

Having a Horizontal size compensation setting that's specific to the 1st layer would solve this nicely. I posted about this in another thread. It seems that this subject keeps popping up.

[zapta]

+1

Having this feature will allow to have a squashed first layer for surface smoothness and adhesion and yet avoiding the elephant foot problem.

BTW, this feature request is from 2015. Any response from Simplify3D? Do you watch this feature request board?

[CompoundCarl]

BTW, this feature request is from 2015. Any response from Simplify3D? Do you watch this feature request board?

I've exchanged plenty of emails with their team and I know they have multiple people reading this forum every single day, so I'm confident they have already seen the request. That being said, this is a user forum, so if you want to talk to their employees, you should contact them here: https://www.simplify3d.com/contact-us/

[zapta]

Thanks Carl. Good to know that S3D actually reading this, even if they don't respond here.

I experiment with the erosion concept and it seems to work very well. I used a test cube when a few bottom layers eroded and could get very clean cube with yet 'squashed' and very smooth bottom layer. (Using Flash Forge Creator Pro, ABS, PEI bed).

The customizable OpenScad model is here on Thingieverse http://www.thingiverse.com/thing:1722081 , to have different inset values, open in in the Thingiverse customizer and edit the inset list.

S3D should be able to do it automatically for arbitrary models, that is, accept such erosion parameters from the user's configuration and apply to the sliced model.

[TheGoofy]

Please add "horizontal size compensation" as option for the first layer. Of course one could say, the print bed is not well levelled, but if I properly level the hight, the first layer adhesion is MUCH worse, because the contact area on the build-plate is maybe only 50%. For a 100% contact area of the bottom layer, material needs to be over-extruded, which results into this ugly brim. Often I'm creating a small chamfer in my designs on the base face in order to compensate this artefact. The result is usually perfect, but I see this just a workaround: it would be better, if the design doesn't need to be modified for the printing process.

Layer height in the image below is 0.15mm

[CompoundCarl]

Please add "horizontal size compensation" as option for the first layer.

You can already do this right now. I use it quite frequently. You just setup 2 processes, one for the first layer only, and the second one for the remainder of the part. Then you set the "horizontal size compensation" for the first layer process only. Pretty simple.