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Skip outer perimeter on bottom layer

Posted: 03 Jan 2015, 16:30
by Msquare
Here is a "strange" request :roll:

I would like a tick box that will not print the outermost perimeter on the first layer. Sort of the opposite of "brim". Tried a negative value for brim, that would have been neat if it did work :) - which is of course a way of avoiding yet another check box.

Why? I am printing gears. The bottom layer is wider because it gets squashed into he bed to get the better adhesion. The result is that one the bed-side of the gear I have a small protruding edge that I need to cut of with my Exacto knife. Tedious for every tooth! The tricks of using Z-offset and bedroughness would reduce the squash, but the it would not adhere well, either.

I am using other people's STL files so I can not adjust the model to be narrower at the bottom.

My current workaround is to handedited the resulting Gcode and removed the perimeter and that works. So 100% THANK YOU for having meaningfull comments in the generated Gcode! In place of the removed the perimeter section, I add a G92 E it the next E value it wants to use.

Re: Skip outer perimeter on bottom layer

Posted: 29 Jan 2015, 01:14
by Garry Bartsch
I see your point and can give this request a +1.

Re: Skip outer perimeter on bottom layer

Posted: 29 Jan 2015, 17:33
by swsch
You could try blender to edit the mesh. Or, if you are on Windows, DesignSpark Mechanical (trimmed SpaceClaim) is available for the cost of registering before download. That one can also make a solid out of a mesh.

Re: Skip outer perimeter on bottom layer

Posted: 31 Jan 2015, 16:23
by Msquare
@swsch : Thanks for the idea - if I do many more of these.

Re: Skip outer perimeter on bottom layer

Posted: 01 Apr 2015, 18:44
by Isaac_alaska
i agree, allowing negative values for brim would be extremely helpful sometimes! (and hopefully not take too much work to implement?)