Brim Layer Height Formula

[inventabuild]

0.35 nozzle
0.22 layer height
0.16 bed roughness

Utilizing bed roughness s/ give me an inflated first layer height so I'm wondering what is the formula for brim so I get the same inflated first layer height for both part and brim? The reason for my question is that the corners on a part were lifting later into a print so I implemented a brim on the next go-round to help keep them down. The weird thing is on the first layer the part was sticking, but the brim was not so at first glance it seems like I cannot set brim = layer height and expect them to print the same first layer height when utilizing bed roughness; hence the reason for my question on brim formula.

Also, how is first layer height calculated when utilizing bed roughness?

[Ros]

For the BRIM Height, there's an option here..

Down Left corner "Brim Ht."

[inventabuild]

Yes, but if first layer height is 0.22 and bed roughness is 0.16 what s/ brim height be equal to so that the first layer of the part and the first layer of the brim are equal in height and width?

[Dreide]

Also, how is first layer height calculated when utilizing bed roughness?

First layer height = Layer height + Bed roughness.
However, this is just done by increasing the extrusion volume for the regularly sliced first layer, so the model is not re-sliced. This means that, with respect to the model, the 2nd layer starts at the same height into the model, no matter what the Bed roughness is set to. So nominally, and if the print bed is well calibrated, the print will turn out higher than the model (nominally by Bed roughness).

Regarding the brim, at least with version 1.5beta 2.7, Bed roughness is also taken into account for the brim (as roughly judged from the E values in the g-code file).

[lonesock]

The brim will occupy at least one layer (if Brim Diameter > 0). It may occupy more than 1 layer if the Brim Height is > 0. Any layers where there is a brim, the brim paths will follow the same rules as the other paths on that layer (layer thickness, etc.). So the Height and the Fillet options basically control how many layers the brim will occupy, and the extra brim extension. (Oops, should probably be a Brim Radius, then, shouldn't it!). The Height will not affect the thickness of the brim extrusion on a given layer.

I may have misunderstood the question, though. [8^)

Jonathan

[inventabuild]

Thanks All for the suggestions; however something is not right. The brim in KISSlicer is not sticking to my PEI build plate, but the part printing inside the brim is sticking. And when I slice the same part in Cura both the part and brim stick to the build plate. I increased the brim height in KISSlicer from one layer height up to nozzle thickness in steps, but brim will not stick in KISSlicer.

[Dreide]

Could it be different printing speeds then (or extrusion temps, or cooling fan speeds)?

[inventabuild]

speeds, extrusion and bed temps all the same and no fan since I'm printing ABS, but if no one else is having an issue w/ brim sticking then there is a difference somewhere. It's weird, I actually have to pry the Cura sliced brim off the bed and like I said the KISSlicer sliced part sticks fine, it's just the brim that delaminates from the bed during the print.

[Dreide]

Could you post the gcode files (Cura and KISS), possibly after having removed the gcode for the upper parts via text editor (to keep file size small)? Also, which KISSlicer version is it?

[inventabuild]

I'm trying to upload gcode and txt files and I'm getting a message that those files are not allowed. What kind of files does the administrator allow?