Print Brim After Printing First Layer of Model

[64Pacific 2]

Hello:

 

I've got a model rigged up and ready to print, the model will print on the Ultimaker 3 after being sliced with Cura 5.2.1. The model will print with Extruder 1 (PLA) and the brim will print with Extruder 2 (Breakaway). In order to maintain the details on the first layer of the print I was hoping to get the printer to lay down the first layer of the model and then place the brim using extruder 2. Currently after slicing during the preview of the printing process it can be seen that the brim is printed first followed by the model itself, this printing order (I believe) is causing me to loose some of the fine details (a radius) on the first few parts of the model.

 

Is it possible to reverse the order of the printing so that the brim is printed after the first layer of the model has been placed onto the build plate?

 

Thanks!

Edited December 23, 2022 by 64Pacific

[GregValiant 1,273]

You can do it manually but there is no setting for that.  The brim is supposed to aid bed adhesion of the model and not the other way around.

You could set the brim distance to 1mm and make it into a wide skirt, or just use a skirt.  Your second extruder isn't going to stick to the model anyway.

 

You can copy and paste the brim code from the beginning of layer:0 and place it at the end.  You would need to sync the extruder with a G92 Exx.xxxxx at the "New" beginning of Layer:0, then a second G92 Exx.xxxxx to sync the extruder at the start of the brim, and then at the end of the brim a third G92 would re-sync back to the gcode that follows.

 

The easiest thing is to just use a skirt.

Edited December 23, 2022 by GregValiant

[gr5 2,181]

Maybe you don't need a brim.  Does your part have rounded corners?  How long is it on the bed in the longest dimension?  Did you use a surface preparation like magigoo?

[64Pacific 2]

I will give it a go and see about modifying the G code as suggested - I've never looked into the code following slicing and am curious what it entails...

 

In the past I have printed the same models without a brim and experience warping. The models in this case are 10 or so small highway dividers with limited build plate contact area. If one print is done at a time I don't see warping but with the time between individual models there is a bit of warping. Currently my post processing (a few minutes with a fine file) cleans up the model.

 

Magigoo is a new one for me, I've never tried, nor heard of it. Currently my surface prep is re-positionable spray adhesive. I am off to google to check out the product you've suggested. One product that I tried to use were the Ultimaker adhesion sheets - I have worked on a lot of really old rusty equipment with bolts seemingly welded together and none of them put up a fight like getting a model off of my build plate with the adhesion sheets applied.