Fix a flat metal bar on the 3D printer bed to avoid ABS warping. I'm using metal bars with 2mm thickness, 19mm width.
Be careful for collision with jig/bar and extruder/frame of 3D printer.
Start printing without jig.
When the raft has been printed, pause printing.
Set this jig and metal bar to hold the raft down, then resume.
In Customizer, you can modify:
-thickness and width of metal bar
-thickness of raft
-thickness of bed of 3D printer
-clearance for all of above (I've set 0.1mm for my UP BOX)
-inner/outer length from the edge of the bed (normally no need to modify)