Amen on the test print for leveling. However my thingiverse print only 20 takes 2 minutes to print. Its set to only do hatching at corners and over each spring adjustments. Thing 80227 waste alot of material and time. Yes, I’ve found that the best leveling leaves the back left corner as an area to avoid. (or minimize with a raft)
Its the cooling personality of ABS that makes it warp. Warping can be avoided by building in a heated chamber, by using PEI (PEI bed surface - Hardware - LulzBot 13) or Buildtak bed liner. Kapton, glue, acetone slurry,hairspray (aqua net), blue tape, white glue mix will all work. The white glue mix can be made so strong that the parts will break the glass coming off so be careful. By using Buildtak we have found the parts become stronger by curing under stress.
Warping can be caused by long unbroken, straight lines of filament being put down in the slic3r engine and breaking up the pattern helps. Build plate heat traces cause some issues too as others have noticed that moving the part around on the plate can help. Avoid drafts and fans with ABS. Use an enclosure.
Currently I am testing and using Buildtak in a production environment. Its been the best stuff that I have used so far.
1. The spring loaded mod is a must, but I had to go another step further for exotic filaments. This knob adjust makes it easy to apply just the right amount of force on the filament. Thingiverse - Digital Designs for Physical Objects 18
2. I’ve found that the NEW large rolls of PLA from MakerBot reguire ABS temps to avoid jamming. That and reduced print speed.
Acrylic warps over time with heat and is impossible to keep flat. I’ve gone another way with build platform issues… 2 items solved this for me. Buildtak http://www.buildtak.com/ 8 for the surface… I’ve not had to replace it after hundreds of hours of jobs… and an alum platform (because i upgraded to a heated platform ). Glass could do the same. I also enclosed the chamber and put an enviromental control on it for better temperature control.