Update abs.md

docs/level_0/abs.md

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 # ABS / ASA
-TBD.
+
+Brainstorming...
+- Need heated bed
+- Need enclosure
+- Need active carbon filter
+- Be aware of VOCs
+- Higher chamber temperature is better
+- Bed adhesive
+
+- Each layer shrinks as it cools
+- Higher layers cool more quickly than lower layers closer to the heated build plate
+- This can cause corners of object to lift off of build plate, causing warping
+- This can cause parts to get knocked off build plate entirely
+- Fixing adhesion not the only problem - parts can lift the build plate off of aluminum base plate
+- Part design can have a big impact on how cooling relates to adhesion and warping
+- Solid parts are more of a problem, whereas gaps lessen the forces being applied
+
+
+- Print monitoring applicable here - watching for parts that have been knocked out of position