Risks

Two plastics or colors mix in one grinder

Risk	A grinder that is moved to another job without being cleaned out carries the old plastic into the new one.
Early sign	Black specks or streaks on parts from a job that takes regrind.
Mitigation	One grinder per plastic and color, cleaned out and checked before it moves.
Impact	One rejected lot can cost more than a year of that grinder's saving.

Risk	Flakes scooped in by eye go in at whatever share the scoop gives, not the share the job allows.
Early sign	The flakes run out, or pile up, faster than the set share explains.
Mitigation	Weigh the flakes into each box of new resin. If the share still drifts, a blender that weighs the mix at the press costs $8,000 to 20,000.
Impact	Parts outside the customer's specification on that job.

Risk	Where a job makes little leftover plastic, the noise, dust and handling outweigh the resin saved, and operators stop using the grinder.
Early sign	Runners back in the bin beside a grinder.
Mitigation	Grinders only at jobs whose bins were weighed first, and slow-turning ones, which make less dust and noise.
Impact	About $8,000 per year for each grinder that stands idle.