That is not telling of precision custom injection molding. perhaps some of the dims were reasonably tight though no mention of holding tooth form to this. was the mesh held and to what class? Also, no mention of number of custom injection mold and production runs. 12 microns is not particularly difficult and is done often in optic and medical products, I, myself, have molded much tighter with high cavitation and production. These were optics and laser components though. to your point, yes the science and understanding of custom injection molding has come a long way as well, polymer behavior has certainly advanced. however, none of this addresses the issue of custom injection molding gears directly. we all have successes in custom injection molding and I don't believe anyone is saying this is impossible. however, the proof is in the pudding. Custom injection molding high precision gears, particularly above class 10 is non-trivial. Custom injection molds more gears than anyone else in the world at a higher precision and quantity. I too have been doing this for a long time, that's why I know this to be true.

I won't be overly critical about ABA-PBT. they do a good job, however, I would not place them in the top of my list for high precision injection molding as for their writing the book, that I do disagree with, much has been done both contemporary with and since they "wrote" the book. Polariod's work on tooth form, circa 1960's for instance. Find more about Aco Mold.