The article analyses the reason why the false waste products appear during the course of manufacturing mechanical parts because of the disagreement between the measure datum and the design datum.

The phenomenon and reason of the false waste products in machining are analysed thoroughly.

The phenomenon of the false waste products in machining are analysed thoroughly by a examples,and the corresponding technolgical measures for dealing with false waste products are presented.

The false scrap analysis of parts based on the dimension chain;

It puts forward effective measures and ways to the confirmation of close-loops,creation of dimension chains,treatment of "false scraps" and solving of public loops.

The paper explains the reason of parts producing false scraps,puts forward the method of judgment the false scrap based on the limiting size travelling,and points out the region parts appearing false scrap and the relation between the false scrap and the base misalignment error.

Diagram and treatment of false waste product on tolerance area;

Question about false waste product produced by process size;

Study on False Junks of Machining;

The cause of false junks,the determination of tolerance zone and the false junks zone formulations of multi-loop size of chain were give under the analysis of a example.

Through the analysis on fifty shares true and false condiment and adulterate part by a-dopting the method of microscope examination finds out the method of distinguishing true and false condiment,solves the problem that true and false condiment is not easy to be distinguished and provides a feasible way for food checker.