We are suppliers to he automobile industry and are in transition from QS to TS. My consultant is insisting that TS requires us to do a product audit in addition to the layout inspection. The difference between the two is that in the product inspection only the critical dimensions /parameters are measured whilst in the layout inspection all the dimensions mentioned in teh drawing are measured. I am iansisting that ONLY the layout inspection is sufficient and product audit can be eliminated. Could someone through some light on this?.

We are suppliers to he automobile industry and are in transition from QS to TS. My consultant is insisting that TS requires us to do a product audit in addition to the layout inspection. The difference between the two is that in the product inspection only the critical dimensions /parameters are measured whilst in the layout inspection all the dimensions mentioned in teh drawing are measured. I am iansisting that ONLY the layout inspection is sufficient and product audit can be eliminated. Could someone through some light on this?.This may not be exactly what your consultant is aiming at, but consider the following two examples:

Layout inspection is equivalent to First Article Inspection in which EVERY dimension and characteristic and attribute is covered. Often, this inspection is done with special lab instruments, Coordinate Measuring Machines, optical comparators, etc.
Product Inspection (in-process or final) considers only critical or typical characteristics and attributes. Measurements may be go-no go with gages, dimensions may be with calipers, micrometers, and other hand held instruments.

Ideally, an organization performs both types of inspection, the Layout or FAI forming the benchmark measurements, while the product inspection is primarily concerned with whether the product meets the specs within the tolerances. Less concern is given in the product inspection to the ultimate decimal point precision available from a Layout or FAI.

The reason for doing both is to "prove" the efficacy of each method and to test the instruments and gages used in the product inspection against the (usually) more sensitive instruments used in FAI.