2、 Analyzing the parts drawings, clarify the key areas of the product and size.To understand important areas of the product and associated key sizes are always the first step when customers' product drawings arrived, then pay more attention on those importance, such as product "End surface" ("End surface" was required most strictly straightness, flatness and form size tolerance requirements, and other parts of the product size will follow their changing),"Tube orifice" area (the dimension of "tube orifice" is also very important, usually the positioning, cylindrical and dimensional tolerances are required)and product "Boss" and "U-shaped" ribs etc., as shown below: