Most key parts of the automobile in the present age are made of die-casting aluminum alloy with complex structure, shape and many step-formed holes which itself has higher quality requirement on roughness, roundness, concentricty, and no flash. In order to meet the machining requirement, our company developed PCD forming step reamer by utilizing imported high precison grinder and form grinding techniques. The PCD forming step reamer makes all the cutting edges have excellent cutting behavior under different maching loads, guarantees the dimensional precision and roughness of the workpiece machined,eliminates the disadvantages of carbide reamer, such as adhering to the reamer, poor resistance to wear, variable dimension, poor quality of machined surface, prolongs the service life of cutting tools and reduces the production costCan restrain the generation of bursfor a longtime,realize high speed and efficiency processing. Most adaptable to plain milling of aluminum alloy parts such as computer parts. Long operating life,beautiful fine finishing facets. Most adaptable to fine finishing non-ferrous metal (aluminium alloy,copper alloy.etc), Used for processing of aluminum alloy hole,extend the varieties of high precision type and common precision type aigulles.Section adjusting of reamer should have back taper.The body of internal cool reamer is made by YG8 or hard alloy with same performance.Other reamers body are made by 9CrSi or alloy steel with same performance.the hardness of shank and flat tail is 30HRC 45HRC.Process colored metal can select the inserts of PCD material,PCBN inserts for machining black metal.