ASTM E618 – 07 Evaluating Machining Performance

Scope:

ASTM E618 – 07 can be used to evaluate a particular grade or type of metal’s machining performance or to compare one type to another. Only at operating circumstances that generate test pieces of comparable quality in terms of surface roughness and dimensional limits for comparable lengths of machining time can the relative machining performance of the various metals be examined using this test method.

Procedure

An automatic screw machine is needed to produce a standard test piece from bar stock. The cutting speed and tool feed rate for the tested metal are changed from one test run to the next to discover the maximum rate at which test pieces can be generated for the stipulated period while staying within the prescribed surface roughness and size criteria. The level and variations in surface roughness, as well as the size of pieces produced, are utilized to evaluate the machining performance of the metal being evaluated when measured as specified.

Specimen size

The test specimen must be made from bars with a diameter of 1 in. (25.4 mm).

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Result 

The size ranges of the pieces produced during the test and the surface roughness of the pieces are essential indicators of machining performance. By comparing the theoretical hourly production rate with that of base metal or by comparing cutting speed or tool-feed rate with those of base metal, the results of a machining-performance test can be stated in percent relative to the machining performance of base metal.