scope:

This Standard specifies the method for measuring the unbalance and the practical inspection method for the acceptance of grinding and cutting-off wheels specified in Table 1 of JIS R 6241, having the outside diameter of 150 mm or more and mass of 0.2 kg or more used at the regular speed, and having the outside diameter of 100 mm or more and the mass of 0.1 kg or more used at the high speed, which are used at the maximum operating speed of over 10 m/s Also this Standard specifies the maximum permissible unbalance of grinding and cutting off wheels.

This Standard is applicable to the grinding and cutting-off wheels in the as-delivered condition; however, not applicable to the following bonded abrasive products.

- Diamond/CBN tool or natural stone grinding wheels

- Control wheels for centreless external cylindrical grinding, grinding wheels for lapping, grinding wheels for steel balls or grinding wheels for glass

NOTE 1 The unbalance obtained in this test method refers to that existing in the grinding/cutting-off wheel itself, independent of any imbalance which may exist in the balancing test arbor (hereafter referred to as the balancing arbor) or in the means of fastening it to this arbor. Various elements, together with the flanges or hub-flanges, are assumed to be balanced, homogeneous and free from geometrical defects.

NOTE 2 The effects of imbalance are basically as follows.

- Additional stresses on the axis, machine and its mounting

- Excessive wear of bearing

- Vibration prejudicial to the quality of machining, and increase in internal stresses in grinding/cutting-off wheel

- Increase in operator fatigue

NOTE 3 The maximum permissible unbalances specified in ISO 6103 are shown in Annex JA.

NOTE 4 The International Standard corresponding to this Standard and the symbol of degree of correspondence are as follows.

ISO 6103 : 2014 Bonded abrasive products - Permissible unbalances of grinding wheels as delivered - Static testing (MOD)

In addition, symbols which denote the degree of correspondence in the contents between the relevant International Standard and JIS are IDT (identical), MOD (modified), and NEQ (not equivalent) according to ISO/IEC Guide 21-1.