736 Каталог ISCAR 2017 Вращающийся режущий инструмент и инструментальная оснастка Стр.732

Каталог ISCAR 2017 Ротационный инструмент Стр. 732 0736 ENG Lab2u

TAPS USER GUIDE Regrinding Regrinding Tap regrinding takes place in two steps: a) regrinding of relieved chamfer b) regrinding of flutes (see picture 1) Regrinding of Relieved Chamfer It is recommended that the resharpening should be executed either on specific tap regrinding machines or on conventional resharpening machines equipped with an auxiliary device to generate the circular back relief. Picture 2 shows the regrinding done with the cylindrical surface of a grinding wheel. Before regrinding, verify that the tap, fixed between points or on the pincer, runs concentrical. Also ensure that angle B is in the correct order to keep the same number of threads on chamfer. Resharpening of Flutes The rake angle g is obtained by moving the tap axis, in relation to the regrinding surface, of an amount X to be calculated with the formula: X = 1/2 d1 sin (g) (see picture 3). (d1 =tap major diameter) Example: Tap 10 X 1,5 to cut on steel strength = 600 N/mm2 d1 = 10 mm ; g = 15° ; sin (g) = 0,25882; X = 0.25885x10 ; X=1.29 mm 2 Picture 1 Picture 2 Picture 3 On all taps with spiral flutes, it is possible to find the pitch of the spiral in reference to the lead screw necessary for resharpening. In case of using taps equipped with a deburring tool, it is necessary to extend the flutes according to the supplier's recommendation. As the wear on a tap is mainly on the chamfer area, for taps with a gun nose, regrinding the flutes can be done on the front area only (see picture 4). In cases where the thread flanks are worn (in addition to the active edges), regrinding as described above is impractical. In this case restoration is done, by cutting the chamfer away (thus creating a shorter tap) and then reproducing the chamfer with same angle and relief. (see picture 5) In the absence of special regrinding machines, such restoration is advisable for regrinding taps with spiral flutes. This is because regrinding the flutes becomes unnecessary. Picture 4 Picture 5 732 ISCAR