Обший каталог Yamawa 2016 - 2017 - страница 781

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Tapping Torque ■Tapping Torque of Cutting type Taps Description of products The torque starts increasing as the threads of chamfer enter the workpiece material. It becomes highest when all threads of chamfer cut into workpiece material, and is in plateau until the chamfer cuts through the workpiece. After that, the torque will decrease until the end of tapping. Tapping Torque Equation for Cutting Taps tanθ .kc×K(D-Do) Table 1 Specific cutting resistance of each material Tc = 24000 ×(D+2Do) Materials to be cut Specific cutting resistance kc N/mm² Material symbols Hardness N/mm² Tc : Tapping Torque (N-m) 5t44-2 133HB 3700 kc : Specific cutting resistance (N/mm2) Ck 15 141HB 3600 K: Correction coefficient depending on tap geometry and chips Ck 35 162HB 3700 D: Nominal Diameter of Tap (mm) Ck 45 188HB 3900 Do : Bored hole diameter (mm) Ck 60 188HB 4000 42 CrMo 4 193HB 3600 θ: Thread half angle (° ) 30HRC 4900 40HRC 5500 kc and K : Refer to Table 1 and Table 2 X 6 CrNi 18 10 209HB 4200 C 105 W2 175HB 5300 CnZn40 − 2300 G-AISi8Cu3 − 1300 GG-25 193HB 2900 Table 2 Correction coefficient depending on each tap geometry Materials to be cut Coefficient K Steel Cast iron・Aluminum alloys Brass Kinds of tap coarse fine coarse fine coarse fine Hand tap plug 1.35 1.15 1.25 1.08 1.60 1.12 Hand tap bottoming 1.43 1.50 1.30 1.25 1.68 − Spiral fluted tap 1.15 1.25 1.05 1.10 0.85 − Spiral pointed tap 0.95 1.00 0.80 1.00 0.75 1.00 ■Cutting Torque Line Cutting torque lines in the test of different kinds of taps, hand tap, spiral fluted tap, spiral pointed tap are shown below. Tapping Condition Tap : HSS P2 M8×1.25 Bored hole size : 6.8mm Cutting speed : 6.1m/min Cutting oil : Water insoluble oil Workpiece material : Ck60 Machine : Drilling machine Tapping type : 10mm Through hole Measurement equipment : Piezoelectric torque tester Type of tap Torque lines Description Hand tap (P2) Plug tap (5 threads) Plateau is observed since whole chamfer threads enter the workpiece material. Tapping time is much shorter than that of the taper tap. Bottoming tap Plateau is also observed since whole short (1.5 threads) chamfer threads enter the workpiece material. Tapping process time is shorter than that of the plug tap. Spiral fluted tap (P2, 2.5 threads) Spiral fluted tap pulls out the chips, good choice for blind hole tapping. The cutting torque of spiral fluted taps is smaller than that of the hand taps. Spiral pointed tap (P2, 5 threads) Spiral pointed tap pushes out the chips forward. Information Technical It is good choice for through hole use. Cutting torque is smallest in all taps. The cutting torque will change depending on the kind of taps, cutting chamfer, number of flutes, workpiece materials and their hardness, lubrication types, and chips. Technical-6 777