Threading Technology – Clamping Technology 520

640 Tap Holders Soft- synchro Speed- synchro KSN MQL SFM HF EM Accessories Tech. Info Product Finder As an example an M10 thread with three different tool holders is formed in material 1045. The axial forces were recorded at two speeds which were 500 rpm = 51.5 SFM (15.7 m/min) and 2000 rpm = 206 SFM (62.8 m/min). The following collet adaptions have been tested: a) Rigid synchronous collet adaption b) EMUGE collet adaption Softsynchro ® size 1 with minimum length compensation on compression and tension c) Synchronous collet adaption of a competitor with minimum length compensation with axial damping With all tested collet adaptions a collet type ER20-GB with integrated square was used. b) c) a) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 3000 2500 2000 1500 1000 500 0 Speed 500 rpm Roll form tap M10 in material 1045 Axial force [N] Time [s] b) c) a) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 3000 2500 2000 1500 1000 500 0 Speed 2000 rpm Roll form tap M10 in material 1045 Axial force [N] Time [s] The following results were verified in these tests: • Axial forces increase with the raise of speed • The forces which come into play in the cold forming of threads are considerably higher with a rigid collet holder than with an EMUGE collet holder type Softsynchro ® • The competition collet holder can absorb the upcoming forces only lightly, in comparison with the rigid collet holder 7.4 Rigid tapping Summary To realize the total effect of the individual influencing factors mentioned before on the axial force component of the thread producing process, the shown possible position faults, length changes resp. the forces causing length changes must be combined. The following graph shows: • With an addition of possible axial faults caused by machine pitch tolerance or temperature influencing factors a position fault between specified position of the tap and real position of the machine spindle of more then 17 µm may arise • This position fault results in an axial force of about 2800 N in the shown example with a threading tool M10. • This force is taken up by the flanks of the tool resulting in increasing flank friction and increased tool wear. Force/Movement graph Required force for the length change of threading tool with shank diameter 10 mm 0 2 4 6 8 10 12 14 16 18 20 0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 1 2 3 4 Force [N] Length change [µm] Thread pitch P = 1.5 mm Sum of 1-3 1 Possible temperature-caused pitch fault 2 Possible machine-caused pitch fault 3 Possible standard resp. threading tool caused pitch fault 4 Possible axial force on the tool flanks These perhaps theoretical reflections of the processes during production of a thread can be proven in practice.