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Best imaginable tool life and thread surface quality with the collet holder softtap by heimatec. Made in Germany!
On many modern CNC machining centres the rotation of the spindle can be synchronized with the feed axis. This makes it possible to produce threads with tool holders without tension compensation. However, practical experience shows that even with this kind of “rigid tapping”, synchronization errors may apear.
Possible causes are:
- machine dynamics, harmonization of spindle and linear drives, especially during the change of rotation direction
- clearance in tooth flanks of Live Tool
- clearance between Live tool drive and machine drive
- tolerances of threading tool
When rigid tool holders are used, these errors can lead to problems. High axial forces apear, and will have serious negative results on the production process, such as:
- reduced tool life, caused by high one-sided teeth flank friction on the threading tool
- unclean thread flanks on the work piece
- threads out of gauge
heimatec softtap collet holder for Live Tools
- Act as a absorbing link between synchronized spindle and tap / cold-forming tap, and compensate pitch differences between threading tool and drive
- provide the high concentricity of a rigid tool holder
- guarantees safe clamping of taps / cold-forming taps by collets with square drive
- do not need tools with special shanks
- guarantee process safety in the synchronous production of threads
Design features
- made of two pieces (holder shank / tool seat)
- easy to disassemble
- allowing trouble-free maintenance
- axial force compensation and torque are separated
- hardly any influence of torque on axial force compensation
- absorption elements made of plastic
- no influence on the cutting edge of the tool through axial vibration during operation
- pre-tensioning of absorption elements
- allowing axial movement only after the pre-tensioning force is exceeded
- axial movement guided by balls
- reduced friction (rolling friction), and consequently extra short reaction times
- suitable for up to 70 bar internal coolant-lubricant pressure
Practical applicationMany tests regarding this topic have been made with taps and cold-forming taps. Depending on the individual case, our customers were able to increase their tool life by up to 150 %. In the following diagram, you will find the axial forces which apear in the cold-forming of an M10 thread in St37 (steel).
We have traced the axial forces at a speed of 2000 rpm.
The following collet holders were tested:
- a) rigid synchronous collet holder
- b) collet holder Softsynchro ® size 01, with minimum compensation on tension and compression
- c) synchronous collet holder of a competitor with minimum tension compensation of axial absorption
All tested collet holders were used with a ER16-GB type collet, i.e. with integrated square.
Axial force [N] Speed 2000 rpm
Time [s]
The following results were verified in these tests:
- axial forces increase with the increase of speed
- the forces which apear in the cold-forming of threads are considerably higher with a rigid collet holder than with an softtap collet holder
- the competition collet holder can absorb the upcoming forces only lightly, in comparison with the rigid collet holder
Conclusion
The softtap collet holder makes the optimum possible use of Live Tools in the production of threads , with the best imaginable tool life and thread surface quality.