Synchronous tapping

GEWEFA has already been active in the field of synchronized tapping for ten years.

Modern control systems for CNC machines with the software option "tapping without compensating chuck" served as the basis for a new generation of synchro-tapping chucks. In conventional milling machines or machining centres, the main spindle rotates independently of other axes. This means that the deceleration and acceleration during a change of direction results in an asynchronous movement of various machine parts. A classic tension/pressure quick-change chuck can compensate these errors. Modern processing machines are generally equipped with a synchronous spindle. This ensures the synchronous movement of the spindle and the feed axis even with a braking and feed axis and even during braking and acceleration processes as well as during a reversal of the direction of rotation.

Service life increases of up to 50 percent

Nevertheless, very small synchronization problems between the rotating and feeding motion may occur even in modern machining centres. Since even a low deviation leads to relative large axial forces act on the flanks of a screw tap, the service life of the screw tap is significantly reduced. This technical challenge has been met by GEWEFA – represented in Austria by ARNO-Kofler – with a synchro-chuck that can achieve a longer service life of the screw tap tool by about 40 up to even 50 percent according to the manufacturer.

Modern synchro-chucks use tapping collets, i.e., the classic screw tap with diam./square. It is clamped as before by force and form fitting in the synchro-chuck with various ER collet chucks with exact concentricity. One practical example is the HSK-A100 GSW synchro-chuck based on an ER20 collet base with a cantilever length of 166 mm. This type of "lean tapping chuck" has become possible only through the use of collet chuck technology. The chucks are designed for internal coolant supply at 50, 70, 100 bar; the use of minimum quantity lubrication is thus possible. The chucks are distinguished by their slenderness ratios, robustness, concentricity and longevity. By using tapping collets, a wide range of different screw taps can be handled by one chuck; this merely requires different tapping collets.