Page 360 - Carbide drills I Thread cutting tools 2023

Technical notes regarding use of thread cutting tools

Thread cutting with micro-compensation or rigid tapping
Modern CNC machine tools can synchronize the spindle speed and feed rate. Despite this,
microscopic pitch errors can arise. These are compensated by micro-compensation or
synchronous tapping attachments and facilitate better results in terms of tool life and quality.

Rigid Tapping
Rigid tapping is designed for modern machines with synchronised spindle drives. All tools have
a clamping flat and are used with conventional chucks.
When using Rigid tapping, a sufficient approach distance must be programmed. If the distance
is too small, the machine spindle may not be able to properly synchronize with the feed before
entering the drillhole. This will result in a pitch error of the thread, even with synchronous
working.
For some machines, it is possible that the recommended spindle speed for synchronous
operation cannot be reached. In these cases it is necessary to operate at the highest possible
spindle speed where synchronism of the machine is still guaranteed.

Thread cutting with functional performance of the compensation chuck or Rigid Tapping

Thread cutting with functional performance of the compensation chuck
A satisfactory compensation function of the chuck must be guaranteed (no jamming).
Otherwise, despite the chuck, the thread may be miscut or pitch errors can arise. The torque
level of the compensation chuck must be selected according to the thread type and the work
piece material.

Programming of a too high RPM value can lead to problems. If a RPM is selected which cannot
be reached (due to the inertia of the spindle), the result may be premature breakage of the tool
or miscutting of the thread. A careful analysis often shows that high spindle speeds do not lead
to overall significant time savings.

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