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Thread tools \ Technical introduction – thread milling
Thread milling strategies
Process:
In contrast to tapping, where sections are cut out of the material, thread forming is a non-cutting, pressure forming procedure.
Advantages:
No chip formation
Up to 30% higher surface quality than with thread cutting
Up to 40% higher processing speed than with thread cutting
Threads in through holes and blind holes can be produced with the same tool
Wide range of materials processable
Cutting of thread eliminated
Thread pitch and thread angle errors as with cut threads eliminated
Shaped threads have higher strength owing to non-continuous cut
Requirements: For all shapeable materials with elongation >10 %.
When milling female threads, there are four differ-
ent strategies for doing so.
Right-hand thread asynchronous milling: In this
process, the start point is at the top and milling
occurs downwards in a circular manner, against
the direction of rotation.
Right-hand thread, synchronous: In this process,
the start point is at the bottom and milling occurs
upwards in a circular manner (see diagram on
the left).
Left-hand thread asynchronous milling: In this
process, the start point is at the bottom and
milling occurs upwards in a circular manner,
against the direction of rotation.
Left-hand thread, synchronous: In this process,
the start point is at the top and milling occurs
downwards in a circular manner (see diagram on
the left).
Right-hand thread, internal machining Left-hand thread, internal machining
H=0
Asynchronous milling Synchronous milling Synchronous milling can be recognised by the fact
that, at the end of the cutter, chips are produced with
h=0
Straight insertion 90° quarter circle descending loop 180° semi-circle descending loop
When the thread milling cutter is inserted in a With the 90° descending loop, the majority of the The 180° descending loop offers the lowest tool
straight line, a very large wrap angle is generated, chip volume is removed from the straight part load on descent because the wrap angle on the
leading to long chips and a high tool load. This of the descending loop. This has the advantage entire descending loop is relatively small. In terms
method also leaves a small dwell mark. of making programming simpler and ensuring a of programming, this method is more complex, but
relatively short descent. has proved to be the most advantageous during
thread milling and in terms of tool wear.
h For more detailed information and explanations, refer to the technical manual.
Source: Hahn+Kolb Werkzeuge GmbH
Technical data subject to change. www.iconridge.com
Availability subject to country specific rules and regulations. 237
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