Shoulder milling has become one of the most popular forms of milling, amounting to more than 30% of all milling operations worldwide, says Tungaloy.

Shoulder milling has always been the most popular style for not only milling a shoulder or a wall but also milling close to a jig or a fixture to avoid interference. Generally, in machining automotive components, the first operation OP10 for machining datums is done by the shoulder mills.

Starting with a two-cornered single-sided indexable insert, the design changed to a four-cornered single-sided insert in a square shape that was popular for a long time. This square insert had a very small clearance at the bottom when positioned at 90 degrees and was unable to use all four cutting edges as secondary cutting edges were often damaged during use. Ramping was also impossible with this design. Countering this challenge and with advancements in design and manufacturing technology of pressing and sintering, Tungaloy developed a four-cornered, high helical, double sided insert – Dorec.

In shoulder milling, chip thickness (hm) is directly proportional to the feed per tooth, unlike the operation by 45° cutters where the hm is 70% of the feed, or high-feed cutters where the hm is 30% of the feed per tooth. Moreover, the cutting force due to the feed is perpendicular to the axis, which may result in bending the spindle. These factors increase the vibrations and reduce productivity.

In continuation to the development, Tungaloy has recently launched a new
six-cornered, double-sided insert in its Tungforce MillLine, DoForce-Tri. The key to the design philosophy behind the development of DoForce-Tri was offering accelerated machining to customers while adding flexibility and prolonging tool life.

DoForce-Tri is a new series of tools with a double-sided triangular insert performing general milling applications.

The unique corner geometry of the DoForce-Tri insert features a dedicated wiper and corner radius for each cutting edge without compromise on the length of the cutting edge. Unlike other six-cornered inserts, DoForce-Tri has the ability to use the full cutting edge length of the insert. The wiper edge was also designed with a large radius, delivering a smooth finish. Its barrel- shaped chips ensure that, even at full depth, there is no chip jamming in the gullet. It also prevents chips from hitting on the work surface, maintaining a clean end result.

Another key aspect of the cutting edge design is its concave shape, designed to form barrel-shaped chips, which is a sign of smooth curling and easy evacuation.

The insert features six cutting edges with the cutting edge full usable length for larger depth of cut up to 11mm, compact chip formation due to the concave cutting edge, the NMJ type chip splitter produces small chips and helps reduce chatter in demanding applications, the long wiper edge achieves good surface finish and the insert’s triangular shape provides high rigidity.

For further details contact Star Tooling on TEL: 011 818 2250 or visit www.startooling.co.za or www.tungaloy.com