Generic vs. proprietary: new approach to turning needed as demands for complexity rise.

Author:Tisdall, Bill
Position:Turning solutions

Proprietary tooling is nothing new to milling applications. While ANSI/ ISO platforms were dominant for many years, the advantages in productivity, tool life, and accuracy allowed proprietary milling cutters to gain a foothold and flourish.

It has been a considerably different story for turning applications.

For parting, grooving, and threading processes, the use of proprietary tools has become somewhat common. However, for indexable turning tools, ANSI/ISO platforms maintain a near monopoly. Predominantly, this has resulted from the high flexibility of the system, which allows it to cover a variety of processes ranging from roughing to extreme finishing.

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Typically, proprietary turning systems only apply to a small range of the substantial application area covered by the ANSI/ISO platform.

While the longstanding ANSI/ISO systems continue to provide a highly flexible solution, changes in manufacturing demands are beginning to highlight the need for suitable alternatives. The requirements for quality, accuracy, and precision have risen sharply in the past several years and the trend shows no signs of slowing.

Additionally, parts have become much more complex, changing the demands placed on the cutting tool. Unfortunately, the ANSI/ISO standard is becoming inadequate for these higher levels of precision and complexity.

With ANSI/ISO turning systems, VBMT and DCMT inserts are located with a screw that makes line contact with the insert hole and pulls the insert back toward the walls of the toolholder. A significant problem arises when this approach is used for profiling or turning in multiple directions. As the direction of the tool path changes from a facing cut to a longitudinal cut, the insert moves slightly.

This small effect results in pocket wear, which in turn allows for a greater degree of insert movement. Of course, increased insert movement leads to a higher rate of wear and the cycle quickly accelerates, leading to multiple problems.

The issue of pocket wear is even more apparent when using more advanced processes. Many of today's multitask machining centers allow operators to change the angle of the B-axis to match a complex part's unique features. As a result, the insert and toolholder in the B-axis are exposed to variable forces both in magnitude and direction. This added strain amplifies the potential weakness of ANSI/ISO systems.

As pocket wear and insert movement occur, the most noticeable result is...

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