It is easy to overlook the significance of chips. After all, they are by-products of the cutting process. While the focus is rightly on the finished product, the formation and management of chips are areas that should not be ignored. Good management of chips can have a huge bearing on productivity and tool life. This in turn casts the spotlight on chip breakers or chipformers.

To help overcome these problems, chipformers are now widely used for the purpose of chip control. In short, chipformers are specially designed geometric depressions located after the cutting edges of turning inserts.

Chipformers channel the machined chips and produce the desired chip shapes that can be effectively controlled. These efficient chip forms consume less power; they result in reduced heat generation and most importantly, they are able to quickly evacuate the work zone.

Poor chip management can be potentially disastrous. It can result in clogging, which increases machine downtime. In addition, according to cutting tool solutions provider Iscar, a major cause of damage to tooling in metalworking is chip interference, which obviously has an adverse effect on component quality.

With so much riding on good chip control, cutting tool makers have reacted quickly to the situation and this is evident in the investment on R&D activities in that area (approximately six percent of the company’s total resources in Iscar’s case) and the resulting new launches in the market.

Mitigating Issues In Chip Formation

There are newly designed turning chipbreakers specially formulated today to decrease the volume of chips removed from the workpieces during the machining process, which consequently provides efficient chip removal.

These turning chipbreakers break the chips into smaller pieces, which pave the way to better workpiece surface finish. It also prevents chips from tangling around the workpiece during the machining process and simplifies chip removal from the machine.

Through the use of new turning inserts and their advanced chipformers, less heat is generated and the problem of chips attaching themselves to cutting tools and components is eliminated. In addition, workpiece quality is improved, insert life is extended and productivity gains are achieved.

Smooth Operator

In the cutting of steel, there are chipformers available to cover all angles, fulfilling demands ranging from finishing to rough turning. Although they can be deployed to achieve different objectives, there is one common factor that binds them, ie: a positive rake angle to reduce cutting forces.

“The chipformer’s role is to split the chip into small and open segments,” said Rafi Ravoach, ISO turning product manager, Iscar. To that end, he said the company is introducing three chipformers: F3P, M3P and R3P, for finishing medium and rough turning of steel, as well as a new chipformer designation system.

According to him, the first character stands for the main relative chip load: F — for Finishing, M — for Medium and R — for Roughing. The number in the system stands for the relative application range within each main application range. The number ‘3’ indicates a general middle range within the main range. The third character stands for the material type to be machined according to the ISO 513 material classification code. ‘P’ in this case stands for alloy steel.

The F3P chipbreaker has positive rake angles for smooth cutting, reduced cutting forces and insert wear, leading to increased tool life. The machining application area is 0.40 - 2.0 mm D.O.C. and 0.05 - 0.25 mm/rev (Figure 1).

The M3P chipbreaker is for medium machining of steel with reinforced cutting edge. It features a positive rake angle to reduce cutting forces and for smooth cutting. The machining application range is 0.5 - 6 mm D.O.C. and 0.15 - 0.60 mm/rev (Figure 2).

Finally, the R3P chipbreaker is for rough machining of steel with a reinforced cutting edge. It has a positive rake angle to reduce cutting forces and for smooth cutting. The machining application range is 4.0 - 12 mm D.O.C. and 0.4 - 1.0 mm/rev (Figure 3).