Whatever we do, we do it right!
Since when has ARNO supplied indexable inserts specially for Swiss type machines?
It all began in the 1990s. At that time, we started to polish and grind high-positive indexable inserts to machine aluminium. The idea then occurred to us to also use the know-how we had gained for Swiss type machining. With materials that are difficult to machine and in the Swiss type machining sector, the general requirement is for tools with a clean sharp cutting edge. So we developed the PS chip-breaker for Swiss type machines with a ground cutting edge and polished chip breaker. It was unusual at that time. Up to 6 or 7 years ago, most Swiss type machine users ground their tools themselves since there was nobody else who could achieve the required precision.
What are the differences between an insert with the PS geometry and a high-positive indexable insert from ARNO?
The main difference is the rake angle – our high-positive indexable inserts have angles ranging from 18 to 25 degrees. The PS has an angle of about 11 degrees. This rake angle is ideal for machining very small parts. The cutting edge on the PS is straight and this is again better for deeper cuts. Raised high-positive cutting edges could cause score marks. And of course straight cutting edges are more rigid. Otherwise high-positive and PS inserts are very similar: They all consist of a special ultra-fine grain substrate, they are periphery ground and have a sharp cutting edge combined with a polished chip-breaker. This makes the inserts so sharp that the workpiece is not displaced, no matter how long and narrow it is. Together with the optimised design of the chip-breakers, we achieve the perfect chip, i.e. shaped like the number six.
What has changed for indexable inserts for Swiss type machines since the 1990s?
Quite a lot. We have continuously expanded our portfolio. For example, all inserts come in a wide variety of corner radius. They start at 0.05 and go up to 3.0 mm. And there are also more combinations of grades and cutting edges. Meanwhile, we have FN inserts with extremely sharp cutting edges, both coated and uncoated. The latest product is an edge-honed insert for rough machining and it also comes with and without coating. The edge-honing has the advantage of prolonging tool life – and this is of course vital in view of steadily rising costs.
What can we expect in future?
When it comes to the topic of rough machining on Swiss type machines, we are in the process of developing something new in addition to edge-honed inserts: precision sintered inserts that can be pressed with such precision that they need no grinding. This makes their price attractive, but of course they can only be used in specific applications. Ground inserts will certainly continue to be needed for complex workpieces. And we are also expanding our range here. For example, at the AMB we presented inserts with undersize radius. And we are continuously expanding our grinding skills. Every year, we grind 2.5 million inserts, so naturally we have an enormous amount of experience here. When new requirements come up, we also test the geometries with different coatings until we find the best technology for a particular application. That is the way we do it at ARNO: whatever we do, we do it right.
Interview with: Josef Storf, Managing Director ARNO Werkzeuge,
talking about indexable inserts for Swiss type machining.