High-feed milling: From the digital twin directly to the machine

Stainless steel, titanium or hardened steel: materials that are difficult to machine do not allow large cutting depths and can therefore lead to complications in HPC (High Performance Cutting) milling. The large wrap-around not only results in vibrations, but heat and high cutting forces also develop. Although the machining process can be implemented at low cutting speeds, it is clearly inferior to other production processes in terms of economic efficiency.

In order to still be able to machine titanium and co. with a large metal removal rate, HSC milling (high-speed cutting) offers a sensible alternative. HSC milling is characterized by low cutting depths and high feed rates. The cutting forces are thus significantly lower and the heat development is also at a very moderate level. The basic principle of HSC milling is based on generating thin chips in order to increase the tooth feeds.

When milling with a torus cutter (cutter with corner radius), the size of the corner radius and the possible cutting depths are directly related. They influence the chip thickness and thus the tooth feeds that can be implemented. Picture 1 makes this clear. With the same depth of cut and the same tooth feed, a thinner chip is produced with a larger corner radius.

As a consequence, it makes sense to use the largest possible corner radius to get the chip as thin as possible. This allows the tooth feed to be increased again, which leads to corresponding metal removal rates. A positive side effect of the large corner radii is that the radial forces are lower than with small corner radii and the same cutting depth.

Picture 2 shows the relationship between cutting depth and radial force. It can be clearly seen that with increasing depth, the resulting force changes more and more in the radial direction. As a result, the lateral displacement of the tool increases, which leads to vibrations and consequently poor surfaces and tool life.

Only low radial forces are generated, which is why the production process is not negatively influenced by vibration. This means that the tool can also be used for large overhang lengths. The flat angle of the face cutting edge creates a chip thinning. As a result, the tooth feeds can be raised considerably. The supposedly low cutting depth is compensated for by increased feed rates.

To simplify the search for suitable products, OSG is represented in the Tool-Arena. Numerous smart technologies are available to users via the online marketplace. For example, they can assemble virtual assemblies across all available manufacturers and view them all around in 3D with a 360° view. Registration and use in the Tool-Arena are completely free of charge.

In the 3D configurator, Tool-Arena users select suitable adapters or cutting inserts for their milling cutter. The creation of digital twins is ideal for planning complete tool systems. With the help of these functions, purchasing saves time-consuming enquiries about drawings and 3D models or compatibility with interfaces. Last but not least, the Tool-Arena facilitates the procurement process, as products from numerous manufacturers can be ordered centrally via the platform – for example directly from OSG, without intermediate suppliers.

For future projects, 3D plans can be saved on tool-arena.com or downloaded directly into the CAD/CAM system for future projects. The data export optimizes programming, minimizes the risk of collisions and makes the workflow faster and easier.

Almost 16,000 OSG products are available in the Tool-Arena. OSG also demonstrates special expertise in the field of inserts. The PHC insert milling cutter is designed with a special geometry on the cutting edges that counteract scour wear, which is widespread in HSC milling cutters.

If extreme tooth feeds are used, there is a lot of chip flow on the cutting edge. This favors scour wear – a washout on the rake face. To minimize wear, OSG has geometrically adapted the plate in the area where the chip flows off (picture 6, marking 1).

OSG has also provided for the worst case: it can happen that a cutting edge breaks out due to the high pressure. Then an indexable insert often breaks through completely. OSG has shaped this edge in such a way that only a part will chip off if damage occurs (picture 6, marking 2). The three remaining cutting edges can still be used.