4. Types of Face Milling Operations
There are dozens of combinations of cutting tools and their entering angles, as detailed. But, only four milling operations can be distinguished:
It is a conventional process that is compatible with all the existing cutters and entering angles. Round insert and large radius cutters are used for this process. They are general-purpose cutters with strong cutting edges and are suitable for heat-resistant alloys, unlike other face milling operations on the list.
When you machine aluminum and, for example, cast iron with ceramic inserts in your tooling, cutting speeds may reach as much as 1000 revolutions per minute. Such a case is considered an example of High-Speed Machining (HSM). Consequently, you can set a high feed rate to employ the increased efficiency fully. That’s what you may know as high feed milling.
Such a process requires using of a cutter with small entering angles, typically 10°, and round inserts. It will help to achieve a feed rate of as much as 4mm/tooth. Needless to mention that the depth of such a cut is limited to 2.8 mm only, but the feed rate makes the entire operation take seconds of time instead of minutes. So, in certain circumstances, you may achieve extremely high productivity.
It is rather a rough face milling process. It is typically applied to material blanks, castings, and welded structures. For heavy-duty milling, manufacturers use powerful machines that can withstand the increased stresses.
Since large amounts of materials are removed in the process, a large amount of energy is generated by high cutting forces. Consequently, both pressure and temperature applied to a cutter are high. It is essential to operate at full depth of cut to reduce the risk of tooling failing. So, not every cutter will suit heavy-duty milling.
10° and 90° entering angles deteriorate rapidly during the process. So, tooling with a 60° entering angle is optimal. It provides good cut capacity depth while not compromising the feed rate. Besides, the axial allowance of such cutters allows a parallel land that benefits the quality of face milling.
- Finishing with wiper inserts
This method provides the highest quality finishes. From a certain perspective, it is a general face milling with a standard insert in combination with one or more wiper inserts. The latter perform ideally at higher feed rates per revolution.
So, finishing with wiper inserts is a great way to modify your conventional milling. It increases the feed by 2-3 times without compromising quality. It also helps to achieve a “mirror finish.”