Face milling: features, applications, and advantages

Face milling is one of the most commonly used cutting techniques – both in the case of classic machining on manually controlled devices and numerically controlled (CNC) ones. It allows for efficient removal of large amounts of material in a short time, and due to its high popularity and many applications, it is considered one of the modern milling standards.

What is face milling and what are its applications?

What is plane face milling and what are the optimal working parameters?

Face milling is a cutting technique that involves removing excess material using the face of the mill applied at a right angle to the machined surface. The mill's spindle makes successive feeds and, using blades set at a 90-degree angle, removes material, according to the given feed depth, depth, and specified velocity (Vc). It is most often used for machining flat surfaces, and due to its low load, accuracy, and the resulting final effect, it is often used for both roughing and finishing machining.

The impact of working parameters in face milling

The working parameters in face milling are directly related to:

• the machined material (different metal alloys or types of polymers require different parameters to achieve satisfactory surface quality),
• the machining stage – roughing can leave visible tool marks, however, in precision machining, the surface should be as close to the final one as possible,
• the choice of face milling type – there is a division into ordinary, HSM (high-speed machining, in this case often called 'face milling with large feed rates'), and heavy face milling (impact). The latter refers to the machining of hardened or quenched materials (e.g., hardened steel) and requires different working parameters,
• the selected type of mill – face mills (with cutting inserts on the cylindrical part of the mill, so when applied to the material, they cut off chips only with this surface) with different lead angles are most often chosen for this type of machining (the smaller, the higher possible feed speeds and reduction in the thickness of the ejected chips). Thus, for HSM machining, low lead angle mills (10 degrees) are often used; for heavy machining – with a lead angle close to 60 degrees; for typical face milling of easily machinable materials, mills with a lead angle of 90 degrees are most often used,
• the axial rigidity of the machined object – milling thin walls requires a different approach than machining stable and rigid blocks of material,
• the expected surface quality – the higher they are, the speed and depth of cutting should be lower.

With this knowledge, professional CNC operators can decide on the appropriate working parameters, such as:

• cutting speed (Vc),
• work feed (ft),
• spindle rotational speed,
• or the milling depth (ap).

Each of them translates into the quality of the obtained surface, work efficiency, and tool wear. For example, increasing the work feed (ft) can affect the degradation of the obtained surface quality, and increasing the depth while maintaining a high cutting speed can further reduce tool life. However, these are pieces of information that a professional CNC mill operator should focus on – from the perspective of a customer ordering the production of parts, this is additional information.

Application and advantages of face milling

The most important advantage of face milling is the efficiency of removing excess material, very favorable chip formation, and working speed. This technique is commonly used at all stages of machining, but it is most often chosen for preliminary (rough) cutting. At this stage, face milling provides real benefits, and surface imperfections (high roughness and tool marks) are removed in further processing. The possibility of using high feeds (when working on very rigid milling machines) allows for significantly speeding up work, even in the case of heavy face cutting.

It is worth noting that this is also a very flexible technique and – with the application of appropriate work parameters – can be successfully used for the final machining of flat surfaces. To improve machining parameters, cylindrical-face milling cutters can also be used, which – in addition to removing excess material with the face part – level the roughly formed surface with blades arranged on the cylindrical part. In addition to machining flat parts, face cutting can also be used – to some extent – for cutting elements with holes.

However, such processing requires a significant reduction in working speed – both due to the need to reduce the load on the cutting tool and the quality of the obtained surface. On the other hand – it is quite demanding for operators and people programming the work of CNC milling machines or directing automatic devices. To achieve the best surface quality and work efficiency, the blade should enter and exit the machined material as rarely as possible. Proper planning of the entire face milling process can positively affect work efficiency (e.g., considering spindle work parameters when it moves radially) and the final quality of the obtained surface.

One order, many benefits - this is how you work with RADMOT

At RADMOT, we offer CNC milling services, CNC turning services, as well as many additional services, including washing, aluminum anodizing, laser marking and assembly. We have at your disposal over 80 modern machines in our machine park, all from renowned manufacturers. Download the presentation and check on which machine tools we produce CNC turned parts and CNC milled parts.

Contact us and tell us what you need. We have been providing CNC services for almost 40 years. Our valuation is completely free. And if you're in doubt about which technology will work best for you, our expertise is at your service.