Face milling is a machining process in which the tool is placed perpendicular to the workpiece. The device is usually placed „face down” on top of the workpiece. Once engaged, the tip of the cutter grinds the top of the workpiece to remove some of the material. If you’re looking for a precisely flat surface or a finish that will make your part shine, face milling can help.
How does face milling work?
When face milling a workpiece, operators divide the process into four parts, which include:
How does face milling work?
When face milling a workpiece, operators divide the process into four parts, which include:
1. positioning the workpiece
Before starting the process, they make sure the workpiece is securely fastened to the milling machine table. Firmly fix the workpiece to the table to prevent it from slipping.
2 Set up the mill
The next thing to do is to make sure the router is in the correct location. The router will be positioned perpendicular to the workpiece. This way, the top of the router works on the material.
3 Adjust the feed and spindle speed.
Next, adjust the feed rate and the speed at which the tool is moved through the machine (spindle speed). These two elements are crucial to ensure that the machine cuts in the right place.
4. machining
Once the machine is set up, machining begins. Since the computer receives the machining process code with CNC machining, it does all the work producing the desired shape and form on the workpiece.
Types of face milling operations
Mechanics often use different types of face milling operations. This section explains the different processes and the best optimization techniques for each.
- Ordinary face milling operation
This process is an ordinary face milling process with no special considerations. Attachment angle is very important in the general face milling process, and a face milling cutter with an attachment angle of 45° is the best choice. Some other tips for optimizing general face milling programs include:
The tool diameter should be larger than the workpiece diameter (minimum 20%, maximum 50%).
The entry point of the workpiece should be off-center to keep the chips as thin as possible.
Remember the size of the spindle and the power of the machine tool.
- Heavy face milling
This facing requires huge materials and large machining centers. In this facing, mechanics have to remove large amounts of material, which requires enormous power. For this operation, the best choice is a face milling cutter with an angle of 60°. They have high feed rates, which increases their efficiency and allows them to cut more material. Additional tips for optimizing heavy face milling programs indicate that:
The process generates a lot of heat. If you need to change inserts in the middle, wear gloves.
It also generates a lot of chips. These chips can litter the workspace and re-enter the workpiece’s cutting path. The constant discharge of chips causes wears and tear on the insert. That’s why workspace organization is so important.
- Milling with high feed rates
High-feed milling involves procedures that require high cutting speeds and feed rates. Typically, these are cutting speeds above 1,000 m/min. A face milling cutter with a high feed rate and low access angle is the best choice for this procedure. The only thing that matters in this process is the degree of access. An angle of about 10° is preferred because it allows for large feeds.
4 Finishing off the honing insert
Face milling can also achieve a clean surface finish using smoothing inserts in addition to standard inserts. Wiper inserts are mainly used for surface preparation. They usually come in different lengths and are made in left and right versions. Whether a smoothing insert is required for this process depends on the type of standard insert used. The higher the feed per revolution produced by standard inserts, the greater the need for a smoothing insert.
Face milling vs. circumferential milling: what is the difference?
Face milling and circumferential milling are two basic types of milling operations. They operate very similarly, but differ in configuration and suitability for component manufacturing. For example, the cutting tool for circumferential milling is placed parallel to the workpiece.
The process of circumferential milling
The unique configuration of circumferential milling ensures that the side of the tool grinds the top of the workpiece. Therefore, circumferential milling effectively removes a large amount of material from the workpiece. On the other hand, face milling uses the tip of the tool to remove a small amount of material, making it more suitable for applications requiring a fine surface finish.
Choosing the ideal tool for face milling
The face milling process can accurately produce a wide range of components. However, the success of this process also depends on the selection of the ideal face milling tool. Let’s take a look at the cutters shown below.
Face milling cutter
Face mills typically have cutting edges (or teeth) on the tip and shank that serve to create a plane along the axis of a high-speed spindle. This unique design makes them ideal for creating complex patterns, small areas, contours and grooves during the surface finishing phase of a product.
Finishing Knife
However, they can be ineffective when voluminous material needs to be removed during the initial processing stages.
Auger
Auger cutters are the most commonly used burrs in face milling operations. The cutting tool has multiple teeth and blades on its outer edge, as shown in the figure below.
CNC tool- three-sided cutter
The unique design of the shell cutter provides uniform cutting force and precise control over the amount of material removed by the cutter at high speeds. For this reason, mechanics often choose shell cutters to achieve a high-quality and uniform surface finish. However, with ordinary cylindrical milling cutters, it may sometimes be necessary to change the insert depending on the material of the workpiece.
Throwing knife
A flying knife is a single-point tool used mainly for machining operations. „Single point” means that the cutting tool has a single cutting edge that removes large pieces of material in one go.
Fly Cutter
Unlike face and roll cutters, which provide impressive cuts and surface finishes at high speeds, flying cutters can achieve better cuts and surface finishes at lower speeds. The driver will need less energy to make high-quality cuts with a throwing knife. When operators want excellent surface finishes and speed is not an issue, they often throw knives.
Tips for face milling
The face milling process is a great way to produce precise and economical products, as long as the operator is skilled and follows the basic rules. The following text contains several tips that apply to all types of face milling processes. They contain advice that includes optimizing the face milling process.
Tools matter
When face milling, make sure the tool is right for the process. The right tools will ensure the highest level of productivity and improve workflow.
Special settings for face milling
Don’t use the same face milling settings as other machining programs. Make specific settings for different types of machining programs. This helps improve the accuracy of different machining procedures.
Make sure the milling parameters are correct.
There are various technical parameters associated with the face milling process. Some examples are depth of cut, feed per blade, feed per revolution, etc. Before starting the procedure, make sure that each of these parameters is correct. This will prevent you from wasting material unnecessarily.
Make sure your tools are sharp.
Using dull cutting tools will only slow down the finishing process. In addition, blunt instruments break easily because they are ineffective with more rigid materials. Therefore, all tools must be sharp and easily accessible.