What Is Face Milling?

In CNC machining, face milling is a method of removing material from the surface of a workpiece to make it smooth and flat. In this milling method, the face milling cutter is placed perpendicular to the surface. This results in the removal of the same amount of material with each milling pass. This process is important in areas where very smooth surfaces are required. Examples include the manufacture of automobiles, aeroplanes, and large machinery.

The machinist can adjust the machining process to obtain different amounts of material removal and surface roughness on the milling machine. This is to meet the specific needs of the milling operation. This article details the face milling method and how it differs from other milling operations. We will also discuss its uses and how to get the best results.

What is Face Milling?

Face milling is a specific type of CNC milling process. Its cutting action takes place on the end face of the tool while the tool rotates perpendicular to the product being machined. The purpose of face milling is to create a flat, smooth surface. This process is usually performed before further machining or as a finishing process to improve surface quality.

Face milling uses specialized tools that cut large areas with each process. It is therefore ideally suited for the levelling of metal, plastic, and composite surfaces. Face milling and end milling are often compared because they serve similar purposes. However, they cut metal in very different ways and use very different tools.

The Face Milling Process Explained

To understand face milling, it’s essential to break down the process into its fundamental components. The face milling process removes material by rotating the cutting tool counterclockwise as the workpiece moves across the cutting tool.

Workpiece Preparation and Setup

Proper workpiece preparation and setup are crucial for successful face milling operations. We ensure that the workpiece is securely fastened to the machine table to prevent movement during machining. The workpiece surface should be clean and free of debris to achieve optimal results.

Tool Positioning and Orientation

Correct tool positioning and orientation are vital for effective material removal. The face mill is positioned to engage with the workpiece at the desired angle, typically perpendicular to the surface. We adjust the tool’s height and orientation to achieve the optimal cutting conditions.

Material Removal Mechanics

The material removal mechanics in face milling involve a complex interaction between the rotating cutting edges and the workpiece surface. Each cutting edge on the face mill removes a small chip of material as it engages with the workpiece, with the chip thickness varying throughout the cut.

The cutting forces in face milling are primarily directed perpendicular to the machined surface, which helps maintain dimensional accuracy. The process creates a unique cutting pattern on the machined surface. This can be optimized by adjusting the feed rate, cutting speed and tool flute type.

By understanding these mechanics, we can predict and control factors like tool wear, surface finish quality, and machining efficiency in face milling operations, ultimately achieving the desired surface finish.

Different Types of Face Milling Cutters and Their Uses

Depending on the amount of material to be removed, the desired surface quality, and the individual properties of the workpiece, face milling can be performed using different cutters. Below we describe some of the most commonly used types of milling cutters:

End Mills: The end mill is a very useful and versatile tool. It can machine complex shapes and give surfaces an excellent finish. As end mills can accomplish fine machining. Hence they are usually used for face milling and peripheral milling tasks.

Shell Milling Cutter: Shell Milling Cutter is a large milling cutter that is mainly used for roughing, i.e. removing large amounts of material. These milling cutters cut powerfully and robustly and are therefore capable of machining even large workpieces. Among milling tools, shell milling cutters are usually used for flattening large surfaces. This is usually in preparation for finer finishing steps.

Fly Cutters: Fly cutters are single-point cutting tools that can be used to machine small parts. Since the fly cutter has fewer cutting edges, the machining speed is slower. However, it gives a smooth and even surface, which is very useful where a smooth surface is required. In addition, fly cutters are also very flexible as they can machine many different materials without making many changes.

Key Parameters in Face Milling Operations

Optimizing face milling operations requires a deep understanding of several key parameters that directly impact the quality and efficiency of the process. We will look at the key factors that affect face milling. This includes cutting speed and feed rate, depth and width of cut. Also included is tool selection based on workpiece material.

Cutting Speed and Feed Rate

Cutting speed and feed rate are crucial parameters in face milling. Cutting speed refers to the rate at which the cutting tool removes material from the workpiece, while feed rate is the speed at which the tool advances along the workpiece. Optimizing these parameters is essential for achieving the desired surface finish and tool life.

For example, increasing the cutting speed can improve surface finish. However, if the feed rate does not match the tool life, the tool life may be shortened.

Depth of Cut and Width of Cut

The depth of cut and width of cut are also vital parameters in face milling operations. The depth of cut determines the amount of material removed in a single cut. The width of the cut, on the other hand, affects the amount of material removed from the entire workpiece.

Balancing these parameters is critical for efficient material removal and maintaining tool integrity. A deeper cut can increase productivity but may also increase tool wear, necessitating a careful balance.

Tool Selection Based on Workpiece Material

Selecting the appropriate cutting tool based on the workpiece material is fundamental to achieving optimal results in face milling. Different materials require tools with specific properties. For example, carbide tools are versatile and suitable for a wide range of materials. Ceramic tools, on the other hand, are ideal for high-speed machining of hard materials.

We recommend considering the workpiece material when choosing a cutting tool to ensure the best possible outcome:

• Cemented Carbide cutters, due to their excellent balance of hardness, wear resistance, and cost-effectiveness. Therefore, it is recommended for most general-purpose face milling applications.
• Ceramic or cubic boron nitride (CBN) tools are necessary for machining harder materials like hardened steels or super alloys.
• Softer materials like aluminum benefit from specialized tool geometries and coatings that prevent built-up edge formation.

Uses of Face Milling

Face milled surfaces are flat and smooth, making them ideal for businesses that need precisely customized parts. Additionally, face milling can be used to level surfaces, punch and slot holes, or prepare them for other steps. Here are some of the most important of these uses:

Leveling Surfaces: Levelling the surface of a workpiece is one of the main jobs of the face milling process. It enables rough or uneven workpiece surfaces to be made smooth and flat. This step is essential in order to provide a stable base for further machining or to make the finished product look clean and smooth.

Removal of Excess: In addition, it is often used for large removal tasks. Especially when large amounts of excess material need to be removed quickly. This function is usually used in the roughing process in preparation for finishing and finer details.

Finishing Operations: For many projects, this is the final step in the finishing process to obtain a smooth surface. After machining, the part has a smooth surface that meets the needs of the design in terms of appearance and function.

Slot and Groove Milling: This type of milling can also be used for groove and slot milling. Holes can be punched in the workpiece by changing the tool path. As it is very flexible, it can be used to machine flat areas and certain types of internal features and details.

Face Milling of Large Workpieces: Heavy-duty face milling cutters are suitable for machining large workpieces. For they can cover large areas quickly. In such cases, shell milling cutters are often used to machine the surface. This makes them ideal for machining parts for the aerospace and automotive industries.

Inclined Face Milling: By changing the direction of the face milling cutter, inclined areas can be machined. This method allows for the machining of angled features on a part, such as chamfers or bevels, without having to switch to another milling method.

Preparing the Part for the Next Machining Step: Face milling is usually performed first in the machining process. This prepares the part for the next operations such as drilling, end milling, or peripheral milling. By machining a flat, smooth surface, the subsequent steps can be completed more precisely.

Advantages of Face Milling

Face milling is one of the most common milling processes in many industries. This is because it offers many advantages.

Flatness and Accuracy: Face milling produces very flat and accurate parts. This is important where precision is important. The process ensures that the workpiece has a reliable base for the next machining steps.

Smooth Surface Finish: If the right face milling cutter is selected, it can give the workpiece a smooth, attractive surface for projects with specific requirements. The surface of the workpiece will be more aesthetically pleasing and smoother if the correct face milling cutter is used and the depth of cut is set correctly.

High Material Removal: Face or shell milling cutters and other CNC tools excel at cutting large amounts of material quickly. During roughing, this high cutting rate helps to reduce machining time and cost.

Versatility: Face milling technology can be used for a wide range of materials and tasks. For example, from roughing large surfaces to finishing complex parts. Due to its versatility, it is ideally suited for both roughing and finishing steps.

Face milling cutters are more durable: Most face milling cutters have a long service life. Especially those with replaceable inserts. Cutters made of carbide or with improved coatings have a longer service life and do not need to be replaced as often.

Disadvantages of Face Milling

The face milling method has many advantages, but there are some disadvantages to consider. By understanding these limitations, the machinist can wisely determine their suitability for a particular job.

Higher Tooling Costs: Purchasing face milling or surface finishing tools is usually more expensive. This is especially true of tools that are used for high-speed machining or that utilize high-tech materials such as carbide. Over time, an indexable face milling cutter with replaceable inserts can save you money. However, it is expensive to purchase, especially when used for large workpieces.

Complex Tool Setup: To set up a face milling process, you must select the tool path, spindle speed, and tool very carefully. In addition, changes in the depth of cut and feed rate need to be carefully calculated. If the process is not set up correctly, poor milling results, tool wear, or surface roughness may result.

Flat Surfaces Only: Face milling is best suited for producing flat surfaces and is less suitable for producing complex shapes. For workpieces requiring fine detail or non-planar surfaces, end milling or peripheral milling may be better.

Surface Variation on Large Workpieces: It is difficult to obtain a consistent surface finish on very large workpieces. The uneven surface finish may result from small variations in tool balance or tool wear. This is especially true on large workpieces that require multiple machining.

How to Apply Coatings and Select Materials for Face Milling Cutters

Selecting the right coatings and materials for face milling cutters has a significant impact on the efficiency, life, and machining productivity of the cutter. The right coatings and materials enable the tool to perform different machining tasks better. And they also extend the tool’s life.

Coatings Commonly Used for Face Milling Cutter

Titanium nitride (TiN) and diamond coatings are two coatings commonly used for face milling cutters. Each coating has its advantages, e.g.

• Titanium Nitride (TiN): TiN-treated tools are harder and more durable. It can therefore be used for high-speed milling and machining of hard materials. In addition, this coating reduces friction and helps to lower machine temperatures.
• Diamond Coating: Tools with diamond coating can be used for machining very hard materials and are not easily damaged. As they work best when machining rough materials such as composites. Therefore, in most cases, they are more expensive than other coatings.

Commonly Used Cutting Tool Materials

Most face milling inserts are made of either carbide or high-speed steel (HSS). Each material has its advantages:

• Carbide: Carbide is ideal for high-speed and heavy-duty applications. Because it is so hard, it will not melt at high temperatures. It is often used in high-end CNC machine tools. This is because durable and efficient tools are very important in these machines.
• High-Speed Steel (HSS): HSS tools are less expensive and can be used for a variety of medium-speed tasks. However, they are well suited for jobs that do not require a lot of power or for cutting soft materials.

How to Make the Most of Face Milling

To achieve effective face milling, different factors need to be considered depending on how the industry works. These factors include choosing the right tool, machining variables, and feature positioning. Some of the following tips may be helpful;

Selecting the Right Tool: Selecting the right tool is the first task in successfully completing a face milling project. Select the right face milling cutter for the workpiece material, the desired surface finish, and the required removal rate. This will then ensure that the job is completed quickly and efficiently while reducing tool wear.

Keeping the Cutter Balanced: To prevent vibration and reduce cutter wear, it is important to keep the cutter balanced. Unbalanced cuts will result in rough surfaces at different locations and may shorten tool life.

Use the Recommended Spindle Speed: The optimum spindle speed for each job depends on the material of the workpiece and the type of tool used. Following the spindle speed recommendations given by the manufacturer will help keep the tool in good working order and reduce wear.

Do not Mill Slots or Holes: When you mill in the face of an existing slot or hole, the tool may tilt, damaging both the tool and the workpiece. Carefully plan the tool path away from these locations. Unless you want to perform slot or recess milling.

Using CNC Automation: The automation features in CNC technology make it easier, more accurate, and more consistent to machine multiple flat-milled parts. Automated milling operations are especially useful for high-volume production where consistency is important.

Face Milling vs. Peripheral Milling

Face milling and peripheral milling are both common in CNC machining, but they are often used for different purposes. Let’s take a closer look at the differences between them.

Surface Finish Comparison

In most cases, face milling is better for machining flat surfaces. Peripheral milling, on the other hand, is better for machining edges and curves, and the finish may not be as good as the former.

The roughness, or Ra value, also differs between these two types of milling. About 0.4 microns for face milling and 1.3 microns for peripheral milling. However, the exact value depends on the feed rate, material type, and spindle speed.

Material Removal Rate Differences

The orientation of the tool in face milling allows it to remove material faster. This is because it is able to machine a larger area with each milling. On the other hand, peripheral milling removes material debris at a slower rate. However, it is the best method to obtain fine features and complex shapes.

Direction of Cutting

In face milling, the tool moves perpendicular to the surface of the workpiece. In peripheral milling, the tool moves along the side of the workpiece. Due to the change in direction, face milling is more suitable for machining flat surfaces. Peripheral milling is more suitable for machining contours and slots.

Yonglihao Machinery’s CNC Milling Services

Yonglihao Machinery offers a complete solution for companies that need reliable, high-precision face milling. With Yonglihao Machinery’s CNC milling services, businesses can choose from different types of materials, surface finishes, and depths of cut to create accurate parts. Whether your job requires face milling or more complex peripheral milling. Yonglihao Machinery can provide you with the tools, knowledge, and support you need to get the results you need.

Yonglihao Machinery ensures that both face milling and peripheral milling jobs are optimized with its state-of-the-art tools and skilled workers. At Yonglihao Machinery, we reduce errors and ensure consistency through advanced automation. This reduces wait times for prototyping and mass production. With our help and customization options, you can be sure that your design will come to life.

Summary

Face milling is one of the most important steps in CNC machining. This is because it enables the machining of smooth, flat surfaces for many different materials. To get good results in your machining operations, you need to understand what face milling is. In addition, you may need to know how to properly use tools, techniques, and best practices. From choosing the right face milling cutter to fully utilizing the spindle speed and feed rate, each step affects the surface quality and accuracy of the overall workpiece.

Face milling is useful in many fields. Examples include automotive, aerospace, and heavy equipment manufacturing. Because it has both shell milling cutters for large surfaces and flying cutters for fine machining.

Yonglihao Machinery’s professional CNC milling services make the process easier by prioritizing accuracy, speed, and stability. Adopting the right method not only improves product quality but also increases productivity. This makes it an important technology in modern manufacturing.

FAQ

What is the Purpose of Face Milling?

Face milling is mainly used to machine flat areas on a piece of work. Face milling is often used in roughing and finishing tasks where smooth surfaces and precise measurements are required. It can be used in many areas and is often the first step in other machining processes. Examples include the automotive, aerospace, and heavy equipment manufacturing industries.

What is the Difference Between Flat Milling and Face Milling?

The main difference between face milling and flat milling is the cutting method and the surface to be machined. Face milling cutters are perpendicular to the surface of the workpiece, so a flat, even surface can be machined. Flat milling, on the other hand, usually places the machine horizontally so that the side of the cutter is in contact with the product. This method is suitable for machining recesses, grooves, and contours along edges.

What is the Difference Between a Face Mill and a Fly Cutter?

A fly cutter is a single-point cutting tool used for machining smooth, flat surfaces on smaller workpieces with high machining quality. Face milling cutters have multiple cutting edges or inserts for rapid material removal over a large area. In addition, fly cutters have fewer cutting edges and have slower machining speeds. On the other hand, fly cutters are mainly used for fine machining. Face milling cutters are better suited for rapid chip removal and a wider range of machining than fly cutters.

How Deep Can Face Milling Cutters Cut?

The depth of cut depends on the type of cutter, the object to be cut, and the performance of the machine tool. Face milling can usually cut a few millimetres deep. To maintain accuracy and surface quality, the optimum depth of cut should be selected based on factors such as tool wear, speed, and material removal rate.

How does the cutting speed affect the surface finish in milling operations?

The cutting speed has a significant impact on the surface finish. Generally, the higher the cutting speed, the better the surface finish. However, it also depends on other factors such as tool material, workpiece material, and feed rate.

How do I select the right tooling for a specific workpiece material?

The selection of tooling depends on the workpiece material, the desired surface finish, and the machining operation. For example, carbide tools are typically used for machining hard materials. HSS tools, on the other hand, are used to machine softer materials.