The process principle , advantages , and types of face milling in machining
Face milling is a cutting process in CNC machining technology. This technique is mainly used to remove material from the surface of parts and primarily to create smooth, flat surfaces. Therefore, by optimizing this machining process on a CNC milling machine, different degrees of material removal and surface roughness can be achieved to meet the precision manufacturing requirements of precision parts. This article will discuss in detail the principles, advantages, disadvantages, and commonly used face milling techniques.
What is face milling machining technology?
Face milling is a method for machining product surfaces. It is suitable for machining large areas, planes, or shapes. By using a CNC system to precisely control the milling cutter path, material can be removed quickly and accurately, ensuring that the workpiece surface achieves the required flatness and surface finish.
The goal of this machining process is to produce a smooth, uniform surface. It is typically used as a preparatory step for subsequent machining or as a finishing process to improve surface quality. This machining technique requires specialized cutting tools and can cover a large area with each pass, making it ideal for producing smooth surfaces on materials such as metals, plastics, and composites.
Face milling is also the most common milling operation, and it can be performed using a variety of different cutting tools. The most commonly used is a milling cutter with a 45° lead angle, but in some cases, round insert milling cutters, square shoulder milling cutters, and three-sided milling cutters are also used. Due to their similar functions, face milling is often compared with end milling, but they differ significantly in tool orientation and metal cutting techniques.
Working principle and process steps of face milling technology
When performing end milling on a workpiece, a machinist divides the machining process into several parts. The workflow and the tasks involved in each part are as follows.
Workpiece setting and alignment
The workpiece is clamped on the milling machine table to prevent accidental movement or displacement during machining. Precise calibration is required to ensure the milled surface maintains its flatness. Modern machine tools are typically equipped with automated systems to achieve precise settings.
Tool Selection
The choice of face milling cutter depends on typical conditions such as workpiece material, surface quality, and machining parameters. Most cutters have multiple cutting edges and are fitted with carbide inserts to enhance the tool’s wear resistance and metal removal speed.
Determination of cutting parameters
Cutting speed, feed rate, and depth of cut depend on the physical properties of the material and production requirements. For example, cutting speeds for aluminum are typically in the range of 800-1,500 surface feet per minute (SFM), while for harder metals such as titanium, lower speeds of 150-300 SFM are usually used.
Initial roughing path
The roughing stage requires removing as much material as possible to obtain a blank on the workpiece. Time is crucial at this stage. Using high feed rates and deep depths of cut allows for the removal of even the smallest pieces of material while maintaining tool stability.
Finishing channel
After roughing, finishing is performed to achieve the desired surface finish and remove any remaining surface roughness. Finishing involves a slow and shallow feed rate, typically resulting in a very smooth surface with a surface roughness (Ra) of less than 32 microinches (Ra).
Coolant application
Throughout the manufacturing process, coolant or cutting fluid is used to cool the tools and workpiece, thereby extending tool life and minimizing workpiece thermal deformation. If necessary, an MQL (Multi-Level Cooling) system or a high-pressure coolant system can be added for optimal performance.
Inspection and quality control
After machining, the workpiece needs to undergo dimensional inspection and surface quality check. A coordinate measuring machine (CMM) or laser scanning is used to ensure that tolerances and surface profiles are within strict limits.
Post-processing
Depending on the application, further steps such as deburring, polishing, or heat treatment may be performed to prepare the finished product for assembly or use in finished products.
The Importance of Face Milling Machining Technology
Face milling is one of the most important steps in CNC machining because it can produce smooth surfaces from a variety of materials. To achieve good results during the machining process, you need to understand how to use tools, techniques, and best practices correctly. From selecting the appropriate face milling cutter to making the most of spindle speed and feed rate, each step affects the surface quality and accuracy of the entire workpiece.
Currently, face milling machining technology is widely used in the manufacture of custom parts for industries such as automotive, aerospace, and heavy equipment manufacturing. It is versatile, utilizing a variety of cutting tools, such as shell end mills for large-area machining and fly end mills for precision machining. This adaptability extends to various specialized applications, where precision and material-specific techniques are crucial for achieving high-quality results.
Manufacturing characteristics of face milling technology
Face milling produces smooth, flat surfaces, making it ideal for machining precision, custom parts across various industries. You can choose face milling technology to finish surfaces, create grooves and recesses, or prepare for subsequent processes.
Smooth surface
The main manufacturing characteristic of face milling is surface smoothness. It can smooth out uneven or rough surfaces of a workpiece, forming a uniform plane. This process is crucial for laying a solid foundation for subsequent machining operations or for achieving a clean, polished appearance in the final product.
Material removal
It is often used in heavy-duty cutting applications, especially where efficient removal of large amounts of excess material is required. This application is common in roughing operations, where finer detailing and finishing of the workpiece are needed.
Finishing operation
The finishing process is the final step in the finishing of faceplates, aiming to achieve a smooth surface finish. This process gives the workpiece a polished, precision surface that meets the aesthetic and functional requirements of the design.
Slot and bag milling
Grooves and cavities can be machined by adjusting the toolpath, thus creating recesses on the workpiece. This flexibility makes it suitable not only for machining planes but also for machining certain types of internal features and details.
Face milling of large workpieces
When working with large workpieces, heavy-duty face cutters can efficiently cover large areas. In such cases, shell cutters are typically used to achieve consistent machining on wide surfaces.
slant milling
Inclined surfaces can be created by adjusting the direction of the face milling cutter. This technique is ideal for creating inclined features (such as chamfers or inclined surfaces) on parts without switching to other milling methods.
Preparation for follow-up actions
Face milling is typically used as a preparatory step in machining processes to set up the workpiece for subsequent operations such as drilling, vertical milling, or peripheral milling. Face milling creates a smooth surface, simplifying the accuracy of subsequent operations.
and disadvantages of face milling
Face milling technology, like other manufacturing techniques, offers many advantages, but it also has some drawbacks that need to be considered. Understanding these limitations can help you make an informed decision.
| advantage | shortcoming | ||
| Flatness and precision | It provides superior flatness and dimensional accuracy, which is crucial in precision-critical applications. It ensures that the workpiece has a reliable foundation for subsequent machining. | Higher tooling costs | Face milling or surface finishing tools, especially those designed for high-speed machining or made of advanced materials such as carbide, are often more expensive. Indexable face mills with replaceable inserts can gradually reduce costs, but the initial investment remains high, especially for complex projects. |
| Smooth surface treatment | Choosing the right face cutter can achieve high-quality surface finishes, making it suitable for applications requiring polishing and a professional appearance. Using the appropriate face cutter and optimizing the depth of cut can enhance the smoothness and aesthetics of the surface. | Complex tool settings | Setting up face milling operations requires precise selection of the tool, spindle speed, and toolpath. Furthermore, adjusting the depth of cut and feed rate also requires careful calculation. Improper settings can lead to low milling efficiency, tool wear, or poor surface finish. |
| High material removal rate | CNC cutting tools such as face cutters or shell cutters can remove large amounts of material efficiently and quickly. This high removal rate is beneficial for roughing, thereby shortening machining time and reducing production costs. | Plane only | This technique is best suited for machining flat surfaces, but performs poorly when machining complex geometries. If the workpiece requires intricate details or non-planar machining, end milling or peripheral milling may be more suitable. |
| Multifunctionality | Face milling technology is suitable for a wide range of materials and applications, from roughing large surfaces to achieving fine machining of complex parts. Its versatility makes it a reliable choice for both roughing and finishing stages. | Manufacturing of large workpieces | Achieving consistent surface finish on large workpieces is no easy task. Even slight variations in tool balance or tool wear can lead to inconsistent surface finishes, especially on ultra-large workpieces that require multiple machining operations. |
How many different face milling operations are there in CNC machining?
Although face milling is a type of CNC machining technology, this sub-technology includes various different types of machining operations. The following are the different operations of face milling.
Traditional face milling
Traditional face milling, also known as conventional milling, involves the cutting tool rotating against the feed direction. When the cutting edge contacts the workpiece, the tool cuts from the minimum thickness to the maximum thickness. A characteristic of this method is that the workpiece is easily lifted during cutting, thus requiring secure clamping. Traditional milling is typically used for roughing because it can handle various depths and widths of cut.
Climb milling surface
In contrast, ramp milling involves the tool rotating in the same direction as the feed. Because the cutting action tends to press the workpiece against the worktable, ramp milling produces a better surface finish than conventional milling. Ramp milling is the preferred method for finishing because it achieves cleaner cuts and extends tool life by reducing cutting resistance.
High-speed face milling
High-speed face milling utilizes advanced tooling technology and machining parameters to achieve high material removal rates and superior surface finishes. This process employs tools with special geometries and materials, such as cemented carbide or polycrystalline diamond (PCD), to withstand the stresses generated during high-speed machining. High-speed milling is ideal for machining non-ferrous metals and hardened steels, as these processes are critical to efficiency and surface finish.
Heavy-duty face milling
Heavy-duty face milling is designed to remove large amounts of material quickly through deep cuts and high feed rates. This process uses robust, durable, large-diameter, multi-tooth end mills to handle the higher loads. Heavy-duty milling is suitable for roughing challenging materials such as cast iron and steel, where durability and chip removal are crucial.
Fine face milling
Finish milling focuses on achieving the highest possible surface finish. This process uses end mills with extremely small tooth pitch and multiple inserts for light and precise cutting. Finish milling is often the final machining step, designed to achieve smooth surfaces and tight tolerances, which are crucial for critical components in the aerospace, automotive, and mold manufacturing industries.
What is the difference between face milling and peripheral milling?
Peripheral milling, also known as end milling, is another milling process used to remove material from a workpiece. However, there are some key differences between peripheral milling and face milling. In peripheral milling, a single-tooth cutting tool is used to remove material from the side of the workpiece. The cutting tool moves in a linear motion along the edge of the workpiece, rather than in a circular motion as in face milling. This makes peripheral milling more suitable for cutting deep cavities or features. Another difference between face milling and peripheral milling is the resulting surface finish. Face milling can produce a smoother surface finish compared to peripheral milling.
How does face milling differ from other milling operations?
Face milling differs from other milling operations in that the milling direction of the face milling cutter and the result of the cutting process both change. In typical CNC machining, the periphery and tip of the milling cutter bear most of the cutting, resulting in a flat, sometimes even smooth, surface. It is primarily used to machine precise features such as grooves, recesses, or contours on workpieces.
Peripheral milling removes surface material from a part using the edge of the tool. In contrast, face milling focuses on machining surfaces or sides, rather than edges, making them more efficient at handling large flat surfaces than any other type of milling machine. Therefore, milling is often used for this type of machining, not only because it has replaceable inserts and can operate at higher feed rates, but also because it is suitable for high-speed cutting or large-scale production environments.
Xtproto’s CNC machining services provide you with high-precision parts.
For businesses seeking reliable, high-precision face milling, Xtproto offers comprehensive custom CNC part solutions. Our CNC machining services enable companies to create precision parts, customizable to surface finish, depth of cut, and material type. Whether your project involves face milling or peripheral milling for more complex cuts, we provide the equipment, expertise, and support needed to achieve high-quality results.
Because Xtproto not only has its own in-house factory, but also advanced milling machines and experienced technicians, it ensures optimal results for both face milling and peripheral milling tasks. By leveraging advanced automation technologies, our manufacturing team minimizes errors, maintains consistency, and shortens the delivery cycle for prototyping and mass production. With Xtproto’s customizable options and support, you can confidently bring your designs to life.
in conclusion
Face milling is a fundamental manufacturing technique in CNC machining, primarily used to produce smooth, flat surfaces on various materials. Understanding the meaning and working principle of face milling is crucial for success in custom parts machining projects. Every step affects surface finish and the overall accuracy of the workpiece.
No matter what type of custom part you need, face milling technology can be used to manufacture parts with large planar designs required by industries such as automotive, aerospace, and heavy equipment manufacturing. Furthermore, companies like Xtproto further streamline this process by offering specialized CNC machining services that prioritize accuracy, speed, and consistency. Adopting the right approach not only improves product quality but also streamlines production efficiency, making it a valuable technology in modern manufacturing.