There are many machining processes available, each with its own unique advantages, but CNC side milling is undoubtedly a leader. When machining on vertical surfaces, these side milling machines can be used to create a variety of cuts and slots. While seemingly tedious to detail, they are highly effective when working on finished products, which often require smooth surfaces to function effectively. CNC side milling is useful in a wide variety of applications and differs from other CNC milling techniques you may already be familiar with. In this article, we’ll fully explain what side milling is, how it works, and more.
What is side milling?
Side milling is a well-known technique that utilizes a variety of CNC milling cutters. These cutters have teeth that can create slots, keyways, and other features on both vertical and horizontal surfaces. Furthermore, the cutter moves perpendicular to the workpiece surface, removing material from the sides. This versatility allows you to effectively work with a variety of materials, including composites, metals, and plastics. Furthermore, machinists often combine side milling with other CNC machining methods, such as drilling, boring, and turning, to create complex geometries on workpieces. Therefore, side milling cutters are used for this type of machining. These cylindrical tools feature cutting edges on the sides, allowing you to gradually remove material from the workpiece. Depending on the size of the tool, the machining task varies. These range from large tools suitable for heavy-duty milling to smaller tools that are more effective for precision milling. Furthermore, CNC tools can be manufactured from a variety of materials, such as carbide and ceramic, depending on the specific application requirements.
How CNC Side Milling Works
Side milling is a machining process that uses the side teeth of the tool to cut the side of a workpiece. It is a common CNC milling method used to create bevels, vertical surfaces, shoulders, slots, and other critical features. To perform side milling, a cutting tool (either an end mill or a plate mill) is mounted on the milling machine spindle. The tool’s cutting edges are located on the periphery of the workpiece, helping to remove material as it rotates. Furthermore, the workpiece must be properly clamped on the milling machine table, which moves in a controlled manner to ensure precise contact between the material and the tool.
You can adjust the depth of cut by moving the tool vertically, and determine the length of cut by moving the tool head or the machine table laterally. Side milling a workpiece requires several important parameters, including spindle speed, tool material, and feed rate, as they determine tool wear and cut quality. You’ll also need to use the right coolant to help achieve accuracy and prevent overheating.
Side milling is useful for machining surfaces that face milling can’t reach. It ensures the operator achieves the precise dimensions, sharp edges, and a smooth, high-quality surface on the side of the part. This type of milling can be used to remove heavy material and perform detailed operations; however, this depends on the setup and tool design. This makes it a reliable choice for many industries, especially manufacturing and metalworking.
Tools and Equipment for CNC Side Milling
CNC side milling operations require certain equipment and tools. These tools are crucial for delivering precise and excellent results. A milling machine (vertical or horizontal) is a key tool. While each machine has different uses, vertical milling machines are more popular across industries because they can be used for a variety of projects.
Another important tool for CNC side milling is the end mill. End mills come in a variety of shapes and designs, some with flat surfaces and others with rounded corners. End mills are available in carbide or high-speed steel. Carbide end mills can be used to machine very hard materials.
Other essential tools for CNC side milling include chucks and toolholders. These tools are mounted on the machine spindle to reduce vibration and ensure stability during the milling process. Vises and clamps also help secure the workpiece during operation. To achieve precision, you need an edge finder to properly align the workpiece. Cutting fluid is also crucial for end mills, as it reduces heat and prolongs tool life. You can add cutting fluid using a coolant system or manually. Other common tools include calipers or micrometers for measuring dimensions and ensuring the product meets dimensional requirements.
The Difference Between Side Milling, Face Milling, and End Milling
CNC side milling is well known for its versatility. It is ideal for machining complex features such as intricate grooves and contours, often located on the side of a part. Its availability of various tool diameters and reliable tool placement makes it highly adaptable when cutting grooves and deep slots. However, CNC face milling involves machining flat surfaces, particularly in areas where high precision and productivity are required. The tool’s helical or spiral design ensures it engages with the workpiece’s multiple teeth, allowing for easy operation and reducing vibration. CNC face milling operations can be categorized as either climb milling or conventional milling. Properly setting up a face milling machine ensures greater efficiency when using wider tools. In CNC end milling, the cutting tool typically rotates about its axis and moves axially along the workpiece surface to remove any material from its end. End mills are available in a variety of sizes and shapes, including ball nose, square, tapered, and radiused, to meet diverse machining needs. End mills also feature teeth at the end of their cutting edges. These sophisticated designs allow them to not only carve workpiece surfaces but also machine various contours and shapes. Furthermore, the geometry of the tool’s cutting edge often determines the range of machining operations you can perform.
Types of Side Milling Cutters
There are two common types of side milling cutters. Generally, a combination of staggered and flat tooth milling cutters is most effective. However, the choice of cutter depends on your application requirements. Each cutter has its own strengths and weaknesses, excelling in different applications.
- Staggered tooth milling cutters: These cutters have side cutting teeth with a moderate spacing between them. Uneven tooth spacing helps minimize cutting forces during operation. The uneven tooth arrangement reduces the load on each tooth. This also helps achieve efficient chip removal. Staggered-tooth milling cutters are ideal for cutting heavy materials or machining wider grooves. Their staggered tooth design reduces vibration and extends tool life. Staggered-tooth milling cutters help you cut tough materials efficiently and ensure smoother operation because they evenly distribute cutting forces.
- Conventional milling cutters: Conventional milling cutters are designed differently. Their teeth are evenly spaced around the tool, making them suitable for machining flat or planar surfaces. Their uniform tooth spacing provides smooth, consistent machining results. Conventional milling cutters are suitable for applications where precision and surface finish are critical. Conventional milling cutters are made from different materials, such as carbide and high-speed steel (HSS). Carbide milling cutters are durable and resistant to high temperatures. High-speed steel (HSS) milling cutters are versatile and can be used to machine different types of materials. Furthermore, these cutters can be used for high-speed or heavy-duty machining.
Factors Affecting CNC Side Milling Part Quality
Milling is a widely used machining process across multiple industries, particularly in manufacturing. It helps manufacturers, engineers, and designers achieve desired shapes and refine materials to specifications. However, the results of CNC side milling operations depend on several factors.
- Cutting Tool Speed: CNC side milling cutters have different speed limits during operation. The speed of the tool determines the surface finish. High speeds can cause overheating and easily wear the tool. On the other hand, low speeds can lead to uneven cutting. The speed limit you choose depends on the type of material being machined. This helps you achieve precise and smooth results.
- Feed Rate: This describes the speed at which the workpiece moves relative to the cutting tool. If the feed rate is too high, you may end up with a rough surface. Furthermore, such feed rates can cause tool breakage and wear. Meanwhile, lower feed rates may not remove material effectively, affecting the surface finish. Finding a balanced feed rate is crucial to ensure a smooth and precise machining process.
- Operator Experience: You need a milling machine operator who can help you achieve precise and consistent cutting. With extensive experience in side milling, your operators will be able to determine optimal cutting parameters, balance feed rates, and appropriate cutting speeds, as well as identify and resolve problems. Taking all of these factors into consideration, making informed decisions will benefit your milling operations. Your experience and skills are crucial during the CNC side milling process.
- Tool Design: CNC side milling cutters come in different designs. The design you choose will impact the final product. When selecting a design, consider factors such as the tool coating and the number of cutting edges. For example, choosing a tool with more cutting edges will produce a smoother surface.
Applications of CNC Side Milling Processes
Side milling is crucial for various manufacturing processes. Here are some of its main applications.
- Machining Flat Surfaces: You can use side milling to create flat surfaces on a workpiece. Cutting along the side of the material ensures a smooth, precise surface, making it ideal for manufacturing structural parts, mechanical components, and more. This method is particularly useful for processing large workpieces where uniformity is crucial.
- Surface Finish: Side milling produces a smooth surface free of large chips and burrs. It removes excess material, which helps improve the surface, resulting in greater precision and smoothness. The tool type and cutting speed determine whether this process can achieve a fine surface finish, eliminating the need for additional polishing. Grooving and Slotting: Another important application for side milling is cutting grooves and slots. It’s useful in a variety of industries, including construction, aerospace, and automotive, where precise machining of interlocking joints, channels, and more is required. This process helps you achieve clean, defined cuts that precisely align with different components.
- Profiling and Profile Machining: Side milling is a suitable method for creating odd-shaped and contoured surfaces. It’s useful in manufacturing molds and custom machine parts that require complex shapes. By adjusting the cutting tool’s path, you can precisely create fine edges, curves, and intricate designs.
- Bevel or Angle Milling: Angled milling is required whenever beveled surfaces are required. Side milling cutters are typically positioned at specific angles to create beveled grooves, tapered edges, and more. You can use this technique in sheet metal, aerospace, and other industries that require precise angled cuts for better functionality and fit.
- Straddle Milling: This involves using two tools on either side of a workpiece to machine parallel surfaces. You can use this method for bracket machining, gear manufacturing, and other applications that require symmetrical parts. This helps you achieve greater efficiency and consistency.
Benefits of CNC Side Milling
Integrating side milling into precision manufacturing offers numerous benefits. This machining process is widely used across various industries due to its advantages:
- Slot and Groove Creation: This is an excellent machining method for creating precise slots and grooves with uniform, smooth edges. You can use it to machine complex structures such as specialized joints and keyways.
- Various Textured Finishes: Side milling allows you to create a variety of textures. To achieve the desired texture, you need to adjust milling parameters such as cutting speed and feed rate. This machining process allows you to achieve any type of texture, from smooth to rough.
- High Precision: One of the advantages of side milling is its high precision and quality. Side milling minimizes errors during machining, resulting in consistent results. Therefore, side milling is ideal for large-scale production where consistency and precision are key.
- Various Tool Types: Different tool types can be used for side milling. These tool types vary in their capabilities and are suitable for different applications. Some tools help you remove large amounts of material, while others provide smooth surfaces and high precision. This helps you choose the right tool type for your application.
Disadvantages of CNC Side Milling
While side milling has proven to be highly effective in machining, it has its limitations. These limitations can make it less effective in certain applications.
- Unsuitable for thin workpieces: Side milling cannot be used to machine very thin materials. This is because the cutting tool exerts excessive force, which can damage thin workpieces. Without proper support, the milled material will end up with a rough surface. For thin workpieces, processes such as high-speed milling are recommended. This process provides smooth surfaces and precise machining accuracy when working with thin materials.
- Suitable only for sides: Side milling can only be used to machine the sides of a workpiece. Therefore, it is not suitable for machining deep cavities or other internal features. For applications requiring internal machining, end milling can be integrated.
- External feature creation only: Side milling is not suitable for certain applications. For example, it can only machine external surfaces. While it can create grooves, flat surfaces, and other complex designs on external edges, it cannot be used to machine internal parts. Therefore, side milling is not suitable for applications where both internal and external machining are critical. In such applications, side milling must be combined with other machining processes.
Challenges that Affect Quality During CNC Side Milling and How to Overcome Them
When performing side milling on a machine, you may encounter one or more challenges. These challenges are common, but there are ways to prevent them.
- Extreme vibration: This is the operator’s biggest concern because extreme vibration can lead to other problems, such as uneven cutting or tool wear. While vibration is normal during side milling, many vibrations are not good. Extreme vibration is caused by incorrect toolholders, unbalanced settings, and tool deflection. Experts recommend using very short toolholders or reducing the radial angle to prevent vibration. Extreme vibration can lead to poor and uneven surface finishes. Therefore, you need to carefully select your tool and set the correct machine parameters during operation. Also, ensure that the tool material you choose is suitable for the workpiece you are machining.
- Tool breakage: Stress and poor machining conditions can cause damage to the machine tool. Furthermore, cutting tools are more susceptible to breakage if used for extended periods. You can prevent this by using shorter tools and properly aligning the workpiece on the machine.
- Workpiece deformation: Deformation is common when processing very thin or flexible materials under high cutting forces or extreme thermal loads. For example, warping can lead to poor cut quality. Therefore, it’s recommended to incorporate a larger diameter during side milling. Alternatively, for very thin workpieces, alternative machining methods can be used.
- Tool Wear: Using high cutting speeds and inappropriate feed rates during side milling can lead to more frequent tool wear. Another cause of tool wear is poor tool quality. Using high-quality tools, balanced feed rates, and appropriate cutting speeds can prevent frequent tool wear. In most cases, the material being side milled will dictate the feed rate and cutting speed you use.
- Regular inspections and proper maintenance can also extend tool life. Regular inspections can easily identify any tool defects. You can also choose tools with high-quality coatings, such as nitrides. These coatings can extend tool life.
- Poor Chip Evacuation: Improper chip evacuation may require recutting, which can result in a poor surface finish. When side milling sticky materials, chips can be difficult to remove from the tool. Therefore, using high-pressure coolant is recommended to facilitate this process. Some tools have features like specialized chipbreakers and the ability to adjust the coolant flow. You can purchase these tools to ensure proper chip evacuation. Trochoidal toolpaths are another machining strategy that facilitates proper chip evacuation.
Why choose Xtproto for your CNC side milling project?
If you are looking to achieve precision for precise CNC side milling of parts, Xtproto is your trusted partner for its reliability and efficiency. We utilize advanced multi-axis CNC machining technology to ensure tight tolerances, smooth surfaces, and higher precision. This makes Xtproto an ideal choice for industries and applications requiring precision machining.
Our streamlined production process ensures fast turnaround times, ensuring customers receive the highest-quality custom parts on time. If you’re working on large-scale production or prototyping, Xtproto offers an efficient workflow to ensure productivity. Furthermore, Xtproto offers competitive pricing, ensuring customers receive top-notch CNC milling services within their budget. With excellent customer support, cutting-edge technology, and a dedicated team of engineers, Xtproto is sure to deliver an excellent experience for your side milling operations.
Conclusion
CNC side milling is one of the most commonly used CNC milling methods across a wide range of industries. This milling process helps you produce high-quality parts with precision. Its applications span a wide range of sectors, including manufacturing, aerospace, electronics, and automotive. CNC side milling has proven to be a suitable technique for creating complex designs. In addition to offering high precision, this type of milling offers many advantages that make it an ideal choice for manufacturers.