Undercut Machining: The Complete Guide to CNC Parts with Undercuts

Undercutting in CNC machining can be both a challenge and a critical advantage for manufacturers, especially when precision and complex geometries are required. Do you find yourself needing to machine intricate parts with deep grooves, slots, or other difficult features? The process of undercutting might be your answer. While undercuts may seem like a daunting task, understanding the underlying mechanics, the tools involved, and the applications of this technique can greatly improve the versatility and functionality of your CNC machined parts. Whether you're in aerospace, automotive, medical device manufacturing, or any other industry where precision is key, learning how to effectively apply undercutting could be a game-changer in your custom CNC machining processes. In this complete guide, we’ll delve into the various aspects of CNC machining parts with undercuts, explaining what undercutting is, why it’s important, and how to optimize it in your production workflow.

Undercutting in CNC machining refers to creating features that cannot be reached directly by a tool along a standard path. This includes deep grooves, slots, and channels that are typically inaccessible using conventional cutting tools. CNC machined parts with undercuts require specialized tools and techniques to ensure precision and functionality, making them critical in industries like aerospace, automotive, and medical devices. Mastering the process can significantly enhance the performance of your parts and streamline manufacturing operations.

Now that you understand the importance of undercutting in CNC machining, it’s time to explore how this process works in more detail. In this guide, we will walk you through the different types of undercutting, the tools you need, the step-by-step process for machining undercuts, and the applications where undercuts are crucial. Whether you’re designing new prototypes or optimizing existing parts, this guide will provide the insights you need to successfully incorporate undercuts into your CNC machined parts.

 

 

 

 

What is Undercutting in CNC Machining?

 

Undercutting is a term used in CNC machining to describe the process of cutting a feature or a geometry that extends beyond the accessible path of a cutting tool. In simple terms, an undercut is a part of the component that cannot be reached by a standard tool due to its orientation or the nature of the feature. These features typically require specialized tools and setups to machine effectively.

 

When creating complex CNC machined parts with undercuts, designers often face challenges related to tool accessibility, geometric constraints, and material removal. Undercuts are commonly required in industries such as aerospace, automotive, and medical device manufacturing, where intricate components often need features like undercut grooves, slots, or tapered holes that are crucial to the part's functionality.

 

In CNC machining, achieving these features requires a deeper understanding of tooling options and machine capabilities. Common tools for machining undercuts include specialized end mills such as dovetail cutters, keyway cutters, and lollipop cutters, all designed to handle the unique geometries of undercut features. The ability to machine undercuts opens up a vast range of possibilities for custom parts with improved fit, function, and performance.

 

 

 

 

Undercutting in CNC Turning

In CNC turning, undercutting involves the use of rotating tools to cut areas of a part that are recessed or hollowed in ways that prevent access by standard turning tools. This is often used in parts with complex external profiles that require grooves, slots, or pockets to be cut into the material. The challenge in CNC turning is typically related to the tool's ability to reach deeper into the part without compromising the part’s surface finish or dimensional accuracy.

 

To achieve undercuts in turning, CNC turning centers often use live tooling or subspindles, which enable the use of tools that can reach into these otherwise inaccessible areas. The process might also involve multiple tool changes or setup modifications to achieve the desired cut without creating tool interference or compromising the integrity of the part.

 

 

Undercutting in CNC Milling

In CNC milling, undercutting is more common and can be achieved using tools like lollipop cutters or dovetail milling cutters. Milling machines can cut both internal and external undercuts, allowing for a wide range of geometries to be produced. The advantage of CNC milling for undercut parts is that it offers greater flexibility with tool movements, enabling the creation of complex shapes that would be difficult or impossible to machine with turning alone.

 

When performing undercuts in CNC milling, careful consideration must be given to the part setup, tool accessibility, and the sequence of cuts. Precision is critical, and it’s important to ensure that the cutting tools do not interfere with other features on the part or cause excessive wear. Additionally, the complexity of the part and the required undercut geometry may dictate the need for multiple passes or different cutting tools to achieve the desired result.

 

 

 

What is the Purpose of Undercutting in CNC Machining?

 

Undercutting serves several critical functions in CNC machining, particularly when producing parts that require precision and specific design features. The main purpose of undercutting is to allow the creation of complex geometries that would be difficult to machine otherwise. These features can include deep recesses, undercuts for interlocking parts, or grooves that serve a functional purpose, such as allowing for the insertion of pins, inserts, or seals.

 

For instance, in automotive parts, undercuts can be used to create interlocking features that help improve assembly or enhance the part's strength. In aerospace, undercuts might be necessary for parts that must fit into tight spaces or where weight reduction is a concern. Medical devices, particularly surgical instruments or implants, often require undercut features for precision fitting or functionality.

 

Undercutting also plays a role in improving the fit and performance of the final part. Features such as undercut threads, barbed fittings, or O-ring grooves are designed to improve the part's sealing capabilities, interlocking features, and overall functionality. Therefore, undercuts can help to improve the overall performance, reliability, and manufacturability of CNC machined parts.

 

 

 

Why Are Undercuts Important in Machined Parts?

 

Undercuts are vital in CNC machined parts because they enable the creation of features that cannot be produced with conventional machining methods. This includes deep grooves, slots, or channels that are essential for the part's function. By using undercuts, manufacturers can design parts that are more intricate, functional, and reliable.

 

One example is in the creation of interlocking features. Many complex mechanical assemblies require parts that fit together in a specific way, and undercuts are essential for creating precise mating surfaces. For example, in the automotive industry, undercuts are often used in injection-molded parts or stamped parts that need to interlock with other components. Without undercuts, these components may not fit together properly, which can lead to assembly problems and performance issues.

 

In other cases, undercuts are used to improve the mechanical strength and integrity of a part. For example, a keyway undercut might be used in a shaft to ensure that a mating part fits snugly and securely, reducing the chances of wear or failure over time. Similarly, in aerospace or medical device manufacturing, undercuts can be used to create precise slots for components that require exact alignment, ensuring the part performs its intended function without error.

 

 

 

 

 

A Step-by-Step Guide to Machining Undercuts

 

 

 

Step 1: Evaluate Geometry

Before machining undercuts, the first step is to evaluate the part’s geometry. Understanding the part's overall shape, size, and the specific undercut features is essential for selecting the right tools and machining process. The geometry will dictate whether the part requires milling, turning, or a combination of both, and it will also determine the specific undercut features that need to be machined.

 

 

Step 2: Select the Right Cutting Tool

Choosing the right cutting tool is crucial for machining undercuts effectively. Tools like dovetail cutters, keyway cutters, or undercut end mills are designed for specific undercut geometries. Selecting the wrong tool can lead to poor results, such as rough surface finishes, excessive tool wear, or dimensional inaccuracies.

 

 

Step 3: Set Up Your CNC Machine

The next step is to set up your CNC machine. This involves loading the part into the machine and ensuring that it is securely clamped to prevent movement during machining. For undercuts, this may require specialized fixturing or a multi-axis CNC machine that can move the tool into various positions to reach the undercut area.

 

 

Step 4: Machining Undercuts

During the machining process, the tool will cut the undercut features into the part according to the designed geometry. Depending on the complexity, this may involve multiple passes or tool changes to ensure that the undercut is cut precisely without damaging the part. CNC machining centers are particularly effective in this step because they can control the tool path with high accuracy.

 

 

Step 5: Quality Control

After the undercuts are machined, quality control is essential to ensure that the features meet the required specifications. This includes measuring the undercut depth, width, and surface finish to ensure they conform to the design tolerances. Any deviations from the expected measurements can be corrected before proceeding to the next step.

 

 

 

 

 

Step 6: Post-processing

Finally, after machining the undercuts, the part may require post-processing, such as deburring, cleaning, or heat treatment. These steps help ensure that the part is free of sharp edges, burrs, or contaminants and is ready for final assembly or use.

 

 

 

 

 

Tools for Machining CNC Parts with Undercuts

 

The tools used to machine undercuts in CNC parts are highly specialized and designed to handle specific geometries. Some of the most common tools used for machining undercuts include:

 

• Dovetail Milling Cutters: Ideal for cutting dovetail shapes or angled slots.
  
• T-Slot Milling Cutters: Used for cutting T-shaped grooves.
  
• Lollipop Cutters: Designed for cutting undercuts and small-radius features.
  
• Keyway Milling Cutters: Used for machining keyways and grooves.
  
• Undercut End Mills: Specialized for reaching into narrow, deep cavities.
  

 

Each tool has its specific use case, and selecting the right one is essential for achieving high-quality results when machining undercuts.

 

 

Special Cuts in Machining Undercut Parts

 

When machining undercut parts, special cuts are often required to achieve specific geometries that are critical to the part's functionality and performance. These cuts are designed to meet precise specifications, ensuring that the final part serves its intended purpose, whether it's for structural integrity, fitment, or specific functional features. There are various types of special cuts in CNC machining that allow manufacturers to produce complex undercut features, and each has its unique application depending on the industry and the part requirements. Let’s explore some of the most common special cuts used in machining undercut parts.

 

 

1. T-Slots

T-slots are one of the most commonly used special cuts in CNC machining, particularly when working with parts that require multiple attachments or interlocking components. These slots are shaped like the letter "T" and allow for easy insertion of fasteners, bolts, or other fixtures. T-slots are crucial in parts that need to be secured or connected during assembly, such as in the automotive or aerospace industries. In CNC machining, T-slots are typically created using a T-slot milling cutter, which allows the tool to cut both the vertical and horizontal elements of the "T" shape in a single pass, providing a clean and precise feature.

 

 

 

2. Dovetails

Dovetail cuts are another essential special cut used in machining undercut parts. Dovetail joints are widely used in mechanical assemblies to provide a strong, secure interlock between two parts, often in situations where precise alignment and durability are crucial. CNC machining uses dovetail cutters to produce these joints, which feature a trapezoidal shape that fits perfectly with the corresponding dovetail cut. Dovetails are commonly used in fixtures, mechanical components, and molds, where the mating parts need to be securely locked together without the use of fasteners. The precision required for dovetail cuts makes them a staple in high-precision manufacturing industries such as aerospace, medical devices, and tooling.

 

 

 

 

 

3. Single-Sided Undercuts

Single-sided undercuts refer to undercut features that extend from one side of a part, creating an overhanging area that cannot be machined from the opposite side. These types of undercuts are often used in parts where one side needs to fit within a particular space, and the other side features a recess or groove. Single-sided undercuts are common in tooling, mold-making, and die-casting, where the part must have an external feature that fits precisely into a mating component. Specialized tools like lollipop cutters or keyway cutters are commonly used to machine these undercuts with high precision.

 

 

4. Tapered Undercuts

Tapered undercuts are undercut features that are not only recessed but also have a taper or angle. These cuts are used to create parts with specific load-bearing characteristics, or for components that need to fit into another part with an angled surface. Tapered undercuts are commonly found in mold cavities, die casting, or aerospace components, where a part needs to mate with an angled surface while maintaining structural integrity. Achieving precise tapered undercuts often requires advanced CNC machines with multi-axis capabilities to ensure the taper angle is consistent throughout the feature.

 

 

5. Spherical Undercuts

Spherical undercuts are used to create rounded, concave features in parts. These are particularly useful in applications where a part needs to fit snugly into another component with a matching spherical shape. In CNC machining, spherical undercuts can be created using ball-end mills, which allow for a smooth, rounded cut. These undercuts are commonly found in medical implants, aerospace components, and consumer products like bearings or housings, where precise fits are necessary for performance and safety. Ball-end mills enable machinists to achieve a smooth spherical surface that meets tight tolerance requirements.

 

 

6. Threaded Undercuts

Threaded undercuts are specific to parts that need to incorporate threads into an undercut feature. These are often found in components that require the ability to thread a fastener or screw into the part itself. Threaded undercuts are especially important in applications such as valve bodies, couplings, or mechanical assemblies that require secure threaded connections in otherwise difficult-to-reach areas. CNC machines equipped with thread-cutting tools or tapping heads can produce these undercuts with high precision, ensuring the threads align correctly within the undercut geometry.

 

 

7. O-Ring Grooves

O-ring grooves are special cuts made to accommodate O-rings, which are commonly used to create seals in various industries, from automotive to medical device manufacturing. The groove is designed to hold the O-ring securely while ensuring that it remains in place during operation, preventing leaks or contamination. CNC machining can create these grooves with high precision, allowing the O-ring to sit perfectly within the groove and providing a reliable seal. The precise machining of these grooves is critical to the part's functionality, as even small deviations can cause O-ring failure and compromise the seal.

 

 

8. Relief Undercuts

Relief undercuts are designed to create space around a part to prevent interference during machining or assembly. These undercuts are used to clear areas where a tool might collide with the workpiece or where material might interfere with the proper fitting of a component. Relief undercuts are common in complex mechanical assemblies, automotive parts, or molds where tight tolerances and clearances are required. Machining relief undercuts ensures that the part can be assembled and function properly without encountering issues related to tool interference or misalignment.

 

 

9. Keyway Undercuts

Keyway undercuts are essential for creating slots or grooves in shafts, gears, and other mechanical components where a key is used to prevent relative rotation between two parts. These undercuts ensure that the key fits precisely into the slot, preventing slippage or rotation during operation. CNC machines equipped with keyway cutters or end mills can create these undercuts with high accuracy, ensuring the correct dimensions and alignment for the key to fit snugly. Keyways are commonly found in automotive, aerospace, and industrial machinery applications.

 

 

 

 

 

Technical Insights of Different Undercuts

 

 

 

 

 

 

 

 

Which Metrics and Measurements are Critical in Machining Undercuts?

 

When machining undercuts, precise measurements and metrics are essential to ensure that the features meet the required specifications and perform as expected. The key metrics that affect the success of undercut machining include the depth of cut, tool diameter, surface finish, cutting speed, feed rate, tolerance level, and material removal rate, among others. Each of these factors plays a role in the overall quality, precision, and efficiency of the machining process.

 

 

 

 

 

 

Depth of Cut

The depth of cut refers to how deep the cutting tool penetrates into the material during each pass. For undercuts, this is a crucial metric, as it determines how much material needs to be removed to achieve the desired feature. Too deep a cut can cause tool wear or breakage, while too shallow a cut may not achieve the required undercut geometry. Managing the depth of cut carefully helps achieve accurate results without compromising the integrity of the part.

 

 

Tool Diameter

The diameter of the cutting tool is another critical measurement in machining undercuts. The tool diameter determines how large of an area the tool can reach and how precise the cut will be. Using the right tool diameter ensures that the undercut features are machined to the correct dimensions and tolerances. For very narrow or deep undercuts, smaller diameter tools may be necessary to access difficult-to-reach areas.

 

 

Surface Finish

The surface finish of the machined undercut is crucial for both aesthetics and functionality. For example, parts with undercuts used in aerospace or medical applications may require a smooth surface finish to meet regulatory standards or to ensure proper fit and function. Achieving the desired surface finish involves optimizing the cutting parameters, such as feed rate, cutting speed, and tool choice.

 

 

Cutting Speed

Cutting speed refers to the rate at which the tool moves through the material. The right cutting speed helps ensure efficient material removal while maintaining tool longevity and precision. For undercuts, choosing the optimal cutting speed is critical to achieving both high-quality finishes and efficient machining cycles.

 

 

Feed Rate

The feed rate determines how quickly the cutting tool advances through the material during the machining process. A correct feed rate is necessary for balancing cutting efficiency and part quality. An improper feed rate can lead to excessive tool wear, poor surface finish, or even tool failure, especially when machining delicate undercut features.

 

 

Tolerance Level

Tolerance level refers to the acceptable deviation from the specified dimensions for the machined part. For undercuts, tight tolerances are often necessary, especially when the feature is part of an interlocking or sealing mechanism. Achieving the required tolerance level ensures that the undercut feature functions as intended without issues like poor fitment or improper assembly.

 

 

Material Removal Rate

Material removal rate is a metric that indicates how quickly material is removed from the workpiece. For undercut machining, a balanced material removal rate is essential to achieve both speed and quality. If the material removal rate is too high, it can lead to poor surface finish or excessive tool wear. Conversely, too low a rate can slow down production and lead to inefficient machining processes.

 

 

Tool Offset

Tool offset refers to the adjustments made to the position of the tool to account for any deviations or variations in tool geometry or machine setup. Accurately compensating for tool offsets is essential in CNC machining to ensure that undercut features are created with the correct dimensions and alignment.

 

 

Spindle Speed

Spindle speed is the speed at which the cutting tool rotates. It plays a significant role in determining the cutting speed and material removal rate. In undercut machining, adjusting the spindle speed to suit the material being machined and the tool used is critical for maintaining efficient machining cycles and achieving a high-quality surface finish.

 

 

Chip Load

Chip load refers to the amount of material the cutting tool removes with each pass, and it’s an important factor to consider when machining undercuts. Maintaining the right chip load ensures that the tool operates efficiently, preventing overheating, tool wear, or poor cutting performance.

 

 

 

 

 

10 Tips for CNC Machining Parts with Undercuts

 

Machining undercuts presents unique challenges, but with the right strategies and tips, you can optimize your processes to achieve high-quality parts. Here are ten essential tips to help you succeed in CNC machining undercuts:

 

 

 

Work with Professionals: Undercutting requires advanced knowledge and expertise. It’s essential to collaborate with professionals who understand the intricacies of undercut machining.

 

Eliminate Undercuts Whenever Possible: While undercuts can be necessary, it’s best to avoid them when possible, as they complicate the machining process. Explore design alternatives before committing to undercuts.

 

Avoid Custom Tools: Whenever possible, opt for standard cutting tools that are readily available. Custom tools can increase costs and lead times, so it’s best to rely on proven toolsets.

 

Make Shallow Undercuts: Shallow undercuts are easier to machine and require less time and effort. If possible, design undercuts with a shallower depth to simplify the process.

 

Standard Sizes: Standardize your part designs to make use of common cutting tools and setups. This will reduce costs and increase machining efficiency.

 

Manage Depth Carefully: Avoid excessively deep undercuts, as they may require specialized tooling or more passes, increasing production time and complexity.

 

Choose the Right Tool: Select the correct cutting tool for the job to ensure that your undercuts are machined efficiently and with the desired quality.

 

Secure the Workpiece Properly: Ensuring your part is securely clamped during machining is critical to avoid movement that could result in errors or poor quality.

 

Use Quality Cutting Tools: Invest in high-quality cutting tools that can handle the specific demands of machining undercuts. Quality tools ensure better precision, longer tool life, and fewer errors.

 

Implement an Effective Machining Strategy: Plan your machining strategy carefully, considering factors such as tool access, feed rate, and cutting sequence to optimize the production process.

 

 

 

 

Applications of Undercut Parts

 

Undercut parts have broad applications across various industries, from aerospace and automotive to medical devices and consumer products. Understanding where and why undercuts are used is essential for any manufacturer involved in custom CNC machining or prototyping.

 

 

 

 

Side Holes

Side holes are commonly machined using undercut techniques, particularly in parts that require channels or slots along the side of a component. These holes are crucial for creating interlocking features or channels that allow for the insertion of fasteners or other components.

 

 

Interlocking Features

Many mechanical assemblies require parts to fit together in a specific orientation. Undercuts are used to create interlocking features that enable the assembly of parts with precise fitment. These features are common in automotive and aerospace applications.

 

 

Custom Inserts

Undercuts are used to machine parts that accommodate custom inserts. These inserts might be used to provide additional functionality, such as sealing features, electrical connectors, or fasteners.

 

 

Vertical Threads

Vertical threads, such as those used in screws or bolts, can be machined with undercuts to ensure that the thread fits into a corresponding part with high precision.

 

 

Barbed Fittings

Undercuts are often used to create barbed fittings in applications where secure fluid or gas connections are needed. The undercut allows the barbed fitting to hold the hose or pipe securely in place without the need for additional fasteners.

 

 

 

 

What Are the Main Applications for Undercut Machining?

 

Undercut machining plays a vital role in industries requiring complex, high-performance components. The main applications include:

 

• Aerospace: For parts that require lightweight structures, intricate geometries, and precise interlocking features.
  
• Automotive: For engine components, brackets, and parts that require tight fits and high performance.
  
• Medical Devices: For implants, surgical tools, and other components where precision, durability, and biocompatibility are critical.
  
• Electronics: For housing, connectors, and custom enclosures that need undercuts for cable routing or assembly.
  
• Tool and Die Manufacturing: For molds, dies, and tooling used to produce mass parts with complex designs.
  
• Consumer Products: For custom fittings, seals, and durable components used in everyday devices.
  
• Oil and Gas: For components such as valves, pumps, and connectors used in high-pressure environments.
  
• Marine: For parts exposed to harsh environments, requiring precision and resistance to corrosion.
  
• Jewelry and Crafts: For intricate designs and components where aesthetics and precision are paramount.
  
• Defense: For mission-critical parts that require exact tolerances and complex undercut features for performance and security.

 

 

 

What Are the Main Design Considerations in Undercut Machining?

 

When designing parts with undercuts for CNC machining, several critical considerations must be taken into account to ensure that the parts are not only manufacturable but also cost-effective and meet functional requirements. These considerations go beyond simply achieving the desired geometry and extend to optimizing the entire manufacturing process. Factors such as tool accessibility, component geometry, material selection, and tolerances play a vital role in the success of machining undercuts.

 

 

Tool Accessibility

Tool accessibility is one of the most significant factors when designing for undercuts. A tool must be able to reach the required undercut geometry, which is often difficult in parts with tight spaces or deep cavities. If the cutting tool cannot access the undercut area effectively, it could lead to incomplete machining, poor surface finishes, or even tool failure. In some cases, multiple setups or specialized tooling, such as lollipop cutters or side-lock end mills, may be required to reach undercut areas.

 

Designers need to ensure that the part design allows the tool to approach the undercut region at an optimal angle. This could involve modifying the part’s geometry slightly to create better tool access or incorporating features like draft angles, which allow tools to reach deeper into the part without interference. Additionally, using multi-axis CNC machines can help achieve the required undercut features, as they provide the necessary flexibility for tool movement.

 

 

Component Geometry

The geometry of the component is also crucial when designing for undercut machining. Undercuts require careful planning of the part's overall shape, as the features need to be compatible with both the cutting tool's capabilities and the machining setup. Complex geometries, such as parts with non-conventional shapes or narrow recesses, may pose challenges during machining. These parts might require special cutting strategies, such as slower feed rates or multiple tool changes, to achieve high-quality results.

 

Additionally, when designing a part with undercuts, it is essential to consider the relationship between the undercut and other features, such as holes, slots, or threaded areas. For example, a designer might choose to incorporate a blend or radius at the transition between the undercut and other features to prevent sharp corners that can lead to tool wear or poor material flow during machining.

 

 

Material Selection

Material selection is another critical consideration in undercut machining. Different materials behave differently under cutting conditions, affecting factors such as tool wear, surface finish, and machining time. Harder materials like steel or titanium may require more advanced tooling, slower feed rates, or specialized cutting fluids to achieve a quality finish without excessive tool wear. Softer materials, on the other hand, may allow for faster machining but could lead to issues such as material deformation, especially in deep undercuts or narrow features.

 

For parts with undercuts, machinists often prefer materials that have predictable cutting characteristics and a stable behavior during the machining process. Choosing the right material ensures that the undercut features are not only achievable but that the part maintains the required strength, durability, and other material properties.

 

 

 

 

 

Tolerances

Tolerance is another essential design consideration when working with undercut features. Due to the complexity of machining undercuts, achieving tight tolerances can be challenging, particularly when the undercuts are deep or narrow. Parts with undercuts often require tighter tolerances to ensure that they fit precisely within mating components or function correctly in assembly.

 

Achieving tight tolerances requires careful selection of cutting tools, machining strategies, and process controls. CNC machines with high precision and multi-axis capabilities can help in this regard, but designers need to account for the limitations of the machine and tools. In some cases, achieving the required tolerances may involve post-processing steps, such as polishing or grinding, to meet the final specifications.

 

 

 

 

Material Properties That Affect Undercut Machining

 

When selecting materials for CNC machined parts with undercuts, it’s important to consider several material properties that can significantly impact the machining process. These properties include:

 

Hardness: Materials with high hardness, such as hardened steel or ceramics, are more difficult to machine and require specialized tooling and machining strategies. These materials may cause excessive tool wear if not managed correctly, requiring more frequent tool changes or slower feed rates.

 

Elasticity: The elasticity of a material affects its ability to withstand stresses and deformation during machining. Materials with high elasticity can deform under the force of the cutting tool, which may lead to inaccuracies in the undercut features. Conversely, brittle materials may crack or fracture under the same conditions, leading to part failure.

 

Thermal Stability: Machining undercuts generates heat, and the thermal stability of the material can influence its machinability. Materials with poor thermal stability may warp or expand under heat, leading to inaccuracies in the undercut geometry. CNC machining of such materials may require additional cooling or slower cutting speeds to maintain dimensional accuracy.

 

Corrosion Resistance: In industries where the machined parts are exposed to harsh environments, corrosion resistance becomes an essential factor. Materials with high corrosion resistance, such as stainless steel or certain alloys, may be preferred to ensure the longevity of the part, especially when it is subject to environmental factors like moisture or chemicals.

 

 

 

 

What Are the Costs Associated with Undercut Machining?

 

While undercut machining provides many benefits in terms of design flexibility and functionality, it also presents certain cost challenges. The complexities involved in producing parts with undercuts often lead to higher production costs, making it crucial to understand the factors that influence these costs. The primary cost factors in undercut machining include tooling costs, machinery costs, labor costs, and material waste. Understanding these costs can help manufacturers determine whether undercut machining is a cost-effective solution for a given project.

 

Tooling Costs

Tooling costs are often one of the most significant factors when machining undercuts. Since undercuts require specialized tools, such as lollipop cutters, dovetail mills, or undercut end mills, these tools can be more expensive than standard cutting tools. Furthermore, tools used for undercut machining may wear out more quickly, especially when machining hard materials, which can lead to additional replacement costs.

 

In some cases, custom tooling may be required to achieve a particular undercut shape, further increasing the tooling costs. However, manufacturers can mitigate these costs by selecting standard tools whenever possible, optimizing tool life, and ensuring proper maintenance.

 

 

Machinery Costs

Machining undercuts typically requires more advanced machinery, such as multi-axis CNC machines. These machines are capable of complex movements and can machine undercuts with high precision. The use of multi-axis machines can increase initial investment costs and maintenance costs. Additionally, some undercut features may require specialized fixtures or machine setups to ensure that the workpiece is correctly positioned during machining.

 

However, the investment in high-quality, advanced machinery can be justified by the enhanced precision, faster cycle times, and ability to machine more complex parts, which can offset the higher upfront costs in the long term.

 

 

Labor Costs

Undercut machining generally requires more skilled labor compared to standard machining. CNC machinists must be well-versed in programming and tool selection to ensure that the undercuts are machined accurately and efficiently. Additionally, because undercut parts often require multiple passes or special techniques, labor time tends to increase.

 

In some cases, machinists may need to manually adjust the machine settings or monitor the process more closely to ensure that the undercuts are produced correctly. This added complexity leads to higher labor costs, which must be factored into the overall cost of the part.

 

 

Material Waste

Material waste can also increase when machining undercuts, especially for parts that have deep or narrow undercuts. Material that is not part of the final feature must be removed during the machining process, which can lead to higher material costs. This issue can be mitigated by optimizing the design to minimize material removal and by selecting materials that are easier to machine with less waste.

 

 

By carefully planning the machining process and employing efficient cutting strategies, manufacturers can reduce material waste, making undercut machining more cost-effective.

 

 

 

 

How Cost-Effective Is Undercut Machining Compared to Other Methods?

 

Undercut machining offers several advantages over other manufacturing methods, including its ability to create intricate and complex geometries without the need for secondary processes like casting or injection molding. However, it’s essential to evaluate the overall cost-effectiveness of undercut machining compared to other methods, such as casting, forging, or additive manufacturing.

 

 

Setup Time

One of the advantages of CNC machining for undercuts is the relatively low setup time compared to methods like injection molding or die casting. CNC machines are highly versatile, and once a part design is finalized, setting up the machine to produce undercut features can be done quickly, especially if a multi-axis machine is used. However, for parts with complex undercuts, setup time can increase, particularly if special fixtures or tooling are required.

 

 

Production Speed

CNC machining tends to be faster than other methods like casting or forging for producing individual parts or low-to-medium production volumes. However, the speed of production can be affected by the complexity of the undercut features and the machining strategy. Parts with deep or narrow undercuts may require slower feed rates or multiple passes, which could impact production speed.

 

 

Flexibility

CNC machining offers high flexibility, which is particularly advantageous for prototypes or custom parts with complex undercut features. Unlike methods like injection molding, which requires custom molds and high initial setup costs, CNC machining allows for quick adjustments to the design and can produce parts with undercuts without the need for expensive tooling.

 

 

Quality and Precision

Undercut machining is known for its high precision, which makes it ideal for industries that demand tight tolerances and high-quality finishes. CNC machining allows for fine control over cutting conditions, ensuring that undercut features meet the required specifications. This level of precision is often difficult to achieve with other methods like casting or stamping, which may require additional post-processing steps to achieve the desired finish.

 

 

 

 

 

 

 

Conclusion: VMT Handles CNC Machined Parts with Undercuts for You

 

At VMT, we specialize in providing high-quality CNC machining services for parts with undercuts. With our advanced CNC machining capabilities, expert knowledge, and attention to detail, we can manufacture custom parts that meet the most complex requirements. Whether you're working on aerospace, automotive, medical, or any other industry, we ensure that your undercut machining needs are handled with precision and efficiency.

 

By understanding the complexities of undercut machining, you can make informed decisions about your manufacturing processes and ensure that your parts meet both functional and cost requirements. If you're ready to bring your next undercut part design to life, reach out to us at VMT for expert CNC machining services tailored to your needs.

 

 

 

 

 

 

 

 

 

Frequently Asked Questions

 

Can undercuts be machined?

 

Yes, undercuts can be machined using specialized cutting tools like lollipop cutters, dovetail mills, and undercut end mills. CNC machines, especially multi-axis models, are designed to handle the complexities of undercut features.

 

 

What are the adverse effects of undercuts?

 

The main challenges of undercuts include higher machining complexity, longer production times, the need for specialized tooling, and increased costs. However, these challenges can be mitigated with proper design and machining strategies.

 

 

Why shouldn’t molds have undercuts?

 

Molds often avoid undercuts because they complicate the mold release process. Molds with undercuts require additional features, such as slides or lifters, to eject the part, increasing the cost and complexity of mold manufacturing.

 

 

What is the difference between undercut machining and overcut machining?

 

Undercut machining involves creating features that undercut existing surfaces, while overcut machining involves cutting beyond the normal boundary of a part. Undercuts are more challenging due to tool access and precision requirements.

 

 

What is the standard undercut for a shaft?

 

The standard undercut for a shaft depends on the specific design and functional requirements, but in most cases, the depth of the undercut is kept to a shallow level to avoid complexity and excessive tooling requirements.

 

 

Can molds have undercuts?

 

Molds can have undercuts, but they are usually avoided or minimized to reduce the complexity of mold design and manufacturing. Special techniques, such as lifters or slides, may be used to handle undercut features.

 

 

This concludes the comprehensive guide to CNC machining parts with undercuts. By understanding the intricacies of undercut machining, you can optimize your design and manufacturing processes to achieve high-quality, cost-effective parts.