When faced with a situation where a particular section of a part cannot be reached using traditional or regular machining methods, it’s essential to consider alternative approaches, such as undercut machining. Particularly for intricate parts like dies, molds, or other complex mechanical components, undercut machining becomes indispensable to enabling these parts to perform at their best.
Therefore, this article comprehensively explores undercut machining, covering its definition, operating principles, applications, and more.
What is Undercut Machining?
Undercut machining is a specialized process utilized to create recessed surface features on a component. It often involves the removal of material from underneath the main surface to achieve the desired geometry or intricate design. Additionally, this process typically encompasses the use of specific cutting tools and machining strategies to address the challenges posed by inaccessible areas within the part.
Moreover, a CNC undercut is the process of creating recessed surface features on a part using a CNC machine. CNC undercutting allows the production of complex, intricate, and recessed parts that would be difficult to achieve using traditional methods. Thus, The CNC machine is programmed to execute the undercutting process with high accuracy and repeatability, making it an essential technique in modern manufacturing processes.
Consequently, undercut in machining necessitates specialized tools such as t-slot cutters, swivel head cutters, or ball-nose end mills to fabricate undercut parts.
How does Undercut Machining Work?
Undercut machining works by employing specialized cutting tools and customized processes.
The process involves the following steps:
Step 1 Structure Analysis:
The first step is vital in analyzing your machined parts to determine whether the undercut is internal or external. Furthermore, recording the necessary machining strategies and the order to achieve the desired design.
Step 2 Tool Selection:
Choosing specialized cutting tools with unique designs to reach the areas requiring undercut machining. Additionally, the choice of undercutting tool depends on the type of material you want to process.
Step 3 Tool Path Planning
Program precise tool paths to ensure cutting tools can effectively remove material from complex or hidden regions of the part. Material Removal: Guide the cutting tool along a programmed path to remove material from specific areas that require undercuts or complex features.
Step 4 Precision Control
The machining process requires CNC technology to ensure accurate material removal, and maintaining tight tolerances and surface finishes.
Step 5 Quality Inspection
The final step in processing is quality inspection and verification. Performing post-machining inspections can ensure that undercuts or complex features have been produced accurately to design specifications.
By utilizing these steps, undercut machining enables the creation of complex geometries and features.
Types of Undercutting Tools
As you can see, undercutting in machining is an intricate and complex process that requires high precision. Thus, it also necessitates the use of special tools to machine the expected parts effectively. The different undercutting tools are as follows:
Undercutting End Mill: This type of tool is designed specifically for undercutting, deburring, and milling slots. Furthermore, it features a unique geometry, such as spherical and tapered shapes, that enables it to access and machine challenging areas.
Undercutting Saw: The main role of undercutting saws is to make precision cuts in materials, and they are commonly used in the aerospace and automotive industries.
Undercutting Router Bit: These specialized router bits are to create undercuts, grooves, and channels in materials such as wood, plastic, and composites. They are frequently employed in cabinetry and furniture making.
T-slot Cutters: T-slot cutters are specifically designed to shape T-slots with their straight cutting edges. This facilitates the smooth creation of slots in a single pass while effectively cutting both the bottom and sides of the slots.
Keyway Cutter： When machining a keyway, this is the ideal cutting tool to utilize due to its straight cutting edge. It is capable of machining all sides of the undercut in a single pass. Simultaneously, the tool’s ability to cover the undercut depth and produce a smooth surface makes it particularly special.
Lollipop Cutter： Lollipop cutters have a shape resembling a lollipop, with a rounder end tip and a narrow shaft. They are particularly useful in assisting the production of spherical bottom undercuts and a smooth finish.
Types of Undercuts in Machining
Depending on the specific application, undercuts can exhibit various profiles. Below are various geometric cuts used in undercut part machining:
T-shot undercutting
U-slot undercutting integrates interconnected horizontal blades and vertical shafts, allowing the equipment to cut the workpiece horizontally in either direction, thereby forming a T-shape. Additionally, the typical tool widths range from 3mm to 40mm. Furthermore, this tool serves to secure parts with a T-shaped clamp by creating a T-shaped undercut. It can be customized according to the specific nature of the work to obtain undercuts in different width ranges.
Dovetail undercutting
The dovetail undercut necessitates a cutting tool with an appropriately angled blade design to achieve the desired dovetail-like feature. This type of cutting tool typically uses angles of 45° and 60°. Additionally, other angles in increments of 10 degrees up to a maximum of 120° can also be utilized. The resulting cuts yield trapezoid-like or dovetail-shaped features, consistently possessing a narrow top and broad bottom. Consequently, dovetail-cutting tools play a vital role in creating undercut parts.
One-sided undercutting
Utilizing CNC undercutting tools, this distinct method creates an asymmetric undercut in machined parts, building upon previous cuts. Therefore, precision in controlling the gap is crucial for the CNC undercutting tools’ smooth operation. Single-sided undercutting targets one side of the workpiece, often necessary for installing specific structures like seals or retaining rings. Moreover, the use of a lollipop cutting mechanism with a single-sided blade, mounted on a multi-axis CNC, moves around the workpiece’s perimeter to execute the cut effectively.
Other types of undercutting machining are as follows:
- Tapered Undercut
- Threaded Undercut
- Spherical Undercut
- Keyway Undercut
- Relief Undercut
- O-ring Groove Undercut Multi-Axis Undercut
Techniques for Undercut Machining
Undercut machining requires the use of various CNC machining technologies because of its intricate and complex process of creating recessed surfaces. Below are some techniques involved in:
- Milling: Milling, refers to hidden features when looking at the part from the spindle. This process is particularly effective in producing intricate designs and precise geometries.
- Turning: In turning, an undercut is like a notch inside a part. By using advanced turning tools and techniques, manufacturers can achieve precise and complex undercut geometries.
- Wire EDM (Electrical Discharge Machining): It utilizes electrical discharges to shape the workpiece accurately, especially in creating intricate and inaccessible features that require high precision.
- 4-Axis or 5-Axis Machining: Employing 4-axis or 5-axis machining capabilities allows for multidirectional cutting, enabling the creation of complex machined parts with enhanced efficiency and precision.
- CAM Programming: CAM programming plays a vital role in undercut machining by generating toolpaths and commands for CNC machines to execute complex undercutting operations accurately and efficiently.
Tips for Perfect Machine Undercuts
Here are some suggestions for achieving perfect undercut machining:
Attention to Gaps
In undercut machining, the gap between the tool and the workpiece is crucial. A good rule of thumb is to maintain a main width that is four times the depth of the undercut. This ensures that the tool has sufficient space to operate effectively.
Collaboration with Other Experts
Collaborating with experienced individuals or companies can help reduce the risk of errors and ensure the production of correct undercut parts. Their expertise and tools can assist you in making progress in various aspects.
Design Considerations
When designing machined parts, it is best to avoid undercuts as much as possible, as they add complexity to the design and may require special tools, potentially leading to additional costs.
Application of Undercuts Parts
The application of undercut parts is widespread across various industries, each benefiting from the unique advantages offered by these specialized components. Here are some common applications:
- Components: Aircraft engine blades, aircraft structural components
- Automotive Engineering: Fuel injectors, transmission parts
- Microelectronics and Microfluid: Microchip components, microfluidic control devices
- Oil and Gas Industry: Oil well pump rods, drilling casings
- Specialized Machinery: Industrial compressor components, hydraulic excavator parts
Challenges of Undercut Machining
Here are the key challenges associated with undercut machining:
- Restricted tool access and clearance
- Fixture design and work holding challenges Machining stability and vibrations
- Surface finish and quality issues
- Tool selection, wear, and breakage
- Complex programming and simulation requirements
- Cost and time considerations
Comprehensively addressing these challenges involves employing advanced techniques, specialized tooling, and meticulous process planning to ensure successful undercut machining.
Conclusion
In the realm of manufacturing, an undercut involves a unique concave surface inaccessible by conventional straight tools. Specialized tools such as t-slot cutters, swivel head cutters, or ball-nose end mills are often utilized in undercut machining to fabricate parts with recessed features effectively. Thus, top-notch machining services are essential to achieve optimal undercut components.
Runsom Specializes in Machining Parts with Undercuts for You
Runsom excels in providing expert CNC machining services for parts with undercuts. Our team of experienced professionals utilizes advanced tools and CNC technology to simplify complex undercutting tasks, ensuring top-quality, precise, and affordable services for every project. Please feel free to contact us or ask for an instant quote.