Machining Copper: Process, Design and Finishing for Copper
A truly versatile metal is copper. Copper is popular for artwork, cookware, kitchen backsplashes, countertops, and even jewelry because of its naturally lovely, lustrous sheen. Additionally, it has superior material and electrical characteristics for intricate, designed parts like EDM electrodes.
Copper has numerous advantages when it comes to machining parts. One of the world’s most useful metals, copper has excellent electrical and thermal conductivity as well as good corrosion resistance.
Following that, we’ll go into machining copper and copper alloy techniques, design factors, and finishing standards that offer more than simply aesthetic advantages.
At Sungplastic, we have mastered mature machining copper techniques. If you need to the service of machining copper,please read more about this.
Techniques for Machining Copper
Machining pure copper poses unique challenges due to its high ductility, plasticity, and toughness. However, the machinability of copper greatly improves when it’s alloyed with elements like zinc, tin, aluminum, silicon, or nickel, making copper alloys easier to work with than many other metals. Copper alloys demand significantly less cutting force in comparison to machining steels or aluminum alloys of similar strength. There are two main machining copper methods: CNC milling and CNC turning.
Copper alloys can be effectively machined using various methods. CNC milling, an automated machining process, relies on computerized controls to oversee the movement and operation of multi-point rotary cutting tools. As these tools rotate and traverse the workpiece surface, they gradually remove excess material to achieve the desired shape and size. Milling allows for the creation of diverse design features such as grooves, notches, pockets, holes, slots, contours, and flat surfaces.
Here are some guidelines for CNC milling copper or copper alloys:
- Utilize carbide cutting materials like the N10 and N20 application groups, or HSS grades.
- Extend tool life by reducing cutting speed by 10%.
- When milling copper cast alloys with a cast skin, reduce cutting speed by 15% for carbide group tools or 20% for HSS grade tools.
Another effective method for machining copper is CNC turning, where the tool remains stationary, and the workpiece moves to attain the desired shape. CNC turning is a versatile machining system employed in the production of numerous electronic and mechanical components.
There are several advantages to using CNC turning, including cost-efficiency, precision, and enhanced manufacturing speed. When turning a copper workpiece, it’s crucial to pay attention to speed since copper, being an excellent thermal conductor, generates more heat than other materials, leading to increased tool wear over time.
Here are some tips for CNC turning copper or copper alloys:
- Set the cutting tool edge angle within the range of 70° to 95°.
- Softer copper variants prone to smearing benefit from a cutting tool edge angle of approximately 90˚.
- Maintaining a constant cutting depth and reducing the cutting tool edge angle minimizes tool stress, increasing tool life and cutting speed.
- Increasing the angle between the major and minor cutting edges (the tool included angle) allows the tool to endure higher mechanical loads and results in reduced thermal stresses.
Design Considerations for Machining Copper Parts
When crafting designs involving machining copper components, several crucial factors warrant your attention. Typically, it’s advisable to use copper judiciously, considering its costliness, and constructing an entire part from copper is frequently unwarranted. A well-crafted design can harness a small portion of copper to capitalize on its unique attributes.
Here are common rationales for opting for copper or copper alloy components:
- Exceptional corrosion resistance
- Remarkable electrical and thermal conductivity, with easy soldering capabilities
- High ductility
- Excellent machinability as an alloy
Selecting the Appropriate Material Grade
During the design phase, selecting the right copper grade for your application is paramount. For instance, using pure copper (C101) for an entirely mechanical part can be not only challenging but also economically inefficient. C101, with its high purity (99.99% copper), offers superior conductivity but is less machinable. In contrast, C110 is generally more machinable and cost-effective. Therefore, the choice of material grade hinges on the properties critical to your design’s functionality.
Design for Manufacturability (DFM) should always be a top priority, regardless of the material used. At Sungplastic, we recommend optimizing tolerances while retaining the necessary functionality for your application. Additionally, it’s wise to minimize dimension inspections, avoid deep pockets with small radii, and limit the number of part setups.
In particular, here are specific best practices for designing machining copper parts:
- Maintain a minimum wall thickness of 0.5 mm.
- Adhere to a maximum part size of 1200 x 500 x 152 mm for CNC milling and 152 x 394 mm for CNC turning.
- When dealing with undercuts, favor square profiles, full radius, or dovetail profiles.
Finishing Copper Components
Following the machining copper process, the finishing stage is vital, and various factors should guide your choice of the most suitable finishing method. To begin, surface finish control can often be optimized within the CNC machining processes themselves. Some CNC machining parameters allow for alterations that affect the surface quality of the machined parts, such as the nose radius or tool corner radius.
For soft copper alloys and pure copper, the quality of the finish is directly influenced by the nose radius. Minimizing the nose radius is crucial, both to prevent smearing of softer metals and to reduce surface roughness. This approach results in a higher-quality cut surface as it diminishes feed marks. Wiper inserts are preferable to traditional nose radius tools since they enhance the surface finish without requiring adjustments to the feed rate.
Additionally, achieving the desired part finish can be accomplished through post-processing techniques, including:
- Hand Polishing: While labor-intensive, hand polishing imparts an appealing surface shine.
- Media Blasting: This method produces a consistent matte finish that conceals minor imperfections.
- Electropolishing: An excellent choice for finishing copper due to its exceptional electrical conductivity, which not only brightens but also enhances the overall shine of the machining copper surface.
Machining Copper at Sungplastic
When creating a copper machined part, it’s a good idea to weigh all of your options because there are a ton of various mechanical and chemical finishing methods. On our website, you may find out more about the CNC machining capabilities we have for copper and copper alloys. You are welcome to talk to us if you have any questions concerning your machining copper design or manufacturing.
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