CNC Machining vs Urethane Casting

CNC machining and urethane casting are widely used in the plastic parts manufacturing and rapid prototyping industry. They work differently to create parts and have their advantages. Sometimes, engineers need to choose between these processes. today, in this article, Kusla will explore the difference between CNC machining and Urethance casting to help you make the final decision for your project.

How does CNC machining work?

CNC machining is a subtractive manufacturing process that removes part of a material block with instructions from a CAD model. The programmed computer software controls the movement of cutting tools and machinery. It is widely used in both plastic and metal prototypes and parts manufacturing.

How does Urethane casting work?

Urethane casting, also called vacuum casting, is a process that uses the master pattern to make a silicone mold in a vacuum state, and then casts the parts using PU, silicone, nylon, ABS, and other materials in a vacuum state, cloning a replica that is the same as the master pattern.

Difference of CNC Machining vs Urethane Casting

Materials

CNC machining materials are extensive and include plastic and metal materials such as ABS, acrylic, PP, PC, POM, nylon and aluminum alloys, copper, steel, iron, and so on. however, only the plastic can be used for urethane casting such as ABS-like, and polycarbonate-like resins.

Precision

The precision of CNC machining is much higher than that of urethane casting. The accuracy of CNC machining is generally between 0.1-0.02mm. In comparison, the precision of urethane casting is generally 0.2mm, this is because of the influence of thermal expansion and cold contraction of silicone mold. So the precision requirements of cast urethane prototypes are usually not so strict.

Volume

CNC machining is commonly used to create one or two prototypes. If it is over three pieces, urethane casting will be perfect. One silicone mold can create 25 copies of parts.

Lead time

Generally, CNC machining takes more time than urethane casting for the same quantities. CNC machining process requires making parts one by one and repeating all the processes. Urethane casting only needs to cast the materials in the silicone mold and cure.

Cost

CNC machining cost is generally higher than urethane casting to make the same part. Usually, a CNC machined prototype costs $50 while a urethane casting prototype costs only $10. check more details about Rapid Prototyping Cost.

Alternatives of CNC machining and Urethane Casting

3D printing

3D printing can make more complex geometry parts than CNC machining, with a faster lead time and lower cost, however, the part strength is not as good as CNC machining and injection molding because it uses a layer-by-layer method to create the plastic part. Anyway, 3D printing prototyping is worth to be considered when you need to make plastic prototypes.

Injection molding prototyping

Injection molding prototyping is the process of creating small batches of plastic parts in a short time with rapid injection mold tooling. it is perfect for the production volume range from 100 to 10000 Pieces.

Conclusion

After you know the difference between CNC machining and the Urethane casting process, before you start a parts manufacturing project, you will need a professional supplier to help you make the final choice. KUSLA, covering all rapid prototyping and most of parts manufacturing capabilities, will help up get your parts quickly and cost-effectively.

You may also interested in other plastic parts manufacturing process comparisons

• Urethane casting vs injection molding
• CNC machining vs 3D Printing
• CNC Machining vs Injection Molding
• Urethane Casting vs 3D Printing

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