A few days ago, I consulted with a CNC engineer about models or part samples. There are various methods for small batch production, but which one is more suitable for the customer?
The engineer provided a comparison of the advantages and disadvantages of CNC, 3D printing, and silicone vacuum casting. I didn’t want to keep this information to myself, so I’m sharing it here in hopes it can help everyone!
CNC Prototyping
Features:
- Good material properties, surface can undergo processes like painting, electroplating, etc.
- Durable and strong, can accommodate screws.
Drawbacks:
- Difficult to fully clear sharp corners during machining, requires manual programming and post-processing or EDM (Electrical Discharge Machining).
- Labor-intensive, high cost, slow machining speed for small parts.
Applications:
- Suitable for parts with high precision requirements, high aesthetic standards, strength, and temperature resistance, with relatively simple structures.
3D Printing
Features:
- Strong capability to create complex structures, including undercuts and internal cross-sections.
- Relatively simple manual processing, fast machining speed for small parts.
Drawbacks:
- Resin is brittle, prone to breaking, difficult to bond.
- Painted surfaces may not look as good, cannot be electroplated, and screws may easily break.
Applications:
- Ideal for producing samples of complex-structured digital products, as well as small enclosures where surface finish and strength are not critical.
Vacuum Silicone Molding
Features:
- Average material properties, but good surface paint results.
- Can produce soft rubber products that CNC and 3D printing cannot.
- Capable of electroplating, accommodating screws, and bonding glue.
- Silicone molds do not deform or shrink, are heat resistant, and can be reused after molding.
- Offers convenience in production, high-quality, affordable, and relatively short production cycles.
- Can prevent unnecessary losses before mass production.
Drawbacks:
- Requires a prototype from 3D printing or CNC, and the cost per set is relatively high.
Applications:
- Suitable for small batch reproduction, fast replication with low precision requirements.
- Ideal for small batch production of large parts, small parts, and soft rubber waterproof rings.
- Suitable for producing personalized products, low-quantity demands, complex structures, and products where traditional steel mold manufacturing is not cost-effective, such as automotive parts, robots, medical devices, and 3C electronic products.
Metal 3D Printing
If the supports are well-prepared, the precision of metal 3D printing is also very high, although the surface texture cannot compare to CNC.
Currently, there is a trend to combine CNC and 3D metal printing for making precision molds. 3D metal printing can create complex internal cooling channels within molds, and then CNC can be used for surface finishing to meet smoothness requirements. This method allows the mold to achieve precision comparable to traditional molds, with better cooling performance in internal channels. The demolding efficiency and quality are superior to traditional molds, representing a trend in precision mold manufacturing.
