A CNC machine is a computer-controlled tool used to cut, shape, or machine materials with high precision, while a mould is a hollow form used in casting to shape molten material into a desired part.
In this article:
Difference Between CNC and Mould in Manufacturing
“CNC” and “mould” are completely different concepts.
1. What is CNC?
CNC (Computer Numerical Control) refers to a manufacturing process in which machines are controlled by a computer program to perform precise operations like cutting, drilling, milling, or turning.
Key points:
- CNC is a process/machine tool concept.
- Controlled using G-codes and M-codes.
- Produces high-precision parts.
- Often used in subtractive manufacturing (removing material from a solid block).
Examples:
- CNC milling of engine components.
- CNC turning of shafts.
- CNC drilling of precision holes.
2. What is a Mould?
A mould is a tool or cavity into which molten metal or plastic is poured or injected to produce a part.
Key points:
- Mould is a tool, not a process.
- Used in casting (metal) or injection molding (plastic).
- Can be permanent (metal) or temporary (sand/ceramic).
- Produces replicated parts, usually by shaping molten material.
Examples:
- Sand mould for iron casting.
- Metal mould for die-cast aluminium parts.
- Plastic injection mould for a bottle cap.
3. Fundamental Differences
| Aspect | CNC | Mould |
|---|---|---|
| Definition | Computer-controlled machine process to remove material | Hollow cavity or tool to shape molten metal/plastic |
| Nature | Process / Technology | Tool / Die |
| Material | Works on solid metal, plastic, wood | Made from metal, sand, or ceramic |
| Working Principle | Subtractive manufacturing (cuts, drills, mills) | Forming by filling (casting/injection) |
| Production Type | Can produce single or batch components | Mainly for mass production / repeated parts |
| Accuracy | Very high | Depends on mould quality (usually high) |
| Flexibility | Highly flexible (different parts by reprogramming) | Low flexibility (mould is fixed) |
| Examples | CNC milling a gear, CNC turning a shaft | Sand mould for pump housing, injection mould for bottle cap |
4. Key Relationship in Manufacturing
- CNC and moulds can work together:
- CNC machines are used to manufacture moulds and dies.
- For example, CNC milling can make a metal injection mould or die-casting die.
- CNC = process to make things
- Mould = tool to make things
5. Summary
- CNC = process/machine controlled by a computer; removes material; flexible; high precision.
- Mould = tool/cavity; shapes molten material; usually for mass production; less flexible.
- They are completely different concepts but CNC is often used to make moulds for casting or injection.
Conclusion
CNC is a computer-controlled manufacturing process that removes material to form parts, while a mould is a tool or cavity used to shape molten metal or plastic into a desired part.
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