Die casting is generally cheaper than CNC machining for high-volume production because parts are produced quickly once the mould is made, while CNC is usually more cost-effective for low-volume or prototype parts due to lower initial setup costs.
In this article:
Is Die Casting Cheaper than CNC Machining?
It depends on quantity.
Die casting can be much cheaper than CNC machining for high-volume production, but it is usually more expensive for low volumes. Let’s break it down properly and in detail.
1. Basic Idea (Key Difference)
| Aspect | Die Casting | CNC Machining |
|---|---|---|
| Manufacturing type | Forming (molten metal in die) | Subtractive (material removal) |
| Tooling | Expensive steel die | Simple tools + fixtures |
| Flexibility | Low (fixed die) | Very high (reprogramming) |
| Best for | Mass production | Prototypes & low volume |
2. Cost Structure Comparison
A. Die Casting Cost Breakdown
- Initial Tooling Cost (Very High)
- Steel die cost: ₹5–50 lakh+ (can be more)
- CNC machining, EDM, polishing needed to make die
- Per-Part Cost (Very Low)
- Fast cycle time (seconds)
- Minimal machining
- Low labour cost
- Low material waste
- Economy of Scale
- As quantity increases, cost per part drops sharply
➡️ Die casting becomes cheap only after thousands of parts
B. CNC Machining Cost Breakdown
- Initial Cost (Low)
- No mould or die
- Only CAD/CAM programming and setup
- Per-Part Cost (High)
- Longer machining time per part
- More material waste (chips)
- Higher machine and labour cost per unit
- Scaling
- Cost per part stays almost constant, even at high volumes
➡️ CNC is cheaper for small quantities
3. Cost vs Quantity Comparison (Conceptual)
| Quantity | Die Casting Cost per Part | CNC Cost per Part |
|---|---|---|
| 1–50 | ❌ Very expensive | ✅ Cheap |
| 100–500 | ❌ Still expensive | ✅ Cheaper |
| 1,000–5,000 | ⚠️ Break-even zone | ⚠️ Similar |
| 10,000+ | ✅ Very cheap | ❌ Expensive |
Break-even point is where die casting becomes cheaper than CNC.
4. Other Factors Affecting Cost
Accuracy & Finish
- Die casting → excellent surface finish, near-net shape
- CNC → best accuracy, but higher cost
Design Changes
- Die casting → design change = expensive die modification
- CNC → easy design change by reprogramming
Material
- Die casting → mostly non-ferrous (Al, Zn, Mg)
- CNC → almost any material
Part Complexity
- Complex shapes → cheaper in die casting (once die exists)
- Complex shapes → expensive in CNC (more tool paths)
5. Real-World Example
Automotive Bracket (Aluminium)
- Quantity: 50 parts
- Die casting → ❌ very expensive
- CNC → ✅ cheaper
- Quantity: 50,000 parts
- Die casting → ✅ much cheaper per part
- CNC → ❌ very expensive overall
6. Final Verdict
✔ Die casting is cheaper than CNC only when:
- Production volume is high
- Design is final
- Part is non-ferrous
- Thin walls and complex shapes are needed
❌ CNC is cheaper when:
- Quantity is low
- Prototyping or custom parts
- Frequent design changes
- Tight tolerances are critical
Summary
Die casting is cheaper than CNC machining for high-volume production due to low per-part cost, but CNC machining is more economical for low-volume or prototype production because it has minimal tooling cost.
Other courses:
