Transparency in Cost Calculation
Many customers wonder why CNC parts have such different prices. The answer lies in the complex cost structure that is composed of many individual factors. In this article, we make the cost drivers transparent.
The Main Cost Components
1. Material Costs
The material often makes up 10–30% of the total cost. Decisive factors:
- Material type: Aluminium is cheaper than stainless steel, titanium is the most expensive
- Blank dimensions: The closer the raw material matches the final dimensions, the less waste
- Order quantity: Small quantities have higher kg prices
- Special alloys: Non-standard alloys require special orders with minimum quantities
More on material selection in our Aluminium Alloys Comparison.
2. Setup Costs
Setup costs include all preparatory activities before actual machining begins:
- Machine setup: Mounting fixtures, indicating and aligning the workpiece (20–60 min)
- Tool setup: Loading tools, presetting, entering tool offsets (10–30 min)
- Programming: Creating or adapting the CNC program (30 min to several hours)
- First part check: Complete measurement of the first piece
These costs are fixed and are distributed across all parts. This is why one-off parts are relatively more expensive than series.
3. Machining Time
The actual machining time multiplied by the machine hourly rate makes up the variable production cost. Influencing factors:
- Part complexity and number of features
- Material machinability — stainless steel is approx. 3–4x slower than aluminium
- Required tolerances — tighter tolerances require slower finishing passes
- Surface requirements — fine surfaces need additional finishing cuts
4. Tool Costs
CNC tools wear out and must be regularly replaced. Tool material and coating influence costs significantly:
- Standard milling cutters: €20–80 per tool
- Special tools (form cutters, micro tools): €100–500
- Tool life strongly depends on the material being machined
5. Quality Assurance
Measurement and documentation cost time:
- Standard inspection: Spot checks with hand-held measuring instruments
- First article inspection: Complete 3D measurement report
- 100% inspection: Every part measured — for safety-critical components
- Documentation: Material certificates and measurement reports
How to Optimise Costs
- Check tolerances: Mark only functionally important dimensions with tight tolerances
- Use standard materials: Standard materials are faster and more affordable
- Combine similar parts: Batch multiple similar parts to share setup costs
- Provide 3D data: STEP files speed up programming
- Increase quantities: Even small lot increases (from 5 to 10) can significantly reduce unit costs
Frequently Asked Questions (FAQ)
How is a machine hourly rate composed?
The machine hourly rate includes depreciation, energy, maintenance, premises and personnel costs. For modern 5-axis machining centres, it is typically between €80–120/hour.
Why are tight tolerances so expensive?
Tight tolerances require slower feed rates, additional finishing passes and more extensive measurement. An IT7 tolerance can be 30–50% more expensive than the standard IT14. More on this in Factors Affecting CNC Precision.
Conclusion: Transparency Creates Trust
Understanding the cost structure in CNC machining helps you make better decisions and optimise costs sustainably — without compromising quality.
Want a transparent quotation? Send us your drawing — we explain every cost item.