How We Calculated This
CNC machining has two types of costs: fixed costs and variable costs. Fixed costs happen once per batch. Variable costs happen once per part. Understanding this split is the key to volume pricing.
Fixed Costs (Per Batch)
Setup costs cover loading the workpiece, indicating the vise, zeroing tools, and running the first part. Simple parts need about $50-75 in setup. Complex parts with 3-4 setups can cost $100-150. Programming costs cover CAM toolpath generation and are typically $75-200 depending on complexity. These costs are paid once per batch, then divided across all parts.
Variable Costs (Per Part)
Machining cost per part stays roughly the same regardless of batch size. It depends on material removal rate, cycle time, and tooling wear. Aluminum 6061 machines fast at about $35-60 per part for a typical bracket. Titanium Ti-6Al-4V takes 3-4 times longer and costs proportionally more.
Pro tip: The biggest per-unit savings happen between 1 and 25 parts. Going from 1 to 10 parts can cut per-unit cost by 30-50%. Going from 100 to 500 parts only saves another 5-10%.
Finding Your Sweet Spot
The "sweet spot" is the quantity where savings start to flatten out. For most parts, this is between 25 and 50 pieces. Below this range, adding more parts gives big per-unit savings. Above it, you are mostly paying for machining time and material, which do not get cheaper with volume.
When to Order More
If you need parts within the next 6-12 months, ordering them all at once saves money. You avoid paying setup costs multiple times. But if your design might change, ordering smaller batches protects you from scrapping inventory.