Where the cost crossover sits between machining, casting and moulding.
This is written for buyers and design engineers rather than machinists. It covers what to put on the drawing, what it costs, and the mistakes that turn a straightforward part into an expensive one.
The rules that matter
- CNC wins below roughly 5,000 pieces for most metal parts
- Die casting breaks even around 5,000 to 10,000 pieces
- Injection moulding breaks even around 2,000 to 5,000 pieces
- Soft tooling can shift the crossover down by 30 to 50%
Common mistakes
- Tooling up for 500 pieces
- Staying on CNC at 50,000 pieces without re-quoting
Both of these are cheap to fix at the drawing stage and expensive to fix after the parts are cut. If you are unsure which side of the line your design is on, send it over before you release it.
How this shows up in a quote
A quote is built from material, machine time, setup, finishing and inspection. Anything that adds a setup, a secondary operation or a tighter inspection method moves the number. When we quote, we show the process route, so you can see which requirement is driving the price and decide whether it is worth keeping.
Frequently asked questions
Does this apply to both milling and turning?
Yes. The principles are the same. Turning is usually cheaper for concentric geometry and milling for prismatic geometry, but the tolerance and finish rules carry across both.
What is the cost of getting this wrong?
Usually one extra setup, one extra operation or a scrapped batch. In practice, fixing it at the drawing stage costs nothing; fixing it after the first article costs a week and a re-quote.
Can you review my drawing before I release it?
Yes, and we would rather do that than quote a design that is going to be expensive. Send the STEP file and drawing and we will come back with DFM comments alongside the price.
Do you work from a PDF drawing or do you need CAD?
We need a STEP file for the geometry and a dimensioned PDF for the tolerances. A PDF alone is not enough for anything with curved surfaces.
Related pages
- Guides — the full index for this section.
- Prototype to Production Transition
- 12 Ways to Cut CNC Part Cost
- What Drives CNC Machining Lead Time
- How to Choose a CNC Machining Supplier
- Instant CNC quote
- Tolerance quick reference
- Frequently asked questions
Get a price for your part
Send a STEP file and a drawing with tolerances, material and quantity. We quote within one working day and machine in our own facility in Shenzhen — milling, turning, EDM, grinding and finishing under one roof, no trading middleman.
Start an instant quote or send your drawings directly. English-speaking engineering support, DFM feedback before you commit to a batch.