CNC vs Injection Moulding: Break-Even for Prototypes and Small Batches
Product teams often ask for a prototype cost comparison: CNC vs injection moulding. The short answer: for very small quantities, CNC (or 3D printing) almost always wins; moulds win only after volume absorbs tooling.
Cheapest way to make 20 plastic parts
If you need about 20 plastic parts, hard tooling is rarely the cheapest path. Steel or aluminium moulds can cost thousands before the first shot. CNC machining POM / PEEK / ABS prototype parts (and similar grades) needs no mould — you pay for material and machine time only. That is usually the cheapest way to make 20 plastic parts for fit checks, electronics housings, or pilot assemblies.
Break-even point for injection moulding vs CNC
There is no universal break-even, but a useful rule of thumb:
| Quantity | Typical preference |
|---|---|
| 1–50 | CNC or additive — no tooling |
| 50–500 | CNC bridge / pilot run, or soft tooling if geometry is mould-friendly |
| 500+ | Injection moulding often wins on unit cost if the design is stable |
The break-even point for injection moulding vs CNC moves earlier when parts are simple, walls are uniform, and you already own a mould. It moves later for undercuts, thick sections, engineering plastics like PEEK, or designs that still change weekly.
Low-volume manufacturing without injection mould
Bridge production on CNC covers pilot run production (for example 50 units) and scale-up toward a few hundred pieces without locking the design. Spare parts and repeat orders stay consistent because the same CAM and fixtures are reused. When the design freezes and forecasts justify tooling, we can help you transition — but you are never forced into a mould for a pilot.
Plastic materials we machine for this path
Delrin (POM), ABS, Nylon, PEEK, PTFE, and Ultem are common. See our engineering plastics guide for grade notes, then request a quote with quantity and target cost so we can recommend CNC vs waiting for a mould.
