From CNC Pilot Production to MIM Volume Manufacturing: When Is a Process Change Worth Considering?

When a metal component moves from small pilot runs to ongoing purchasing, the original manufacturing route may need to be reassessed. For a project currently using CNC machining, the useful question is not whether MIM is always cheaper, but whether expected purchasing quantities can justify tooling investment while meeting material, dimensional and acceptance requirements.

1. Separate pilot needs from future purchasing needs

In ChuangLe’s experience with projects, some customers use CNC machining for initial small pilot runs to validate their products and markets before considering a subsequent manufacturing route. This is one practical situation; it does not mean that a process change should occur at a fixed quantity.

If the design is still changing, or demand is limited to a single small batch, consider modifications after tooling is made, sample approval and delivery arrangements together. For projects with expected repeat purchases, tooling investment can be compared alongside subsequent part costs.

2. Compare part costs and project investment

When requesting quotations, use consistent material, quantity, secondary-operation and acceptance requirements wherever possible. Otherwise, differences between quotations may also reflect specification changes and cannot be attributed entirely to the process change.

Check these items separately:

CNC and MIM part costs, and which operations each quotation includes.
One-time costs such as molds, fixtures, development or samples.
Whether secondary machining, surface treatment, inspection or assembly is needed, and who is responsible.
Timing for sample approval and volume supply.

A reduction in the cost of a set of parts does not mean that total project costs, including tooling investment, fall by the same percentage. Specific quotations and quantity plans are needed to compare overall economics.

3. An actual order: a complete automotive door hinge set changed from CNC to MIM

ChuangLe has fulfilled an actual order converting a complete automotive door hinge set from CNC machining to MIM, with volume deliveries completed.

According to ChuangLe’s confirmation of this order, the cost of that set of parts fell by 50% after the process change, excluding mold costs. This result belongs to that project. It cannot directly predict savings for other parts or be interpreted as a 50% reduction in total project investment.

The specific material, quantities, tolerances and before-and-after quotation conditions for this case are not currently disclosed. Therefore, no general break-even quantity is provided, and the case does not establish the performance or suitability of other automotive components.

4. What needs confirmation beyond the ability to make the part?

A process-change assessment needs drawings that define material, critical dimensions, mating interfaces and acceptance requirements. Potential secondary operations and inspection should also be included in the comparison.

Similar appearance alone cannot establish that parts are directly interchangeable. Accuracy or cost results from one project should not be extended to all parts. The decision to switch to MIM should be based on the specific manufacturing plan, sample approval and project requirements together.

5. What information should you send to ChuangLe?

For an initial assessment, provide 3D drawings, 2D drawings, the required material and the first-batch quantity.

If available, also share future quantity plans, key acceptance requirements or the current manufacturing approach to help explain the purpose of the assessment. ChuangLe evaluates manufacturing based on the supplied information; the specific plan and delivery arrangements are confirmed for each project.

Send drawings for a manufacturing assessment