For custom CNC machining, a DFM review can include:
Design for Manufacturing (DFM) is the process of reviewing a product or component before production to determine whether it can be manufactured efficiently and reliably.
- Material selection
- Dimensional tolerances
- Part geometry
- Surface finish
- Machining processes
- Tool accessibility
- Production quantity
- Inspection requirements
- Additional manufacturing processes
The purpose is not to change a customer’s design unnecessarily.
Instead, the goal is to identify areas where the design or manufacturing requirements may create unnecessary cost, production difficulty or uncertainty.
Case 1: Material Selection for a Children’s Product
One recent quotation provided a good example of why material selection should be reviewed together with the final application.
The customer initially requested brass for a small CNC machined component. The component was intended for a product similar to children’s building blocks.
During our material review, we noticed that the proposed brass material contained lead.
Because the final product would be used by children, we raised the material issue with the customer before production rather than simply proceeding with the requested material.
The customer reconsidered the material requirement and ultimately chose C11000 copper for the component.
This does not mean that lead-containing brass is inherently unsuitable for every application. Different brass grades are designed for different purposes, and the suitability of a material depends on the specific application and applicable requirements.
The important point is that material selection should not be separated from the final use of the product.
A material that is suitable for one industrial component may require further evaluation when the application, end user or regulatory requirements are different.
What This Means for CNC Machining
When reviewing a drawing for custom CNC parts, we do not only ask:
Can this material be machined?
We also consider:
Is this material appropriate for the intended application?
This type of review can help customers identify material-related questions before production starts.
Case 2: Is Polishing Really Necessary?
Material is not the only factor that can affect CNC machining cost.
In another recent quotation, we received a drawing for a small component used in a product similar to building blocks.
The drawing did not clearly specify whether the parts required polishing.
Based on the appearance and application of the product, we initially assumed that polishing would be required and included the process in our quotation.
During further communication, the customer clarified that polishing was not necessary.
Removing this additional process reduced the manufacturing cost by approximately $0.70 per piece.
The dimensions of the part did not change.
The material did not change.
The basic machining process did not need to change.
We simply clarified what the customer actually required.
This is a simple example of how DFM and requirement clarification can reduce CNC machining cost before production.
For a small order, the difference may be relatively limited. For thousands or tens of thousands of parts, however, even a small unnecessary process can have a significant impact on total manufacturing cost.