DESIGN FOR MANUFACTURING (DFM) GUIDE

Designing for Cost Reduction

The most significant impact on part cost happens at the design stage. This guide covers the essential strategies to make your parts more affordable to manufacture without sacrificing quality.

The Pillars of Cost-Effective Design

1. Simplify Your Design

Complexity is expensive. The simplest designs with the fewest features are always the cheapest to produce. Eliminate any feature that is not absolutely critical to the part's function.

2. Reduce Part Count

Consolidate multiple parts into a single, more complex component where possible. This eliminates the cost of fasteners, assembly labor, and managing multiple part numbers.

3. Loosen Tolerances

This is a major cost driver. Only apply tight tolerances to the few features that truly need them for assembly or function. Use the standard, looser tolerance for all non-critical features.

4. Choose Cost-Effective Materials

Don't over-specify. Use a low-cost commodity material like ABS or Aluminum 6061 unless your application's performance requirements justify the expense of a high-performance polymer or metal.

Process-Specific Cost Reduction

Optimizing for cost also means designing for your specific manufacturing process.

For CNC Machining: The primary cost driver is machine time. To reduce cost, design parts that require less material removal. Avoid deep pockets and small internal radii, which require slow, delicate cutting operations.
For Injection Molding: The primary cost driver is tooling complexity. To reduce cost, design parts with uniform wall thickness and zero undercuts. This allows for a simple, fast, and inexpensive "straight-pull" mold.

An injection molded part, where DFM for cost is critical

Cost Reduction FAQ

Does adding a secondary finish add significant cost?

Yes. Any secondary operation, whether it's bead blasting, anodizing, painting, or tapping holes, adds labor and handling costs to the part. The "as machined" or "as molded" finish will always be the cheapest option.

How much does an undercut add to the cost of a mold?

A single side-action mechanism to create an undercut can increase the cost of an injection mold by 15-30% or more. If a part requires multiple side-actions, the tooling cost can quickly double. This is why designing to avoid undercuts is so important for molded parts.