A component can perform perfectly and still cost more than necessary. To redesign a component to reduce cost, focus on the decisions that drive material, cycle time, tooling, scrap, inspection and assembly. The objective is not to remove quality; it is to meet the real functional requirements with a simpler production route.
The example below shows a disciplined DFM approach. Exact savings depend on geometry, volume and process, but the method applies across machined, cast, moulded, fabricated and assembled parts.
Start with the current cost breakdown
Separate material, machine time, tooling, special processes, inspection, scrap, assembly, packaging and logistics. Ask the supplier which features create the most time or risk. A price-only negotiation cannot remove cost embedded in the design.
Use annual volume and cost per accepted part. A feature that adds one minute may be insignificant for 100 parts but substantial for 100,000 parts.
Example: an over-engineered equipment housing
Consider a small equipment housing machined from a solid aluminium block. It includes deep pockets, several thin walls, tight general tolerances, a cosmetic finish on every surface and separate brackets fixed with screws. The component works, but it requires extensive material removal, multiple setups and detailed inspection.
A redesign team begins by confirming functional interfaces: mounting points, enclosure volume, connector positions, heat transfer and environmental protection. Features unrelated to those functions become candidates for change.
Optimise tolerances by function
The original drawing applies tight tolerances broadly. The redesign keeps precision on the mounting datums and sealing interface but relaxes non-critical wall and clearance dimensions. General tolerances are assigned to suitable features.
This reduces inspection time and allows a more stable process. Use a tolerance stack-up to ensure the assembly still meets fit and performance requirements.
Reduce material and machining time
The team reviews stock size, pocket depth, corner radii and tool access. Larger internal radii permit stronger cutters and faster machining. Wall thickness is made more uniform, and unnecessary deep pockets are removed.
Near-net-shape alternatives are also considered. At higher volumes, a casting or extrusion plus finish machining may use less material and machine time. The business case must include tooling, validation and volume uncertainty.
Simplify the part and assembly
Separate brackets and fasteners create purchase, handling and assembly cost. The redesign integrates one bracket function into the housing and standardises the remaining fasteners. Tool access is improved so assembly uses fewer orientations.
Part consolidation should not create a component that is difficult to manufacture or service. Evaluate manufacturing and lifecycle consequences together.
Review material and finish
The specified alloy may have been selected historically rather than functionally. Compare strength, corrosion, thermal behaviour, machinability, availability and finishing. A standard grade or more available stock size can reduce both purchase cost and lead time.
Apply cosmetic or protective finish only where needed, while preserving corrosion and electrical requirements. Clearly mask functional surfaces and define measurable appearance criteria.
Design inspection into the component
Critical features should be accessible to normal gauges or coordinate measurement. Avoid datum schemes that require complex fixtures unless function demands them. Standard thread and tool sizes simplify both production and inspection.
Reducing measurement ambiguity lowers dispute and repeated inspection. It also supports faster supplier qualification and more reliable series control.
Compare production routes at realistic volumes
Create cost models for the current machining route, the improved machining design and any near-net-shape alternative. Include tooling, fixture, unit cost, scrap, lead time and change flexibility.
At low volumes, the redesigned machined version may be best. At stable higher volumes, casting or extrusion may offer a lower unit cost. Use break-even analysis instead of assuming that tooling automatically pays back.
Prototype and validate the redesign
Update the controlled CAD model and drawing, then build production-relevant prototypes. Test fit, load, sealing, thermal performance and assembly. Compare dimensional evidence with the original acceptance criteria.
Do not release savings until function is verified. Our guide to outsourcing prototype manufacturing explains how to structure the validation build.
Measure savings without hiding new costs
The redesigned unit may reduce material, cycle time, inspection and fastener count, but include engineering, tooling and validation in the calculation. Confirm that packaging, logistics or warranty risk has not increased.
The relevant result is total cost per conforming assembled unit. Use the broader framework for reducing manufacturing cost per part.
DFM redesign checklist
- Which requirements directly support function or compliance?
- Where do tight tolerances drive production or inspection?
- Can material volume, setups or operations be reduced?
- Can standard materials, tools and fasteners be used?
- Can parts be consolidated without harming serviceability?
- Is another process economical at the forecast volume?
- Can critical features be inspected simply and reliably?
- Has the complete redesigned product been validated?
TOS supports product optimisation, 3D CAD development, prototypes and supplier sourcing as one route. See developing custom technical components or contact us to review a high-cost component.