Designing for Manufacturability ELEC 422 Spring 2003

Manufacturing The combination of materials and processes to produce a finished product. Designing for manufacturability minimizes production cost and maximizes reliability.

Costing Components

Labor Often split by skill level; e.g., assembly and test Principal cost driver Assembly plan Test plan Tooling plan

Overhead Average out costs that are cumbersome to account for directly or spread across multiple products Material overhead –Purchasing and distribution –Inventory costs Labor overhead –Equipment –Occupancy –Management and services

Key Decisions Process flow –Assembly plan –Test plan Make vs. buy Tooling

Process Centers Manufacturing area specializing in a particular category of process. A small company will most often subcontract lower level processes.

Tooling Volume dependent –Savings per unit × #units > tool cost Example: Custom IC –Mask charges –Run sizes

Design Guidelines Minimize the number of components Minimize the number of part numbers –Multiple usage –Common parts Minimize interconnect hardware –Cables –Connectors Minimize the number and types of fasteners

Design Guidelines Eliminate ambiguities in the assembly process –Mistake-proof assemblies Design for ease of servicing Modular subassemblies where appropriate

Design Guidelines Avoid tight tolerances Avoid pushing processes to their limits Design circuits that work reliably over a wide range of temperatures

More Information Websites – – Books –Schonberger, R., World Class Manufacturing : The Lessons of Simplicity Applied, Macmillan, –Bowman, M.S., Applied Economic Analysis for Technologists, Engineers, and Managers. Prentice Hall, 1999.

Product Costing ELEC 422 Spring 2003

Course Requirements At the mid-term review and in the final report, each team should provide an estimate of the factory cost of their product. The costing should include material, labor, and overhead.

Labor Rates Assembly$10/hr Subassembly test$16/hr Top-level test$20/hr

Overhead Rates Assemblyx 2.0 Subassembly testx 2.6 Top-level testx 2.6 Materialx 0.14