Happy’s Essential Skills: Design for Manufacturing and Assembly, Part 1

Estimated reading time: 9 minutes

1. Know Your History—Learn from the past: Returns, corrective action processes, recalls, etc. Know and understand problems and issues with current and past products.
2. Standardize Design Methods & Tools: Standardize design, procurement, processes, assembly and equipment. Don’t redesign the wheel—use existing parts and assemblies and limit exotic or unique components.
3. Simplify the Design—Methods for Part Reduction: Parts reduction is one of the best ways to reduce the cost of fabrication, assembling a product overhead and increase quality and reliability.
4. Simplify the Design—Parts Commonality via Multi-use/Multi-functional Parts: Develop an approved or preferred parts lists or a standardized BOM. Use one-piece structures from molding, extrusions, castings and powder metals. Use multi-functional parts that perform more than one function.
5. Design for Total Quality Management—Fundamental Principle of Lean: Lean supply, fabrication and assembly processes are essential design considerations. Develop and use standard guidelines appropriate for the process being performed. Know and apply lean principles to design manual operations for the capabilities of the operator. Practice ergonomics to maximize productivity and reduce operator fatigue and discomfort.
6. Eliminate Waste: Overproduction, delays—waiting, transporting/moving, process inefficiencies, queues-inventories, unnecessary motions and defective products.
7. Design for Parts Handling: Minimize handling to correctly position, orient and place parts to avoid multiple or complex assembly orientations.
8. Design for Efficient Joining and Fastening: Avoid threaded fasteners when possible, consider alternatives; if used, minimize variety. Screws, bolts, nuts and washers are time-consuming to assemble and difficult to automate.
9. Use Error-Proofing Techniques: Mistakes will happen. What can go wrong will go wrong. Use error-proofing techniques in product design and assembly.
10. Design for Process Capabilities: Make unnecessary the tight tolerances and tolerances that are beyond the inherent capability of the manufacturing processes or operators in a continuous production situation.
11. Design for Test, Repair & Serviceability: Defects will occur. Designing for ease of test and repair will make these processes more efficient, cost effective, and reliable. Failed products are often returned to the manufacturer for service and failure analysis. Where possible, use the production test equipment/setup for return analysis.       

The foundation of a robust DfM system is a set of design guidelines and tasks to help the product team improve manufacturability, increase quality, reduce life cycle cost and enhance long term reliability. These principles need to be customized to your company's culture, products, and technologies, and based on a solid understanding of the intended production system—whether internal or external. The basis for these principles is “Measures of Performance & Metrics” where design choices have a score that can be shared by all.

Develop and use standard guidelines appropriate for the process being performed. Know and apply lean principles to design manual operations for the capabilities of the operator. Practice ergonomics to maximize productivity and reduce operator fatigue and discomfort.

Design Planning and Predicting Cost

The need for cost reduction in order to remain competitive is a principle responsibility of product planning. On the average, 75% of the recurring manufacturing costs are determined by the design drawing and specifications ^[2]. This was one of the conclusions found by an extensive study General Electric conducted on how competitive products were developed. Manufacturing typically determines production set-up, material management and process management costs (Figure 2), which are a minor part of the overall product cost.

Time-To-Market along with competitive prices can determine a product's ultimate success. The first of a new electronic product in the market has the advantages. By planning the PWB layout and taking into consideration aspects and costs of PWB fabrication and assembly, the entire process of design and prototyping can be done with minimum redesign (or respins).

Figure 2: Design determines the majority of the cost of a product.

Design Planning and Manufacturing Planning

Electronics is one of the biggest enterprises there is globally. It is common for design to be done in one hemisphere and manufacturing in another. It is also common for manufacturing to be done in a number of different places simultaneously. An integrated approach must be adopted when the intention is to rationalize fabrication and assembly as part of the entire production system and not as individual entities as shown in Figure 3. This dispersed manufacturing must be taken into consideration during the design planning and layout process. No finished product is ever better than the original design or the materials it is made from.                                                        

Figure 3: Fabrication and assembly rationalized by planning and design.

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