Product Design

Lecture Outline l The design process l Concurrent engineering l Design for Manufacture l Failure Modes and Effects Analysis l Value analysis l Quality Function Deployment (QFD)

Product Design l Specifies materials l Determines dimensions & tolerances l Defines appearance l Sets performance standards

An Effective Design Process l Matches product characteristics with customer needs l Meets customer requirements in simplest, most cost-effective manner l Reduces time to market l Minimizes revisions

Breaking Down Barriers

Stages In The Design Process l Idea Generation Product Concept l Feasibility Study Performance Specifications l Preliminary Design Prototype l Final Design Final Design Specifications l Process Planning Manufacturing Specifications

No Idea generation Final design Preliminary design Feasibility study Process planning Product feasible? Yes Prototype Manufacturing Design & Manufacturing Specifications The Design Process

Idea Generation l S uppliers, distributors, salespersons l Trade journals and other published material l Warranty claims, customer complaints, failures l Customer surveys, focus groups, interviews l Field testing, trial users l Research and development

More Idea Generators l Perceptual Maps visual comparison of customer perceptions l Benchmarking comparing product/service against best-in-class l Reverse engineering dismantling competitor’s product to improve your own product

Perceptual Map Of Breakfast Cereals Good taste Bad taste High nutrition Low nutrition Cocoa Puffs Rice Krispies Wheaties Cheerios Shredded Wheat

Feasibility Study l Market Analysis l Economic Analysis l Technical / Strategic Analysis

Preliminary Design l Create form & functional design l Build prototype l Test prototype l Revise prototype l Retest

Form Design (How The Product Looks)

Functional Design (How The Product Performs) l Reliability probability product performs intended function for specified length of time l Maintainability ease and/or cost or maintaining/repairing product

Computing Reliability x 0.90 = (1-0.95) = Components in series Components in parallel

Final Design & Process Planning l Produce detailed drawings & specifications l Create workable instructions for manufacture l Select tooling & equipment l Prepare job descriptions l Determine operation & assembly order l Program automated machines

Distribution Of Design Changes Production begins Months Number of Design Changes Company 1 90% of Total changes complete Company 2

Improving The Design Process 1. Design teams 2. Concurrent design 3. Design for manufacture & assembly 4. Design for environment 5. Measure design quality 6. Utilize quality function deployment 7. Design for robustness

Design Teams l Marketing, manufacturing, engineering l Suppliers, dealers, customers l Lawyers, accountants, insurance companies

Concurrent Design Customers Marketing Design Engineering SuppliersProduction

Concurrent Design l Also, simultaneous or concurrent engineering l Simultaneous decisionmaking by design teams l Integrates product design & process planning l Details of design more decentralized l Encourages price-minus not cost-plus pricing l Needs careful scheduling - tasks done in parallel

General Performance Specifications l Instructions to supplier: “Design a set of brakes that can stop a 2200 pound car from 60 miles per hour in 200 feet ten times in succession without fading. The brakes should fit into a space 6” x 8” x 10” at the end of each axle and be delivered to the assembly plant for $40 a set.” l Supplier submits design specifications and prepares a prototype for testing.

Role Of Design Engineer l No longer totally responsible for product design l Responsible for more than what was traditionally considered “design” l Merging of design engineer and manufacturing engineer

Design For Manufacture l Design a product for easy & economical production l Consider manufacturability early in the design phase l Identify easy-to-manufacture product-design characteristics l Use easy to fabricate & assemble components l Integrate product design with process planning

DFM Guidelines l Minimize the number of parts l Develop a modular design l Design parts for multi-use l Avoid separate fasteners l Eliminate adjustments l Design for top-down assembly l Design for minimum handling

DFM Guidelines l Avoid tools l Minimize subassemblies l Use standard parts when possible l Simplify operations l Design for efficient and adequate testing l Use repeatable & understood processes l Analyze failures l Rigorously assess value

Design Simplification (c) Final design Design for push-and-snap assembly (b) Revised design One-piece base & elimination of fasteners (a) The original design Assembly using common fasteners

More Design Improvements l Standardization uses commonly available parts reduces costs & inventory l Modular design combines standardized building blocks/modules into unique products

Design For Assembly (DFA) l Procedure for reducing number of parts l Evaluate methods for assembly l Determine assembly sequence

Analyzing Failures l Failure Mode and Effects Analysis (FMEA) a systematic approach for analyzing causes & effects of failures prioritizes failures attempts to eliminate causes l Fault Tree Analysis (FTA) study interrelationship between failures

Failure Mode & Effects Analysis

Fault Tree For Potato Chips And Or

Value Analysis (Engineering) l Ratio of value / cost l Assessment of value : 1. Can we do without it? 2. Does it do more than is required? 3. Does it cost more than it is worth? 4. Can something else do a better job? 5. Can it be made by less costly method, tools, material? 6. Can it be made cheaper, better or faster by someone else?

Design For Environment l Design from recycled material l Use materials which can be recycled l Design for ease of repair l Minimize packaging l Minimize material & energy used during manufacture, consumption & disposal

Measures Of Design Quality  Number of component parts and product options  Percentage of standard parts  Use of existing manufacturing resources  Cost of first production run  First six months cost of engineering changes

Measures Of Design Quality  First year cost of field service repair  Total product cost  Total product sales  Sustainable development

Quality Function Deployment (QFD) l Translates the “voice of the customer” into technical design requirements l Displays requirements in matrix diagrams l First matrix called “house of quality” l Series of connected houses

House Of Quality 6. Technical assessment and target values 1. Customer requirements 4. Relationship matrix 3. Product characteristics Importance 2. Competitive assessment 5. Tradeoff matrix

Series Of QFD Houses

Benefits Of QFD l Promotes better understanding of customer demands l Promotes better understanding of design interactions l Involves manufacturing in the design process l Breaks down barriers between functions and departments l Focuses the design effort

Benefits Of QFD l Fosters teamwork l Improves documentation of the design and development process l Provides a database for future designs l Increases customer satisfaction l Reduces the number of engineering changes l Brings new designs to the market faster l Reduces the cost of design and manufacture

Design For Robustness l Product can fail due to poor design quality l Products subjected to many conditions l Robust design studies controllable factors - under designer’s control uncontrollable factors - from user or environment l Designs products for consistent performance

Consistency Is Important l Consistent errors are easier to correct than random errors l Parts within tolerances may yield assemblies which aren’t l Consumers prefer product characteristics near their ideal values

Technology In Design l CAD - Computer Aided Design assists in creating and modifying designs l CAE - Computer Aided Engineering tests & analyzes designs on computer screen l CAD/CAM - Design & Manufacturing automatically converts CAD data into processing instructions for computer controlled equipment

Benefits Of CAD l Produces better designs faster l Builds database of designs and creates documentation to support them l Shortens time to market l Reduces time to manufacture l Enlarges design possibilities l Enhances communication and promotes innovation in design teams

Summary l The design process l Concurrent engineering l Design for Manufacture l Failure Modes and Effects Analysis l Value analysis l Quality Function Deployment (QFD)