Product Design. Chapter 5. Product and Service Design. Service Design. An Effective Design Process. Stages In The Design Process

Transcription

1 Chapter 5 Product and Service Design Product Design Specifies materials Determines dimensions & tolerances Defines appearance Sets performance standards Service Design Specifies what the customer is to experience physical items sensual benefits psychological benefits An Effective Design Process Matches product/service characteristics with customer needs Meets customer requirements in simplest, most cost-effective manner Reduces time to market Minimizes revisions Breaking Down Barriers Stages In The Design Process Idea Generation Product Concept Feasibility Study Performance Specifications Preliminary Design Prototype Final Design Final Design Specifications Process Planning Manufacturing Specifications

2 The Design Process Idea Generation Idea generation Feasibility study Product feasible? Yes Preliminary design Suppliers, distributors, salespersons No Trade journals and other published material Final design Prototype Process planning Warranty claims, customer complaints, failures Customer surveys, focus groups, interviews Field testing, trial users Research and development Design & Manufacturing Specifications Manufacturing More Idea Generators Perceptual Maps visual comparison of customer perceptions Benchmarking comparing product/service against best-inclass Reverse engineering dismantling competitor s product to improve your own product Perceptual Map Of Breakfast Cereals Low nutrition Cocoa Puffs Good taste Rice Krispies Bad taste Wheaties High nutrition Cheerios Shredded Wheat Feasibility Study Market Analysis Economic Analysis Technical / Strategic Analysis Preliminary Design Create form & functional design Build prototype Test prototype Revise prototype Retest

3 Form Design (How The Product Looks) Functional Design (How The Product Performs) Reliability probability product performs intended function for specified length of time Maintainability ease and/or cost or maintaining/repairing product Computing Reliability Components in series x 0.90 = 0.81 Components in parallel (1-0.90)(1-0.95) = Final Design & Process Planning Produce detailed drawings & specifications Create workable instructions for manufacture Select tooling & equipment Prepare job descriptions Determine operation & assembly order Program automated machines Distribution Of Design Changes Improving The Design Process Number of Design Changes Company 1 90% of Total changes complete Company Production 3 Months begins 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

4 Design Teams Concurrent Design Marketing, manufacturing, engineering Suppliers, dealers, customers Lawyers, accountants, insurance companies Customers Marketing Design Engineering Suppliers Production Concurrent Design Also, simultaneous or concurrent engineering Simultaneous decision making by design teams Integrates product design & process planning Details of design more decentralized Encourages price-minus not cost-plus pricing Needs careful scheduling - tasks done in parallel General Performance Specifications 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. Supplier submits design specifications and prepares a prototype for testing. Role Of Design Engineer No longer totally responsible for product design Responsible for more than what was traditionally considered design Merging of design engineer and manufacturing engineer Design For Manufacture Design a product for easy & economical production Consider manufacturability early in the design phase Identify easy-to-manufacture product-design characteristics Use easy to fabricate & assemble components Integrate product design with process planning

5 DFM Guidelines 1. Minimize the number of parts 2. Develop a modular design 3. Design parts for multi-use 4. Avoid separate fasteners 5. Eliminate adjustments 6. Design for top-down assembly 7. Design for minimum handling 8. Avoid tools 9. Minimize subassemblies 10. Use standard parts when possible 11. Simplify operations 12. Design for efficient and adequate testing 13. Use repeatable & understood processes 14. Analyze failures 15. Rigorously assess value Design Simplification More Design Improvements (a) The original design (b) Revised design (c) Final design Assembly using common fasteners One-piece base & elimination of fasteners Design for push-and-snap assembly Standardization uses commonly available parts reduces costs & inventory Modular design combines standardized building blocks/modules into unique products Design For Assembly (DFA) Procedure for reducing number of parts Evaluate methods for assembly Determine assembly sequence Analyzing Failures Failure Mode and Effects Analysis (FMEA) a systematic approach for analyzing causes & effects of failures prioritizes failures attempts to eliminate causes Fault Tree Analysis (FTA) study interrelationship between failures

6 Failure Mode & Effects Analysis Failure Mode Stale Broken Too Salty Causes of Failure Low moisture content, expired shelf life, poor packaging Too thin, too brittle, rough handling, rough use, poor packaging Outdated recipe, process not in control, uneven distribution of salt Effects of Corrective Failure Action Tastes bad, won t Add moisture, cure crunch, thrown longer, better out, lost sales package seal, shorter shelf life Can t dip, poor display, injures mouth, choking, perceived as old, lost sales Change recipe, change process, change packaging Eat less, drink Experiment with more, health recipe, experiment hazard, lost sales with process, introduce low salt version Fault Tree For Potato Chips And Or Value Analysis (Engineering) Ratio of value / cost 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 Design from recycled material Use materials which can be recycled Design for ease of repair Minimize packaging Minimize material & energy used during manufacture, consumption & disposal Measures Of Design Quality 1. Number of component parts and product options 2. Percentage of standard parts 3. Use of existing manufacturing resources 4. Cost of first production run 5. First six months cost of engineering changes 6. First year cost of field service repair 7. Total product cost 8. Total product sales 9. Sustainable development Quality Function Deployment (QFD) Translates the voice of the customer into technical design requirements Displays requirements in matrix diagrams First matrix called house of quality Series of connected houses

7 House Of Quality House Of Quality For Steam Iron 5. Tradeoff matrix Importance 3. Product characteristics 1. Customer requirements 4. Relationship matrix 2. Competitive assessment 6. Technical assessment and target values Series Of QFD Houses Classical Models of QFD Matrix What How House of Quality Subsystem Design Matrix Piece/Part Design Matrix Process Design Matrix Voice of Customer Tech. Performance Measures Piece/Part Characteristics Process Parameters Tech. Performance Measures Piece/Part Characteristics Process Parameters Production Operations Management & Planning Tools for QFD Affinity Diagram (Idea grouping) Tree Diagram (Hierarchical structure) Matrix Diagram ( =9, = 3, =1) Priotization Matrix (Weighted) Customer Needs Customer Needs Importance to the Customer Absolute Importance Relative Importance Ordinal Importance (ranking)

8 The Planning Matrix Current satisfaction performance Competitive satisfaction performance Goal Improvement ratio = Goal / Current S. P. Sales point (1= no change, 1.2 = medium, 1.5 = strong) Raw weight = Importance x Imp. Ratio x S.P. Normalized raw weight = R.W. / Σ R.W. Substitute Quality Characteristics (Technical Response) Performance Measurements Product Functions Impacts, Relationships, & Priorities Amount of Impact Strongly linked = 9, Moderately linked = 3 Possibly linked = 1 Priorities of SQC (Σ Impacts) Negative Impacts Technical Correlations : Strong positive impact : Moderate positive impact Blank: No impact : Moderate negative impact : Strong negative impact Direction of impact Technical Benchmarks Benchmarking performance measures Benchmarking functionality Competitive Benchmarks Own Performance Targets Benefits Of QFD Promotes better understanding of customer demands Promotes better understanding of design interactions Involves manufacturing in the design process Breaks down barriers between functions and departments

9 Focuses the design effort Fosters teamwork Improves documentation of the design and development process Provides a database for future designs Increases customer satisfaction Reduces the number of engineering changes Brings new designs to the market faster Reduces the cost of design and manufacture Design For Robustness Product can fail due to poor design quality Products subjected to many conditions Robust design studies controllable factors - under designer s control uncontrollable factors - from user or environment Designs products for consistent performance Consistency Is Important Consistent errors are easier to correct than random errors Parts within tolerances may yield assemblies which aren t Consumers prefer product characteristics near their ideal values Technology In Design CAD - Computer Aided Design assists in creating and modifying designs CAE - Computer Aided Engineering tests & analyzes designs on computer screen CAD/CAM - Design & Manufacturing automatically converts CAD data into processing instructions for computer controlled equipment Benefits Of CAD Produces better designs faster Builds database of designs and creates documentation to support them Shortens time to market Reduces time to manufacture Enlarges design possibilities Enhances communication and promotes innovation in design teams Characteristics Of Services 1. Intangible 2. Variable output 3. High customer contact 4. Perishable 5. Service inseparable from delivery 6. Decentralized 7. Consumed more often 8. Easily emulated

10 Service Design Performance Specifications Design Specifications Delivery Specifications A Well-designed Service System Is Consistent with firm s strategic focus User friendly Robust Easy to sustain Effectively linked between front & back office Cost effective Visible to customer