Design for X Quality Function Deployment Failure Mode and Effect Analysis

Transcription

1 MECH152-L17(1.0) - 1 Design for X Quality Function Deployment Failure Mode and Effect Analysis What is Design for X MECH152-L17(1.0) - 2 Design for X is a term evolved after sustained interests in developing design methodology to cover various aspects, such as Design for Assembly, Design for Manufacturing, Design for Quality, etc. In general, this is being adopted by the product design community to cover a wide range of issues. It is important NOT to over emphasis its usage and focus on a few key items. 1

2 MECH152-L17(1.0) - 3 Example for DFX Design for assembly Design for disassembly Design for ease of use Design for maintenance Design for manufacture Design for quality Design for reliability Design for reuse Design for cost Design for environment Key Topics in DFX MECH152-L17(1.0) - 4 Key topics Design for Assembly and Disassembly Design for Manufacture Design for Recycling/Disposal Design for Life Cycle Other useful topics: Quality Function Deployment (QFD) Failure Mode and Effect Analysis (FMEA) 2

3 Design for Life Cycle MECH152-L17(1.0) - 5 Design considerations related to total product life cycle: Testability/Inspectability Maintainability/Serviceability Design for the Environment Upgradeability Installability Safety and Product Liability Human Factors lifecycle.html Paradigm Shift MECH152-L17(1.0) - 6 3

4 MECH152-L17(1.0) - 7 Quality Function Deployment A method to translate the customers demands (Voice of Customers) of the products to specific plans to produce products to meet those needs. Market survey 3D Matrix of customer requirements, design considerations and design alternatives with assign weighted scores based on market research information collected Cross functional teams participate in the process MECH152-L17(1.0) - 8 Typical QPD Matrix Auxiliary Power Unit Product Planning Matrix 4

5 QFD Key Steps MECH152-L17(1.0) Define product requirements from customer needs (Product Planning Matrix). 2. Develop product concepts to satisfy these requirements. 3. Evaluate product concepts to select most optimum (Concept Selection Matrix). 4. System Decomposition and define functional requirements or technical characteristics for the subsystems. 5. Derive detail product requirements (assembly or part characteristics) and specifications from subsystem requirements (Assembly/Part Deployment Matrix). 6. For critical assemblies or parts, generate process planning from detail product requirements (assembly or part characteristics). 7. Determine manufacturing process steps to meet these assembly or part characteristics. 8. Based in these process steps, determine set-up requirements, process controls and quality controls MECH152-L17(1.0) - 10 Customer Needs 5

6 Customer Needs (VOC) -1 VOC Collection Plan MECH152-L17(1.0) - 11 Customer requirement documents, requests for proposals, requests for quotations, contracts, customer specification documents, customer meetings/interviews, focus groups/clinics, user groups, surveys, observation, suggestions, and feedback from the field. Include both current and potential customers Special attention to lead customers as future trend setter Plan human resources support for data collection Schedule activities such as meeting, focus groups and surveys. MECH152-L17(1.0) - 12 Customer Needs (VOC) - 2 VOC Data Collection Preparation Identify required information Prepare Questionnaires, Meeting agendas, Survey forms, Presentation for users group/focus group Consolidation of needs Grouping and consolidation to define functional needs using tools like affinity diagram Ranking of VOC Ranking of customer priorities (typically 1 to 5) 6

7 Product Planning (1) Categorize the customer needs in groups Define customer priorities (1 to 5 rating) MECH152-L17(1.0) - 13 Check on standards, regulatory, and industry requirements (normally 3) Critical requirements (5) Competitive analysis of product Get feedback from customers and potential customers on product competitiveness (surveys, meeting, focus group) Rank company and competitor s product on a 1 to 5 scale. MECH152-L17(1.0) - 14 Competitive analysis 7

8 Product Planning (2) MECH152-L17(1.0) - 15 Based on Competitive Analysis, set the improvement goal Improvement No planned improvement: Improvement factor 1 Planned improvement from a rating of 2 to 4: Improvement factor of 1.2 Warranty, service, reliability & compliant reduction are potential areas of improvement Sales points to emphasize Major sales points weighting factor 1.3 Minor sales points weighting factor 1.1 Maximum: 3 major sales point or 2 major sales point and 2 minor sales points Product Planning (3) MECH152-L17(1.0) - 16 Product Strategy Brief Value proposition behind the product. To focus development resources on areas of greatest value to customer and to gain management support Sales point emphases Competitive strengths Market differentiation Market positioning relative to other products 8

9 MECH152-L17(1.0) - 17 Product requirements and direction Product Planning (4) MECH152-L17(1.0) - 18 Establish and classify product requirements in response to customer needs. Classification: functional or sub-systems Classification should be generic to allow room for alternative solutions consideration Identify the direction of the objective for each requirement (target value or range, maximize or minimize) 9

10 MECH152-L17(1.0) - 19 Product requirements vs customer needs Technical evaluation Product Planning (5) MECH152-L17(1.0) - 20 Relate customer needs to product requirements: satisfying customer needs Evaluate against the goal for the requirement Use the weighting factors (strong, medium, weak) Perform technical evaluation of the product against competitive products Source: websites, industry publications, customer interviews, published specifications, catalogs and brochures, trade shows, purchasing information, patents, technical publications, trade benchmarks, 3 rd party organizations, former employees, testing reports Warranty, service repair occurrences and costs 10

11 MECH152-L17(1.0) - 21 Initial target values Requirements interaction Product Planning (6) Define initial target values for product requirements MECH152-L17(1.0) - 22 Use technical evaluation data Set appropriate target values and not be over-aggressive on non-focused areas Determine potential interactions between product requirements Strong positive, moderate positive, moderate negative and strong negative Overly positive bias means redundancy in requirements Focus on negatives: negative means potentially conflicting requirements 11

12 MECH152-L17(1.0) - 23 Importance ratings Difficulty ratings Product Planning (7) Calculate the importance ratings MECH152-L17(1.0) - 24 products of customer priority rating and requirement weighting factor. Improvement factors and sales point factors Sum of the product under the requirement column Define the difficulty ratings 1 to 5 point scale (5, very difficult and risky) Consider technology maturity, personnel technical capability, resources availability, technical risk, manufacturing capability, supply chain capability, and schedule Generate composite rating by classification 12

13 Product plan Product Planning (8) Analyze the matrix and finalize the product plan. Determine required actions and areas of focus Finalize target values Based on: Product strategy objectives Importance of various product requirements Conflict resolutions of the interaction matrix Technical difficulty ratings Technology solution and maturity Maintain the matrix as customer needs or conditions changes MECH152-L17(1.0) - 25 MECH152-L17(1.0) - 26 FMEA 13

14 MECH152-L17(1.0) - 27 Failure Mode and Effect Analysis FMEA is a method which is used to find and judge potential sources of error in products or manufacturing processes. FMEA includes a judgment of how serious the consequences of a presumed error would be. FMEA also estimates the failure in terms of the frequency of the occurrence, the severity, and its detection. Action to eliminate or reduce risk forms the outcome of the analysis. Typical FMEA Chart MECH152-L17(1.0)

15 MECH152-L17(1.0) - 29 Failure Modes Possible Failure Mode: potential failures of parts in the system Effects of failure on system: failure of the part leading to adverse effect on the system Cause of Failure (Failure Mode): underlying mechanism leading to failure Case Study MECH152-L17(1.0) - 30 Product: Component Name: Component Number: Issue Nunber: Automatic Transmission Shaft & Lever Assembly Q Engineer Sheet Issue Number 1 of 1 1 Last Updated: Part, Process or System Name/Number Function Possible Failure Mode Effects of Failure on System Cause of Failure (Failure Mode) O S D R Action to eliminate or reduce risk Manual level assembly Transmit manual selector motion from external linkage to manual valve and park linkage Plastic level breaks No drive, Locked in park Overload on lever when disengaging park on grade, Brittle when cold, Damaged in handling Redesign lever- Thicker material and strengthening ribs to carry 100% overload. In progress Wear at hole in lever Loose fit at shaft and lever serration Excessive free-play in manual linkage Excessive free-play in manual linkage Lever slides off serration Cannot select drive position High unit loading at rod, Inferior material Thermal set of plastic. Inadequate press-fit interference Assemble with lubricant Install load sensor on assembly press to detect light press fit. Status open. Mis-orient lever to shaft flat in assembly Improper linkage geometry, Cannot select low, Cannot select park 15

16 FMEA Procedure MECH152-L17(1.0) - 31 The FMEA analysis is built on a table with a number of columns: Product/Process name Product/Process function Possible failure mode Effects of failure on system Cause of failure (failure mode) O Occurrence S Severity D Detection R Risk priority number = O x S x D Action to eliminate or reduce risk 16