Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:1 Environmentally Conscious Design & Manufacturing Class 27: Quality & ECDM Prof. S. M. Pandit

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:2 Quality l Questions: »What are the possible quality constraints in Environmentally Conscious Design and Manufacturing (ECDM) »How does “Total Quality” relate to ECDM »Quality issues in Product & Process design

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:3 Quality of a manufactured product Quality of DESIGN Quality of CONFORMANCE Quality of PERFORMANCE Quality characteristics Variables Attributes Quality ‘Type’

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:4 Customer Need Design Quality Quality of conformance Quality of performance Influencing factors Type of product Cost Profit policy Product demand Product availability Product safety Defect Prevention Finding Analysis & rectification cost value Degree to which product satisfies the customer

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:5 Quality of conformance Design Quality Quality of performance

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:6 Quality characteristics StructuralSensoryTime oriented Ethical Examples - Strength of a beam - Viscosity of fluid Examples - Reliability - Maintainability

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:7 Product: Switchgear Example = Dimensional Accuracy Type = ? Comment on the consequences of dimensional inaccuracy and the remedy Type = Design Example = ? Product: Tire Example = Elasticity Type = ? Type = Performance Example = ? Examples of Quality Constraints

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:8 Objective Statement Customer Requirement s ‘Whats’ Importance Rating Technical Competitive assessment of ‘hows’ (to become the benchmark) Customer assessment of competition Relationship Matrix Total Quality & Quality Function Deployment

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:9 Objective function(s) - examples:- Maximize profit - Improve ‘quality’ Customer requirements - examples:- Increase reliability Technical Competitive Assessment of ‘How’ - Multi- disciplinary team - Product design and development - Marketing, Sales, Accounting, finance, … - Process Design - Manufacturing

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide: H - 1 H - 2H - 3H - 4 Strong positive correlation between H - 1 and H - 3 (I H - 1  then H - 3 

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:11 w1w1 w2w2 w3w3 w4w4 h 11 h 12 h 13 h 14 h 21 h 22 h 23 h 24 h 31 h 32 h 33 h 34 h 41 h 42 h 43 h 44 w 1 h 11 Relation between ‘how’ and ‘what’

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:12 * A module o a satellite monitoring system has 500 components in series. The reliability of each component is Find the reliability of the module. If the number of components in series is reduced to 200, what is the reliability of the module? Example 1 - Reliability

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:13 With 500 components in series, the system reliability is; R s = = With only 200 components in series, R s = = RsRs n

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:14 Reliability Evaluation Reliability of component with exponential failure distribution: Mean Time to failure: Reliability of a system with two independent components in series is : Reliability of a system with n independent components in series is : :the constant failure rate for the component

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:15 An auto - focus unit in a camera has 10 components in series. If the system reliability is to be 0.95 after 2000 hours of operation, what would be the mean time to failure of the individual components if they have identical failure rate ? Example 2 - Reliability

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:16 R s = exp [-( ) t]= exp [-( s t] Therefore, 0.95 = exp [- s (2000)] and, s = / h {Failure rate of the focus unit} Since 1 = 2 =... = 10 = c, c = s /10= / h MTTF of each component: MTTFc = 1/ c = 389,915 h

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:17 Homework #9 1. A reclamation center produces two products, A and B. The sales volume for produce A is at least 60 % of the total sales of the two products. Both products use the same raw material, of which the daily availability is limited to 100 lb. Products A and B use this raw material at the rates of 2 lb/unit and 4 lb/unit, respectively. The sales price for the two products are $20 and $40 per unit. Formulate the problem as a linear programming problem.

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:18 Homework #9 2.For the data given in the last problem of midterm exam, reproduced in slide # 14 of class 26, does the actual observation lie within: i) 68 % probability interval on the observation? ii) 90 % probability interval on the observation? iii) 99 % probability interval on the observation? 3.Use slide 24 of class 8 (3/22/00) to write down a model for the feedback loop of X 2t as the output and X 4t as the input.

Environmentally Conscious Design & Manufacturing (ME592) Date: May 10, 2000 Slide:19 Homework #9 4. For the auto-focus unit reliability example of class 27, determine the component MTTF if the number of components is reduced to 5. What will the component reliability be after 2000 hours of operation? (Answer: MTTF c :194,957 h; R c = )