Environmentally Conscious Design & Manufacturing (ME592)

Date: April 19, 2000 Slide:1

Environmentally Conscious Design & Manufacturing

Class 19: Reuse

Prof. S. M. Pandit

Environmentally Conscious Design & Manufacturing (ME592)

Date: April 19, 2000 Slide:2

Agenda

• Needs and Benefits

• Elements

• Limits

• Implementation

• Evaluation

• Example

Environmentally Conscious Design & Manufacturing (ME592)

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Reuse and Life Cycle Analysis

Environmentally Conscious Design & Manufacturing (ME592)

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End-of-life Product Recovery Strategies

• Repair• Refurbishing• Remanufacturing• Reuse of components• Material recycling and disposal• Energy recovery

Environmentally Conscious Design & Manufacturing (ME592)

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Needs and Benefits - 1

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Needs and Benefits - 2

• Design for reusability (Technology)• Better quality - ease of reuse• Bookkeeping and control over effect of

- Design- Materials- Manufacturing- Use

Environmentally Conscious Design & Manufacturing (ME592)

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Needs and Benefits - 3

Costs are reduced because:

• Consistent guidelines are established for all mechanics

• When the part can and cannot be reused• Forms the basis for a quality control program

that lowers redo & warranty costs

Environmentally Conscious Design & Manufacturing (ME592)

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Elements - 1

• New Product Design

• Developing guidelines- e.g. small project:reusability limitations and

salvage procedures for a shaft or a gear- e.g. Large project: reusability limitations and

salvage procedures for all the piece parts in a family of components such as a turbocharger

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Elements - 2

• Defining the project- grouping

• Setting priorities- Costs of parts/ components- Field population- Wear or failure rate

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Element - 3

• Define reusable- Life? (80 % -100 %)- Used only on the same machine?- Risk of failure?- Fatigue life?

• Remaining failure is often impossible

to determine

Environmentally Conscious Design & Manufacturing (ME592)

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Limits

• Approximate reusable limits• Salvaging options• Second life probability

- Laboratory tests- Field tests- Historical data

Environmentally Conscious Design & Manufacturing (ME592)

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Implementation - 1

• Measuring• Inspection tools

- Visual, transducers, machine optics• Applications

- severity factor

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Implementation - 2

• Failure analysis

- Credibility of guidelines- Standardizing failure interpretation- Improves service quality- Sells more parts and service

Environmentally Conscious Design & Manufacturing (ME592)

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Evaluation

• Maintain historical data on

- Repair- Performance- Life- Failure modes and effects- Correlation with product batch

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Example: Motor Reuse - 1• Today’s automobiles carry up to 100 electric

motors• There are two brushless and two stepping motors

and one or two brushless fan motors in a laptop

computer.• It is estimated for an average North American

household to have 60-80 electric motors, without

accounting for automobiles.

Source: Klausner et al., 1998, Journal of Industrial Ecology, 2(2), pp.89-102.

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Example: Motor Reuse - 2

• Commutator motors mainly consist of steel, copper, and plastics. These materials cannot be easily separated at end of life.

• Revenues of only some $22 per ton or $0.02 per motor (1998).

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Example: Motor Reuse - 3

Reuse Potential

• Not compromise product quality• Meet functional requirements of new

motors• Need a thorough understanding of used

motors’ failure mechanisms and causes

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Example: Motor Reuse - 4

Assessment of the Reuse Potential

• Need information on the degradation of the motors

• Approaches to assess reuse potential- Testing parameters after product return- Recording parameters during product use

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Example: Motor Reuse - 5

Testing parameters after product return

• Requires the identification of parameters that indicates degree of degradation (e.g., noise, torque.

• Shortcoming:- Long time required for testing- High labor cost- Hard to identify the parameters that

reliably shows the degree of degradation

Environmentally Conscious Design & Manufacturing (ME592)

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Example: Motor Reuse - 6

Recording parameters during product use

• The temperature of certain spots on the motor

• The number of starts and stops of the motor• The accumulated runtime of the motor• The power consumption

Environmentally Conscious Design & Manufacturing (ME592)

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Example: Motor Reuse - 7

Changes in Design

• Introduce one electronic data log (EDL), which records the history of the product’s usage and shows the degradation of the product when product is recovered.

• Design for disassembly to allow the old motor to be removed intact.

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Example: Motor Reuse - 8

EDL records and analyzes the following data

• The number of starts and stops of the motor• The accumulated runtime of the motor• Motor temperature and the power

consumption• Peak and average values of all parameters of

interest

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Example: Motor Reuse - 9

Economic efficiency

• Additional cost incurred by EDL • Return rate

- Depends on consumers’ willing etc.• Recovery rate

- Determined by the return rate of old products and the yield in the product recovery stage

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Big Picture - 1

• Less resources used• Resources diverted from waste

stream• Savings in cost

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Big Picture - 2

- Setting up:- Classification

- Clustering, group theory- Design for reuse

- Tolerances, nominal dimensions, effect on performance

- Failure mode and effects analysis