Question $1$

a$)($i$)$ List the $5$ basic stages in any Quality Control System $(3$ marks$)$

$($ii$)$ Taguchis Quality Loss Function offers an alternative view of Quality losses compared to the

traditional view. Explain the distinction between Taguchis premise and the traditional view

$(3$ marks$)$

$($iii$)$ Explain clearly the meaning of the term attribute when used in the context of Quality parameters

$(2$ marks$)$

b$)$ An engineer was employed by TUClean, a manufacturer of washing machines. Her primary goal

was to improve the design of one washing machine model already two years on the market in order

to address field failures. Table $1\mathrm{.}0$ lists failure categories and quantities for each of the four

consecutive $6$ month periods prior to the re$-$design project

Failure

Category

Counts $($June

Year $1-$November

Year $1)$

Counts $($December

Year $1-$May Year

$2)$

Counts $($JuneNovember Year $2)$

Counts $($December

Year $2-$May Year $3)$

Drum Bearing $95100150165$

General

Corrosion

$13121312$

Electronic

Controller

$78728070$

Internal Fuse $40454550$

Miscellaneous

Effects

$6833$

Door Seal $80909090$

Drive Belt $20251926$

Table $1\mathrm{.}0$: Field failure counts by category in each of the previous four six month periods

$($i$)$ Using the total dataset available in Table $1\mathrm{.}0,$ construct and fully label a pareto chart for

defect categories over the previous $24$ months. $(5$ marks$)$

$($ii$)$ What are your key insights and recommendations from analysis of this pareto chart?

$(2$ marks$)$

$($iii$)$ Following the re$-$design, the product demand for the new model was the same as for the old

model. In Table $1\mathrm{.}1,$ the engineer captured and categorised all $616$ field service failures for the

new model across a full $24$ month period subsequent to the re$-$design. Citing all relevant

information available to you, determine the effectiveness of the re$-$design from a Quality

perspective