Quality Systems - Taguchi Loss Function

Question 1

According Taguchi’s quality loss function, quality loss occurs when

A. Product characteristics deviate from Target value
B. Product fails inspection
C. Product reaches customer
D. Product requires rework

Answer 1

A. Product characteristics deviate from Target value

Taguchi argues that any deviation from Target value even with specification, limits, results and quality loss to society

Question 2

The shape of Taguchis quality loss function is

A. Quadratic
B. Linear
C. Step function
D. Binomial

Answer 2

A. Quadratic

The loss function is quadratic showing that loss increases exponentially as deviation from Target increases

Question 3

Taguchi’s approach to quality improvement focuses primarily on

A. Inspection methods
B. Statistical process control
C. Robust design
D. Customer surveys

Answer 3

C. Robust design

Taguchi emphasizes designing products and processes to be insensitive to variation in manufacturing and usage conditions

Question 4

In Taguchis view, the traditional definition of quality costs is flawed because

A. It only considers manufacturer costs
B. It ignores prevention costs
C. It assumes no loss within specifications
D. It overestimates inspection costs

Answer 4

C. It assumes no loss within specifications

Traditional views assume products within specification limits have zero quality loss which Taguchi argues is incorrect

Question 5

According to the taguchi lost function, when does quality loss begin

A. Only when a product is outside specification limits
B. As soon as a product deviates from the Target value
C. When defects are detected in the final inspection
D. When production cost increases

Answer 5

B. As soon as a product deviates from the Target value

Unlike traditional quality approaches that consider only specification limits taguchi’s loss function States that any deviation from the Target results any loss

Question 6

Which formula represents the taguchi loss function

A. L(x)=k(x-T)^2
B. L=(x)=k(x+T)
C. L(x)=x/k
D. L(x)=x^2-k

Answer 6

A. L(x)=k(x-T)^2

The taguchi loss function is defined as L (x) = k (x- t) squared. Where x is the actual value t is the Target value and k is a proportionally constant. Please note that the terminology in this formula is slightly different from the one used in the video. For tolerance we used m in video and it is t here.

Question 7

A company produces metal rods with a target length of 100 mm and a tolerance of plus or minus 5 mm according to traditional quality control. When is a product considered defective?

A. When it is exactly 95 mm or 105 mm
B. When it deviates slightly from 100 mm
C. When it is exactly 100 mm
D. When it is shorter than 95 mm or longer than 105 mm

Answer 7

D. When it is shorter than $95 mm or longer than 105 mm

Additional quality control defines defects only when a product is outside tolerance limits but taguchi considers any deviation as wells

Question 8

A manufacturer determines that repairing a defective part costs $1,000. When the part deviates by four units from the target, what would be the loss if the part deviates by two units

A. 125
B. 250
C. 500
D. 750

Answer 8

B. 250

K=L/(y-m)^2
K=1000/(4-0)^2
K=1000/4^2
K=1000/16
K=62.5

So, now you can fill in for 2 instead of 4 to verify.
K=1000/2^2.
K=1000/4
K=250

Question 9

A machine produces parts with a Target weight of 250 g. If the maximum allowable deviation 10 g results any loss of $400, what is the expected loss if a part weighs 255 g

A. 50
B. 100
C. 200
D. 250

Answer 9

B. 100

400(Cost) / 10 (Grams)