5.the common methods to determine the parameters of technical standards

8/19/2019 5.the Common Methods to Determine the Parameters of Technical Standards

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The Common Methods to

Determine the Parameters of

Technical Standards

Zhang Yue-yi

China Ji Liang University


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Content

Introduction

Classification of quality characteristic

Methods to determine the technical parameters Methods to determine the specification limits

Conclusion


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Introduction

There are always some technical

parameters and specification limits

in the technical standardsThe technical parameters and

specification limits of each

characteristic are all different


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!uality

characteristic

Measurement

characteristic

Countingcharacteristic


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Measurement

characteristic

the nominal the "etter

the smaller the "etter

the larger the "etter

m ± ∆ 21

m+∆

−∆or

0 x ≤ + ∆

x ≥ ∞ − ∆


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Methods to Determine the Parameters

Parameter design

Quality function deploymentReliability design


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Parameter design

Parameter design is the chief component of the

aguchi!s three stage design"

he basic idea of the parameter design is to determine

the optimal le#el of all technical parameters by usingthe orthogonal array and $%& ratio' including ra(

materials' electronic parts and components"

Mean(hile' in order to minimi)e the qualityfluctuation' (e must decrease the influence of all *inds

of interference by the parameter design"


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Quality function deployment

!uality function deployment#!$D% is

the method of product design and

development driven "y customer& itadopts certain method to accurately

transform the customer demands into

the technical and process parameters


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T h eh o u s e

of

q u al i t y ( H O Q

)


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Reliability design

'elia"ility is the a"ility of the product

or system to perform and maintain its

functions in routine circumstances& aswell as hostile or une(pected

circumstances

'elia"ility design is to solve productrelia"ility at the design stage


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Methods to Determine the specification limit

!uality loss function

Safety coefficient


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Quality loss function

The quality loss function of the nominal the

better characteristic:

The quality loss function of the smaller the


The quality loss function of the larger the


2( ) ( ) L y K y m= −

2( ) L y Ky=

2

1( ) L y k

y

=


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Quality loss model of the nominal

the better characteristic

)

*


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Method to determine the loss

coefficient k

+hen the product "ecomes out of

use& that is to say& the ,uality

characteristic value is "eyond the

functional limit& the loss is )* yuan

Thus-

So& loss coefficient-

2

0 0 A K = ∆

0

2

0

Ak =

∆


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Method to determine

If the product is un,ualified& the

rewor. cost of the product is )

yuan& the specification limit of the,uality characteristic is-

0

0

A

A∆ = × ∆


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Examle

The target value of the output voltage of

the television power circuit is //01& the

functional limit & the loss of losing

functionality yuan

)、 Determine the loss coefficient of the

loss function2

25o V ∆ =

300o A =

0

2 2

0

3000.4

25

Ak = = =

∆


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! 3、 If the rewor. cost of the un,ualified

product )4/ yuan& the specification limit of

the ,uality characteristic can "e determined

!hus' the technical parameter and specificationlimit of the output #oltage of the tele#ision

po(er circuit+

0

0

125 1.4

300

AV

A∆ = × ∆ = × =

115 1.4V ±


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Quality loss model of the smaller

the better characteristic

2

0 0 A K = ∆

0

2

0

Ak =∆

0

0

A

A∆ = × ∆


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Quality loss model of the larger the

better characteristic

2

0 0 K A= × ∆

2

1( ) L y k

y=

0

0

A

A∆ = × ∆


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"afety coefficient

#: the loss of the unqualified roduct$

#%: the loss of the roduct that the

characteristic &alue is beyond thefunctional limit'

"afety coefficient:

(enerally) safety coefficient '

0 A

A

φ =

4 " 5φ =


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the nominal the "etter

The relationshi bet*een the secification

limit and the functional limit△ △% of the

nominal the better characteristic:

Then) the secification limit :

0

0

A

A∆ = × ∆

0

ϕ

∆

∆ =


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Conclusion

#s the customer demand is becoming

higher and higher) not only for roduct

erformance) but also for security)

economy) reliability) aearance quality)

ser&ice) etc'

The technical arameter and secification

limit of e&ery characteristic need to bedetermined by certain methods'


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han* you,

5yysh6/78com

5.the common methods to determine the parameters of technical standards

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