17: EVALUATION OF THE QUALITY OF MISCELLANEOUS PRODUCTS

Lecture questions:

1. The concept of heterogeneous products

2. Product quality index

3. Defectiveness Index

1. The concept of heterogeneous products

Under heterogeneous products understand the totality of

products designed to achieve a single production

Noah goal. It can be a variety of technological machines.

us that make up the technological complex or system

production process machines. In addition, if the enterprise

Since it produces several types of products, it creates

native products.

2. Product quality index

To assess the level of quality of heterogeneous products is-

enjoy quality indices.

Under the product quality index understand complex

indicator of the level of quality of heterogeneous products, equal to

the average value of the weighted average

all types of estimated and basic products.

The main indicator used in complex

assessment of the quality level of heterogeneous products is the

weighted average weighted arithmetic index of

properties - and to u

eight

S





nK

ots

U

ots

n1

AND



,

toU 

U

bases



M 

k

K

bases

k

1

where s and m - the number of different types of evaluated and basic products;



and



- weight coefficients of the nth estimated and kth ba-

n

k

special type of products;

Kots and Kbaz are complex indicators of sets of properties correspondingly

relevant samples of estimated and base products.

Weight coefficients are determined by the formulas:

S

M





C



C

;





C

/

C

,

n

n

n

k

k



k

n



one

k

1

Where

C

n

and

C

k

- the cost of individual samples of products of the nth and kth

kinds of similar, but heterogeneous products.

Another quality indicator also used in

comprehensive assessment of the quality level of the heterogeneous

is the weighted average geometric in-

quality dex

kV

AND

determined by the formula:



N

'

AND







K

 n

,

kV

n

n1

'

Where

K

- relative quality indicator of the nth type of product,

n

determined by the differential method, i.e.

n

P

K '

; ( n = 1 , ..., N ),

n

P

base

where r n - the main single or integrated quality indicator

n-th type of product;

Rpbaz - a basic indicator of the quality of the n-th product;

N is the number of products manufactured;



- relative volume of production of the nth species, i.e. coefficient

n

weightiness.

Weighting factor



define as follows:

n

N

N



 C



C

,



1

,



0

n

n



n



n

n

n1

n1

Where

C

- planned or actual output of the nth

n

type in monetary terms (in selling, wholesale prices)

For piece products

N

N

C

n

 

nS

n

;



C

n







n

C

n

,

n1

n1

Where



- the number of products of the nth type of product;

n

CN - the selling price of the n-th type of product.

In cases where the company manufactures products

tion of several varieties, then for a relative quality indicator

products ( K p ) Grade factor is accepted ( K s ) , determined by

divided as the ratio of the actual cost of production in

wholesale prices to the notional value, i.e. to the value subject to

All products will be of the highest grade.

To simplify the calculations, instead of the weighted average

metric index can be applied weighted average

an arithmetic quality index, but only when

variable initial quality indicators compared

differ slightly from each other.

3. Defectiveness Index

Id Defectiveness Index is a comprehensive indicator of

native products that can be used to

assessment of the quality of manufacturing products issued for

considered time interval. It is equal to the average weighted

shennom defectiveness coefficients of the product assessed:

N

AND





R

,

d



n

d

n1

Where

R

- the coefficient of defectiveness of products of the nth type, which is

d

an indicator of the quality of manufacturing of these products;

N is the number of types of evaluated heterogeneous products;



- weight coefficient of this type of product.

n

For example, the classification of defects at closed

careful inspection of car production and testing

in road conditions.

1. Critical defects (zero defects per 100 machines):

fuel leaks; leaks in the cooling system; leaks in the lubrication system

ki; brake fluid leakage; reduction of cooling

liquids; foot brake does not work; tight or loose

steering, etc.

2. Major defects (15 defects per 100 machines):

clutch slips, jerks; malfunction

pressure sensor; temperature sensor malfunction; overheat

all parts of the transmission; the whole lighting system does not work;

wipers do not work, etc.

3. Minor defects

(150 defects per

100

cars): unusual engine noise; the failure of candles for-

burning; beep does not work, etc.

4. Low defects (400 defects per 100

machines): defects in metal sheets of the coating; defects are

paints; defects in finishes; lifting brackets are poorly installed

etc.

Defect ratio is determined by selective

(or full) inspection control of finished products.

It is a characteristic of average losses caused by

Tami per unit of a particular type of product

and is equal to:

m

one

R





S

,

d

n

i1

here n is the number of proven product samples (sample size);

t is the number of all types of defects found in a given product.

during sampling;

S

- the number of defects of the i -th type;

i

ji

- the weight coefficient of the i- th type of defects (in shares of costs

or points).

When mass production account data of technical

control for n units of proven products for a specific

The time interval is grouped by the same species.

and for the group their number S i is calculated . Weight ratios

bounds of defects are determined by the cost (or point) method

sob.

For example, let's calculate the quality level of a bike. Of course

It is necessary to determine the defectiveness coefficient ( R d ) and the level of

for the manufacture of a bicycle for a bicycle at the cost of its manufacture

C = 870 rub. and sample size n = 30 pcs.

The initial data for the calculation ( R d ) are given in table 14

Table 14

Initial data for calculating the quality level

Coefficient

Number

No

Cipher

weight,

defects

Si =



i



m

i

payment order

defect



i

, rub.

ti

one

001

0.03

142

4.26

2

002

0.21

7

1.47

3

003

0.10

four

0.40

four

004

20.00

12

240.00

five

005

3.04

130

395.20

6

006

0.02

27

0.54

6





im

i



641.87

i

1

According to the table determine the coefficient of defective

to

641.87

R





21,

four

d

thirty

With the cost method of determining the coefficients of

The number of defects is determined by the quality of manufacture.

according to the formula:

R

d

21.4

Y

1

1



0.98

k

WITH

870

Defects indices and defect factors

ductions are recommended for use in evaluating technical

the level of production in large, structurally complex associations

enterprises - in firms, associations, etc.