STANDARDIZATION AND PREFFERED NUMBERS

 

 STANDARDIZATION AND

PREFFERED NUMBERS

It is the development and implementation

of technical standards. Standardization

helps mass production for safety, quality,

interchangeability and compatibility. The

standards are for size, weight, quality and

 strength. There are National and

International standards. National

standards are for almost every item. In

India it is BIS(Bureau of Indian Standards).

International standards are for many items.

It is not for each item. International

uniformity has its own advantages. ISO

International Standards touch everyone to

improve customer satisfaction. These bring

(i) Quality and reliability

(ii) Consistency in the delivery of services

(iii) Choice and fair competition

(iv) Credibility of standards to support consumer protection laws

(v) Transparency in production information

Following are some of the popular International Standards:

(a) Quality management is ISO 9000

(b)  Environmental management-ISO 14000

(c)  Social responsibility-ISO 26000

(d) Country codes- ISO 3166

(e)  Risk management- ISO 31000

(f)  Energy management-ISO 50001

(g)  Food safety management-ISO 22000

(h) Anti bribery management systems-ISO 37001

(i) Occupational health and safety- ISO 45001

(j) I Information security management- ISO 27001

ADVANTAGES OF STANDARDIZATION

1. Simplify decision making.
2. Helps in improving decisions.
3. Makes mass production possible.
4. Increases efficiency of both machines and men.
5. Reduces time of manufacture.
6. Decreases manpower requirements.
7. Reduces the cost of production.
8. Standard testing methods improve quality of products.
9. Increases durability and life of products.
10. Makes interchangeability possible for worn out and damaged parts.

DISADVANTAGES OF STANDARDIZATION

1. Small scale industry suffers.
2. Loss of motivation
3. Loss of morale

Preferred Numbers

Standardization reduces number of sizes and variety of items. It  reduces cost and improves quality. Express these sizes numerically.  Large number of sizes reduce to a smaller number of sizes. Use Renard numbers for this in FIVE GEOMETRIC SEQUENCES. Round off these up to two decimal places. Preferred values / preferred series become preferred numbers . Resulting values are nearly in geometric sequence. Renard series are R5, R10, R20, R40 and R80.

R5 means five standard sizes between 1 and 10.

These are

Firstly 100/5 = 1.00
Secondly 101/5 = 1.584… ~ 1.60
Thirdly 102/5 = 2.511… ~ 2.50
Fourthly 103/5 = 3.981… ~ 4.00
Fifthly 104/5 = 6.309… ~ 6.30
Sixthly 105/5 = 10 (Do not include in the preferred numbers)

Thus five standard sizes between 1 and 10 are 1.00,1.60, 2.50, 4.00 and 6.30
R10 means 10 standard sizes between 1 and 10
Firstly 100/10 = 1.00,

Secondly 101/10 = 1.25,

Thirdly 102/10 = 1.60,

Fourthly 103/10 = 2.00,

Fifthly 104/10 = 2.50 ,

Sixthly 105/10 = 3.15
Seventhly 106/10 = 4.00,

Eighthly 107/10 = 5.00,

Ninthly 108/10 = 6.50,

Tenthly 109/10 = 8.00

Eleventhly 1010/10 = 10      (not included in the preferred numbers)

Ten standard sizes between 1 and 10

1.00,1.25, 1.60, 2.00, 2.50, 3.15, 4.00, 5.00, 6.00, 8.00

TABLE: PREFERRED NUMBERS (AS PER RENARD SERIES)

Designation         Preferred Numbers as per Renard Series
R5                        1.00   1.60   2.50   4.00   6.30
R10                      1.00   1.25   1.60   2.00   2.50   3.15   4.00   5.00   6.30   8.00
R20                      1.00   1.25   1.60   2.00   2.50   3.15   4.00   5.00   6.30   8.00

1.12   1.40   1.80   2.24   2.80   3.55   4.50   5.60   7.10   9.00
R40                       1.00   1.25   1.60   2.00   2.50   3.15   4.00   5.00   6.30   8.00
1.06   1.32   1.70   2.12   2.65   3.35   4.25   5.30   6.70   8.50
1.12   1.40   1.80   2.24   2.80   3.55   4.50   5.60   7.10   9.00
1.18   1.50   1.90   2.36   3.00   3.75   4.75   6.00   7.50   9.50
R80                       1.00   1.25   1.60   2.00   2.50   3.15   4.00   5.00   6.30   8.00
1.03   1.28   1.65   2.06   2.58   3.25   4.12   5.15   6.50   8.25
1.06   1.32   1.70   2.12   2.65   3.35   4.25   5.30   6.70   8.50
1.09   1.36   1.75   2.18   2.72   3.45   4.37   5.45   6.90   8.75

Now Renard series R80 is not in much use.

Convert Preferred number series to sizes in a number of ways.  Multiply or divide these by some multiple of ten.

For example

(100, 160, 250, 400, 630) for R5 series of  1.0, 1.6, 2.5, 4.0, 6.3 & 10.

Example:  Select preferred numbers between sizes of 28 and 70 mm. These as per R5 series are 40 and 63 mm only.

Example:  Select preferred numbers between sizes of  30 and 380 mm.

These as per R5 series as 40, 63, 100, 160 and 250 mm respectively.

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