Mass production

 

2.6 Time limit diagram of the production line

With help of this graphic it’s possible to determine the level of load of unloaded working places and their working time during the period of servicing, determine the back logs and  plot the graph of their move.

The choose of the period of servicing of the production line (To) have a great importance for establishing of the working regime. ). Its increase causes an increase in backlogs at the same time increases the possibility to load machines with other work.

In this project time limit diagram will be plot for period of servicing To = 2 hours.

 

 

 

Figure 2.3 – Time limit diagram

№ of opera tion	tшт, min	n, unit	n *Т0*ηз hours	Period of service production line T0, hours		Personnel workers number
				1 hour	2 hour
1	7,13	2	3,6
2	2,26	1	1,14
3а	10,81	3	5,46
4	5,77	2	2,91
5	3,88	1	1,96
6	2,89	1	1,46
7	2,06	1	1,04
8	5,85	2	2,95
9	9,52	3	4,8
10	4,84	2	2,44

 

2.7 Calculation of the backlog on the production line 
To ensure continuity of production line along with other operations it’s needed to create a number of backlog. Internally linear backlogs in the production lines are: technological, transportation, insurance and working interoperating.

 

2.7.1 The technological backlog

Technological backlog ( ) - the total number of tools which are just now in the processing of treatment on the all operations of production line: 

 , (2.8) 

Where:

m - number of operations on the line; 
pi - the number of jobs in each transaction; 
S - number of workpieces at the same time every workplace, S = 1. 
З_техн= (2 +1 +3 +2 +1 +1 +1 +2 +3 +2) * 1 = 18 units 

2.7.2 Transport backlog 
Transport backlog (З_тр) is created with tools which are between the working place of production line:

    , (2.9) 
Where:

p - the size of the transport of the unit details. 
When the piece transfer details from surgery operation value p = 1. 
З_{тр а} = (18-1) * 1 = 17 units 

2.7.3 Insurance backlog 
Insurance backlog (З_стр) is created before the most labor-intensive operation. It’s size is determined as 4-5% of the shift task. Before each operation there are 15-20 minutes of insurance backlog to supply independent beginning of the work.

Where:

З_стр  - insurance backlog on i-th operation, pieces; 
pi - the number of machines at this operation, pieces; 
tшт – labor intensity of operations, min.

Зстр(1) =( 20 / 7,13)* 2  ≈6 units 

Зстр(2) =( 20 / 2,26) * 1 ≈ 9 units.;

Зстр(3) = (20 / 10,81) * 3 ≈ 6 units

Зстр(4) = (20 / 5,77) * 2 ≈ 7 units.;

Зстр(5) = (20 / 3,88) * 1 ≈ 5 units.;

Зстр(6) = (20 / 2,89) * 1 ≈ 7 units.;

Зстр(7) = (20 / 2,06) * 1 ≈ 10 units.;

Зстр(8) = (20 / 5,85) * 2 ≈ 7 units.;

Зстр(9) =(20 / 9,52)* 3 ≈ 6  units.;

Зстр(10) = (20 / 4,84) * 2 ≈ 8 units.

 

2.7.4 Working interoperating backlog

 

Working interoperating backlog ( ) is created among cooperating operations because of their different labor intensiveness (efficiency). It’s necessary period of maintenance T is divided into particular limits of time (tm). When there is invariable number of working machines on 2 cooperating operations. Maximal size of the working interoperating backlog is defined according to the formula:

 

, (2.11)

Where:

ni, ni+1 – number of machines working on the same time on the former and next operations during particular time (tm).

 

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Conclusion

So in this course project the production line that produces vertical sleeve hole with gloss on one side have been designed. During designing we’ve calculated technical and economic parameters of the production line, built graphics that present the synchronization of operations and load of equipment, also the time limit graph have been made.

The production line, we’ve got include 10 operations, use 18 machines and refer to the unsynchronized production lines.