HIGH VOLUME PRODUCTION ACTIVITY CONTROL

DO WE KNOW THE ANSWER FOR THE FOLLOWING QUESTIONS?

1. What will be the production quantity ?

2. Characteristics of the products to be manufactured

3. The availability of the equipment and what kind of equipment are to be purchased?

4. What kinds of labor are required?

5. What should be the level of automation?

6. Make or buy the components required

If the answer to the above questions are known, then the next step in the process

of conversion of raw materials in to finished products is to decide on how each

component is to be manufactured and the sequence of operations to be performed

on it.

PRODUCTION ENVIRONMENT

1. MAKE TO STOCK

2. ASSEMBLE TO ORDER

3. MAKE TO ORDER

PRODUCTION METHODS/SHOP FLOOR TYPES

Mass Production creates a homogeneous product through a continuous series of standard procedures.

Batch Production produces discrete groups (batches) of products. Each item in the batch is similar.

Job shop Production involves the fabrication of discrete products in accordance with customer specifications.

INTRODUCTION-ELEMENTS OF THE FLOW SHOP

An assembly line is a classic example of flow shop Every cars go through all the stations one by one in the same sequences; Same tasks are performed on each car in each station; Its operations scheduling is simplified as assembly line balancing; An assembly balancing problem is to determine the number of stations and to

allocate tasks to each station.

Flow shop: Each of the n jobs

must be processed through the m machines in the same order.

Each job is processed exactly once on each machine.

INTRODUCTION-JOB SHOPTurnning Center Drilling Center

Milling CenterGrinding Center

A job shop is organized by machines which are grouped according to their functions.

Job Shop: Vol. - low Skilled labor are required Layout - product is moved to various work

centers Production usually does not begin before an

order, materials purchased after an order Production scheduling - intensive

scheduling and routing on the shop floor

9

I. Shop Typea. (Flow Shop : Uni-direction)

b. (Job Shop : Multi-direction)

c. (Open Shop: No direction)

M1 M2 M3 M4

M1M2

M3M4

Batch Production

Volume

Variety

JobShop

BatchProducti

on

FlowShop

The major problem is to attain the desired production rate. To this the problems to be addressed are:1. Sequencing of operations2. Ordering of stations3. Number of stations required

Process planning helps in doing this.

Process planning:

Factors effecting Process planning:

Some definitions:

Workstation: A workstation is a location on assembly line where given amount of work is done

Cycle time : It is the amount of time the product (In - process) spends at each workstation.

Cycle time (CT) = Available Time period / Output units required per period

Task: The smallest grouping of work that can be assigned to a workstation

Predecessor Task: A task that must be performed before performing another task.

Balance delay: Percentage of total idle time on the line to total time spent by the product from the beginning to end of line

Balance Delay

BD = (Total idle time for all workstations)/ (Total available working time on all stations)

= (n.CT - ∑ti ) * 100/ (n.CT)

n = Number of workstations ti = station time of specific workstation ∑ti = Total standard station time

BD indicates the inefficiency of the system, which is induced by the idle time

The problem of line balancing arises due to the following factors:

1. The finished product is the result of many sequential operations

2. There is a difference in production capacities of different machines (The /p from different machines is not identical)

Line Balancing: It is the apportionment of sequential work activities in to workstations in order to gain a high utilization of labor and equipment so as to minimize the idle time.

Heuristic methods of line balancing:

• This method tries to reach an acceptable solution rather than an optimal solution .

• Used where optimal solutions are not feasible or are too costly

Procedure:1. Draw the precedence diagram• Numbers are assigned to each operation to denote how many

predessors it has• Operations showing the lowest predecessor number are taken first

on the workstation2. Select feasible cycle time3. Assign work elements to work stations• sum of elemental times should not exceed cycle time• If it does identify the WE due to which this happens and carry it

forward to next station

1. Make a precedence diagram for the following problem and calculate Balance delay, if the Cycle time is 8 min.

Work elements

precedence process

Time

1 0 42 1 23 2 34 1 25 2 56 5 4