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CLOSE THIS BOOKForming Techniques for the Self-Reliant Potter (GTZ, 1991, 194 p.)
10. Work flow and factory layout
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VIEW THE DOCUMENT10.1. Work flow example

Forming Techniques for the Self-Reliant Potter (GTZ, 1991, 194 p.)

10. Work flow and factory layout

Work flow is simply all the steps that are necessary from beginning to end of any production process. For anybody engaged in production, it is very useful to take the time to list all the steps, and to find out where time and energy are being wasted.

The various steps in a production work flow can all be broken down into the following, and shown in a graphic way with symbols:

Analyzing your work flow is very helpful for increasing production efficiency. When you understand all the steps, you can often make work easier and increase profitability by:

STEP

SYMBOL

EXPLANATION

Raw materials’ storage

V


Operation

O

action which changes the form of a material, like cutting, pressing, throwing, etc.

Transport

D

moving material from one location to another

Delay

>

necessary step which takes significant time, like drying

Operation/delay

#

operation that takes significant time, like firing

Inspection

*

quality control check

Finished goods’ storage

^


- ORGANIZING THE WORKPLACE

The location where forming or finishing work is done should be furnished with a good source of light and enough space around the workplace to allow easy movement. Remove all unnecessary equipment and rubbish which will hamper work. Only equipment that is needed should be kept at the workplace. Frequently-used tools could be hung on the wall. Keen racks for storing products nearby.

- TRANSPORTING EQUIPMENT

Ceramic products go through many operations so they are moved around a lot. Carrying one pot at a time is a waste of time. Most pottery can be carried on ware boards about 120 cm long and 10 - 20 cm wide. A ware board can carry 20 cups at a time and they can be stored on stationary racks or on trolley racks.

Raw materials and heavy products like bricks and pipes can be moved on carts.

- MAKING TRANSPORTATION DISTANCES AS SHORT AS POSSIBLE

If you can rearrange your workshop so that clay only has to be carried 10 meters instead of 50 meters, this saves a lot of wasted effort. Another example is a pipe factory, where pipe has to be carried over rough ground and around heaps of coal, etc., to get to the kiln. This creates a lot of extra work, and disturbs the workers, as well as possibly being the cause of injuries. It would make good economic sense to take a day to construct a clear pathway, as the work would go much better afterwards.

- REDUCING DELAYS AS MUCH AS POSSIBLE

Often there is not much that can be done about delays. For example, it may not be possible to shorten firing time. Another frequent delay is drying - in this case, it is worth getting some help to compare the cost of artificial drying with air drying.

Even though the initial investment may be high, sometimes the time saved makes it financially advisable. This may be especially true for jigger production, where a forced air dryer can cut down on the number of moulds required and increase daily production capacity at the same time.

However, we do not recommend investing in expensive equipment unless the benefits have been carefully analyzed beforehand. Factory owners often buy the latest equipment just because it is new, and regret it later when it does not meet expectations.

production capacity

Once you have analyzed your production flow and made a good plan for reducing time wasted on internal transport, etc., you will also find that some sections in your production are bottlenecks. That means they delay the flow of products causing other sections to be idle while they wait for materials or semifinished products. There are various possibilities for curing bottlenecks or increasing production capacity in general:

- reorganize work procedures and workplace
- increase number of workers
- introduce incentive pay scheme
- work in two or three shifts
- increase capacity of machinery.

Several options may be used at the same time. Before you start to change anything try to make two or three different plans and then compare the cost of them.

consultants

There are actually industrial consultants who make very detailed work flows, to the point of finding out how many seconds each step takes, and then try to find ways to shorten the time. This is useful up to a point, but most small producers either operate a family business, or have quite a small number of workers, who are not likely to cooperate if they are asked to take 5 seconds for an operation that normally takes them 6 seconds. People are not machines, after all, even though management would often like to see them that way.

Work flow is the starting point for planning factory layout. This is true for planning new factories, as well as remodeling old ones (which often have expanded gradually and have become inefficient in the process).

10.1. Work flow example

The following work flow analysis of a jigger cup production in Burma is an example of how production can be reorganized with simple means.

original situation

Before the reorganization of the production, jigger moulds were placed on racks behind the jigger machines and two assistants for each jigger machine would run between the rack and the jigger machine with 2 to 3 moulds at a time. After being taken out of the moulds, the jiggered cups were carried by hand in stacks 15 to 20 cups high to fettling machines. This system was very laborintensive and the stacking caused many cracks.


FIGURE 10.1-A Work flow plan of the jiggering production analyzed below.

reorganization

A system for internal transport of products was established. Ware boards for carrying cups and moulds were introduced together with stationary racks and trolleys to hold the boards. One board could carry 6 cup moulds. A trolley could hold 36 boards or a total of 216 cup moulds. In the work flow analysis 216 cups are used as the batch unit.

A drying chamber was constructed so that it could accommodate four trolleys with ware and moulds. The jigger machines were relocated and placed so that they were close to both drying chamber and the fettling machines. The layout is shown in the process flow plan in Fig. 10.1-A, which corresponds with the work flow chart in Fig. 10.1-B.

The jigger operator (B) would always have one trolley next to her and she would pick one mould at a time directly from the board on the trolley. When the moulds on one side were filled with jiggered cups she would just turn the whole trolley and start with fresh moulds. An assistant (C) would replace the boards with filled moulds with fresh ones from the rack next to the jigger machines. During the rainy season the assistant would take the whole trolley to the drying chamber and replace it with another. With this system one assistant could service two jigger machines.

Another worker (A) would supply clay to all jigger machines and would also transfer dried cups to the fettling machines. The stationary racks were placed between the jigger section and the fettling section so that jiggered products placed in the rack from one side could be taken out by the fettling operators on the other side.

The work flow chart below shows the minutes it takes for each operator to finish one batch, equal to 216 cups. The production capacity is planned according to the daily output of the four jigger machines. If another step in the production flow cannot finish this quantity per day it becomes a bottleneck. A work flow chart shows such bottlenecks and indicates how to solve them.

The longest time it takes on average for one group of operators to finish one batch is 20 minutes. That means that during a workday of 7 hours, 21 batches or 4536 cups can be produced. If the fettling unit could produce more by having an extra machine or working overtime, average batch time could be 16 minutes. This would increase production to 5040 cups per day. This could be achieved by having the fettling unit work 45 minutes extra per day.

The flow chart also shows that operator A only spends 11 minutes per batch. He could therefore be given an additional task like looking after the drying chamber.


ACTIVITIES


OPERATORS

MINUTES



A

B

C

D


1 clay storage

V






2 clay to jigger machines


D




1

3 jiggering cups



O



64

4 replacing filled moulds




D


15

5 emptying moulds of cups




O


15

6 cups to dryer




D


2

7 cups drying

>





240

8 dryer to fettling rack


D




10

9 rack to fettling machine





D

3

10 fettling cups





O

74

11 cups to decoration rack





D

3

Minutes per type of operator:


11

64

32

80


Number of respective operators:


1

4

2

4


Average batch time per operator


11

16

16

20


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