Method Sudy can be applied at several different levels, i.e. we may be considering one man, a whole department or even a whole enterprise. In the latter cases, recordings usually show movement of men and materials. This is controlled, to a large extent, by the layout of the working area and, in order to reduce movement of men and materials handling, an improved layout might well be considered. Before discussing the potential Work Study techniques involved, it may be useful to consider some aspects of factory layout in different industries. It is important to note, however, that although frequent reference is made, in these examples to manufacturing industry, the techniques are of equal value when planning the layout of any working area such as offices, stores, canteens, retail shops, hospital wards, garages and farm bulidings.
Layout in Various Industries
Bad layout adds to the cost of a process, by causing unnecessary movement. In many factories, there has been no properly thought out change of layout since they were first commissioned. Items have been added wherever space could be found and located according to the whim of some member of management. Services such as gas, electricity and water and, later, compressed air have been added in a similar haphazard manner. Indeed, if many such services are already installed and if, in addition, machines are well bedded in concrete, this may be an excuse to leave well enough alone. Eventually the department strangles itself, or at least a situation is reached where the majority of the cost of the product is in handling - handling adds cost to a product but NO VALUE.
The importance of attaining the best possible layout is directly proportional to four things:
- The weight, size or mobility of the product - if the product is heavy, delicate or difficult to handle it should be moved as little as possible. Conversely, when the product is small and light and perhaps several day's supply of work can easily be carried out by one person, layout is of less importance.
- The complexity of the product - if the product is made up of a very large number of parts and many people are likely to be engaged in moving them from department to department, good layout becomes important.
- The length of the process time compared to the handling time - if a large proportion of the total time of manufacture is taken up in handling, an improvement in layout could have a marked effect on production throughput (productivity). Conversely, if the process time is long, perhaps as much as several days for one operation, layout is less important.
- The extent to which the process tends towards mass production - in semi or complete mass production, good layout takes on significant importance because high performance machines increase the volume of work, and delays in handling and positioning components soon react on the whole factory.
Logicality of altering layout, once established
The difficulty of meaningfully debating layout change in some industries, e.g. heavy chemical plant and complex textile machinery, underlines the importance of applying Work Study at the planning stage. In lighter industries, this is not so much of a problem and in some firms, machines are moved around as a matter of policy to form different production lines for new products. In all cases, however, management will need convincing that real savings will be made, before sanctioning a layout change.
Types of Factory layout
There are two types; viz. PROCESS & PRODUCT layout - although some enterprises embrace both within the organisation:
PROCESS LAYOUT (GROUP LAYOUT / BATCH PRODUCTION)here all machines of one type are grouped together and the main advantages are as follows:
- The manufacturing sequence is flexible and the minimum investment of machines is involved.
- Machines are usually kept busy and short runs do not incur idleness.
- There is no fixed flow so handling and production control may become complicated.
- Workers tend to become over specialised on one type of machine.
- As there is no 'line', a breakdown on one machine need not hold up other production areas.
PRODUCT LAYOUT (FLOW / LINE / CONTINUOUS SYSTEM)here all machines concerned in making one product are grouped together and the main advantages and disadvantages are:
- There is a fixed flow of work, reducing handling and simplifying production control.
- The total production time and therefore the cost is kept low but capital may be needed to duplicate machines in several lines.
- Manufacturing costs are low while long runs are the rule, but rise so steeply on short runs that to execute very small orders may be impossible.
- Workers can become skilled at operating several machines.
- A single machine breakdown may shut down a whole production line.
Work Study Techniques concerned with Layout
The basic techniques are FLOW DIAGRAM, the STRING DIAGRAM and the TRAVEL CHART. All plot movement of men and/or materials which can later be transfered to a scale drawing of the workplace. When critically analysing the layout, the need often arises for a means of experimenting with different arrangements. One could, of course, make a series of drawings but this is time consuming and does not allow experiments and discussion of alternatives by a group of people. Therefore several techniques have been evolved to enable alternative layouts to be built up. The simplest of these is the use of 'cut out' TEMPLATES in connection with a scale drawing. The templates, of course, must be to the same scale as the drawing and should preferably be cut from strong thin cardboard. Different colours may be used for, say, machines, bins and trolleys. When trying out new ideas, the templates can be secured with pins and when a suitable layout is ready to be discussed, the templates can be fixed to the drawing with transparent tape, thus enabling the whole thing to be transported. Although this technique is adequate for most jobs, more refined techniques have evolved, chiefly the use of two dimensional translucent material and three dimensional models - now principally computer aided - these have advantages and disadvantages compared with the use of simple templates.
Two Dimensional Planning Aids
Use is made of a gridded plastic sheet on to which are fixed transparent templates which are adhesive on one side. Walls, stanchions and gangways etc. are represented by lengths of adhesive tape which can be purchased in many different forms. The main advantage of this technique is the ease by which a copy can be made of a layout, by simply printing it like a drawing. Disadvantages are cost. especially if a very large area is being dealt with in detail, and the fact that when planning an area such as a garage, loading bay or bus station, most of the templates will represent vehicles and they will need to be loose to move about and not fixed down in a permanent position.
Although the most expensive technique, models have many advantages. They give the essential third dimension, they are easily appreciated by anyone without concentration or technical background and they are useful in selling ideas, because most people identify with and like modelling and models. Although simple block wooden models will usually suffice, even these need care and skill in the making. Commercial models are available but these are mainly restricted to engineering machines. Other models can now be commercially made to special order but are likely to be very expensive. Probably the time and money involved in making any sort of models would not be warranted purely for a Work Study application, and would only be sanctioned if the models could also be used for publicity and display purposes.
Installing the New Layout
Once management sanction has been given, plans must be made for the installation of the new or revised layout. This will usually be the responsibility of the Works Manager or Plant Engineer or lattterly a Project Manager - Work Study practitioners are now unlikely to be associated with such an application, although the installation programme might itself be method studied.
There are several points to remember:
- There should be as little disturbance as possible to normal production and this may be a gradual change over during evenings or perhaps a complete change during a holiday period.
- Management must also have a policy, well in advance, to deal with such things as method of payment to operatives who are affected by the change or who may need re-training on new equipment.
- It will also be surprising if everything works out exactly according to plan, and the new scheme should not be condemned if modifications are needed as time goes on.
- For these reasons, there should be ongoing consultation and discussion during the early stages of operating a new or revised layout between management and the workforce representatives.