|Low-Cost Ways of Improving Working Conditions: 100 Examples from Asia (ILO, 1989, 190 p.)|
|CHAPTER I: WORK ORGANISATION AND WORKSTATION DESIGN|
The first group of examples deals with arrangements at individual workstations. These arrangements are important as efficiency at work is greatly affected by how a workplace is designed. This is particularly true when similar operations are repeated at a workstation. If work can be done effectively and easily, productivity will be higher and quality will be better.
A workstation is a place which a worker occupies when performing a job. It may be occupied all the time or only occasionally. A workstation often contains a work stand or work table for machine operation, assembly or inspection.
At workstations, people repeat similar operations many times. It is therefore important to keep good people-work relationships so that Work is done smoothly and without unnecessary disruptions. It often happens, however, that materials and controls are placed inconveniently far away, that the work table wobbles, that the worker's body is twisted each time an operation is done, or that the worker is easily confused when reading a meter or moving a control. Each of these inappropriate situations can easily lead to wasted production time, increased fatigue and a fall in product quality. The worker may suffer from troubles due to work, such as low back pain. Even an accident may result.
Workstations should be adjusted to the capacity and needs of individual workers. For example, the work table height should correspond to body height. If the top of a table is too high and cannot be lowered, a foot platform should be provided. It is also important to make sure that the strength and skills required by the job are appropriate to individual workers who do the work. This is the reason why modifications are often needed when machines are imported or workstations designed without much attention to the special abilities and needs of local people.
Improvements in workstation design can be discovered by examining the worker's motions and the layout of visual information. Many of these improvements are applicable at low cost. For example, the worker's time can be saved by putting materials, tools and controls within easy reach. The worker's hands can be used more effectively by using jigs or other fixtures. Likewise, work motions can be made easier and postures less tiring by changing the height of work tables or by using foot platforms. Mistakes will be less frequent if different shapes or colours are allocated to different categories of switches or signals. All these measures can contribute to improving productivity and reducing strain and accidents.
Case 1: A work stand for easier handling of a heavy product
In a workshop of a transport agency in India where there were about 300 workers, four were engaged in the cleaning, rasping and trimming of tyres. Each tyre, placed on a work stand made of wood, had to be lifted and turned so that cleaning and other operations could be made on its different parts. It had to be supported on the knees while being turned. This meant awkward posture, bending of the upper body to pick up tools, and strain on the back.
To make turning the tyre easier, two round pipes were fixed at the appropriate height replacing the old square-shaped wooden tyre-holder. The original and new work stands are shown in Figure 1. Because of the round structure of the new tyre-holder, turning the tyre became easy. The two pipes held up the tyre, eliminating the need for knee support. Since the Cools were kept at working height, there was no need to bend for them.
Figure 1: Original (left) and new (right) work stands for cleaning, rasping and trimming of tyres.
This new stand was fabricated from scrap materials. Welding was done in the workshop. Hence, costs incurred were marginal except for work hours for fabricating, which cost less than US$ 10. The manager of the workshop noted not only a reduction in the workers' fatigue but also a considerable increase in productivity. The output per work stand almost doubled. This was apparently due to the easiness of tyre turning that could be done at the new stand with only one hand and without requiring knee support.
In this example, the advantage of the improvement was clear and remarkable. The cost was minimal. A careful look at the way work was done showed how to raise productivity and reduce strain and fatigue.
Case 2: Work stand for garment work
Many manufacturing processes require manual operations. Though such operations are quite simple, it is often difficult or costly to mechanise them. As they consist of brief operations repeated many times, they easily result in boredom and discomfort. In a trouser production unit of a garment manufacturing factory in Thailand, a few jobs consisted of turning the trousers produced inside out. The workers complained of skin irritation and discomfort from inserting their hands into the trousers and pulling them inside out (Figure 2).
The production manager consulted with others on ways to eliminate the skin irritation. They drew up a plan to construct an iron stand with two parallel pipe arms. Two standard water pipes were welded on the top of the stand. The stand height was 120 cm. A small wheel was placed at the tip of each arm. The wheel served as a turning point. A pair of trousers was placed on the two pipe arms, the bottom ends fixed at the wheels, and was easily turned inside out (Figures 3 and 4).
Figure 2: The original method of turning the trousers inside out.
Figure 3: Two pipe-arms with wheels at the end for inserting and fixing a pair of trousers.
Figure 4: Placing a pair of trousers on proper arms. They will be turned inside out when taken off.
The approximate cost of making the stand, including materials and labour costs, was US$ 20. The problem of skin irritation disappeared, with a reduction in medical expenses for its treatment. A slight increase was seen in production.
The wheels on the tips of this iron stand serve as fixtures for holding the trousers while they are turned inside out. This is a good example of how small mechanical aids can help eliminate unnecessary human arm motions. These aids can enhance productivity, thereby reducing strain and discomfort.
Case 3: A core-making workstation in a foundry
In a steel foundry in India which employed 60 workers, about 20 were engaged in making a variety of cores. These core makers, squatting on the floor, took core sand from a heap over one metre away. Then they made each core on a plate with the aid of a trowel, a venting rod and a rammer. Split-type wooden core boxes were used to form the cores. The work arrangement is shown in Figure 5. All the operations were performed on the floor, the squatting worker reaching for sand, searching for tools and scattering sand and cores around. The workplace was over-crowded and untidy, necessitating frequent rearranging and cleaning.
Figure 5: Original work arrangement for core making with the worker in a squatting position.
Seated workstations were introduced for better housekeeping and efficiency. For each worker, a bin made of metal and wood was made and placed on a workbench. The bin had an opening for scooping out the sand, with the bin bottom sloping towards the worker. A number of clips and brackets were added on the outer side of the bin for positioning the tools required for core making. The worker could sit on a stool. Additional, special places were provided for keeping water, nails and other materials and for empty boxes and finished cores. The new arrangement is shown in Figure 6.
Figure 6: A new workstation for core making. The worker is now seated.
The bins were made out of available drums. Cutting the drums and welding was done in the workshop. Each bin with a table and a stool cost about US$ 40. The number of cores made during a shift increased by nearly 30 per cent. The workers welcomed the new work arrangements which helped to reduce fatigue and keep the workshop clean.
This example illustrates appropriate work height, use of bins for easy reach, designation of places for tools and materials, and the use of gravity for making materials readily available. Accompanying benefits were the saving of space and improved housekeeping.
Case 4: Simplifying lathe operations
In the machine shop of an engineering factory in Burma, lathe operators who tapered the ends of square rods complained of injury risks and physical strain. The management was also dissatisfied with the low output from the lathes. A survey made by the production management staff and safety committee members established that clamping and releasing a square rod on a four-jaw independent chuck was complicated and strenuous. A few accidental injuries had occurred when the operators failed to take the chuck key off before switching on the machine.
The lathe design was modified so as to eliminate the work of clamping and detaching the workpiece in the chuck and to reduce the required work steps. A tool head with six radially-mounted single-point cutting tools was fixed to the lathe head stock spindle. A quick-release workpiece holding a feeding device was then mounted on the saddle. The device had a base frame with a square hole guide, a swivelling nut which fitted to the centre hole on the top surface of the base frame, and a feed screw with a handle at one end. The feed screw was used for feeding the workpiece into the revolving cutting tool head and releasing it. As the feed screw advanced, the taper was cut and stopped by a pre-set travel limit. Then the feed screw was unscrewed and again another cycle of operation ensued. To reduce the risk of accidental injury from the revolving tool holder, it was encased with a metal enclosure that had a square hole coinciding with the hole in the guide block.
Figure 7: Holding a workpiece on the chuck.
All these attachments were produced in the factory itself. The materials were from ready stock in the factory. A rough estimate of the cost by the engineers was US$ 400, including the cost of materials. The work process was simplified and far less effort was needed for machining. The rate of finished products increased from the previous level of 200 pieces per eight-hour shift to nearly 1,000 pieces. The accident risk was greatly reduced. Both the management and operators were satisfied with the new work method.
Figure 8: Tapering the rod on the machine.
Figure 9: A modified tool holder and new workpiece holding device with a square hole guide, a swivelling nut and a feed screw.
Figure 10: Modified tapering using the new method.
Figure 11: Metal enclosure for the revolving tool.
Case 5: Better placement of components and instruction sheets
In a factory producing radio sets in Indonesia, it was felt that the components to be installed on particle circuit boards and the instructions for the work were too far from the workers. Component boxes were placed on a table about 60-70 cm from each worker and the instruction sheets at a distance of 110 cm. The workers complained that often the instructions were not easy to read.
The placement of the components and instructions was improved and the environment of the workshop cleaned up. First, two-ties shelves were made from thick boards, which were readily available. These shelves were placed in front of each worker. Component containers were put on these shelves within easy reach of the worker. The distance the worker had to reach to the components was reduced to 40 cm. Second, new instruction boards were made. They were slightly smaller in size than the old ones. More space was made between the lines on the boards (0.75 cm instead of 0.5 cm). Each instruction board was placed much nearer to the worker, at a distance of 50 cm.
Figure 12: Original arrangements for instructions and circuit board components.
Figure 13: New placement of instructions and two-tier shelves for components.
As a result, the workers could reach components and read the instructions much more easily than before. Space occupied by the component boxes was reduced and inventory of components was made easier. Errors in the instalment on the circuit board were reduced. Cleanliness at the workshop also improved with the new arrangement.
The cost per worker was about US$ 2.50 for shelves and about US $0.50 for the new instruction boards (plastic, plywood and paper). The cost was small as all the necessary work was done by the workers themselves.
Case 6: Locking device for power loom levers
In a textile mill in Malaysia, a worker-management safety committee was formed to look into workers' safety, health and welfare. The committee found that many accidents occurred during cleaning or maintenance work when the power looms were started by other workers.
The maintenance crew fitted a hinged U-shaped safety catch to the starting lever of these power looms. Whenever a loom was repaired or cleaned, the lever was pushed towards the stop position and locked by the safety catch. This prevented anyone from pushing the lever and activating the loom inadvertently. This is shown in Figures 14 and 15.
Figure 14: U-shaped hinged safety catch locking the power lever of a power loom.
The committee then drew up a training programme for the workers. The programme included instruction on starting and stopping the power looms and related safety procedures. The committee also decided to organise safety seminars on a regular basis, i.e. every six months.
The fitting of safety catches to the starting levers of the power looms cost only US$ 5 per lever. The frequency rate of accidents was reduced by about 70 per cent. This level was maintained thereafter. In 1984, the factory achieved 255 accident-free days. This result was apparently due to the higher safety consciousness among workers. The provision of the locking device, which itself increased workplace safety, thus helped instil safety consciousness among the workers.
Figure 15: Diagram of the hinged safety catch.
Case 7: Fixtures for spindle moulding machine operators
In a spindle moulding section of a furniture factory in Burma, the moulding machine operation required particular concentration due to high injury risks. Various forms of spindle moulding were being done on short wood workpieces. The management, together with the safety committee, studied the operation and conventional safety measures. They found that a conventional guard was not suitable and sometimes caused injuries to fingers.
Figure 16: An operator holding the workpiece for moulding dangerously without any fixtures.
It was decided to design fixtures of different types so that an appropriate one could be selected for each different kind of form. The operators were then given some time for adaptation to these workpiece holding devices. It was then made compulsory for all workers to make appropriate use of the fixtures.
In addition, barriers were fixed to keep the point of operation as little exposed as the work would permit. The use of these barriers proved useful to further reduce exposure to risks of injury.
Figure 17: The operator using a fixture. The barrier is not shown for clarity.
Each fixture cost about US$ 20-30. These holding devices proved suitable for the type of work done on the spindle moulders. During a one-year period after the use of fixtures and barriers was started, no more accidents occurred in this section.
Figure 18: A vertical barrier which minimises the cutter exposure.
Case 8: Use of a pneumatic device
Workers in a shock absorber section of a car factory in Indonesia were complaining of muscular pains in the chest. This was due to the forceful efforts needed to pull shock absorbers to a standardised length before their installation. The required force was equal to around ten kilograms, lasting about 12 seconds. In addition, pulling the absorbers did not result in uniform length. Readjustment was usually necessary when the shock absorbers were installed.
The workers tried to find better ways of pulling out the shock absorbers. Of the three suggestions made, they selected the use of pneumatic pressure from an air cylinder. This seemed inexpensive as they could utilise an air cylinder and a solenoid valve available from broken spot welders. Using these and other materials, mostly scraps, a mechanical puller was made which could pull seven shock absorbers simultaneously.
Figure 19: Manually pulling out a shock absorber.
Figure 20: Seven shock absorbers being pulled to standard length by a piston air-cylinder.
There were several advantages of this new device. There were no more complaints about chest pains. The pulled length was uniform. It took 42 seconds for the device to pull seven units together, but this meant six seconds per unit, half the duration of that needed in the case of manual pulling. The cost incurred was practically nil except for the extra work by the workers themselves to construct the device.
Other inexpensive improvements using pneumatic systems were also reported. In the car plant in Indonesia, a pneumatic device was used to compress a glass plate to its holder. Before the device was designed, workers had been compressing the glass door manually with a wooden lever. The new device was made by utilising unused materials. In addition, shelves for the glass and other components were moved nearer to the worker. A place was made under the compression device for keeping rubber materials and glass holders. While the cost was also practically nil in this case, the benefits were multiple: the worker's movements were shorter, production time was reduced by about 25 per cent and the right shoulder stiffness of the workers disappeared.
Another example comes from a detergent factory in Thailand. In packaging detergent products manually, workers had to twist the upper part of the body and lift heavy boxes afterwards to place them on a conveyor line. The workers complained of low back pains. These pains seemed to affect work efficiency. A simple pneumatic device using an air cylinder was attached to lift each packed box up to the level of the conveyor line. The operations then could be carried out without strain.
The direct cost amounted to approximately US$ 400, including expenses for pneumatic cylinders, the conveyor belt and packaging platform. The labour cost was not included as the construction was done by the maintenance department during working hours. The investment was considered worthwhile as the packaging operations became much smoother.
Case 9: Multi-level chairs for furniture production
In the sanding section of a furniture manufacturing factory in the Philippines which employed 25 workers, the manager found that workers were complaining of back strain. It appeared that the complaints were related to various postures taken while sanding different parts of the furniture products. Rather bulky chairs were provided in this section, but the workers quite often did not use them. The chairs were too bulky to move around, and were not suitable to work at varying heights.
With the help of the workers, the manager was able to design a small multiple-level chair. The top and one side of the chair had a padded seat. The top was used as a seat when the level of the work was high and the side was used when it was low.
The chair was made of pine. It was light enough to be easily carried. It could be used flexibly depending on the height of the furniture parts being sanded. Five such chairs were made.
Figure 21: A worker sanding wood products using a multi-level seat.
The direct cost was minimal since the raw materials used were scrap pieces of wood and materials from the factory. With the workers' time in building the chairs taken into account, each chair cost approximately US$ 2. The total cost for making the five chairs was only US$ 10. Advantages from the use of these chairs included an increase in production and a reduction in complaints about backache.
The problem of providing suitable work chairs is often neglected, although chairs are used in many different kinds of work. Modern, comfortable office chairs are rarely used in workshops either because they do not meet the different needs of such workers or because they are too bulky. Appropriate chairs in workshops should allow flexible use, as illustrated by the present example.
Figure 22: The original chairs used in an electronics factory and a new adjustable chair.
An additional problem in improving chairs is the relatively high cost of good chairs available on the market. In the case of microscope work among female workers in an electronics factory in Pakistan, provision of better adjustable chairs required an outlay of about US$ 30 per chair. New chairs with adjustable backrests for 60 workers were purchased. In view of the resulting high quality of work, the management considered the cost a necessary and useful investment. Backache and elbow pains had been a common problem reported by the workers. An increase in work efficiency of over 10 per cent was seen after the purchase of the new chairs.
As this last example shows, good chairs are especially necessary in the case of work done in a constrained posture. Availability of good work chairs at reasonable prices seems necessary. It should be noted, however, that there are many ways to improve existing chairs using available materials.
Case 10: Cottage-industry workstations
In a village in Bali, Indonesia, there were about 70 households which were engaged in the production of household goods such as cutlery products which required blacksmith work. Previously, this work was done squatting or sitting on the floor (Figure 23). This was found to be inefficient and tiring. The villagers, in consultation with health experts, designed a new workstation for blacksmith work. Similar workstations were built in most households, mainly using concrete. Each workstation had in the middle a flat work surface about 80 cm high. A fireplace to heat iron was annexed to the work surface. The surface was broad enough for doing the main blacksmith work. Tools also could be placed on the surface. When necessary, work could be done together by a few people surrounding it. An example is shown in Figure 24.
Figure 23: Original methods for blacksmith work.
Figure 24: An improved blacksmith workstation with a broad work surface allowing work in standing positions.
The cost for constructing a new workstation ranged between US$ 40-100. The differences in the cost were due to the materials used. The re-construction plan was welcomed by these households. In almost all of them, all family members except children were doing blacksmith work. The workplaces were inside the house premises, but separated from the living quarters. This also made it easier to re-construct the workplaces. There were still some old-style workplaces left. But according to interview results, the villagers preferred to work at new workstations. The reasons given were increased efficiency, especially in the case of group work, and reduced fatigue.
Similar improvements were made in the ceramic cottage industry in a village in Bali. In this village, about 80 households were producing ceramic products. Potters were working at wheels sitting on a low makeshift seat. The wheel was rotated by using the feet to move a bamboo stick connected to the wheel shaft by a strap. A wooden worktable with a normal seat height was made using the same wheel rotation mechanism (Figure 26). The table surface was made low enough to allow the pot shaping work around elbow height. Space for the knees and feet was also considered. Each worktable cost about US$ 40. As the worktable could be easily carried, the villagers preferred to use it in some shady, open place.
Figure 25: Original workplace for a village potter.
Figure 26: A wooden worktable for a potter which keeps the traditional foot-operated wheel rotation mechanism.