Apparel manufacturing is a labour-intensive assembly line process requiring significant amounts of repetitive and skilled manipulations. Therefore, like any other manufacturing industry, it has its own share of ergonomic problems where poorly designed and unorganized workstations contribute to musculoskeletal discomfort among the sewing operators. Research has found that ergonomic interventions including redesign and proper adjustment of workstations, use of ergonomically-designed seating and training in low-risk methods and posture substantially improve workers’ efficiency.
The analysis of a workplace is crucial to establish a safe and effective system for an operator to work in. ‘Ergonomics’ in a workplace is usually controlled by two broad factors: Human factor or ‘cognitive’ ergonomics influenced by decision making process, organization design, human perception relative to design; and ‘industrial’ or ‘physical’ ergonomics which involves physical aspects of the workplace and human abilities such as force required to lift, vibrations and reaches.
To find a solution, first the problem has to be identified. Some of the common problems faced by a worker include:
This can make tasks more physically demanding by increasing the exertion required from smaller muscle groups, and preventing the stronger, larger muscle groups from working at maximum efficiencies. Handling or assembling very small parts and materials or performing extremely precise tasks may contribute to eye strain and awkward postures.
Force is the amount of muscular effort expended to perform work. Exerting large amounts of force can result in fatigue and physical damage to the body. Pressure points result from the body pressing against hard or sharp surfaces.
Tools that are not properly maintained or are inappropriate for the task may increase the amount of hand-arm vibration and result in fatigue, pain, numbness, and tingling, increased sensitivity to cold and decreased sensitivity to touch in the fingers, hands, and arms.
Repetitive work involves duplication of certain motions over and over again resulting in awkward postures and forceful exertions of the same muscles, tendons or joints. This subsequently increases the risk of injury and results in wastage of time leading to delays in production.
Therefore, one must analyse the work environment thoroughly and understand each worker’s need to apply ergonomic solutions making the work atmosphere congenial.
Loading the spreading machine
The activity of loading the spreading machine involves lifting a roll of fabric from the floor into a spreader, or on to a spreading table if the fabric is to be spread by hand. These fabric rolls are rarely in the proper location and lifting them often results in back injury. Usually a heavy metal spreader bar is required to lift these rolls as the operator is unable to move them by his bare hands. However, the metal bar itself can be very heavy and so the operator may find it difficult to manoeuvre the same.
The risk of loading by hand can be reduced by implementing simple measures like limiting the weight of the roll, making two people lift the roll and using the turn-table on the spreader for lifting one end of the roll at a time. One can also use hand-made roll stands for lifting to a tall spreader. Loading with a fixed sewing loader accompanying the spreader has a lower risk of injury than using bare hands.
Place the rolls on a sloped skid so that they are in the proper position for loading. Also ensure that they are at the waist height of the operator to improve posture when placing the metal spreader bar through the roll.
Spreading the fabric
In manual spreading, ‘long’ reaches are required to cut across the width of the fabric each time a layer is completed or flaws are removed from the fabric.
With the automatic spreading machine, operators either ride on a platform or walk beside the automatic spreader as it moves along the table. The table is often very low in height and operators have to lean forward while smoothing the fabric. This is a risky posture, especially when maintained for extended periods of time.
By using two people, one on each side of the table, who cut towards each other. This reduces the problem of reaching over to a large extent and controls poor postures when cutting across the width of the fabric. Fabric catchers can be used to eliminate the need for the operator to pick up and manipulate weights in order to hold the fabric in place. Table and platform heights should be at an appropriate level for the operator handling the automated spreading machine.
Effective workplace ergonomics programes eventually not only help to reduce the risk of workplace injuries and their severity, but also control physical and mental stress, besides worker’s fatigue.
Cutting the fabric
Excessive reaching or stretching caused by improper workstation height, inability to get close to the blade and poor waste disposal are some of the problems. Guarding is also an issue with the band saw technique. Sometimes it is also difficult to align the cloth being fed into the automatic cutter and requires awkward postures to do the needful.
The table should be at an appropriate height and the operator should be able to reach the blade without fully extending his/her arms and leaning forward. For the in-feed table in automatic cutters, probable solutions include usage of air tables, tables with width as per requirement and using two people to align the cloth. A good out-feed table has narrow sides to allow the operator to get close to the cut fabric when necessary to work from the sides of the table. However, working from the end of the table is usually preferred.
The controls should be placed in an accessible location to encourage the operator to advance the fabric toward the end of the table rather than to reach out for it. The out-feed table should also be adjustable in height to meet the requirements of each operator. Waste bins should be placed at the end of the table, running the entire width of the table and providing space for feet underneath. Install tracks flush with the floor to eliminate the tripping hazard. For low-ply cutters, folding the fabric in half before cutting creates pieces that are mirror images of each other. This folding procedure reduces the reach necessary to remove cut pieces from the table.
Stacking cut pieces
Once the fabric has been cut, it has to be removed from the table and delivered to the assembly department. Typically, a worker removes the piles by hand and stacks them on rolling carts. However, piling cut fabric on skids, into large boxes or carts/trollies near the floor requires a stooped posture.
The best carts for this job have one shelf which is at the same height as the cutting table. The cut pieces can be slid off the table directly onto the cart with very little lifting by the operator. Carts with multiple shelves located close together are also good. This minimizes the operator’s range of lifting.
Pick-up and loading of parts from back and lower height involves frequent bending and twisting of upper body.
Fusing operations bind two fabrics together to make them stronger.
A good fusing workstation includes a worktable that is directly in-line with the fuser so that the cut components moved from one end to the other. This should both be at a good working height for the operator. A fusing workstation with an automatic catcher and stacker at the out-feed area allows the fabric to cool before it is touched and it presents the fabric at a good height for pick-up.
Assembly tasks have many different components that must be considered in an ergonomic assessment including supply and removal of garments, sewing table, chair, floor surface, foot pedals, lighting, hand tools and work organization.
Supply and removal of garments
Different supply methods are used to hold various pieces of the unfinished garment at the workstation prior to the operator assembling them. Then there is the issue of removal and deposit of the garment once the operator has completed the job. The operator has to reach to both the supply and removal locations at least once in the work cycle.
Place small boxes on a platform to supply the operator with the necessary pieces at a good height and within easy reach. Pickup and disposal tables should match the height of the sewing table, or be slightly lower if bundles are placed on them. They should be stable and sufficiently large or should have raised edges to hold the garments. Use friction tape if the fabric or table is too slippery.
The requirements for a sewing table to be considered are height, size, shape, tilt and legroom. Lack of task lighting (local lighting) is often an important deficiency noticed in the sewing machine. The workers complain of headache and occasional accidents like needle-piercing because of the visual strain caused by insufficient light at the point of operation. The hazard identification and risk analysis indicated insufficient illumination as a risk for the sewing machine operators.
A good height for sewing tables is at or slightly above the elbow height. The height should be easily adjustable with the press of a button. Sewing tables can also be modified to meet the requirements of specific garments, machines or operators by making the table smaller to allow carts to get closer to the sewing machine. Putting an extension on the table to increase its size can help to support the weight of larger garments or even act as an input location for the sewing table. Raising the edges of the table prevents the material or components from falling down. A sewing table tilted at 10° to 25° towards the operator, improves visibility of the task and helps to keep the neck in a more upright position. Appropriate height of the table also gives the operator sufficient legroom.
The chair is a critical piece of equipment for sewing machine operators who work in a seated position. It can have a very large impact on the comfort of the worker and can affect the risk of muscle pain and injury.
Adjustable chairs reduce shoulder and neck pain of the operators. A custom-designed chair is adjustable in height, has no wheels to ensure that the operator stays firmly seated in place, has no arm support to interfere with the movements and has a seat pan that slants slightly downward to support forward-leaning postures. The chair is also upholstered with a breathable cloth and foam appropriate for the high-temperature environment of the garment shopfloor.
For seating and standing work, the workstation height should be such that it allows workers to function with elbows placed at 90 degrees. This will reduce stress on the body. If the workstation is too low, the worker is forced to bend at the waist to reach the work being done. This puts stress on the lower back. If the station is too high, the worker is forced to lift his shoulders or move elbows away from the body to reach the work. This puts increased stress on the shoulders which may lead to injury. During seated work, if a good back support is not present or used, the body is subjected to static postures, which results in constant use of the back muscles. Therefore, it is important to adjust the workstation in order to allow the worker to use the backrest. It is also important to adjust the worker’s chair for him to work in a comfortable body position.
Most sewing machine operators use one treadle, which controls the direction and speed of the sewing machine. Some operators use additional smaller pedals that lift the presser foot or cut the thread.
One can increase the size of the treadles by placing a thin wooden board over the surface of the pedal, thus positioning it at the most comfortable position and angle for the operator. This way, if there is a requirement of a pedal, it will be at the same angle and position as the treadle, thus making it easily accessible by one of the feet. If only one foot is being used, a footrest should be located at the same height and angle as the treadle. Pedals for standing operators have to be close to the floor in order to support his body weight over both feet. The pedal could also be moved so that the operator is able to rotate between activating the pedal with his right or left foot.
Awkward postures can make tasks more physically demanding. Besides, the stronger and larger muscle may not work at maximum efficiencies. Using force and excess of muscular effort can also lead to mental exhaustion. Vibrations of machines that are not properly maintained may lead to numbness in body and affect health. Repeating of acts may lead to injury, excess fatigue and delays in production. This is where the science of ergonomics comes into use.
Knee switches and hand controls
The knee switches are often not conveniently located for the operator.
Place the knee switch at a convenient position for the operator so that it rests very close to the leg, just above the knee and ensure that it is also well-padded. Make sure that the controls are located at a place which does not have any obstruction. In addition, controls should activate with a light feather touch even from different angles.
Without proper lighting, an operator may be encouraged to adopt poor postures in order to see his work better and may subsequently strain his eyes or be less productive. Lighting requirements may vary depending on the task, fabric and individual preferences.
Ensure that there is good general lighting and task lights are provided to the operators who desire them or have visually demanding tasks. The task lights should have a “goose-neck” so that the lights can be directed to the work area. Lampshades should have ventilation holes, but wherever necessary, these could be covered so that the light is not directed through these holes towards the operator disturbing his concentration.
Finishing department involves various standing jobs such as thread trimming, spotting and finishing which also contribute to static postures. If the worker stands in one posture for a very long period of time, the back and leg muscles are constantly activated. This leads to increased fatigue and decreased blood circulation to the legs. To counter this, a worker should try to walk around in order to facilitate blood flow. He should also try and sit for short periods of time while working to give the leg and back muscles a rest.
The worker should move his feet instead of twisting at the waist in order to face the area where the object is going to be placed. He should also try not to twist his upper body when placing objects on the side. By keeping his feet in place and only moving the upper body, he puts immense stress on his back, which may lead to injuries.
The height of the workstation is a typical problem that does not accommodate with the operator’s height. This result in inconvenience, stress, poor visibility and the operator is unable to work in a relaxed atmosphere.
A good working height permits an operator to work with his shoulders relaxed and back in an upright position. A working height with adjustable workstation is ideal. This enables an individual operator to adjust the height throughout the day to give relief to the body parts that are carrying greater stress. Tilting the work surface towards the operator is often possible with pressing operations and can improve posture and visibility.
Both the closing of the press and the steam can be activated with one well-designed foot pedal. A good design for multiple workstations would be to have two manual presses parallel to each other with sufficient, but not excessive space between them. The operator turns around and walks several paces when switching from one press to the other.
The task of final inspection typically involves visually inspecting the garment for flaws, trimming threads along seams and in some cases cleaning chalk or lint from the garment. The important aspects of the task to consider are the work surface, input/output, support surface, hand tools, lighting and work organization.
An inclined easel with clips holds the garment and allows the inspector to sit or stand in an upright position without having to support the weight of the garment. The inspector should select the desired height for the easel and clips. A large, inclined table improves the posture of the neck and arms. Small, sharp clippers are more suitable for the task as they are easier to use and lighter than large scissors. Ensure that clippers are available by storing them on a shelf or hanging them directly beside the work surface. Improve visibility by contrasting the colour of the garment being inspected with the colour of the work surface.
This task involves folding and packaging the garments in a bag or a box. Important features to consider include the work surface, input/output, support surface and accessories.
After the garments are stitched and pressed, they are bought to the packing section, where the garments of various sizes and colours are filled into individual polybags, sealed with a tape, then sorted as per their colour and size and piled up on the floor. No furniture is provided to the workers working in the packing department.
The jobs involved in packing section include putting individual garments into poly bags, piling up poly bagged garments as per their size and colour ratios, filling the cartons as per the size and colour ratio and finally sealing the cartons with a strap/tape. The common postures adopted are squatting on the floor and frequent bending to handle the material lying on the floor. Thus, musculoskeletal pain frequently occurs as a result of these awkward and faulty postures.
An ideal workstation for the packing department is wooden furniture, with an inclined L-shaped wooden shelve, which can hold the carton in an inclined position while it is getting filled with garments. The L-shaped shelve can be adjusted with the help of a C-shaped wooden frame, which is hinged to the L-shaped shelve. The value of L has been taken in such a way that the centre of gravity will not go beyond the point of support and the carton will not topple in the length direction.
The poly bagged garments can be piled up on to a table as per their size and colour ratio. This table can be placed beside the workstation, so that the worker can pick up the garments from the table and place them into the carton placed on the L-shaped shelve. The table should ideally have fencing on three sides, to avoid the poly bagged cartons from slipping onto the floor. After filling the required number of garments into the cartons, the worker can push the same onto the table/station ahead by lifting the L-shaped shelve. The carton will slide and fall onto the table which is placed aside.
Ideally the management should either talk to employees to seek their views, assess the work system or look at sickness absence and staff turnover levels in order to identify the problems related to the ergonomics of the workplace. Effective workplace ergonomics programmes eventually not only help to reduce the risk of workplace injuries and their severity, but also control physical and mental stress and worker fatigue. Consequently, there is a fall in absenteeism and substantial improvement in employee morale and productivity. Thus, continuously identifying problems and, more importantly, implementing solutions to reduce the risk of injuries in situations will improve the working environment of the industry.