Work Systems Design

10.	Work Systems Design The following are examples of approaches to work systems design that have been used in an attempt to bring these desirable job characteristics to people’s work leading to an improved mental state and thus increased performance.
	10.1.	Job Enlargement This involves the horizontal integration of tasks to expand the range of tasks involved in a particular job. If successfully implemented this can increase task identity, task significance and skill variety through involving the worker in the whole work task either individually or within the context of a group. Job Rotation is a common form of job enlargement and involves a worker changing job roles with another worker on a periodic basis. If successfully implemented this can help increase task identity, skill variety and autonomy through involvement in a wider range of work task with discretion about when these mix of tasks can be undertaken. However this method does not actually improve the design of the jobs and it can mean that people gravitate to the jobs that suit them and are not interested in initiating rotation with colleagues. At worst it can mean rotation between a number of boring jobs with no acquisition of new skills.
	10.2.	Job Enrichment Job enrichment involves the vertical integration of tasks and the integration of responsibility and decision making. If successfully implemented this can increase all five of the desirable job characteristics by involving the worker in a wider range of tasks and providing responsibility for the successful execution of these tasks. This technique does require feedback to so that the success of the work can be judged. The managerial and staff responsibilities potentially given to an employee through enrichment can be seen as a form of empowerment. This should in turn lead to improved productivity and product quality
	10.3.	Implementation of Work Design Approaches There are a number of factors which account for the fact that job enlargement and job enrichment are not more widely implemented. Firstly the scope for using different forms of work organisation will be dependent to a large extent on the type of operation in which the work is organised. Job shop manufacturing will require skilled workers who will be involved in a variety of tasks and will have some discretion in how they undertake these tasks. Sales personnel may also have a high level of discretion in how they undertake their job duties also. The amount of variety in a batch manufacturing environment will to a large extent depend on the length of the production runs used. Firms producing large batches of a single item will obviously have less scope for job enrichment than firms producing in small batches on a make-to-order basis. One method for providing job enlargement is to use a cellular manufacturing system, which can permit a worker to undertake a range of tasks on a part. When combined with responsibility for cell performance this can lead to job enrichment. Jobs in mass production industries may be more difficult to enlarge. Car plants must work at a certain rate in order to meet production targets and on a moving line it is only viable for each worker to spend a few minutes on a task before the next worker on the line must take over. A way of overcoming this problem is to use teams. Here tasks are exchanged between team members and performance measurements are supplied for the team as a whole. This provides workers with greater variety and feedback, but also some autonomy and participation in the decisions of the team. Secondly financial factors may be a constraint on further use. These may include the performance of individuals who actually prefer simple jobs, higher wage rates paid for the higher skills of employees increasing average wage costs and the capital costs of introducing the approaches. The problem is that many of the benefits associated with the technique, such as an increase in creativity, may be difficult to measure financially. Finally the political aspects of job design changes have little effect on organisational structures and the role of management. Although job enrichment may affect supervisory levels of management, by replacement with a team leader for example, the power structures in which technology is used to justify decisions for personal objectives is intact
	10.4.	Methods Analysis Dividing and analysing a job is called method study. The approach takes a systematic approach to reducing waste, time and effort. The approach can be analysed in a six-step procedure :
		1.	Select Tasks most suitable will probably be repetitive, require extensive labour input and be critical to overall performance.
		2.	Record This involves observation and documentation of the correct method of performing the selected tasks. Flow process charts are often used to represent a sequence of events graphically. They are intended to highlight unnecessary material movements and unnecessary delay periods.
		3.	Examine This involves examination of the current method, looking for ways in which tasks can be eliminated, combined, rearranged and simplified. This can be achieved by looking at the flow process chart for example and re-designing the sequence of tasks necessary to perform the activity.
		4.	Develop Developing the best method and obtaining approval for this method. This means choosing the best alternative considered taking into account the constraints of the system such as the performance of the firm’s equipment. The new method will require adequate documentation in order that procedures can be followed. Specifications may include tooling, operator skill level and working conditions
		5.	Install Implement the new method. Changes such as installation of new equipment and operator training will need to be undertaken.
		6.	Maintain Routinely verify that the new method is being followed correctly New methods may not be followed due to inadequate training or support. On the other hand people may find ways to gradually improve the method over time. Learning curves can be used to analyse these effects.
	10.5	Motion Study Motion study is the study of the individual human motions that are used in a job task. The purpose of motion study is to try to ensure that the job does not include any unnecessary motion or movement by the worker and to select the sequence of motions that ensure that the job is being carried out in the most efficient manner possible. For even more detail videotapes can be used to study individual work motions in slow motion and analyse them to find improvement - a technique termed micromotion analysis. The principles are generally categorised according to the efficient use of the human body, efficient arrangement of the workplace and the efficient use of equipment and machinery. These principles can be summarised into general guidelines as follows :
		-	Efficient Use of the Human Body Work should be rhythmic, symmetrical and simplified. The full capabilities of the human body should be employed. Energy should be conserved by letting machines perform tasks when possible
		-	Efficient Arrangement of the Workplace Tools, materials and controls should have a defined place and be located to minimise the motions needed to get to them. The workplace should be comfortable and healthy.
		-	Efficient use of Equipment Equipment and mechanised tools enhance worker abilities. Controls and foot-operated devices that can relieve the hand/arms of work should be maximised. Equipment should be constructed and arranged to fit worker use.
		Motion study is seen as one of the fundamental aspects of scientific management and indeed it was effective in the design of repetitive, simplified jobs with the task specialisation which was a feature of the mass production system. The use of motion study as declined as there as been a movement towards greater job responsibility and a wider range of tasks within a job. However the technique is still a useful analysis tool and particularly in the service industries, can help improve process performance.
	10.6.	Work Measurement The second element of work-study is work measurement which determines the length of time it will take to undertake a particular task. This is important not only to determine pay rates but also to ensure that each stage in a production line system is of an equal duration (i.e. ‘balanced’) thus ensuring maximum output. Usually the method study and work measurement activities are undertaken together to develop time as well as method standards. Setting time standards in a structured manner permits the use of benchmarks against which to measure a range of variables such as cost of the product and share of work between team members. However the work measurement technique has been criticised for being misused by management in determining worker compensation. The time needed to perform each work element can be determined by the use of historical data, work sampling or most usually time study.
		10.6.1.	The purpose of Time Study is through the use of statistical techniques to arrive at a standard time for performing one cycle of a repetitive job. This is arrived at by observing a task a number of times. The standard time refers to the time allowed for the job under specific circumstances, taking into account allowances for rest and relaxation. The basic steps in a time study are indicated below :
			1.	Establish the standard job method It is essential that the best method of undertaking the job is determined using method study before a time study is undertaken. If a better method for the job is found then the time study analysis will need to be repeated
			2.	Break down the job into elements The job should be broken down into a number of easily measurable tasks. This will permit a more accurate calculation of standard time as varying proficiencies at different parts of the whole job can be taken into account.
			3.	Study the job This has traditionally been undertaken with a stopwatch, or electronic timer, by observation of the task. Each time element is recorded on an observation sheet. A Video camera can be used for observation, which permits study away from the workplace, and in slow motion which permits a higher degree of accuracy of measurement.
			4.	Rate the worker’s performance As the time study is being conducted a rating of the worker’s performance is also taken in order to achieve a true time rating for the task. Rating factors are usually between 80% and 120% of normal. This is an important but subjective element in the procedure and is best done if the observer is familiar with the job itself.
			5.	Compute the average time Once a sufficient sample of job cycles have been undertaken an average is taken of the observed times called the cycle time. The sample size can be determined statistically, but is often around five to fifteen due to cost restrictions.’
			6.	Compute the normal time Adjust the cycle time for the efficiency and speed of the worker who was observed. The normal time is calculated by multiplying the cycle time by the performance rating factors. Normal Time (NT) = cycle time (CT) x rating factor (RF)
			7.	Compute the standard time The standard time is computed by adjusting the normal time by an allowance factor to take account of unavoidable delays such as machine breakdown and rest periods. The standard time is calculated as Standard Time (ST) = Normal Time (NT) x allowance
		10.6.2.	Predetermined Motion Times One problem with time studies is that workers will not always co-operate with their use, especially if they know the results will be used to set wage rates. Combined with the costs of undertaking a time study, a company may use historical data inthe form of time files to construct a new standard job time from previous job element. This has the disadvantage however of the reliability and applicability of old data. Another method for calculating standard times without a time study is to use predetermined motion time system (PMTS) which provides generic times for standard micromotions such as reach, move and release which are common to many jobs. The standard item for the job is then constructed by breaking down the job into micromotions that can then be assigned a time from the motion time database. The standard time for the job is the sum of these micromotion times. Factors such as load weight for move operations are included in the time motion database. The advantages of this approach are that standard times can be developed for jobs before they are introduced to the workplace without causing disruption and needing worker compliance. Also performance ratings are factored in to the motion times and so the subjective part of the study is eliminated. The timings should also be much more consistent than historical data for instance. Disadvantages include the fact that these times ignore the context of the job in which they are undertaken i.e. the timings are provided for the micromotion in isolation and not part of a range of movement. The sample is from a broad range of workers in different industries with different skill levels, which may lead to an unrepresentative time. Also the timings are only available for simple repetitious work which is becoming less common in industry.
		10.6.3.	Work Sampling Work Sampling is useful for analysing the increasing proportion of non-repetitive tasks that are performed in most jobs. It is a method for determining the proportion of time a worker or machine spends on various activities and as such can be very useful in job redesign and estimating levels of worker output. The basic steps in work sampling are indicated below :
			1.	Define the job activities All possible activities must be categorised for a particular job. e.g. “worker idle” and “worker busy” states could be used to define all possible activities.
			2.	Determine the number of observations in the work sampl  The accuracy of the proportion of time the worker is in a particular state is determined by the observation sample size. Assuming the sample is approximately normally distributed the sample size can be estimated using the following formula. n = (z/e)2 * p (1 - p) where n = sample size z = number of standard deviation from the mean for the       desired level of confidence e = the degree of allowable error in the sample estimate p= the estimated proportion of time spent on a work activity The accuracy of the estimated proportion p is usually expressed in terms of an allowable degree of error e (e.g. for a 2% degree of error, e = 0.02). The degree of confidence would normally be 95% (giving a z value of 1.96) or 99% (giving a z value of  2.58).
			3.	Determine the length of the sampling period There must be sufficient time in order for a random sample of the number of observations given by the equation in 2 to be collected. A random number generate can be used to generate the time between observations in order to achieve a random sample.
			4.	Conduct the work sampling study and record the observations Calculate the sample and calculate the proportion (p) by dividing the number of observations for a particular activity by the total number of observations.
			5.	Periodically re-compute the sample size required It may be that the actual proportion for an activity is different from the proportion used to calculate the sample size in step 2. Therefore as sampling progresses it is useful to re-compute the sample size based on the proportions actually observed.
	10.7.	Learning Curves Organisations have often used learning curves to predict the improvement in productivity that can occur as experience is gained of a process. Thus learning curves can give an organisation a method of measuring continuous improvement activities. If a firm can estimate the rate at which an operation time will decrease then it can predict the impact on cost and increase in effective capacity over time. The learning curve is based on the concept of when productivity doubles, the decrease in time per unit is the rate of the learning curve. Thus if the learning curve is at a rate of 85%, the second unit takes 85% of the time of the first unit, the fourth unit takes 85% of the second unit and the eighth unit takes 85% of the fourth and so on. Mathematically the learning curve is represented by the function y = ax-b where y = time to produce the xth unit a = hours required to produce the first unit x = number of units produced b= constant equal to -(ln p)/(ln 2)   where ln = log10 p = learning rate (e.g. 80% = 0.8) Thus for a 80% learning curve b = - (ln 0.8)/ ln(2) = -(-0.233)/ 0.693 = 0.322 Learning curves are usually applied to individual operators, but the concept can also be applied in a more aggregate sense, termed an experience or improvement curve, and applied to such areas as manufacturing system performance or cost estimating. Industrial sectors can also be shown to have different rates of learning. It should be noted that improvements along a learning curve do not just happen and the theory is most applicable to new product or process development where scope for improvement is greatest. In addition step changes can occur which can alter the rate of learning, such as organisational change, changes in technology or quality improvement programs. To ensure learning occurs the organisation must invest in factors such as research and development, advanced technology, people and continuous improvement efforts.

Facility Location and Layout

 

9.	Facility Location and Layout
	9.1.	Facility Location The organisation’s strategy will need to address the issue of facility location. This must be considered in terms of the need to serve customer markets effectively and to meet long-range demand forecasts. The issues can be considered in terms of the competition and cost of the location decision and the size of the facility. A company’s competitiveness will be affected by its locations as it will impact on costs such as for transportation and labour. In service operations when the facility may not only produce the good but also deliver it to the customer from the facility, the convenience of the location for the customer is vital. A location decision is costly and time consuming to change. The costs include the purchase of land and construction of buildings. An organisation may be located inappropriately due to a previous poor location decision and an unwillingness to face the costs of a subsequent relocation. A change in input costs, such as materials or labour, may also lead to a need to change location. Finally in order to meet the long-term demand forecast it is necessary to consider the size of the facility. Within a medium term planning cycle the size of the facility will impose an upper limit on the organisation’s capacity. Purchasing additional components from suppliers or sub-contracting work can however increase this level. However these strategies may lead to higher costs and thus a loss of competitiveness. The ability to supplement capacity is most restricted in service operations when contact with the customer is required.
	9.2.	Location Factors        Many factors affect the location decision including the following.
		9.2.1.		Proximity to Customers For many service organisations in particular the location of the facility must be convenient for the potential customer. This can range from restaurants were customers may be prepared to travel a short distance to hospitals were the speed of response is vital to the service. High transportation costs for heavy or bulky materials may also lead to locating close to the customer.
		9.2.2.		Proximity to suppliers The volume and bulk of the raw material involved in operations such as steel production means that a location decision will tend to favour areas near to suppliers. A manufacturer and seller of custom-built furniture however will need to be near potential customers. For service companies such as supermarkets and restaurants the need to be in a market-oriented locations means that the cost of transportation of goods will not be a major factor in the location decision. Distribution across country borders means that a whole series of additional costs and delays must be taken into account, including import duties and delays in moving freight between different transportation methods. A site near to an airport or a rail link to an airport may be an important factor if delivery speed is important
		9.2.3.		Proximity to labour   Labour costs have generally become less important as the proportion of direct labour cost in high volume manufacturing have fallen. What is becoming more important is the skills and flexibility of the labour force to adapt to new working methods and to engage in continuous improvement efforts. The wage rate of labour can be a factor in location decisions, especially when the service can be provided easily in alternative locations. Information Technology companies involved in data entry can locate in alternative countries without the customer being aware.
	9.3.	Layout Design Layout design concerns the physical placement of resources such as equipment and storage facilities. Layout design is important because it can have a significant effect on the cost and efficiency of an operation and can entail substantial investment in time and money. In many operations the installation of a new layout, or redesign of an existing layout, can be difficult to alter once implemented due to the significant investment required on items such as equipment. There are four basic layout types of process, product, hybrid and fixed-position layout. The characteristics of each of the layout types will now be considered.
		9.3.1.		Process layout A process layout is one in which resources (such as equipment and people) which have similar processes or functions are grouped together. Process layouts are used when there is a large variety in the products or services being delivered and it may not be feasible to dedicate facilities to each individual product or service. A process layout allows the products or customers to move to each group of resources in turn, based on their individual requirements. Because of their flexibility process layouts are widely used. One advantage is that in service systems they allow a wide variety of routes that may be chosen by customers depending on their needs. Another advantage is that the product or service range may be extended and as long as no new resources are required may be accommodated within the current layout   An important issue with process layouts is the management of the flow of products or services between the resource groups. One problem is that transportation between process groups can be a significant factor in terms of transportation time and handling costs. Another problem is that the number of products or services involved and the fact that each product/service can follow an individual route between the process groups, makes it difficult to predict when a particular product will be delivered or a service completed. This is because at certain times the number of customers or products arriving at a particular process group exceeds its capacity and so a queue forms until resources are available. This queuing time may take up a significant part of the time that the product or customer is in the process. This behaviour can lead to long throughput times (i.e. the time taken for a product or customer to progress through the layout). In a manufacturing organisation a significant amount of time may be spent ‘progress chasing’ to give certain products priority to ensure they are delivered to customers on time. In a service system the customers may feel they are queuing in the system longer than they perceive is necessary for the service they require. However in services there may be flexibility to add or remove staff to match the current arrival rate of customers to the service delivery point. Examples of process layouts include supermarkets, hospitals, department stores and component manufacturers.
		9.3.2.		Product Layout Product layouts, also termed line layouts, arrange the resources required for a product or service around the needs of that product or service. In manufacturing applications such as assembly lines with a high volume of a standard product the products will move in a flow from one processing station to the next. In contrast to the process layout in which products move to the resources, here the resources are arranged and dedicated to a particular product or service. The term product layout refers to the arrangement of the resources around the product or service. In services the requirements of a specific group of customers are identified and resources setup sequentially so the customers flow through the system, moving from one stage to another until the service is complete. A key issue in product layouts is that the stages in the assembly line or flow line must be ‘balanced’. This means that the time spent by components or customers should be approximately the same for each stage, otherwise queues will occur at the slowest stage. The topic of line balancing is considered later in this chapter. The product or line layout is an efficient delivery system in that the use of dedicated equipment in a balanced line will allow a much faster throughput time than in a process layout. The major disadvantage of the approach is that it lacks the flexibility of a process layout and only produces a standard product or service. Another issue is that if any stage of the line fails, then in effect the output from the whole line is lost and so it lacks the robustness to loss of resources (for example equipment failure or staff illness) that the process layout can provide. Examples of product layouts include car assembly, self-service cafes and car valeting.
		9.3.3.		Hybrid Layout  A hybrid layout attempts to combine the efficiency of a product layout with the flexibility of a process layout. Hybrid layouts are created from placing together resources which service a subset of the total range of products or services. When grouping products or services together in this way the grouping is termed a family. The process of grouping the products or services to create a family is termed group technology. Group technology has three aspects :
				1.	Grouping parts into families Grouping parts or customers into families has the objective of reducing the changeover time between batches, allowing smaller batch sizes, and thus improving flexibility. Parts family formation is based on the idea of grouping parts or customers together according to factors such as processing similarity.
				2.	Group physical facilities into cells to reduce transportation time between processes Physical facilities are grouped into cells with the intention of reducing material or customer movements. Whereas a process layout involves extensive movement of materials or customers between departments with common processes, a cell comprises all the facilities required to manufacture a family of components or delivery a service. Material and customer movement is therefore restricted to within the cell and throughput times are therefore reduced. Cells can be U-shaped to allow workers to work at more than one process whilst minimising movement.
				3.	Creating groups of multi-skilled workers Creating groups of multi-skilled workers enables increased autonomy and flexibility on the part of operators. This enables easier changeovers from one part to another and increases the job enrichment of members of the group. This in turn can improve motivation and have a beneficial effect on quality. Creating cells with dedicated resources can significantly reduce the time it takes for products and services to pass through the process by reducing queuing time. It also offers the opportunity for automation due to the close proximity of the process stages. Thus process technology can be used to replace a number of general purpose resources with a single dedicated multi-functional system such as a Flexible Manufacturing System. A disadvantage of hybrid layouts can be the extra expenditure due to the extra resources required in creating cells. Examples of hybrid layouts include custom manufacture, maternity unit in a hospital, cafeteria with multiple serving areas. In services a cell layout could involve an insurance organisation organised by type of claim (e.g. car, home, travel).
		9.3.4.		Fixed-Position layout This layout design is used when the product or service cannot be moved and so the transforming process must take place at the location of product creation or service delivery. In a fixed position layout all resources for producing the product, such as equipment and labour must move to the site of the product or service. The emphasis when using a fixed-position layout is on the scheduling and coordination of resources to ensure that they are available in the required amounts at the required time. For example on a construction site most activities are dependent on the completion of other activities and cannot be undertaken simultaneously. The space available on the site may also constrain the amount of work activity that can take place at any one time. This means detailed scheduling of resources is required to minimise delays. In a restaurant it is important that the order is taken and food delivered to the table at the appropriate time. Examples of fixed-position layouts include construction sites such as for buildings or for large ships, aircraft manufacture and full service restaurants.
	9.4.	Designing Product Layouts - Line Balancing A product layout consists of a number of processes arranged one after another in a ‘line’ to produce a standard product or service in a relatively high volume. These systems which have a characteristic flow (product) layout use specialised equipment or staff dedicated to achieving an optimal flow of work through the system. This is important because all items follow virtually the same sequence of operations. A major aim of flow systems is to ensure that each stage of production is able to maintain production at an equal rate. The technique of line balancing is used to ensure that the output of each production stage is equal and maximum efficiency is attained. Line balancing involves ensuring that the stages of production are co-ordinated and bottlenecks are avoided. Because of the line flow configuration the tasks in the line must be undertaken in order (precedence) and the output of the whole line will be determined by the slowest or bottleneck process. The actual design of the line is thus guided by the order of the tasks which are involved in producing the product or delivering the service and the required output rate required to meet demand. This provides information which determines the number of stages and the output rate of each stage. The steps in line balancing are as follows :
		1.	Draw a precedence diagram The first step in line balancing is to identify the tasks involved in the process and the order that these tasks must be undertaken in. Once the tasks have been identified it is necessary to define their relationship to one another. There are some tasks that can only begin when other tasks have been completed and this is termed a serial relationship. The execution of other tasks may be totally independent and thus they have a parallel relationship. Precedence diagrams are used to show the tasks undertaken in a line process and the dependencies between these tasks.
		2.	Determine the cycle time for the line For a particular line process we will wish to reach a desired rate of output for the line to meet projected demand. This is usually expressed in work items per time period, for example 30 parts per hour. Another way of expressing this output rate is that 30 parts per hour means that a part must leave the system every 2 minutes (60 minutes/30 parts). This measure, termed the cycle time, represents the longest time any part is allowed to spend at each task. Cycle Time = Available Time/Desired Output Taking into consideration the discussion of bottleneck processes above, the cycle time for the line process is thus determined by the task with the highest cycle time or lowest output level.
		3.	Assign tasks to workstations Once the cycle time for the line has been calculated we have the cycle time for each stage or workstation in the line process. We can now allocate tasks to each workstation based on their task times. As a rule of thumb it is more efficient to allocate eligible tasks to a workstation in the order of longest task times first. When the total task time would exceed the cycle time for a workstation then it is necessary to start a new workstation and repeat the allocation of tasks as before. If a task time is longer than the workstation cycle time then it is necessary either to allocate multiple tasks in parallel in order to meet the target time or to break the task down into smaller elements.
		4.	Calculate the efficiency of the line When tasks are assigned to workstations it is very unlikely that their total tasks times at each workstation will match the cycle time exactly. A measure of how close these two values do meet for the whole line, is called the line efficiency. To calculate the line efficiency : Line Efficiency % = (Sum of the task times/(number of workstations  desired cycle time)) *100