Operations Management – Process Design Notes

Process Design

WHAT IS PROCESS DESIGN?

• To design is to conceive the looks, arrangement and workings of something before is is created.

• At the start of the process design activity it is important to understand the design objectives, especially at first, when the overall shape and nature of the process is being decided.

• The most common way of doing this is by positioning it according to its volume and variety characteristics/

• Eventually the details of the process must be analysed to ensure that it fulfils its objectives effectively.

Process Design and Product/Service Design are Interrelated

• Small changes in the design of products and services can have profound implications for the way the operation eventually has to produce them.

• The design of a process can constrain the freedom of product and service designers to operate as they would wish.

• The overlap between the two design activities is generally greater in operations which produce services.

• Because many services involve the customer in being part of the transformation process, the service as far as the customer sees it cannot be separated from the process to which the customer is subjected.

• When product designers also have to make or use the things which they design, it can concentrate their minds on what is important.

WHAT OBJECTIVES SHOULD PROCESS DESIGN HAVE

• The whole point of process design is to make sure that the performance of the process is appropriate for whatever it is trying to achieve.

• Operations performance objectives translate directly to process design objectives.

• Because processes are managed at a very operational level, process design also needs to consider a more micro and detailed set of objectives. These are largely concerned with flow through the process.

• When whatever are being processes enter a process they will progress through a series of activities where they are transformed in some way.

• Between these activities they may dwell for some time in inventories, waiting to be transformed by the next activity. This means that the time that a unit spends in the process (its throughout time) will be longer than the sum of all the transforming activities it passes through.

• Also the resources that perform the process activities may not be used all the time because not all units will necessarily require the same activities and the capacity of each resource may not match the demand placed upon it.

• So neither the units moving through the process or the resources performing the activities may be fully utilised.

• It is common for more micro performance flow objectives to be used that describe process flow performance:

  • Throughput rate – the rate at which units emerge from the process i.e. the number of units passing through the process per unit of time.

  • Throughput time – the average elapsed time taken for inputs to move through the process and become outputs.

  • Work in progress - the number of units in the process as an average over a period of time.

  • Utilisation – the proportion of available time that the resources within the process are performing useful work.

Environmentally Sensitive Design

• With the issue of environmental protection becoming more important, both process and product/service designers have to take account of green issues.

• Interest has focused on some fundamental issues:

  • The sources of inputs to a product/service.

  • Quantities and sources of energy consumed in the process.

  • The amounts and type of waste material that are created in manufacturing processes.

  • The life of the product itself.

  • The end life of the product.

• Designers are faced with a complex trade-off between these factors, although it is not always easy to obtain all the information needed to make the best choices.

• To help make more rational decisions in the design activity, some industries are experimenting with life cycle analysis.

• This technique analyses all the production inputs, the life cycle use of the product and its final disposal in terms of all energy used. o

• The inputs and wastes are evaluated at every stage in its creation.

PROCESS TYPES – THE VOLUME/VARIETY EFFECT ON PROCESS DESIGN

• Usually the two dimensions of volume and variety go together. Low volume operations processes often have a high variety of products and services and high volume operations processes often have a very narrow variety of products and services.

• Thus there is a continuum from low volume and high variety through to high volume and low variety, on which we can position operations.

• Many manufacturing plants will have a large area organised on a mass production basis which makes its high volume bestselling products. In another area it may also have a part where it makes a wide variety of products in much smaller volumes.

• No type of process design is best for all types of operation in all circumstances.

Process Types

• The position of a process son the volume variety continuum shapes its overall design and the general approach to managing its activities. These general approaches to designing and managing processes are called process types.

• Project processes

  • Those which deal with discrete, usually highly customised products (high variety and low volumes).

  • Often the timescale of making the product/service is relatively long, as is the interval between the completion of each product or service.

  • The activities involved in making the product can be ill defined and uncertain, sometimes changing during the production process itself.

  • The essence of project processes is that each job has a well-defined start and finish, the time interval between starting different jobs is relatively long and the transforming resources which make the product will probably have been organised especially for the product.

  • The process map for project processes will almost certainly be complex, partly because each unit of output is so large with many activities occurring at the same time and partly because the activities in such processes often involve significant discretion to act...

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