Process design
Source: Slack, N. et al. 2016. Operations Management. 8th Ed.
Harlow: Pearson Education Limited.
Outline
• What is process design?
• What objectives should process design have?
• How do volume and variety affect process design?
• How are processes designed in detail?
• What are the effects of process variability?
Introduction
• While there is no universally recognized definition of ‘design’, we
take it to mean ‘the process by which some functional
requirement of people is satisfied through the shaping or
configuration of the resources and/or activities that comprise a
product, or a service, or the transformation process that produces
them’.
• All operations managers are designers. When they purchase or
rearrange the position of a piece of equipment, or when they
change the way of working within a process, it is a design decision
because it affects the physical shape and nature of their processes
What is process design
• To ‘design’ is to conceive the looks, arrangement, and workings of
something before it is created . In that sense it is a conceptual
exercise. Yet it is one which must deliver a solution that will work in
practice.
• 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.
• Eventually the details of the process must be analysed to ensure that it
fulfils its objectives effectively.
• There may be aspects concerned with the objectives, or the broad
positioning of the process, that will need to be modified following its
more detailed analysis.
•
Process design and service/product 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.
• Similarly, 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
• Overlapping product and process design has implications for the organization
of the design activity
• For example, in the early days of flight, the engineers who designed the
aircraft were also the test pilots who took them out on their first flight. For
this reason, if no other, safety was a significant objective in the design
activity.
The design of products/services and processes are
interrelated and should be treated together
Objectives of process design
• 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.
• For example, if an operation competed primarily on its
ability to respond quickly to customer requests, its processes
would need to be designed to give fast throughput times.
• Similarly, if an operation competed on low price, cost-related
objectives would be likely to dominate its process design.
• Process flow objectives should include throughput rate,
throughput time, work-in-progress, and resource utilization;
• All of these are interrelated.
• The design of any process should be judged on its quality, speed,
dependability, flexibility and cost performance.
Throughput rate & Cycle time
• Throughput rate (or flow rate) is the rate at which items emerge
from the process, i.e. the number of items passing through the
process per unit of time.
• Cycle time, or takt time, is the reciprocal of throughput rate – it is
the time between items emerging from the process.
The impact of strategic performance objectives on
process design objectives and performance
Standardization of processes
• One of the most important process design objectives, concerns the
extent to which process designs should be standardized.
• By standardization in this context we mean ‘doing things in the same
way’, or more formally, ‘adopting a common sequence of activities,
methods and use of equipment’.
• It is a significant issue in large organizations because very often
different ways of carrying out similar or identical tasks emerge over time
in the various parts of the organization.
• But, why not allow many different ways of doing the same thing?
• The problem is that allowing numerous ways of doing things causes
confusion, misunderstandings, and eventually, inefficiency. In healthcare
processes, it can even cause preventable deaths.
For example
• In 2012, the Royal College of Physicians in the UK revealed that there
were more than 100 types of charts that were used for monitoring
patients’ vital signs in use in UK hospitals.
• This leads to confusion, they said. Potentially, thousands of hospital
deaths could be prevented if doctors and nurses used a standardized bed
chart. Because hospitals can use different charts, doctors and nurses
have to learn how to read new ones when they move.
• They recommended that there should be just one chart and one process
for all staff that check on patients’ conditions.
• The practical dilemma for most organizations is how to draw the line
between processes that are required to be standardized, and those that
are allowed to be different.
Environmentally sensitive process design
• The sources of inputs to a product or service. (Will they damage
rainforests? Will they use up scarce minerals? Will they exploit the poor
or use child labour?)
• Quantities and sources of energy consumed in the process. (Do plastic
beverage bottles use more energy than glass ones? Should waste heat be
recovered and used in fish farming?)
• The amounts and type of waste material that are created in the
manufacturing processes. (Can this waste be recycled efficiently, or
must it be burnt or buried in landfill sites?)
• The life of the product itself. (If a product has a long useful life will it
consume fewer resources than a short-life product?)
• The end-of-life of the product . (Will the redundant product be difficult
to dispose of in an environmentally friendly way?)
Life-cycle analysis
• This technique analyses all the production inputs, the life-cycle
use of the product and its final disposal, in terms of total energy
used and all emitted wastes.
• The inputs and wastes are evaluated at every stage of a service
or product’s creation, beginning with the extraction or farming of
the basic raw materials.
Process types – the volume–variety effect on
process design
• The design of any process should be governed by the volume and
variety it is required to produce.
• Usually the two dimensions of volume and variety go together –
but in a reversed way.
• So low-volume processes often produce a high variety of products
and services, and high-volume operations processes often produce
a narrow variety of products and services.
• Thus there is a continuum from low volume/high variety through
to high volume/low variety, on which we can position processes.
For example
Compare the approach taken in a medical service during
mass medical treatments, such as large-scale
immunization programmes, with that taken in transplant
surgery where the treatment is designed specifically to
meet the needs of one person.
Process types
• The position of a process on 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.
Different process types imply different volume–
variety characteristics for the process
Project processes
• Project processes deal with discrete, usually highly customized
products; often with a relatively long timescale between the
completion of each item, where each job has a well-defined start
and finish.
• Project processes have low volume and high variety.
• The process may be complex, partly because the activities in such
processes often involve significant discretion to act according to
professional judgement.
• Examples of project processes include software design, movie
production, most construction companies, and large fabrication
operations such as those manufacturing turbo generators.
•
Jobbing processes
• Jobbing processes also deal with high variety and low volumes.
• In jobbing processes each product has to share the operation’s resources
with many others.
• Resources will process a series of items but, although each one will
require similar attention, they may differ in their exact needs.
• Many jobs will probably be ‘one-offs’ that are never repeated.
• Jobbing processes could be relatively complex; however, they usually
produce physically smaller products and, although sometimes requiring
considerable skill.
• Examples of jobbing processes include made-to-measure tailors, many
precision engineers such as specialist toolmakers, furniture restorers,
and the printer who produces tickets for the local social event.
Batch processes
• Batch processes may look like jobbing processes, but do not have the
same degree of variety.
• Each time batch processes produce more than one item at a time.
• Each part of the process has periods when it is repeating itself, at least
while the ‘batch’ is being processed.
• The batch type of process can be found over a wide range of volume and
variety levels.
• Examples of batch processes include machine tool manufacturing, the
production of some special gourmet frozen foods, and the manufacture
of most of the component parts which go into mass-produced assemblies
such as automobiles.
Mass Processes
• Mass processes are those which produce items in high volume and
relatively narrow variety
• The activities of mass processes are usually repetitive and largely
predictable.
• Examples of mass processes include frozen food production,
automatic packing lines, automobile plants, television factories,
and DVD production.
Continuous processes
• Continuous processes have even higher volume and usually lower
variety than mass processes.
• They also usually operate for longer periods of time.
• Their predominant characteristic is of smooth flow from one part of
the process to another.
• Examples of continuous processes include water processing,
petrochemical refineries, electricity utilities, steel making and
some paper making.
Professional services
• Professional services are high-contact processes where customers
spend a considerable time in the service process.
• They can provide high levels of customization
• Professional services tend to be people-based rather than
equipment-based.
• Professional services include management consultants, lawyers’
practices, architects, doctors’ surgeries, auditors, health and
safety inspectors and some computer field service operations.
Service shops
• Service shops have levels of volume and variety (and customer
contact, customization and staff discretion) between the extremes
of professional and mass services.
• Service is provided via mixes of front- and back-office activities.
• Service shops include banks, high street shops, holiday tour
operators, car rental companies, schools, most restaurants, hotels
and travel agents.
Mass services
• Mass services have many customer transactions, involving limited
contact time and little customization.
• Staff are likely to have a relatively defined division of labour and
have to follow set procedures.
• Mass services include supermarkets, a national rail network, an
airport, telecommunications service, library, television station,
the police service and the enquiry desk at a utility.
The product–process matrix
Detailed process design
• After the overall design of a process has been determined, its
individual activities must be configured.
• The detailed design of a process involves identifying all the
individual activities that are needed to meet the objectives of the
process, and deciding on the sequence in which these activities
are to be performed and who is going to do them.
• Some activities must be carried out before others and some
activities can only be done by certain people or equipment.
• Process design is often done using some simple visual approach,
such as process mapping.
Process mapping
• Process mapping simply involves describing processes in terms of
how the activities within the process relate to each other.
• There are many techniques which can be used for process
mapping.
• All the techniques identify the different types of activity that
take place during the process and show the flow of materials or
people or information through the process.
• Process mapping is needed to expose the reality of process
behaviour.
Some common process mapping symbols
Process map for ‘enquire to delivery’ process
at stage lighting operation
The ‘collect and check’ process mapped to
show different levels of process visibility
Little’s law
• The mathematical relationship (throughput time = work-inprogress * cycle time) is called Little’s law.
• It is simple but very useful, and it works for any stable process.
• Little’s law states that the average number of things in the system
is the product of the average rate at which things leave the
system and average time each one spends in the system.
• Little’s law states that Throughput time = Work-in-progress * Cycle
time.
For example
• Suppose it is decided that in a new sandwich assembly and sales
process, the average number of customers in the process should
be limited to around ten and the maximum time a customer is in
the process should be on average four minutes. If the time to
assemble and sell a sandwich in the new process has been reduced
to 1.2 minutes, how many staff should be serving?
• Putting this into Little’s law: Throughput time = 4 minutes and
Work-in-progress, WIP = 10
• So since: Throughput time = WIP * cycle time
Cycle time = Throughput time
WIP
Let’s discuss
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What is process design?
What objectives should process design have?
How do volume and variety affect process design?
How are processes designed in detail?
Any questions?
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