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Part Three
Planning and control
2 Waiting time. Equipment efficiency and labour efficiency are two popular measures which
are widely used to measure equipment and labour waiting time, respectively. Less obvious
is the amount of waiting time of items, disguised by operators who are kept busy producing
WIP which is not needed at the time.
3 Transport. Moving items around the operation, together with the double and triple
handling of WIP, does not add value. Layout changes which bring processes closer
together, improvements in transport methods and workplace organization can all reduce
waste.
4 Process. The process itself may be a source of waste. Some operations may only exist because
of poor component design, or poor maintenance, and so could be eliminated.
5 Inventory. All inventory should become a target for elimination. However, it is only by
tackling the causes of inventory that it can be reduced.
6 Motion. An operator may look busy but sometimes no value is being added by the work.
Simplification of work is a rich source of reduction in the waste of motion.
7 Defectives. Quality waste is often very significant in operations. Total costs of quality are
much greater than has traditionally been considered, and it is therefore more important
to attack the causes of such costs. This is discussed further in Chapter 17.
Between them, these seven types of waste contribute to four barriers to any operation achieving
lean synchronization. They are: waste from irregular (non-streamlined) flow, waste from
inexact supply, waste from inflexible response, and waste from variability. We will examine
each of these barriers to achieving lean synchronization.
Eliminate waste through streamlined flow
The smooth flow of materials, information and people in the operation is a central idea of lean
synchronization. Long process routes provide opportunities for delay and inventory buildup,
add no value, and slow down throughput time. So, the first contribution any operation
can make to streamlining flow is to reconsider the basic layout of its processes. Primarily,
reconfiguring the layout of a process to aid lean synchronization involves moving it down
the ‘natural diagonal’ of process design that was discussed in Chapter 4. Broadly speaking,
this means moving from functional layouts towards cell-based layouts, or from cell-based
layouts towards product layouts. Either way, it is necessary to move towards a layout that
brings more systematization and control to the process flow. At a more detailed level, typical
layout techniques include: placing workstations close together so that inventory physically
just cannot build up because there is no space for it to do so, and arranging workstations
in such a way that all those who contribute to a common activity are in sight of each other
and can provide mutual help, for example by facilitating movement between workstations
to balance capacity.
Value stream mapping
Examine all elements of throughput time
Throughput time is often taken as a surrogate measure for waste in a process. The longer
that items being processed are held in inventory, moved, checked, or subject to anything else
that does not add value, the longer they take to progress through the process. So, looking at
exactly what happens to items within a process is an excellent method of identifying sources
of waste.
Value stream mapping (also known as ‘end-to-end’ system mapping) is a simple but
effective approach to understanding the flow of material and information as a product or
service has value added as it progresses through a process, operation, or supply chain. It
visually maps a product or services ‘production’ path from start to finish. In doing so it
records, not only the direct activities of creating products and services, but also the ‘indirect’
information systems that support the direct process. It is called ‘value stream’ mapping
because it focuses on value-adding activities and distinguishes between value-adding and