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Before
Process Analysis

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High Cash Flow and Profit
Leakage |
After
Process Analysis

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Cash Flow and Profit Leakage
Has Been Stopped |
Process Analysis Overview
An operation is composed of processes designed to add value by transforming
inputs into useful outputs. Inputs may be materials, labor, energy, and capital
equipment.
Outputs may be a physical product (possibly used as an input to another process)
or a service. Processes can have a significant impact on the performance of a
business, and process improvement can improve a firm’s competitiveness.
The first step to improving a process is to analyze it in order to understand
the activities, their relationships, and the values of relevant metrics. Process
analysis generally involves the following tasks:
● Define the process boundaries that mark the entry points of the process inputs
and the exit points of the process outputs.
● Construct a process flow diagram that illustrates the various process
activities and their interrelationships.
● Determine the capacity of each step in the process. Calculate other measures
of interest.
● Identify the bottleneck, that is, the step having the lowest capacity.
● Evaluate further limitations in order to quantify the impact of the
bottleneck.
● Use the analysis to make operating decisions and to improve the process.
Process Flow Diagram
The process boundaries are defined by the entry and exit points of inputs and
outputs of the process.
Once the boundaries are defined, the process flow diagram (or process flowchart)
is a valuable tool for understanding the process using graphic elements to
represent tasks, flows, and storage. The following is a flow diagram for a
simple process having three sequential activities:
Process Flow Diagram
The symbols in a process flow diagram are defined as follows:

● Rectangles: represent tasks
● Arrows: represent flows. Flows include the flow of material and the flow of
information. The flow of information may include production orders and
instructions. The information flow may take the form of a slip of paper that
follows the material, or it may be routed separately, possibly ahead of the
material in order to ready the equipment. Material flow usually is represented
by a solid line and information flow by a dashed line.
● Inverted triangles: represent storage (inventory). Storage bins commonly are
used to represent raw material inventory, work in process inventory, and
finished goods inventory.
● Circles: represent storage of information.
● In a process flow diagram, tasks drawn one after the other in series are
performed sequentially. Tasks drawn in parallel are performed simultaneously.
In the above diagram, raw material is held in a storage bin at the beginning of
the process. After the last task, the output also is stored in a storage bin.
When constructing a flow diagram, care should be taken to avoid pitfalls that
might cause the flow diagram not to represent reality. For example, if the
diagram is constructed using information obtained from employees, the employees
may be reluctant to disclose rework loops and other potentially embarrassing
aspects of the process.
Similarly, if there are illogical aspects of the process flow, employees may
tend to portray it as it should be and not as it is. Even if they portray the
process as they perceive it, their perception may differ from the actual
process. For example, they may leave out important activities that they deem to
be insignificant.

Process Performance Measures
Operations managers are interested in process aspects such as cost, quality,
flexibility, and speed. Some of the process performance measures that
communicate these aspects include:
● Process capacity - The capacity of the process is its maximum output rate,
measured in units produced per unit of time. The capacity of a series of tasks
is determined by the lowest capacity task in the string. The capacity of
parallel strings of tasks is the sum of the capacities of the two strings,
except for cases in which the two strings have different outputs that are
combined. In such cases, the capacity of the two parallel strings of tasks is
that of the lowest capacity parallel string.
● Capacity utilization - the percentage of the process capacity that actually is
being used.
● Throughput rate (also known as flow rate ) - the average rate at which units
flow past a specific point in the process. The maximum throughput rate is the
process capacity.
● Flow time (also known as throughput time or lead time) - the average time that
a unit requires to flow through the process from the entry point to the exit
point. The flow time is the length of the longest path through the process. Flow
time includes both processing time and any time the unit spends between steps.
● Cycle time - the time between successive units as they are output from the
process. Cycle time for the process is equal to the inverse of the throughput
rate. Cycle time can be thought of as the time required for a task to repeat
itself. Each series task in a process must have a cycle time less than or equal
to the cycle time for the process. Put another way, the cycle time of the
process is equal to the longest task cycle time. The process is said to be in
balance if the cycle times are equal for each activity in the process. Such
balance rarely is achieved.
● Process time - the average time that a unit is worked on. Process time is flow
time less idle time.
● Idle time - time when no activity is being performed, for example, when an
activity is waiting for work to arrive from the previous activity. The term can
be used to describe both machine idle time and worker idle time.
● Work In process - the amount of inventory in the process.
● Set-up time - the time required to prepare the equipment to perform an
activity on a batch of units. Set-up time usually does not depend strongly on
the batch size and therefore can be reduced on a per unit basis by increasing
the batch size.
● Direct labor content - the amount of labor (in units of time) actually
contained in the product. Excludes idle time when workers are not working
directly on the product. Also excludes time spent maintaining machines,
transporting materials, etc.
● Direct labor utilization - the fraction of labor capacity that actually is
utilized as direct labor.

Little’s Law
The inventory in the process is related to the throughput rate and throughput
time by the following equation:
W.I.P. Inventory = Throughput Rate x Flow Time
This relation is known as Little’s Law, named after John D.C. Little who proved
it mathematically in 1961. Since the throughput rate is equal to 1 cycle time,
Little’s Law can be written as:
Flow Time = work-in-process inventory (W.I.P.) x Cycle Time
The Process Bottleneck
The process capacity is determined by the slowest series task in the process;
that is, having the slowest throughput rate or longest cycle time. This slowest
task is known as the bottleneck. Identification of the bottleneck is a critical
aspect of process analysis since it not only determines the process capacity,
but also provides the opportunity to increase that capacity.
Saving time in the bottleneck activity saves time for the entire process. Saving
time in a non-bottleneck activity does not help the process since the throughput
rate is limited by the bottleneck. It is only when the bottleneck is eliminated
that another activity will become the new bottleneck and present a new
opportunity to improve the process.
If the next slowest task is much faster than the bottleneck, then the bottleneck
is having a major impact on the process capacity. If the next slowest task is
only slightly faster than the bottleneck, then increasing the throughput of the
bottleneck will have a limited impact on the process capacity.

Starvation and Blocking
Starvation occurs when a downstream activity is idle with no inputs to process
because of upstream delays. Blocking occurs when an activity becomes idle
because the next downstream activity is not ready to take it. Both starvation
and blocking can be reduced by adding buffers that hold inventory between
activities.
Process Improvement
Improvements in cost, quality, flexibility, and speed are commonly sought. The
following lists some of the ways that processes can be improved.
● Reduce work-in-process inventory - reduces lead time.
● Add additional resources to increase capacity of the bottleneck. For example,
an additional machine can be added in parallel to increase the capacity.
● Improve the efficiency of the bottleneck activity - increases process
capacity.
● Move work away from bottleneck resources where possible - increases process
capacity.
● Increase availability of bottleneck resources, for example, by adding an
additional shift - increases process capacity.
● Minimize non-value adding activities - decreases cost, reduces lead time. Non-
value adding activities include transport, rework, waiting, testing and
inspecting, and support activities.
● Redesign the product for better manufacturability - can improve several or all
process performance measures.
● Flexibility can be improved by outsourcing certain activities. Flexibility
also can be enhanced by postponement, which shifts customizing activities to the
end of the process.
In some cases, dramatic improvements can be made at minimal cost when the
bottleneck activity is severely limiting the process capacity. On the other
hand, in well optimized processes, significant investment may be required to
achieve a marginal operational improvement. Because of the large investment, the
operational gain may not generate a sufficient rate of return. A cost-benefit
analysis should be performed to determine if a process change is worth the
investment. Ultimately, net present value will determine whether a process
“improvement” really is an improvement.

Consider The Vickers Company Analysts
The Vickers Company is staffed with trained, analytical minds: men and women who
have proven themselves as professional managers in large, multi-business
corporations and in smaller, private operations.
Many have owned their own businesses. Many have degrees in statistical analysis,
engineering, economics, business administration, law and accounting.
They know how to recognize a problem, lay the causes bare, prescribe effective
remedies and help you put a corrective plan to work.
You can rely on our Business Analysts to make an unbiased inspection of every
aspect of your business and play no politics with you.
You will be treated with respect, but you will be told exactly what is wrong and
where the responsibility lies.
We will discuss your position with you realistically and in detail describing
corrections to be made.
Then, with your approval, we will provide you with a detailed analysis, a plan
of action and the active help you need to straighten things out.
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