Manufacturing Practices

Lean
Doing more with less by employing 'lean thinking'. Lean manufacturing involves
never ending efforts to eliminate or reduce 'muda' (Japanese for waste or any
activity that consumes resources without adding value) in design, manufacturing,
distribution, and customer service processes. It was developed by Toyota
Executive Taiichi Ohno during the post- Second World War reconstruction period
in Japan.

The primary elements of Lean are:

To have only the required inventory when needed; to improve quality to zero
defects; to reduce lead times by reducing setup times, queue lengths, and lot
sizes; to incrementally revise the operations themselves; to accomplish these
things at minimum cost.

Seven types of wastes (7 deadly wastes):

1. Unnecessary Transportation: This waste refers to any unnecessary
transportation, such as that commonly associated with the transit of materials or
parts. Transportation is not a value add activity as it does not help transform the
product into the customer requirement and can add further problems through
delays, damage or items being lost.

2. Unnecessary Processing: Over processing is typified by carrying out more

work on a product than is required
– this might be using more precision tools than are required through to, in the
example of office activity, bureaucratic approval systems for documents
requiring multiple signatories or reviews. Removing over processing requires
careful consideration to ascertain the actual requirement and ensuring that the
process is engineered to meet this without any further burden.

3. Unnecessary Motion: An effective working environment can help reduce

motion for a given process. This may entail providing tools and equipment at
point of use or making material handling processes more efficient. A common
tool used to analyze motion is the spaghetti diagram which can be very effective
at highlighting issues.

4. Inventory: Any parts or materials that are not immediately required are
considered waste – Inventory is one of the seven wastes that is most easy to spot
in that it is easy to physically see around the business. Inventory is waste as it ties
up resources to manage it for example storage space, personnel, capital outlay
and processing.

5. Waiting Time: It is very common – take looks at your business are parts
stacked up waiting for next part of the assembly process? Are office in-tray‘s
piled high with documents waiting to be processed? A number of causes can
result in waiting – often with product batch sizes being a primary trigger.

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6. Defects: Getting it wrong results in waste – whether that‘s manufacturing
faulty parts that require rework or at worst being scrapped or documents that are
incorrectly completed which can result in confusion or mistakes. Defects have a
very real impact on the bottom line of your business and can be one of the key
contributors to inefficiency.

7. Overproduction: Producing more of something than is required by the

customer is waste – close attention to batch sizes and change over times can be
imperative in not over producing. The impact of overproducing can be
considerable – not only is extra-material consumed but extra processing and
storage requirements add to the problem causing another of the seven wastes –
inventory.

Kaizen
Kaizen is a lean manufacturing tool that encourages continuous improvement in
quality, technology, processes, productivity, safety, and workplace culture.
Kaizen focuses on applying small, daily changes that result in major
improvements over time.

It provides one simple principle: look at how things can be improved, improve
them, and then improve them again and again. Some of the tools used to achieve
kaizen are :

Automation: Look for processes that can be automated to improve efficiency

and make work easier.

Kanban: Reduce waste by getting the inventory you need, when you need it.
5S: Adopt 5S as a system for continuous improvement by achieving facility-wide
organization and cleanliness.

TPM: Eliminate downtime and boost overall production through Total

Productive Maintenance.

Toyota Production System

The production system was developed by Toyota Motor Corporation to provide
best quality, lowest cost, and shortest lead time through the elimination of waste.
TPS is comprised of two pillars, Just-in-Time and Jidoka (autonomation)

TPS is maintained and improved through iterations of standardized work and

kaizen (continuous improvement), following Plan–Do-Check-Act.

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Jidoka
The term jidoka used in the TPS (Toyota Production System) can be defined as
"automation with a human touch." Providing machines and operators the ability to
detect when an abnormal condition has occurred and immediately stop work.
This enables operations to build in quality at each process and to separate men
and machines for more efficient work. Jidoka sometimes is called autonomation,
meaning automation with human intelligence. This is because it gives equipment
the ability to distinguish good parts from bad autonomously, without being
monitored by an operator. This eliminates the need for operators to continuously
watch machines and leads in turn to large productivity gains because one
operator can handle several machines, often termed multiprocess handling.
Jidoka originated in the form of a simple device that could stop the shuttle of an
automatic loom if the thread broke. The mechanism was able to detect if a
thread is broken and therefore immediately shut down the machine and signal
that there’s a problem to avoid producing defects. Afterward, the worker
operating the loom had to fix the problem and resume the production process.

Since equipment stops when a problem arises, a single operator can visually
monitor and efficiently control many machines. As an important tool for this
"visual control" or "problem visualization," Toyota plants use a problem display
board system called "andon" that allows operators to identify problems in the
production line with only a glance.

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Heijunka
A technique to facilitate Just-In-Time (JIT) production, levelling the type and
quantity of production over a fixed period of time. This enables production to
efficiently meet customer demands while avoiding batching and results in
minimum inventories, capital costs, manpower, and production lead time through
the whole value stream.

Say a hat producer receives orders for 500 of the same hat per week: 200 orders
on Monday, 100 on Tuesday, 50 on Wednesday, 100 on Thursday, and 50 on
Friday. Instead of trying to meet demand in sequence of the orders, the hat
producer would use heijunka to level demand by producing an inventory of 100
hats near shipping to fulfill Monday’s orders. Every Monday, 100 hats will be in
inventory. The rest of the week, production will make a 100 hats per day – a level
amount. The inventory might look a little suspicious to Lean purists, but it has its
fans – it is the method the Toyota Production System uses today.

What if the situation involves multiple types of hats? Consider that orders are
being placed for hat models A, B, C and D. A mass producer will want to minimize
waste around equipment changeovers. Its production schedule will look
something like this: AAAAABBBCCDD.

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But what if a buyer decides at the last minute that orders of A need to be B
instead? What if order volumes for A suddenly drop off the map and orders for C
begin to increase? A mass producer might be desperate to find capacity to make
more C while its A capacity sits. To avoid such waste, a heijunka production
schedule might look like AABCDAABCDAB, with emphasis placed on efficient
changeover times and buffer inventories that meet demand for more popular
items.

Poka Yoke
The term means “foolproof” and refers to a device or mechanism that prevents
defects from occurring. Example:

● Electric plugs have an earth pin that is longer than the other pins and is the
first to make contact with the socket. The protective shield of the neutral and
earth sockets are then opened safely.
● The device could be a clamp that can be placed only in a certain way
● A lid that can be turned in only one direction.
● In McDonald’s, the French fry scoop and standard size bag used to measure
the correct quantity are poka-yokes.
● Checklists are another type of poka yoke.

Just-In-Time (JIT)

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Just-in-time is an inventory strategy companies employ to increase efficiency
and decrease waste by receiving goods only as they are needed in the
production process, thereby reducing inventory costs. This method requires
producers to forecast demand accurately.

This inventory supply system represents a shift away from the older just-in-case
strategy, in which producers carried large inventories in case higher demand had
to be met.

● The main objective of JIT manufacturing is to reduce manufacturing lead

times.
● This is primarily achieved by drastic reductions in work-in- process (WIP).
● 100% capacity utilization is not the predominant objective.
● The result is a smooth, uninterrupted flow of small lots of products
throughout production.

Example: Dell has leveraged JIT principles to make its manufacturing process a
success. Dell’s approach to JIT is different in that they leverage their suppliers to
achieve the JIT goal. They are also unique in that Dell is able to provide
exceptionally short lead times to their customers, by forcing their suppliers to
carry inventory instead of carrying it themselves and then demanding (and
receiving) short lead times on components so that products can be simply
assembled by Dell quickly and then shipped to the customer.

Kanban
Kanban is a visual system for managing work as it moves through a process.
Kanban visualizes both the process (the workflow) and the actual work passing
through that process. The goal of Kanban is to identify potential bottlenecks in
your process and fix them so work can flow through it cost- effectively at an
optimal speed or throughput. It is a method for managing the creation of
products with an emphasis on continual delivery while not overburdening the
development team.

Kanban is based on 3 basic principles:

● Visualize what you do today (workflow): seeing all the items in context of
each other can be very informative
● Limit the amount of work in progress (WIP): this helps balance the flow-
based approach so teams don’t start and commit to too much work at once
● Enhance flow: when something is finished, the next highest thing from the
backlog is pulled into play. Kanban promotes continuous collaboration and
encourages active, ongoing learning and improving by defining the best
possible team workflow.

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Kanban WIP Limits
A key aspect of Kanban is to reduce the amount of multi- tasking that most
teams and knowledge workers are prone to do and instead encourage them to
“Stop Starting! And Start Finishing!”, a mantra coined by Dr. Arne Roock (of
www.Software-Kanban.de). WIP – Work-in-Progress – Limits defined at each
stage of the workflow on a Kanban board encourage team members to finish
work at hand and only then, take up the next piece of work.

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Gemba, Gembutsu, Genjitsu
Gemba – Place of Production
Gemba is a term that is often used to describe ‘where the action occurs’ or in the
case of most manufacturing facilities, the shop floor. A related term gemba walk,
means to get out of your office and go out to the shop floor where the actual
work is performed.

The idea behind gemba walks, and gemba in general, is to end the trend of
managers sitting in their offices and making decisions based exclusively on
reports or second hand information. While this type of information is critical, it is
no substitute for actually seeing how things are running and interacting with the
front line employees.

Gembutsu – The Actual Product

Looking at the actual end product and the product at various stages of
manufacturing helps you see where the value is added throughout the
manufacturing process. It helps you to streamline its creation by eliminating
costly or time consuming steps that don’t add significant value to the customers.
This is critical because anything that expends the facility’s time or other
resources without adding value in the eyes of the customer is a significant form
of waste.

Genjitsu – The Facts

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Genjitsu means ‘the facts.’ In this context it means that managers need to work
hard to find the facts of any given situation. Many people mistake this for
meaning they need to find out who or what to blame for problems, but that is not
the case. Making an effort to determine the facts of the matter will give you the
information needed to make changes required to avoid problems and eliminate
waste wherever possible. Even if it is determined that someone is doing
something wrong, that does not necessarily mean that they need to be
disciplined or even fired. Instead, it should be looked at as a learning opportunity
for both the employee and the whole team.

Theory of Constraints
The core concept of the Theory of Constraints is that every process has a single
constraint and that total process throughput can only be improved when the
constraint is improved. A very important corollary to this is that spending time
optimizing non-constraints will not provide significant benefits; only
improvements to the constraint will further the goal (achieving more profit).The
Five Steps of the

Theory of Constraints:
Identify the System Constraint: Identify the current constraint (the single part of
the process that limits the rate at which the goal is achieved).
Decide How to Exploit the Constraint: Make quick improvements to the
throughput of the constraint using existing resources (i.e. make the most of what
you have). Subordinate Everything Else: The non-constraint components of the
system must be adjusted to a "setting" that will enable the constraint to operate
at maximum effectiveness. Once this has been done, the overall system is
evaluated to determine if the constraint has shifted to another component. If the
constraint has been eliminated, the change agent jumps to step five.
Elevate the Constraint: If the constraint still exists (i.e. it has not moved), consider
what further actions can be taken to eliminate it from being the constraint.
Normally, actions are continued at this step until the constraint has been “broken”
(until it has moved somewhere else). In some cases, capital investment may be
required. This step is only considered if steps two and three have not been
successful. Major changes to the existing system are considered at this step.
Return to Step One, But Beware of "Inertia"

What are Constraints?

Constraints are anything that prevents the organization from making progress
towards its goal. In manufacturing processes, constraints are often referred to as

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bottlenecks. Interestingly, constraints can take many forms other than
equipment.

Physica Typically equipment, but can also be other tangible items, such as material
l shortages, lack of people, or lack of space.

Required or recommended ways of working. May be informal (e.g. described to

new employees as “how things are done here”). Examples include company
Policy procedures (e.g. how lot sizes are calculated, bonus plans, overtime policy),
union contracts (e.g. a contract that prohibits cross-training), or government
regulations (e.g. mandated breaks).

Deeply engrained beliefs or habits. For example, the belief that “we must always
Paradig
keep our equipment running to lower the manufacturing cost per piece”. A close
m
relative of the policy constraint.

Occurs when production capacity exceeds sales (the external marketplace is

constraining throughput). If there is an effective ongoing application of the
Market
Theory of Constraints, eventually the constraint is likely to move to the
marketplace.

5S
"A place for
everything,
What does it What problems are
and Why is it important?
mean? avoided?
everything in
its place" Pillar

Sort Remove all Space, time, money, The factory becomes

items not energy, and other increasingly crowded and
needed for resources can be hard to work in. Storage of
current managed and used unneeded items gets in
production most effectively. the way of communication.
operations.
Reduces problems Time wasted searching for
Leave only the and annoyances in the parts/tools.
bare work flow.
essentials: Unneeded inventory and

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 machinery are costly to
maintain.
Improves
communication
Excess stock hides
between workers.
When in doubt, production problems.
Increases product
throw it out
quality.
Unneeded items and
equipment make it harder
Enhances productivity
to improve the process
flow

Arrange Eliminates many kinds

needed items Motion waste. Searching
of waste, including:
so that they waste. Waste of human
are easy to energy.
Searching waste.
use.
Set in order Waste of excess inventory.
Waste due to difficulty
Label items so
in using items.
that anyone Waste of defective
can find them products. Waste of unsafe
or put them Waste due to difficulty
conditions
away. in returning items

Statistical Process Control

Statistical Process Control (SPC) is an industry-standard methodology for
measuring and controlling quality during the manufacturing process. Quality data
in the form of Product or Process measurements are obtained in real-time during
manufacturing. This data is then plotted on a graph with pre- determined control
limits. Control limits are determined by the capability of the process, whereas
specification limits are determined by the client's needs.

Data that falls within the control limits indicates that everything is operating as
expected. Any variation within the control limits is likely due to a common cause
—the natural variation that is expected as part of the process. If data falls outside
of the control limits, this indicates that an assignable cause is likely the source of
the product variation, and something within the process should be changed to fix
the issue before defects occur.

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Control Limits and Specification Limits
Control limits are determined by the capability of the process, whereas
specification limits are determined by the client's needs.
Specification limits are the targets set for the process/ product by customer or
market performance or internal target. In short it is the intended result on the
metric that is measured.

Control limits on the other hand are the indicators of the variation in the
performance of the process. It is the actual values that the process is operating
on. It is the real time value.

For example, consider a process of filling chips into packets of 100gm. The
process may have control limits of 95 gm to 105 gm. This means the current
process though ideally should fill exactly 100 gms of chips in each packet, fills
anywhere between 95 to 105 gm of chips.

On the other hand, the specification limits are those which are set by the
processor/customer. For example, in this case there may be a specification limit
between 98 gm to 102 gms, i.e customer will tolerate only if there is a +/- 2 gm of
variations. Hence generally, the specification limits should be greater than the
control limits (measured from the mean of the process). This ensures that client
and other needs are satisfied. 48

PDCA
PDCA is an iterative four-step management method used in business for the
control and continuous improvement of processes and products. It is also known
as the Deming circle/cycle/wheel, Shewhart cycle, control circle/cycle, or plan–
do–study– act (PDSA).

The steps in each successive PDCA cycle are:

PLAN
Establish the objectives and processes necessary to deliver results in accordance
with the expected output (the target

or goals).

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DO
Implement the plan, execute the process, and make the product. Collect data for
charting and analysis in the following "CHECK" and "ACT" steps.

CHECK
Study the actual results (measured and collected in "DO" above) and compare
against the expected results (targets or goals from the "PLAN") to ascertain any
differences.

ACT
Request corrective actions on significant differences between actual and planned
results. Analyze the differences to determine their root causes. Determine where
to apply changes that will include improvement of the process or product.

Six Sigma
Six Sigma is a disciplined, data-driven approach and methodology for eliminating
defects. To achieve Six Sigma, a process must not produce more than 3.4 defects
per million opportunities. A Six Sigma defect is defined as anything outside of
customer specifications. A Six Sigma opportunity is then the total quantity of
chances for a defect.
There are two Six Sigma sub-methodologies: - DMAIC and DMADV. The Six
Sigma DMAIC process (define, measure, analyze, improve, control) is an
improvement system for existing processes falling below specification and
looking for incremental improvement.

DMADV process (define, measure, analyze, design and verify) is a Six Sigma
framework that focuses primarily on the development of a new service, product
or process as opposed to improving a previously existing one.

How are DMAIC and DMADV Different?

Despite the shared first three letters of their names, there are some notable
differences between them. The main difference exists in the way the final two

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steps of the process are handled. With DMADV, the Design and Verify steps deal
with redesigning a process to match customer needs, as opposed to the Improve
and Control steps that focus on determining ways to readjust and control the
process. DMAIC typically defines a business process and how applicable it is;
DMADV defines the needs of the customer as they relate to a service or product.

With regards to measurement, DMAIC measures current performance of a

process while DMADV measures customer specifications and needs. Control
systems are established with DMAIC in order to keep check on the business’
future performance, while with DMADV, a suggested business model must
undergo simulation tests to verify efficacy.

DMAIC concentrates on making improvements to a business process in order to

reduce or eliminate defects; DMADV develops an appropriate business model
destined to meet the customers’ requirements.

The Six Sigma DMADV process (define, measure, analyze, design, verify) is an
improvement system used to develop new processes or products at Six Sigma
quality levels.

Quality Function Deployment

QFD is a structured method that uses the seven management and planning tools
to identify and prioritize customers’ expectations quickly and effectively.
Beginning with the initial matrix, commonly termed the house of quality, the QFD
methodology focuses on the most once you have prioritized the attributes and
qualities, QFD deploys them to the appropriate organizational function for action
important product or service attributes or qualities. Thus, QFD is the deployment

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of customer-driven qualities to the responsible functions of an organization.

51

Zero Defects – The Theory and Implementation

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Zero defects theory ensures that there is no waste existing in a project. Waste
here refers to all unproductive process, tools, employee etc. So, anything that is
unproductive and does not add value to a project should be eliminated from the
project. By doing this, you reduce waste and thus cut down the cost involved in
the waste. Besides eliminating waste, there should be a process of improvement.
Any scope of improvement that is possible in a project should be experimented.
This ensures the movement towards perfection. Zero defects theory also closely
connects with “right first time” phrase. This means that every project should be
perfect at the very first time itself. Here, again perfect refers to zero defects. Zero
defects theory is based on four elements for implementation in real projects.

Quality is a state of assurance to requirements. Therefore, zero defects in project

means fulfilling requirement at that point of time. Quality should be taken care of
at the very first go rather than solving problems at a later stage.

Quality here is measured in financial terms. One needs to judge waste,

production and revenue in terms of money.

Performance should be judged as per zero defects theory, i.e. near to perfection.
Just being good is not good enough.

Pros and Cons

Zero defects ensure that all waste existing in a project is eliminated in the very
first go itself that leads to cost reduction. Thus, Zero defects leads to waste
reduction along with cost cutting. All these process improves services and
therefore, there is improvement in quality leading to happy customers. However,
there are certain disadvantages of this theory as well. As there is a quest for
perfection and zero defects, more people and process might be involved to find
out the defects which will lead to extra cost. Also over strictness might hamper
the work culture and production in projects. To overcome the cons, along with
following zero defects theory, one needs to ensure continual service
improvement as well.

International Organization for Standardization (ISO)

ISO 9000 is a set of international standards on quality management and quality
assurance developed to help companies effectively document the quality
system elements to be implemented to maintain an efficient quality system.

They are not specific to any one industry and can be applied to organizations of
any size. ISO 9000 can help a company satisfy its customers, meet regulatory
requirements, and achieve continual improvement. However, it should be
considered to be a first step, the base level of a quality system, not a complete
guarantee of quality.

ISO 9000 vs. 9001

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ISO 9000 is a series, or family, of standards. ISO 9001 is a standard within the
family. The ISO 9000 family of standards also contains an individual standard
named ISO 9000. This standard lays out the fundamentals and vocabulary of
quality management systems (QMS).

ISO 9000 Series standards

The ISO 9000 family contains these standards:

● ISO 9001:2015: Quality management systems -Requirements

● ISO 9000:2015: Quality management systems - Fundamentals and vocabulary
● ISO 9004:2009: Quality management systems – Managing for the sustained
success of an organization (continuous improvement)
● ISO 19011:2011: Guidelines for auditing management systems

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