Lean Manufacturing
Cellular Manufacturing
One Piece Flow for Workteams
Chapter 1
An Introduction to
Cellular Manufacturing
Chapter 1 Overview

What Is Cellular Manufacturing?
• One-Piece Flow
• High-Variety Production

Understanding Process and Operations
• Process
• Operations

Benefits of Cellular Manufacturing
• How It Helps Companies
• How it Helps You

Summary
What Is Cellular Manufacturing?






A lean manufacturing approach that helps companies build a
variety of products with as little waste as possible
Equipment and workstations arranged in a sequence that
supports smooth material flow through the process, with minimal
transport or delay
Derived from the word Cell
A Manufacturing Cell consists of people and machines or
workstations required for performing the process steps
For example - if a process for a product requires cutting, followed
by drilling and finishing, the cell would include the equipment for
performing those steps, arranged in that order
Helps companies achieve two important goals of lean:
• One-piece flow
• High-variety production
One Piece Flow

One-piece flow is the state that exists when products move
through a manufacturing process one unit at a time, at a rate
determined by the needs of the customer
 The opposite of one-piece flow is large-lot production
• Goods produced in large lots build delays into the process
• No items can move on to the next process until all items in the lot
have been processed
• The larger the lot, the longer the items sit and wait between steps

One-piece flow is an ideal state
 In daily operation, it is not always possible or desirable to
process items just one at a time
The important thing is to promote continuous flow of
products, with the least amount of delay and waiting
One-Piece Flow Vs. Large-Lot Production
LARGE-LOT PRODUCTION CAN
LOWER A COMPANY’S
PROFITABILITY
ONE-PIECE FLOW SOLVES
THESE PROBLEMS
Makes leadtime between
customer’s order and delivery of
product longer
Allows to deliver a flow of products
to customers with less delay
Requires labor, energy, and space
to store and transport products
Reduces resources required for
storage and transport
Increases chances of product
damage or deterioration
Lowers risk of damage,
deterioration, or obsolescence
Exposes other problems so they
can be addressed
High-Variety Production

In the early days, a company could produce one type of product
• Customers would buy it even if it wasn’t exactly what they liked

Today customers expect variety and customization
• Specific quantities delivered at a specific time

If your company is not flexible enough to serve their needs
customers will go to your competitor
 Cellular manufacturing offers flexibility to give customers the
variety they want
• By grouping similar products into families that can be processed on
same equipment in the same sequence
• Encourages companies to shorten changeover time between
products
• Eliminates a major reason for large-lot production
Understanding Processes and Operations

Converting a factory to cellular manufacturing means
eliminating waste from processes as well as from operations
 How do Processes and Operations differ and intersect?
PROCESSES

A process is a continuous flow through
which raw materials are converted into
finished products in a series of operations.
 The focus is the path of the materials as
they are transformed into something to sell.
 Manufacturing processes have four basic
types of steps or phases:
•Transformation – assembly, machining
•Inspection – comparison to standard
•Transport – change of location
•Storage – waiting period
Only Transformation adds value!
OPERATIONS

In contrast to process, which focuses on
flow, an operation focuses on action.
 An operation is any action performed by
workers or machines on the materials.
 Operational improvements focus on how
specific actions are carried out, and include
studying the motions required for a specific
action.
Understanding Processes and Operations

To improve production for lean manufacturing, it is not enough
to improve operations
 Companies must also improve their processes
 Improving a process involves streamlining the flow of materials
to minimize obstacles and wastes such as:
1. Time spent in non-value-adding steps
 Such as waiting and transport
2. Downtime caused by changeover and adjustments
3. Distance materials or WIP must travel between transformation
steps
4. The need for inspection or rework
The cellular manufacturing approach works on improving the
process as well as specific operations
Benefits of Cellular Manufacturing

Promoting one-piece flow through cellular manufacturing can
help make your company more competitive
 Cut costly transport and delay from the manufacturing process
 Shortens the production leadtime
• Serves customer needs
• Gives an earlier return on the investment in the product

Saves space in the factory
• Can be used for other value-adding purposes

Promotes continuous improvement
• By forcing solutions to problems that block low-inventory production
How Cellular Manufacturing Helps You?

Cellular manufacturing also helps you as a company employee
 By straightening the company’s competitiveness, it helps
support job security
 Makes daily production work go smoother by:
•
•
•
•

Removing clutter of excess WIP inventory
Reducing transport and unnecessary handling
Reducing walking required to complete processes
Addressing causes of defects and machine problems that cause
delays
You may have to learn a process sequence you have not done
before.
• Raise your skill and flexibility, and may change how you think
about your role in the company

Learning about and participating in a JIT transformation
ultimately will make you more employable!
Summary

Cellular Manufacturing
• Lean manufacturing approach that helps build a variety of products
with minimum waste

Equipment and workstations arranged in a sequence with a
smooth flow of materials and components through the process
• Minimal transport or delays

One-piece flow
• Products move through a manufacturing process one unit at a
time, at a rate determined by the customer’s needs

Cellular Manufacturing gives the flexibility to give customers the
variety they want
 Converting a factory to cellular manufacturing means
eliminating waste from processes and from operations
Lean Manufacturing
Cellular Manufacturing
One Piece Flow for Workteams
Chapter 2
Working in a Manufacturing Cell
Chapter 2 Overview

Operating in a U-Shaped Cell

Becoming Multi-skilled, Multi-machine Operators
• Cross-Training for Maximum Flexibility
• Moving with the Work

Using Small, Flexible Machines

Using Autonomation (Jidoka) to Eliminate Machine Watching

Summary
Operating in a U-Shaped Cell

Changing from an operation-based layout to manufacturing
cells will change how people do their work in the factory

In a manufacturing cell, the equipment and workstations are
arranged close together in sequence of processing steps
• Reduce unnecessary walking and transport to promote flow

The equipment in a cell is usually laid out in a curved shape
• The operator’s path is like a U or C

These shapes bring the end point of the process close to the
beginning point
• Minimizes distance the operator has to travel to begin the next
cycle
Typical Manufacturing Cell
Working in a Cell
Operating in a U-Shaped Cell
Cell Lay-Out
input
output
Becoming Multiskilled/Multimachine Operators

Creating a manufacturing cell often changes the relationship
between people and machines in the workplace

Operators may need to learn how to run different types of
equipment to support the process

In cells where automatic machines are used, most of the
operator’s time is spent watching the equipment run
• Such waste is avoided by teaching people to operate
several different machines in the process
• Operators can be setting up a workpiece for step 2 while
step 1 machine is processing another workpiece
Becoming Multiskilled/Multimachine
Operators..

A cell may be run by one person or by several people
working together
• Depending on the size of the cell, cycle times, or
production volume

Flexibility to change how people work together in a cell
comes from cross-training
Cross-Training for Maximum Flexibility

Cross-training enables employees to perform different
functions within a process
• Lets teams take full responsibility for their processes.

Operator trained on several machines is qualified to
respond to changes in production needs by performing
different tasks as needed
• This versatility (flexibility) makes employees more
valuable to their teams and to their companies
Cross-Training for Maximum Flexibility

Cross-training is a source of employee pride in many
workplaces

Visual display charts are often used to recognize people’s
skill attainment (achievement) in a public way
• Cross-training metrics
Moving with The Work

Running several machines in sequence
• An operator needs to work standing up rather than
sitting down

To assist one-piece flow manufacturing
• People stand and walk so that work moves smoothly
through the process

Working while standing
• Enables people to respond more quickly if machine
problems occur
Using Small, Flexible Machines

A cellular manufacturing process may use equipment
different from that used in large-lot production
• Works best with machines that are smaller and often
slower than large-lot equipment

Smaller machines save space
• Placing them close together reduces walking distance
• Leaves no space for excess WIP to accumulate

Slower machines are appropriate
• They can produce one piece at a time at a speed
determined by customer requirements
Using Small, Flexible Machines…

Machines for cellular manufacturing
• Flexible and be easy to set up quickly
• Used to make a greater variety of products during a
single shift

Smaller machines are less expensive
• Easier to operate and maintain
Using Autonomation (Jidoka) to
Eliminate Machine Watching

Autonomation - an approach to automation that gives
equipment “intelligence” so people don’t have to monitor
automatic operation

“Autonomated” machines - semi-automatic machines that
autonomously (independently) support one-piece flow
processing:
• Stop and signal when a cycle is complete or when problems occur
• Often loaded by operators
• Often set up to unload automatically after processing

Many companies invest in automation
• People don’t have to perform difficult, dangerous, or repetitive work
Summary

Equipment and workstations arranged close together in
sequence of processing steps (U or C)
 Relationship between people and machines changes
• Operators may need to learn how to run different types of
equipment to support the process

Machine-watching is avoided
• Teaching people to operate several different machines

Flexibility to change how people work together in a cell comes
from cross-training
 Cellular manufacturing works best with smaller and often slower
machines
 Autonomation (jidoka) is an approach to automation that gives
equipment “intelligence” so people don’t have to monitor
automatic operation