IE 484: Integrated Production Systems II

– Spring 2024

Chapter 5

Mohamed Salama, Ph.D.,

Visiting Assistant Professor
School of Industrial Engineering,
Purdue University, West Lafayette, IN

Introduction
Based on our discussion of Chapter 1- slide 11,
Material Handling System design is an important
component of the overall facilities design.

The layout design and the

material handling system
design are inseparable.
i.e., Both designs must
be jointly considered.

There is typically NO one “best” solution to

a material handling system design problem.
Scope and Definitions of Material Handling
In a typical industrial facility, material handling accounts for
• 25% of all employees
• 55% of all factory space Material handling system is the
• 87% of production time backbone of any industrial facility.
• Between 15% and 70% of the total cost of a manufactured product.

At almost any facility,

many improvements to material handling can be achieved.

Ideal goal: “Totally eliminate” material handling activities!

But this is impossible!

What is your goal in practice as a “facilities planner”?

Reducing the number of times each specific product is handled.
Result: reduced requirements for material handling equipment.
A different perspective:
Not simply handling less, but focusing on reducing total manufacturing costs
through more efficient material flow control.

Scope and Definitions of Material Handling (cont.)

Definition 1 (of 2) of “Material Handling”:
(by the Material Handling Institute of America)
Art and science associated with the
o movement
o storage
o control
o protection
of goods and materials
throughout the process of their
o manufacture
o distribution
o consumption
o disposal.

We mainly focus on the flow of materials within the facility,

NOT the entire Supply Chain.
Scope and Definitions of Material Handling (cont.)
Definition 2 (of 2) of “Material Handling”:
Providing
the right amount • “Right amount” refers to the problem of
how much inventory is needed.
of the right material • Optimal for material handling:
in the right condition The just-in-time (JIT) philosophy ‫ؠ‬
not having inventories.
at the right place • “Right amount” ‫ ؠ‬what is needed and
NOT what is anticipated.
in the right orientation • A pull-type material flow control
in the right sequence structure is preferred.
• Smaller load sizes are preferred.
at the right time
for the right cost
by the right method(s).

Scope and Definitions of Material Handling (cont.)

Definition 2 (of 2) of “Material Handling”:
Providing
the right amount • Two most common errors in manual
order picking:
of the right material o picking the wrong amount
o picking the wrong material.
in the right condition • Therefore, an accurate identification
at the right place system is needed. (e.g., Automatic
identification)
in the right orientation o a bar-code-based system.
o Radio-frequency-identification-
in the right sequence based (RFID-based) system.
at the right time • Other basic approaches:
o simplifying the parts numbering
for the right cost system.
o maintaining the integrity and
by the right method(s). accuracy of the database system.
Scope and Definitions of Material Handling (cont.)
Definition 2 (of 2) of “Material Handling”:
Providing
• “Right condition” ‫ ؠ‬the state in which
the right amount the customer desires to receive the
of the right material material.
• Examples of different customer desires:
in the right condition o the material be delivered packed or
unpacked
at the right place o painted or unpainted
in the right orientation o delivered in customer-specified
returnable containers
in the right sequence • The goods must also be received
without damage.
at the right time
for the right cost
by the right method(s).

Scope and Definitions of Material Handling (cont.)

Definition 2 (of 2) of “Material Handling”:
Providing
the right amount • “Right place” ‫ ؠ‬right transportation
route.
of the right material • It is desirable to directly transport
in the right condition material to the point of use rather than
store the material at some intermediate
at the right place location.
• A common undesirable situation:
in the right orientation Materials are left along aisles, causing
in the right sequence disruptions in lift truck operations.
• Centralized versus decentralized storage
at the right time must be explicitly addressed.
for the right cost
by the right method(s).
Scope and Definitions of Material Handling (cont.)
Definition 2 (of 2) of “Material Handling”:
Providing
• “Right orientation” ‫ ؠ‬positioning the
the right amount material for ease of handling.
• Positioning is critical in automated
of the right material
systems, such as in robot handling
in the right condition operations.
• Examples for easing positioning:
at the right place o Changing the part design can
reduce the handling time.
in the right orientation
o Using four-way pallets versus two-
in the right sequence way pallets.

at the right time For a more efficient material flow.

• eliminating unnecessary operations
for the right cost • combining steps
by the right method(s). • changing the sequence of operations

Scope and Definitions of Material Handling (cont.)

Definition 2 (of 2) of “Material Handling”:
Providing
• “Right time” ‫ ؠ‬on-time delivery
the right amount (i.e., neither early nor tardy)
• Reduction in the variance of delivery
of the right material
time is the key to this element
in the right condition • An automated material handling system
(e.g., AGV) is preferred to a manual
at the right place system (e.g., forklift).
• The manual systems have relatively
in the right orientation
very wide deviations in transport times.
in the right sequence • Goal:
o Lower production cycle times
at the right time o Not to lower material handling
delivery times.
for the right cost
o Variance reduction is the key.
by the right method(s).
Scope and Definitions of Material Handling (cont.)
Definition 2 (of 2) of “Material Handling”:
Providing • “Right cost” ് lowest cost
the right amount ‫ ؠ‬most reasonable cost
• Minimizing cost is the wrong objective
of the right material in material handling system design.
• Goal:
in the right condition
Design the most efficient material
at the right place handling systems at the most reasonable
cost.
in the right orientation • Rationale:
o On-time deliveries often result in
in the right sequence
increased customer satisfaction.
at the right time o This can in turn result in increased
demand for the product, thus
for the right cost increasing revenue.
by the right method(s). Requirements-driven material handling
systems. (NOT solution-driven nor
technological-driven)

Scope and Definitions of Material Handling (cont.)

Scope of Material Handling: (according to Apple Inc.)
Three views on the scope of material handling activities —
• Conventional view:
o It focuses solely on the movement of material from one location to another,
within the same manufacturing and distribution facility.
o Example: “How do we move material from the receiving dock to the storage
area?”
o Very little attention to interrelationships among the overall handling tasks
that may occur within the same facility.
• Contemporary view:
It expands the focus to the overall movement of materials in a factory or
warehouse.
• Progressive view:
o It is a total system view.
o Material handling from all suppliers, handling material within the
manufacturing and distribution facility, and the distribution of finished goods
to customers.
Material Handling Principles

NO mathematical model can provide extensive

solutions to the overall material handling problem.
Thus, material handling principles are important in practice.

Ten principles: (for material handling system designers)

1. Planning Principle.
• You must plan (i.e., define a course of action) in advance of
implementation.
• Simple form of a plan:
o the material (what)
o the moves (when and where)
o the method (how and who).
2. Standardization Principle.
Less variety and customization in the methods and equipment employed.

Material Handling Principles (cont.)

3. Work Principle.
Measure of work ‫ ؠ‬material flow (volume, weight, or count per unit of time)
ൈ the distance moved.
4. Ergonomic Principle.
Adapting work (or working conditions) to suit the abilities of the worker.
5. Unit Load Principle.
A unit load is one that can be stored (or moved) as a single entity at one time
(e.g., a pallet, container, or tote) regardless of the number of individual items
that make up the load.
6. Space Utilization.
Space in material handling is three-dimensional.
7. System Principle.
A system is a collection of interacting entities that form a unified whole.
Material Handling Principles (cont.)

8. Automation Principle.
Automation is a technology concerned with the application of
electromechanical devices, electronics, and computer-based systems to operate
and control production and service activities.
9. Environmental Principle.
Not to waste natural resources and to predict and eliminate the possible
negative effects of our daily actions on the environment.
10. Life-Cycle Cost Principle.
It includes all cash flows that will occur from the time the first dollar is spent
to plan or procure a new piece of equipment, or to put in place a new method,
until that method and/or equipment is totally replaced.

Material Handling Principles (cont.)

Material Handling Checklists:

Example:
Designing Material Handling Systems
Six-step engineering design process:
1. Define the objectives and scope for the material handling system.
2. Analyze the requirements for moving, storing, protecting, and controlling
material.
3. Generate alternative designs for meeting material handling system
requirements.
4. Evaluate alternative material handling system designs.
5. Select the preferred design for moving, storing, protecting, and controlling
material.
6. Implement the preferred design (including the selection of suppliers; training
of personnel; installation, debugging, and startup of equipment; and periodic
audits of system performance)

• The material handling system may NOT operate

perfectly the first time.
• Continuous improvement will result in far more
efficient operation of a material handling system.

Designing Material Handling Systems (cont.)

How to develop alternative material handling system designs?
Using an approach consisting of four phases:
1. Aim for the theoretical ideal system.
i.e., a perfect system having zero cost, perfect quality, no safety hazards, no
wasted space, and no management inefficiencies.
2. Conceptualize the ultimate ideal system.
i.e., an achievable system in the future (the technology exists but its application
has not been accomplished yet).
3. Design the technologically workable ideal system.
i.e., a system for which the required technology is available.
However, very high costs (or other conditions) may prevent some components
from being installed now.
4. Install the recommended system.
i.e., a cost-effective system that will work now without obstacles.

Advantages of using this approach:

• Expanding our horizon beyond the current state of the technology.
• Expanding the search for alternatives beyond what the designer knows at present.
Designing Material Handling Systems (cont.)
The Material Handling System Equation:

Why do we need this equation?

A framework to help guide the development of alternative material handling system
designs.

There are six types of questions:

• The what defines the type of materials moved.
• The where identifies the place requirements
• The when identifies the time requirements
• The how and who point to the material handling methods.
• The which leads us to the recommended system.

Designing Material Handling Systems (cont.)

1. What are the types of material to be moved?

2. What are their characteristics?
3. What are the amounts moved and stored?
Designing Material Handling Systems (cont.)

1. Where is the material coming from? Where should it come from?

2. Where is the material delivered? Where should it be delivered?
3. Where is the material stored? Where should it be stored?
4. Where can material handling tasks be eliminated, combined, or simplified?
5. Where can you apply mechanization or automation?

Designing Material Handling Systems (cont.)

1. When is material needed? When should it be moved?

2. When is it time to mechanize or automate?
3. When should we conduct a material handling performance audit?
Designing Material Handling Systems (cont.)

1. How is the material moved or stored? How should the material be moved or
stored? What are the alternative ways of moving or storing the material?
2. How much inventory should be maintained?
3. How is the material tracked? How should the material be tracked?
4. How should the problem be analyzed?

Designing Material Handling Systems (cont.)

1. Who should be handling material? What are the required skills to perform the
material handling tasks?
2. Who should be trained to service and maintain the material handling system?
3. Who should be involved in designing the system?
Designing Material Handling Systems (cont.)

1. Which material handling operations are necessary?

2. Which types of material handling equipment, if any, should be considered?
3. Which material handling system is cost effective?
4. Which alternative is preferred?

Designing Material Handling Systems (cont.)

Material Handling Planning Chart:
It can be used to
• gather information pertaining to a specific material handling problem.
• organize data, analyze material handling problems, and generate alternatives.
• provide a preliminary examination of the alternative solutions.

Note that the resulting solution from the chart should be

analyzed further (for example, using a simulation model.)

A typical “Material Handling Planning Chart” of a product should include

information on operations, transportations, delays, storages, and inspections.

Example:
Designing Material Handling Systems (cont.)
Example of a “Material Can we determine the Distance
Handling Planning Chart”: without a facility layout design?

Unit Load Design

Unit Load ‫ ؠ‬a single item, a number of items, or bulk material which is arranged
and restrained so that the load can be stored, and picked up and moved between
two locations as a single mass.

Examples:
• A single item picked up and moved manually between two locations constitutes
one unit load.
• Two tote pans with identical components picked up and moved by a dolly from
one machine to another constitute one unit load.
• One pallet load of nonuniform-sized cartons with different products picked up
and moved by a lift truck from the packaging area to the shipping dock
constitutes one unit load.
• One full load of products delivered by a truck trailer from a warehouse to a
customer store constitutes one unit load.
• If the trailer is half full, it is still one unit load.

Thus, the MOVE defines the Unit Load.

Unit Load Design (cont.)
The size of the unit load can be
• a single part carried by a person
• a carton moved through a conveyor system
• a number of cartons on a pallet moved by fork lift trucks
• a number of containers moved by rail across states (or by container ships across
continents).

The unit load size specification has a major impact on

specifying the operation of the material handling system.

Small Unit Load Large Unit Load

Equipment Simple (or manual) Big and Heavy
Aisles Narrow Wide
Floor load capacity Low High
Why?
Work-in-process
Low High
inventory
Frequency of moves High Low

Unit Load Design (cont.)

Small unit load size specification supports the Lean Production philosophy.

Example:
Effect of the unit load size on
job completion time

Best!
Large!

Small!

EXCESSIVE small unit load requires VERY fast material handling.

Unit Load Design (cont.)
Two elements in determining the size of the unit load:
• “Cube” limit
• Weight limit
Example: a single carton with outside dimensions 16″ ൈ 12″ ൈ 6″ and a gross
weight limit of 65 lbs.
Standard of writing the box dimensions:
• The length and the width refer to the long and
short side of the box opening, respectively.
• The depth is orthogonal to the length and width.
How can we maintain the “Unit Load” integrity?
Two ways:
• By containing the unit load using
Tote boxes Cartons Pallets
• By enclosing the unit load using
Strapping Shrinkwrapping Stretchwrapping
Loose plastic film Elastic plastic film.
requires heating.

Unit Load Design (cont.)

Dimensional relationships between the various forms of unit load:

Cartons are stacked on pallets.

The full pallet loads are either

o block-stacked in a warehouse
before they are loaded on trailers
for shipment to customers.
OR
o loaded directly on trailers.
Unit Load Design (cont.)
The use of returnable containers:
Material Handling Designers should select containers with the following features:
• Stackability
o a full container can be stacked on top of another full container in the same
spatial orientation.
o Lids or tabs that are integrated into the design of the container are often used
to support the container above.
• Nestability
o the shape of the containers permits an empty container to be inserted into
another empty container.

Why?
To reduce Material handling costs

Example:

Unit Load Design (cont.)

Efficiency of Returnable Containers:
How to select the right kind of returnable containers?
Using a progressive dimensions container system.

Example:
A smaller container is
half the size of the larger
container, and so on.

Advantage:
Simplification of the pallet loading
of mixed-sized containers.
Unit Load Design (cont.)
Pallets and Pallet Sizes:
Besides containers (in the previous two slides),
the use of pallets is another common method of containing the unit load.

Common pallet sizes: Common wooden pallet designs:

A common pallet classification:

• Two-way.
The fork entry can be only on two opposite
sides of the pallet.
• Four-way.
The fork entry can be on any side of the pallet.

Material Handling Designers must select

the appropriate pallet size and design.

Unit Load Design (cont.)

Comparison of various types of pallets:
Unit Load Design (cont.)
Pallet Loading Problem:
Loading a pallet of a specific size by drawing from a set of “ܰ" rectangular boxes.

Examples of loading patterns:

Objectives:
• Maximizing the use of space (i.e., the “pallet cube”)
• Maximizing load stability (i.e., uniform loading for safety considerations)

Unit Load Design (cont.)

• In practice, it is common to limit the number of alternative pallet sizes to two or
three popular sizes. (Recall the Standardization Principle)
• A similar “space utilization” problem exists in the loading of cargo on truck
trailers, container ships, and cargo airplanes.
• Pallet loading can be complicated by international supply chain considerations.
Example:
The most common pallets used in North American measurements differ from
Europe and Asia and from Japan and Korea .
¾ North American pallet ‫ ؠ‬48 ൈ 40 inch (or 1219 ൈ 1016 mm)
¾ European and Asian pallet ‫ ؠ‬1200 ൈ 1000 mm.
¾ Japan and Korea pallet ‫ ؠ‬1100 ൈ 1100 mm.
• Many industries in Europe are switching to 1200 ൈ 800 mm pallet due to
practical considerations (it fits through standard doorways).
• The most cost-effective pallet loading choice for the overall supply chain is to
use the pallet size of the receiving country.
Unit Load Design (cont.)
Unit Load Interactions with Transportation:
Warehouse Components: Cartons are
transported to a Palletization:
Assume only one product
palletizer via a Pallet loads are
category (e.g., pens).
belt conveyor. formed using a
Packaging: mechanized
Finished goods are palletizer.
packaged using closed-
top cardboard cartons.
Storage: Retrieval:
Full pallet loads are then stored Upon receiving customer
in the finished-goods warehouse orders, full pallet loads
using a powered lift truck. are retrieved from the
warehouse by a powered
Shipping: lift truck.
Retrieved pallet loads are then
loaded on highway trailer trucks
for delivery to customers. Different unit load sizes!

Unit Load Design (cont.)

• Critical factors:
Specification of the used carton size and the pallet size.
• These two factors directly affect
o the selection of the material handling equipment.
o the physical configuration of the storage facility.
o the utilization of the warehouse.
o the utilization of the highway trailer.
• “Packaging station” to the “Palletizer”:
The carton size is the most critical element in the design of the unit load system
as it determines
o the parts flow rate to the packaging stations.
o the number of parts contained in each carton.
o the time required to package each carton.
o the total number of cartons that may be packaged and transported to the
palletizer.
o the carton flow rate to the palletizer.
Unit Load Design (cont.)
• “Palletizer” to the “Warehouse”:
o The pallet load is formed through a palletizer after determining
¾ the type and size of the pallet
¾ the pallet loading pattern
¾ the rate of forming a full pallet load
(a function of the palletizer capacity, carton size, and pallet size).
o From the palletizer, the full pallet loads are stored in a warehouse.
o A powered lift truck is used to pick up loads from the palletizer for stacking
at the warehouse.

• “Warehouse” to the “Shipping dock area”:

o A powered lift truck is used to retrieve loads from the warehouse to the
shipping dock area.
o The selected type of material handling equipment influences
¾ how high the storage building should be.
¾ the floor space requirement for the warehouse.
Example: “expensive” narrow aisle truck vs. “large” required floor space.

Unit Load Design (cont.)

• “Shipping dock area” to the “Highway trailer truck”:
o Loading of the pallet loads into a highway trailer truck for delivery to the
customers.
o The number of pallet loads delivered per truckload is constrained by
¾ the inside dimensions of the trailer truck used.
¾ the dimensions and capability of the dock lift truck to maneuver the load
inside the trailer.
o Tradeoffs must be considered between warehouse storage space utilization
and trailer truck utilization.

Note that the discussion above is about the interactions in a

simplified system (i.e., assuming only one product category).
Unit Load Design (cont.)
Procedure for generating alternative designs:
1. Define system component specifications for
a. Carton
b. Pallet
c. Palletizer
d. Lift truck (warehouse)
e. Warehouse storage
i. Clear height of the building
ii. Pallet rack vs. block stacking
f. Lift truck (shipping dock)
g. Highway trailer truck
2. Determine the number of carton layers per unit load based on weight and
height limits:
a. Unit load weight
b. Unit load height
3. Determine the number of unit loads per bay (or stack) subject to
a. Building height constraint
b. Maximum height capacity of lift trucks

Unit Load Design (cont.)

Procedure for generating alternative designs (cont.):
4. Calculate the area required and cube utilization of the warehouse.
5. Determine the total number of unit loads per trailer based on the following:
a. Dimensional constraints
b. Method of loading trailer
i. One pallet per entry to a trailer
ii. One pallet stack per entry to a trailer
6. Calculate the utilization of the highway trailer.
7. Repeat steps 1 through 6 for all combinations of system components.

See a numerical example on pages 197-201 in the textbook.

(it includes 36 alternative designs, i.e., system configurations)
Unit Load Design (cont.)
Container and Pallet Pooling:

For saving by renting, instead of buying!

• An alternative way of designing unit load systems is to participate in a

container/pallet pooling system.
• Instead of buying, companies rent containers and pallets for a fee per day per
container or pallet.

How it works?
• Whenever you need them, you go to the nearest depot and get as many as you
need.
• After use, they are
o returned to the nearest depot
o used by another company in the supply chain with the daily rent.

Unit Load Design (cont.)

Empty pallets/containers (not requiring repair) can be transferred as a

regular load to another user facility on the same common carrier delivery.
Unit Load Design (cont.)
Advantages of Pooling:
• Minimizing the movement of empty pallets/containers.
• Maximizing utilization of pallets/containers.
• No need for allocating extra space to store pallets.
• The operator (an owner) of the pooling is responsible for managing and
maintaining pallets/containers.
o Quality of the containers and pallets tends to be much better.
o Less product damage
o More efficient interfacing with material handling equipment.

Advancement in pallets/containers pooling:

Using the RFID technology.

• Real-time tracking of pallets via RFID tags.

• Improved accuracy and cost-effectiveness.

Material Handling Equipment

Based on our discussion so far,
Material handling ് Material handling equipment.
Material handling is NOT just equipment specification.

In material handling, the focus should be

1) the material
2) the move
3) the method. i.e., the last step is specifying
Material Handling Equipment.
For a “facility planner”,
knowledge of equipment alternatives is an essential tool.
Why?
To generate alternative designs!
Also, as new generations of equipment are continually being developed,
the “facility planner” must constantly be aware
of the most current technologies available.
Material Handling Equipment (cont.)
Material handling equipment can be classified into the following four categories:
1. Containers and unitizing equipment
• Containers
• Unitizers
2. Material transport equipment
• Conveyors
• Industrial vehicles
• Monorails, hoists, and cranes Material Handling Equipment
Classifications on pages 205-
3. Storage and retrieval equipment 208 of the textbook.
• Unit load storage and retrieval
• Unit load storage equipment
• Unit load retrieval equipment
• Small load storage and retrieval
4. Automatic data collection and communication equipment
• Automatic identification and recognition
• Automatic paperless communication

Estimating Material Handling Costs

The development of material handling design alternatives covers the specification
of both
• the “right method of handling.”
• the “right cost.”

How to estimate the cost?

Traditional approach:
• using standard data and rules of thumb.
• verify the accuracy of the information used before making decisions.
• continually update the cost values in the available listings.
Contemporary approach:
• using a complex pricing model.
• including as many of the relevant pricing factors as possible.
• the key to maintaining the accuracy of these complex modules is to have a
validation process wherein “real and actual data” is continuously factored back
into the model.
Estimating Material Handling Costs (cont.)
Example: “Conveyor cost model”
A model can be developed based on different container sizes and alternative
conveyor components
(1) varying conveyor widths based on the dimensional requirements of a container.
(2) the use of slider beds versus roller beds.
(3) different types of belt material
(4) different drive-end configurations.
(5) alternative motor sizes based on calculated horsepower requirements.

Even for a simple task of moving parts using a conveyor, there exist
many possible conveyor equipment component configurations.

Safety Considerations
The “facilities planner” must ensure
safe interface between the workforce and the equipment.

Bad design can cause injury or death!