Government College of Engineering

Kalahandi, Bhawanipatna

DEPARTMENT OF MECHANICAL ENGINEERING

Lecture Notes on
COMPUTER INTEGRATED MANUFACTURING AND
FMS

Prepared by

Mr. Ajit Kumar Pattanaik Mr. Dilip Kumar Bagal

Asst. Professor Asst. Professor

Mechanical Engg Department Mechanical Engg Department

1
2
 Module-1
1. Introduction to CIM

Initially, machine tool automation started with the development of numerical control in
1950s. In less than 50 years, it is amazing that today’s manufacturing plants are
completely automated. However, establishment of these plants gave relatively a few
varieties of product. At first we define what do we mean by a manufacturing plant?
Here, we are considering a several categories of manufacturing (or production) for the
various manufacturing plants. Manufacturing can be considered in three broad areas:

(i) Continuous process production,

(ii) Mass production, and

(iii) job-shop production.

Among these three, mass production and job-shop production can be categorized as
discrete- item production.

Continuous Process Production

Such type of product flows continuously in the manufacturing system, e.g. petroleum,
cement, steel rolling, petrochemical and paper production etc. Equipment used here are only
applicable for small group of similar products.

Mass Production

It includes the production of discrete unit at very high rate of speed. Discrete item
production is used for goods such as automobiles, refrigerators, televisions, electronic
component and so on. Mass production contains the character of continuous process
production for discrete products. That’s why mass production has realized enormous
benefits from automation and mechanization.

Job Shop Production

A manufacturing facility that produces a large number of different discrete items and
requires different sequences among the production equipments is called job shop.
Scheduling and routine problems are the essential features of job shop. As a result
automation has at best been restricted to individual component of job shop. But there have
been few attempts in the field of total automation. Physical components of an
automated manufacturing system do not include continuous flow process as it only
consists of a small percentage of manufacturing system. Mass production of discrete
items is included in this category, where segments of production line are largely
automated but not the entire line. Job shop facilities have used automated machines, but
transfer of work among these machines is a difficult task. Apart from some physical
equipment needed, a major component of the automated information that needs to be made

3
available to the manufacturing operation must come from product design. This allows
a plant to be automated and integrated. However, manufacturing is more concerned
with process design rather than product design.

The characteristic of present world market include higher competition, short product life
cycle, greater product diversity, fragmented market, variety and complexity, and smaller
batch sizes to satisfy a variety of customer profile. Furthermore, non price factors such as
quality of product design innovation and delivery services are the preliminary
determinant for the success of product. In today’s global arena, to achieve these
requirements manufacturing company needs to be flexible, adaptable and responsive to
changes and be able to produce a variety of products in short time and at lower cost. These
issues attract manufacturing industries to search for some advanced technology, which can
overcome these difficulties. Computer integrated manufacturing (CIM), which emerged in
1970, was the outcome of this protracted search.

A CIM System consists of the following basic components:

I. Machine tools and related equipment

II. Material Handling System (MHS)

III. Computer Control System

IV. Human factor/labor

CIM refers to a production system that consists of:

1. A group of NC machines connected together by

2. An automated materials handling system

3. And operating under computer control

In Production Systems CIM is appropriate for batch production as shown in Fig. 1.

Transfer Lines: is very efficient when producing "identical" parts in large volumes at high

product rates.

Stand Alone: NC machine: are ideally suited for variations in work part configuration.

4
CIM involves a fundamental strategy of integrating manufacturing facilities and systems in
an enterprise through the computer and it’s peripheral. CIM can be defined in
different ways depending upon its application. CIM involves integration of advanced
technologies in various functional units of an enterprise, in an effective manner to
achieve the success of the manufacturing industries. A deep knowledge and
understanding of all the technology is required for an effective integration. At first
integration of advanced manufacturing technology (AMT) is required to get success in the
application of CIM. Computers act as a subordinate to the technologies. Computers help,
organize, and restore information in order to achieve high accuracy and speed. Their
basic aim is to achieve the goals of the objectives within limited available capital.
Traditionally, all the efforts were focused on achieving single goal to improve the
effectiveness and competitiveness of the organization. But they failed because they
didn’t satisfy the overall objectives of the manufacturing companies. Hence, a multiple goal
selection or mult- criteria optimization is proposed to make the CIM an effective tool
to improve the economy of the company. The new approach should be developed for
improving the existing multi-criteria optimization mechanism, so that CIM can be
realized globally. In addition, global integration approach should be applied to make
globally distributed company as a single entity. This concept is applied to make virtual CIM
more effective and hence helps in meeting the present global economic circumstances
using intelligent manufacturing. Therefore, manufacturing technology should be blended
with intelligence. This will help manufacturing enterprise to produce better quality. It will
also facilitate the manufacturing equipments to solve problems posed during normal
course of the operations. Computer technology is the necessary input to implement
automation in manufacturing system. The term CIM denotes the widespread use of computer
systems to design the product, to plan the production, control the operation, and perform the
business related functions required in the manufacturing firm. True CIM includes
integration of these functions in the system that operates throughout the enterprise. Other
words are used to identify specific element of the CIM system. For example, computer
aided design (CAD) denotes the use of computer system to support the product
design system.
Computer aided manufacturing (CAM) denotes the use of computer system to perform the
functions related to manufacturing engineering, such as process planning and
numerically controlled (NC) part programming. Some computer system performs the
CAD and CAM, and so the term CAD/CAM is used to indicate the integration of the two
systems into one. In addition to CAD/CAM, CIM also includes the firm business function
that is related to manufacturing.
Computer Integrated Manufacturing (CIM) encompasses the entire range of product
development and manufacturing activities with all the functions being carried out with the
help of dedicated software packages. The data required for various functions are passed
from one application software to another in a seamless manner. For example, the
product data is created during design. This data has to be transferred from the modeling
software to manufacturing software without any loss of data. CIM uses a common database
wherever feasible and communication technologies to integrate design, manufacturing
and associated business functions that combine the automated segments of a factory or a

5
manufacturing facility. CIM reduces the human component of manufacturing and thereby
relieves the process of its slow, expensive and error-prone component. CIM stands for a
holistic and methodological approach to the activities of the manufacturing enterprise in
order to achieve vast improvement in its performance. This methodological approach is
applied to all activities from the design of the product to customer support in an integrated
way, using various m ethods, means and techniques in order to achieve production
improvement, cost reduction, fulfillment of scheduled delivery dates, quality
improvement and total flexibility in the manufacturing system. CIM requires all those
associated with a company to involve totally in the process of product development
and manufacture. In such a holistic approach, economic, social and human aspects
have the same importance as technical aspects. CIM also encompasses the whole lot
of enabling technologies including total quality management, business process
reengineering, concurrent engineering, workflow automation, enterprise resource
planning and flexible manufacturing. The challenge before the manufacturing engineers is
illustrated in Fig. 2

Manufacturing engineers are required to achieve the following objectives to be

competitive in a global context.

• Reduction in inventory

• Lower the cost of the product

• Reduce waste

• Improve quality

• Increase flexibility in manufacturing to achieve imm ediate and rapid response to:

o Product changes

o Production changes

o Process change

o Equipment change

o Change of personnel

CIM technology is an enabling technology to meet the above challenges to the

manufacturing.

6
2. Production System:

The production system is the collection of people, equipment, and procedures organized to
accomplish the manufacturing operations of a company (or other organization). Production
systems can be divided into two categories or levels as indicated in Figure 3

Manufacturing
Support System

Production
System
Facilities:
Factory
Equipments

Fig:3 Production System Consisting of Manufacturing Support System and Facilities

l . Facilities. The facilities of the production system consist of the factory, the equipment in
the factory, and the way the equipment is organized.

2. Manufacturing support systems·. This is the set of procedures used by the company to
manage production and to solve the technical and logistics problems encountered in ordering
materials, moving work through the factory and ensuring that products meet quality
standards. Product design and certain business functions are included among the
manufacturing support systems.

In modern manufacturing operations, portions of the production system are automated and/or
computerized. However, production systems include people. People make these systems
work. In general, direct labor people (blue collar workers) are responsible for operating the
facilities, and professional staff people (white collar workers) are responsible for the
manufacturing support systems.
Facilities:
The facilities in the production system are the factory, production machines and tooling,
material handling equipment, inspection equipment, and the computer systems that control
the manufacturing operations. Facilities also include the plant layout, which is the way the
equipment is physically arranged in the factory. The equipment is usually organized into
logical groupings, and we refer to these equipment arrangements and the workers who
operate them as the manufacturing systems in the factory. Manufacturing systems can be
individual work cells, consisting of a single production machine and worker assigned to that
machine. We more commonly think of manufacturing systems as groups of machines and
workers, for example, a production line. The manufacturing systems come in direct physical
contact with the parts and/or assemblies being made.

7
In terms of human participation in the processes performed by the manufacturing system,
three basic categories can be distinguished (a) Manual work systems, (b) worker-machine
systems and (c) automated systems.
Manual work systems: A manual work system consist of one or more workers performing
one or more tasks without the aid of powered tools. Manual material handling tasks are more
common activities in manual work systems. Production tasks commonly require the use of
hand tools. A hand tool is a small tool that is manually operated by the strength and skill of
the human user. Examples are:
 A machinist using a file to round the edges of a rectangular part that has just been
milled.
 A material handling worker using a dolly to move cartons in a warehouse.
Worker – machine systems: In a worker machine system , a human worker operates powered
equipments such as machines tool or other production machines. This is one of the most
widely used manufacturing systems. Worker-machine systems include combination of one or
more workers and one or more pieces of equipment. The worker and machines are combined
to take advantage of their relative strengths and attributes. Examples are:
 A machinist operating an engine lathe in a tool room to fabricate a part for a customer
designed products.
 A fitter and an industrial robot working together in an arc welding work cell.
Automated Systems: An automated system is one in which a process is performed by a
machine without the direct participation of a human worker. Automation is implemented
using a program of instructions combined with a control system that executes the instructions.
There are mainly two levels of automation: Semi-automated and fully automated. A semi
automated machine performs a portion of the work cycle under some form of program control
and a human worker tends to the machine for the remainder of the cycle by loading and
unloading it or performing some other task each cycle. A fully automated machine is
distinguished from semi automated counterpart by the capacity to operate for the extended
periods of times with no human attention.

Manual Work
System

Worker – machine
systems

Automated Systems

8
Manufacturing Support Systems:
To operate the production facilities efficiently, a company must organize itself to design the
processes and equipment, plan and control the production orders, and satisfy product quality
requirement. These functions are accomplished by manufacturing support systems- people
and procedures by which a company manages its production operations. Most of these
support systems do not directly contact the product, but they plan and control its progress
through the factory.

Manufacturing support involves a cycle of information-processing activities. The

information-processing cycle consisting of four functions: (1) business functions, (2) product
design, (3) manufacturing planning. and (4) manufacturing control.

Business Functions: The business functions are the principal means of communicating with
the customer. They are therefore, the beginning and the end of the information-processing
cycle. Included in this category are sales and marketing, sales forecasting, order entry, cost
accounting, and customer billing.

The order to produce a product typically originates from the customer and proceeds into the
company through the sales and marketing department of the firm. The production order will
be in one of the following forms: (l) an order to manufacture an item to the customer's
specifications, (2) a customer order to buy one or more of the manufacturer's proprietary
products, or (3) an internal company order based on a forecast of future demand for a
proprietary product.

Product Design: If the product is to be manufactured to customer design, the design will have
been provided by the customer. The manufacturer's product design department will not be
involved. lf the product is to be produced to customer specifications, the manufacturer's
product design department may be contracted to do the design work for the product as well as
to manufacture it.

Manufacturing Planning: The information and documentation that constitute the product
design flows into the manufacturing planning function. The information-processing activities
in manufacturing planning include process planning, master scheduling, requirements
planning, and capacity planning. Process planning consists of determining the sequence of
individual processing and assembly operations needed to produce the part. The
manufacturing engineering and industrial engineering departments are responsible for
planning the processes and related technical details. Manufacturing planning includes
logistics issues, commonly known as production planning. The authorization to produce the
product must be translated into the master production schedule. The master production
schedule is a listing of the products to be made, when they are to be delivered. and in what
quantities. Months are traditionally used to specify deliveries in the master schedule. Based
on this schedule, the individual components and sub assemblies that make up each product
must be planned. Raw materials must be purchased or requisitioned from storage. Purchased
parts must be ordered from suppliers, and all of these items must be planned so that they are
available when needed. This entire task is called material requirements planning. In addition,

9
the master schedule must not list more quantities of products than the factory is capable of
producing each month with its given number of machines and manpower. A function called
capacity planning is concerned with planning the manpower and machine resources of the
firm.

Manufacturing Control: Manufacturing control is concerned with managing and controlling

the physical operations in the factory to implement the manufacturing plans. The flow of
information is from planning to control. Information also flows back and forth between
manufacturing control and the factory operations. Included in the manufacturing control
function are shop floor control, inventory control, and quality control.

Shop floor control deals with the problem of monitoring the progress of the product as it is
being processed, assembled, moved and inspected in the factory. Shop floor control is
concerned with inventory in the sense that the materials being processed in the factory are
work-in-process inventory. Thus shop floor control and inventory control overlap to some
extent. Inventory control attempts to strike a proper balance between the danger of too little
inventory (with possible stock-outs of materials) and the carrying cost of too much inventory.
It deals with such issues as deciding the right quantities of materials to order and when to
reorder a given item when stock is low.

The mission of quality control is to ensure that the quality of the product and its components
meet the standards specified by the product designer. To accomplish its mission, quality
control depends on inspection activities performed in the factory at various times during the
manufacture of the product. Also, raw materials and component parts from outside sources
arc sometimes inspected when they are received and final inspection and testing of the
finished product is performed to ensure functional quality and appearance.

10
Reasons for Automation of system:

1. To increase labour productivity. Automating a manufacturing operation usually

increase production rate and labour productivity This means greater output per hour of
labour input.
2. To reduce labour cost. Ever-increasing tabor cost has been and continues to be the
trend in the world's industrialized societies. Consequently, higher investment in
automation has become economically justifiable to replace manual operations.
Machines are increasingly being substituted for human labour to reduce unit product
cost.
3. To minimise the effect of labour shortage. There is a general shortage of labor in
many advanced nations and this has stimulated the development of automated
operations as a substitute for labour.
4. To reduce or eliminate routine manual and clerical tasks. An argument can be put
forth that there is social value in automating operations that are routine, boring,
fatiguing. Automating such tasks serves a purpose of improving the general level of
working condition.
5. To improve worker safety. By automating a given operation and transferring the
worker from active participation in the process to a supervisory role, the work is made
safer.
6. To improve product quality. Automation not only results in higher production rates
than manual operations; it also performs the manufacturing process with greater
unifermity and conformity to quality specifications. Reduction of fraction defect rate
is one of the chief benefits of automation.

Automation Principles and Strategies:

1. USA Principle:
The USA Principle is a common sense approach to automation
projects. Similar procedures have been suggested in the manufacturing and
automation trade literature, but none has a more captivating title than this one. USA
stands for
a. Understand the existing process
b. Simplify the process
c. Automate the process
Understand the Existing Process. The obvious purpose of the first step in the
USA approach is to comprehend the current process in all of its details. What arc the
inputs? What are the outputs? What exactly happens to the work unit between input
and output? What is the function of the process? How does it add value to the
product? What are the upstream and downstream operations in the production
sequence, and can they be combined with the process under consideration?
Simplify the Process. Once the existing process is understood, then the search
can begin for ways to simplify. This often involves a checklist of questions about the
existing process. What is the purpose of this step or this transport? Is this step
necessary? Can this step be eliminated? Is the most appropriate technology being used

11
 in this step? How can this step be simplified? Are there unnecessary steps in the
process that might be eliminated without detracting from function?
Automate the Process. Once the process has been reduced to its simplest
form, then automation can be considered. The possible forms of automation include
those listed in the ten strategies. An automation migration strategy might be
implemented for a new product that has not yet proven itself.

2. Ten Strategies for Automation and Production Systems:

a. Specialisation of operations; The first strategy involves the use of special-

purpose equipment designed to perform one operation with the greatest possible
efficiency. This is analogous to the concept of labor specialization, which is
employed to improve labor productivity.
b. Combined operations. Production occurs as a sequence of operations. Complex
parts may require dozens, or even hundreds, of processing steps. The strategy of
combined operations involves .reducing the number of distinct production
machines or workstations through which the part must be routed. This is
accomplished by performing more than one operation at a given machine, thereby
reducing the number of separate machines needed. Since each machine typically
involves a setup, setup time can usually be saved as a consequence of this
strategy. Material handling effort and non operation time are also reduced.
Manufacturing lead time is reduced for better customer service.
c. Simultaneous operations. A logical extension of the combined operations
strategy is to simultaneously perform the operations that are combined at one
workstation. In effect, two or more processing (or assembly) operations are being
performed simultaneously on the same workpart, thus reducing total processing
time.
d. Integration of operations. Another strategy is to link several workstations
together into a single integrated mechanism, using automated work handling
devices to transfer parts between stations. In effect, this reduces the number of
separate machines through which the product must be scheduled. with more than
one workstation. several parts can be processed simultaneously, thereby
increasing the overall output of the system.
e. Increased flexibility. This strategy attempts to achieve maximum utilization of
equipment for job shop and medium-volume situations by using the same
equipment for a variety of parts or products, It involves the use of the flexible
automation concepts . Prime objectives are to reduce setup time and programming
time for the production machine. This normally translates into lower
manufacturing lead time and less work-in-process.
f. Improved material handling and storage. A great opportunity for reducing non-
productive lime exists in the use of automated material handling and storage
systems. Typical benefits include reduced work-in-process and shorter
manufacturing lead times.

12
 g. On-line inspection; Inspection for quality of work is traditionally performed after
the process is completed. This means that any poor-quality product has already
been produced by the time it is inspected. Incorporating inspection into the
manufacturing process permits corrections to the process as the product is being
made. This reduces scrap and brings the overall quality of the product closer to the
nominal specifications intended by the designer.
h. Process control and optimization. This includes a wide range of control schemes
intended to operate the individual processes and associated equipment more
efficiently. By this strategy, the individual process times can be reduced and
product quality improved.
i. Plant operations control. Whereas the previous strategy was concerned with the
control of the individual manufacturing process, this strategy is concerned with
control at the plant level. It attempts to manage and coordinate the aggregate
operations in the plant more efficiently. Its implementation usually involves a high
level of computer networking within the factory.
j. Computer-integrated manufacturing (CIM). Taking the previous strategy one
level higher. we have the integration of factory operations with engineering design
and the business functions of the firm, ClM involves extensive use of computer
applications, computer data bases, and computer networking throughout the
enterprise.

Automation Migration Strategy:

Phase 1: Manual production using single-station manned cells operating

independently. This is used for introduction of the new product for reasons already
mentioned: quick and low-cost tooling to get started.
Phase 2: Automated production using single-station automated cells operating
independently. As demand for the product grows, and it becomes clear that automation can be
justified, then the single stations are automated to reduce labor and increase production rate.
Work units are still moved between workstations manually.
Phase 3: Automated integrated production using a multi station automated system
with serial operations and automated transfer of work units between stations. When the
company is certain that the product will be produced in mass quantities and for several years,
then integration of the single-station automated cells is warranted to further reduce labor and
increase production rate.

13
PLANT LAYOUT :

In addition to the organizational structure, a firm engaged in manufacturing-must also

be concerned with its physical facilities. The term plant layout refers to the arrangement of
these physical facilities in a production plant. A layout suited to flow-type mass production is
not appropriate for job shop production, and vice versa. There are three principal types of
plant layout associated with traditional production shops:

1. Fixed-position layout

2. Process layout

3. Product-flow layout

1. Fixed-position layout

In this type of layout, the term "fixed-position" refers to the product. Because of its
size and weight, the product remains in one location and the equipment used in its
fabrication is brought to it. Large aircraft assembly and shipbuilding are examples of
operations in which fixed-position layout is utilized. As product is large, the
construction equipment and workers must be moved to the product. This type of
arrangement is often associated with job shops in which complex products are
fabricated in very low quantities.

2. Process layout

In a process layout, the production machines are arranged into groups

according to general type of manufacturing process. The advantage of this type of
layout is its flexibility. Different parts, each requiring its own unique sequence of
operations, can be routed through the respective departments in the proper order.

3. Product-Flow Layout

Productions machines are arranged according to sequence of operations. If a

plant specializes in the production of one product or one class of product in large volumes,
the plant facilities should be arranged to produce the product as efficiently as possible with
this type of layout, the processing and assembly facilities are placed along the line of
flow of the product. As the name implies, this type of layout is appropriate for flow-type
mass production. The arrangement of facilities within the plant is relatively inflexible
and is warranted only when the production quantities are large enough to justify the
investment.

14
 PRODUCTION CONCEPTS AND MATHEMATICAL MODELS

A number of production concepts are quantitative, or require a quantitative

approach to measure them.

Manufacturing lead time

Our description of production is that it consists of a series of individual steps:

processing and assembly operations. Between the operations are material handling, storage,
inspections, and other non productive activities. Let us therefore divide the activities in
production into two main categories, operations and non operation elements. An operation on
a product (or work part) takes place when it is at the production machine. The non operation
elements are the handling, storage, inspections, and other sources of delay. Let us use T0 to
denote the time per operation at a given machine or workstation, and Tno to represent
the non operation time associated with the same machine. Further, let us suppose that there
are nm separate machines or operations through which the product must be routed in order to
be completely processed. If we assume a batch production situation, there are Q units of the
product in the batch, A setup procedure is generally required to prepare each production
machine for the particular product. The setup typically includes arranging the workplace and
installing the tooling and fixturing required for the product. Let this setup time be denoted as
Tm.

Given these terms, we can define an important production concept,

manufacturing lead time. The manufacturing lead lime (MLT) is the total time required to
process a given product (or work part) through the plant. We can express it as follows:

Where i indicates the operation sequence in the processing, i = 1,2, . .n The

MLT equation does not include the time the raw work part spends in storage before its turn in
the production schedule begins.

Let us assume that all operation times, setup times, and non operation times
are equal, respectively then MLT is given by

For mass production, where a large number of units are made on a single machine, the
MLT simply becomes the operation time for the machine after the setup has been completed
and production begins. For flow-type mass production, the entire production line is set up in
advance. Also, the non operation time between processing steps consists simply of the time to
transfer the product (or pan) from one machine or workstation to the next. If the
workstations are integrated so that parts are being processed simultaneously at each station,
the station with the longest operation time will determine the MLT value. Hence,

15
 In this case, nm represents the number of separate workstations on the production line.

The values of setup time, operation time, and non operation time are different
for the different production situations. Setting up a flow line for high production requires
much more time than setting up a general-purpose machine in a job shop. However, the
concept of how time is spent in the factory for the various situations is valid.

16
17
18
19
20
Scanned by CamScanner
Scanned by CamScanner
Scanned by CamScanner
Scanned by CamScanner
Scanned by CamScanner
Scanned by CamScanner