CHAPTER 1 - INTRODUCTION TO AUTOMATION (EDITED)

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DDE 3443 INDUSTRIAL AUTOMATION

DDE 3443 INDUSTRIAL AUTOMATION

CHAPTER 1

INTRODUCTION TO AUTOMATION

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INTRODUCTION

Production system: manufacturing support systems and facilities.

Mfg Support System

Facilities(Factory

Equipments)

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• Mfg. Support System - procedures used to manage prod. and

to solve logistics & technical prob.Facilities - the equipments in factory and the way

the equipment is organized. It includes machines, tooling, material handling equipment, inspection equipment, comp. & plant layout.

INTRODUCTION… cont.

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Production Facilities• A manufacturing company attempts

to organize its facilities in the most efficient way to serve the particular mission of the plant

• Certain types of plants are recognized as the most appropriate way to organize for a given type of manufacturing

• The most appropriate type depends on:– Types of products made– Production quantity– Product variety

Production Quantity

Number of units of a given part or product produced annually by the plant

• Three quantity ranges:1. Low production – 1 to 100 units2. Medium production – 100 to 10,000

units3. High production – 10,000 to millions

of units

Product VarietyRefers to the number of different

product or part designs or types produced in the plant

• Inverse relationship between production quantity and product variety in factory operations

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• Product variety is more complicated than a number– Hard product variety – products differ

greatly• Few common components in an

assembly– Soft product variety – small

differences between products• Many common components in an

assembly

©2008 Pearson Education, Inc., Upper Saddle River, NJ.

All rights reserved. This material is protected under all

copyright laws as they currently exist.

No portion of this material may be reproduced, in any

form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of

the book Automation, Production Systems, and Computer-

Integrated Manufacturing, Third Edition, by Mikell P.

Groover.

Product Variety vs. Production Quantity

Low Production Quantity

Job shop – makes low quantities of specialized and customized products

• Also includes production of components for these products

• Products are typically complex (e.g., specialized machinery, prototypes, space capsules)

• Equipment is general purpose• Plant layouts:

• Fixed position• Process layout








Groover.

Fixed-Position Layout








Groover.

Process Layout








Groover.

Medium Production Quantities

1. Batch production – A batch of a given product is produced, and then the facility is changed over to produce another product– Changeover takes time – setup time– Typical layout – process layout– Hard product variety

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2. Cellular manufacturing – A mixture of products is made without significant changeover time between products– Typical layout – cellular layout– Soft product variety

Cellular Layout








Groover.

High Production1. Quantity production – Equipment

is dedicated to the manufacture of one product– Standard machines tooled for high

production (e.g., stamping presses, molding machines)

– Typical layout – process layout

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2. Flow line production – Multiple workstations arranged in sequence– Product requires multiple processing

or assembly steps– Product layout is most common

Product Layout

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INTRODUCTION… cont.

• Industrial Automation:• The technology by which a process or

procedure is accomplished without human assistance.

• A technique that can be used to reduce costs and/or to improve quality.

• Can increase manufacturing speed, while reducing cost.

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• Can lead to products having consistent quality, perhaps even consistently good quality

• It is implemented using a program of instructions combined with a control system that executes the instructions.

INTRODUCTION…cont.

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• To automate a process, power is required, both to drive the process itself and to operate the program and control system.

• Automated processes can be controlled by human operators, by computers, or by a combination of the two.


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Definition 1• Automation is a technique that can be used to

reduce costs and/or to improve qual ity. Automation can increase manufacturing speed, while reducing cost. Automation can lead to products having consistent quality, perhaps even consistently good quality.

Definition 2• Automation is a technology concerned

with application of mechanical, electronic and computer-based system to operate and control system. This technology includes;

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• Automatic assembly machines• Automation machine tools to

process parts• Industrial robots• Automatic materials handling and

storage system• Automatic inspection system and

quality control• Feedback control and computer

process control• Computer system for planning,

data collection and decision making to support manufacturing activities

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• If a human operator is available to monitor and control a manufacturing process, open loop control may be acceptable.

• If a manufacturing process is automated, then it requires closed loop control, also known as feedback control.

• example of open loop control and closed loop control.


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Example of open loop control system

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Example of closed loop control

Temperature

instruction

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Example of closed loop control

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Arguments in favor of Automation

• Automation is the key to shorter work week – working hours per week reduces and , allowing more leisure hours and a higher quality of life.

• Automation brings safer working conditions for workers.

• Automated production results in lower prices and better products

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Arguments against Automation

• It result in the subjugation of human being by a machine – reduces the need for skilled labor

• There will be reduction in the labor force – resulting un employment.

• Automation will reduce purchasing power- markets will become saturated with products that people cannot afford to purchase.

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SOME CONSIDERATIONS

• What automation and control technology is available?

• Are employees ready and willing to use new technology?

• What technology should be used?• Should the current mfg process be

improve before automation?• Should the product be improved before

spending millions of ringgit acquiring equips.

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MANUAL LABOR IN PRODUCTION SYSTEMS

• Task is too technologically difficult to automate.

• Short product life cycle.• Customized product.• To cope with ups and downs in demand.• To reduce risk of product failure.

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BASIC ELEMENT OF AN AUTOMATED SYSTEM

• Consists of 3 basic elements: 1) The actuator (which does the

work)• Controlled by the controller.• The actuator in a automated

process may in fact be several actuators, each of which provides an output that drives another in the series of actuator.

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• Some actuators can only be on and off. Other actuators respond proportionally with the signal they receive from a controller

• Actuators can be selected for the types of inputs they require, either DC or AC.

BASIC ELEMENT OF AN AUTOMATED SYSTEM…cont.

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2)The controller (which ‘tells’ the actuator to do work)» A controlled system either

may be a simple digital system or an analog system.

» Digital and analog controllers are available ‘off the shelf’ so that systems can be constructed inexpensive and with little specialized knowledge required.


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3) The sensor (which provides feedback to the controller so that it knows the actuator is doing work) • Obviously, controlled

automation requires devices to sense system output.

• Sensors also can be used so that a controller can detect and respond to changing conditions in its working environment.


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• Switches and transducers are another name for sensors.

• Switches can detect when a measured condition exceeds a pre-set level. Examples, closes when a work-piece is close enough to work on.

• Transducers can describe a measured condition. Examples, output increased voltage as a work-piece approaches the working zone.

BASIC ELEMENT OF AN AUTOMATED

SYSTEM…cont.

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TYPE OF AUTOMATION

• Hard Automation– Controllers were built for specific

purposes and could not be altered easily.

– Early analog process controllers had to be rewired to be reprogrammed.

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– This controllers do what they are designed and built to do, quickly and precisely perhaps, but with little adaptability for change (beyond minor adjustments).

– Modification of hard automation is time-consuming and expensive, since modifications can only be performed while the equipment sits idle.

TYPE OF AUTOMATION…cont.

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• Soft Automation– Modern digital computers are

reprogrammable.– It is even possible to reprogram them

and test the changes while they work.– Even if hardware changes are

required to a soft automation system, the lost time during changeover is less than for hard automation

TYPE OF AUTOMATION…

cont.

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• Automated Mfg. System can be classified into three basic types:

Fixed Automation– A system which the sequence of

processing (or assembly) operations is fixed by the equipment configurations.

– Each operations in the sequence is usually simple.

AUTOMATED MFG. SYSTEM

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– The features of fixed automation;• High initial investment for custom-

engineered equipment• High production rates• Relatively inflexible in

accommodating product variety.• Examples, machining transfer lines

and automated assembly machines.

AUTOMATED MFG. SYSTEM… cont.

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• Programmable Automation– The production equipment is

designed with the capability to change the sequence of operations to accommodate different product configurations.

– The operation sequence is controlled by a program, which is a set of instruction coded so that they can be read and interpreted by the system.


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– New programs can be prepared and entered into the equipment to produce new products.

– The physical setup of the machine must be changed for each new products.

– This changeover procedures takes time.

– Eg: numerical control (NC) machine tools, industrial robots and PLC.


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– The features of programmable automation;• High investment in general purpose

equipment.• Lower production rates than fixed

automation.• Flexibility to deal with variations

and changes in product configuration.

• Most suitable for batch production.


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• Flexible Automation– An extension of programmable

automation.– Capable of producing a variety of

parts/products with virtually no time lost for changeovers from one part style to the next.


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– The features of flexible automation;• High investment for custom-

engineered system.• Continuous production of variable

mixtures of products.• Medium production rates.• Flexibility to deal with product

design variations.


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– Examples, flexible manufacturing systems for performing machining operations. The relative positions of the three types of automation for different production volume and product varieties are shown below.


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Relationship between product variety & quantity

Low

Medium

High100 10000 1,000,000

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Relationship of fixed, programmable and flexible automation

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REASON FOR AUTOMATING

• To increase labor productivity• To reduce labor cost• To improve worker safety• To improve product quality• To mitigate the effects of labor

shortages• To reduce/eliminate routine

manual & clerical tasks.

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REASON FOR AUTOMATING…

cont.

• To reduce mfg lead time• To accomplish processes that

cannot be done manually• To avoid the high cost of not

automating

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MANUAL LABOR IN PROD. SYSTEM

There are situations which manual labor is usually preferred over automation:

• Task is too technologically difficult to automate.

• Short product life cycle• Customized product• To cope with ups and downs in demand• To reduce risk of product failure

Human Vs MachineRelative Strengths of

Humans• Sense unexpected stimuli

• Develop new solution to problems

• Cope with abstract problem

• Adapt to change• Generalized from

observation• Learn from experience• Make difficult decision base

incomplete information

Relative Strengths of Machine

• Perform repetitive task consistently

• Store large amount of data• Retrieve data from memory

reliably• Perform multiple tasks at

the same time• Apply high force and power• Perform simple computation

quickly• Make routine decision

quickly

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American Prod. And Inventory Control Society(APICS) gives three principles:

• Understand the existing process• Simplify the process• Automate the process

PRINCIPLES AND STRATEGIES

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10 STRATEGIES FOR AUTO./PROD SYSTEM

1. Specialization of operation2. Combined operations3. Simultaneous operations4. Integration operations5. Increased flexibility6. Improved material handling and

storage7. On-line inspection

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STRATEGIES FOR AUTO./PROD SYSTEM… cont.

8. Process control and optimization9. Plant operations control10. Computer-integrated

manufacturing

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• 4 keys parameters: i. Qualityii. Variety

iii. Complexity of assembled products iv. Complexity of individual parts.

PRODUCT/PRODUCTION RELATIONSHIPS

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Quantity and variety

Consider: Q= prod. Quantity, P=prod. Variety

: Qj=annual quantity of prod j : Qf= total quantity of all part

p

Qf = Qj, where P = total no. of diff. j=1 part, j = 1,2,3,…

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Product and Part complexity

• Complexity refer to the no.of components used to produce a product-the mere parts, the more complex.

• Let, np = the no. of part per product

no = the no. of operation/pros. Steps

The total no. of parts manufactured/year: npf=total no.of part/yr

p npf = Qjnpj Qj = annual quantity/yr

j=1 npj = no. of parts/prod

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Product and Part complexity… cont.

• The total no. of processing operations performed in the plant:

p npj

nof = Qjnpj nojk

j=1 k=1

Where; nof= total no. ofoperation cycles

nojk= no of processing operation for each part k

npj = no.of parts in product

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Product and Part complexity… cont.

Conceptualize:Consider P = no. of product design

Q = quantitiesSo, the total no. of product produced,

Qf = PQ the total no. of parts produced, npf = PQnp

the total no. of mfg operation performed,

nof = PQnpno

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Example

P=100 different product, each product produced 10,000 unit/yr, each consist of 1000 components, average processing step=10/component, each processing step=1min. Determine:

- how many product- how many part- how many prod. operation- how many workers needed

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Solution

i. Total no. of unit produced, Qf = PQ100 x 10,000 = 1,000,000

prod./yrii. Total no of part produced = npf =

PQnp 1.000.000 x 1000 = 1,000,000,000 parts/yr

iii. Prod. operation = nof =PQnpno

iv. Total time = 10,000,000,000 x 1/60=166,666,667 hr

v. Workers= 1666,6666,661/2000=83,333 workers

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Production rate

• Normally expressed as an hourly rate.• Also called operation cycle time, Tc.

Tc is defined as the time that one work unit spends being processed/assembled.

Tc = To + Th + Tth

where Tc = operation cycle time (min/pc)

To = time of actual processing/assemb.

Th = handling time (min/pc) Tth= tool handling time(min/pc)

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Production capacity

• Is defined as the max. rate of o.p that the production facilities is able to produce under a given set of assumed operation cond.( num. of shift/day).

• Let PC = prod. Capacity, n = num. of m/c

Rp = prod. Rate, H = hr/shift, S =num. of shift/week.

PC = n SH Rp

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Production capacity… cont.

• If no = num. of distinct operation through which work units are routed.

• To increase/decrease prod. Capacity: i. Short term: changes of S and H will increase prod.

Capacity ii. Long term to increase capacity, change n, increase Rp

and reduce no.

PC = n SH Rp / no

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Manufacturing Lead Time (MLT)

• Total time required to process a given part or product through the plant

• MLT = no(Tsu + QTc + Tno )

no = no, of machine/process

Tsu = average setup time (hr)

Q = quantity part/productTc = operation cycle time (hr)

Tno = non-operating time (hr)

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MANUFACTURING OPERATION COSTS• Mfg costs – fixed and variable costs.• Fixed costs-remains constant for any

level of prod.• Variable costs-varies in proportion to

the level of prod.• Let TC = total annual costs (RM/yr), FC

= fixed annual costs (RM/yr), VC= variable costs (RM/pc) and Q = annual quantity produced (pc/yr).

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MANUFACTURING OPERATION COSTS… cont.

TC = FC + VC(Q)

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• Costs also depend on labor, materials and overhead.

• Labor costs- paid to workers• Materials costs- cost of raw materials to

produce product.• Overhead costs- factory and corporate

o.head - factory o.h to operate the factory - corporate o.h to run the factory

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• J.T Black.

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• Overhead rate (burden) to be calculated and to used in the following year to allocate overhead costs.

FOHR = FOHC / DLC Where FOHR = factory overhead

rate FOHC = annual factory

overhead costs DLC = annual direct labor

costs

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MANUFACTURING OPERATION

COSTS… cont.

• Corporate overheat rate, COHR = COHC /DLC where COHR = annual corporate

overhead rate, COHC = annual corporate

overhead costs, DLC = annual direct labor costs

DLC = annual direct labor costs

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• Eg:

determine a) FOHR for each plant

b) COHR

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Solution:a) FOHR1 = 2,000 / 800,000 = 250%

FOHR2 = 1,100,000 / 400,000 = 275%

b) COHR = 72,000 / 1,200,000 = 600%

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TQ

Get ready for QUIZ!!!

Documents

CHAPTER 1 - INTRODUCTION TO AUTOMATION (EDITED)