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ME18702-CIM-Unit-1

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ME 18702
Computer Integrated Mfg.
(CIM)
by
Dr.K.S.Badrinathan
Professor
Department of Mechanical Engineering
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Course Outline
• Unit – 1 : CIM Concepts, Automation & Computer Aided
Process Planning
• Unit – 2 : Cellular Manufacturing
• Unit – 3 : Flexible Manufacturing System (FMS) &
Automated Guided Vehicle System (AGVS)
• Unit – 4 : Industrial Robotics
• Unit – 5 : Open System & Database for CIM
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Text & Reference Books
• Textbooks
• 1. Mikell. P. Groover “Automation, Production Systems and Computer
Integrated Manufacturing”, Prentice Hall of India, 4th edition, 2016.
• 2. R Radhakrishnan P, Subramanyan S and Raju V., “CAD/CAM/CIM”,
4th edition, New Age International (P) Ltd, New Delhi, 2018.
• Reference Books
• 1. Xun Xu, “Integrating Advanced Computer-Aided Design,
Manufacturing, and Numerical Control”. Information Science
Reference, 2009.
• 2. Kant Vajpayee S, “Principles of Computer Integrated
Manufacturing”, Prentice Hall India, 2009.
• 3. David D.Bedworth, Mark R.Hendersan, Phillip M.Wolfe “Computer
Integrated Design and Manufacturing”, McGraw-Hill Inc, 2004.
• 4. Roger Hannam “Computer Integrated Manufacturing: From
concepts to realisation”, Addison –Wesley, 2007.
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Course Outcomes (COs)
Outcome
Description
CO1
Student will be able to apply the concepts of CIM, Automation and CAPP for
sustained productivity.
CO2
Student will be able to derive the GT code for the given drawing using Opitz
part coding system; group parts & machines into families; arrange machines in a
GT Cell.
CO3
Student will be able to solve simple quantitative analysis problems in FMS. Also
understand AGVS, its applications and vehicle guidance management and
safety.
CO4
Student will be able to select an appropriate type of robot configuration for the
given task.
CO5
Students will be able to apply the standards in database management and in
interconnection of CIM system elements for compatible communication
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Unit - 1
• CIM Concepts
• Meaning & Origin of CIM
• Production Systems
• Automation in Production Systems
• Automation Principles & Strategies
• Basic Elements of an Automated System
• Advanced Automation Functions
• Levels of Automation
• Computer Aided Process Planning (CAPP)
• Variant & Generative approaches
• Integration of CAD/CAPP/CAM/CNC
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Significance of CIMS
Industry 4.0
• Intelligent Machining
• Advanced Sensors
• Connected Machines, within factory (LAN/Internet)
• Connected Factories – IOT ´âáIIOT
• Artificial Intelligence / Big Data
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Industrial Revolution
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Industry 4.0
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Product
• How is a Product arrived at?
Design
Mfg.
Assembly
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Product
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Traditional Engineering
Design
Production
Operate
Service
Retirement
(Functionability)
(Manufacturability)
(Operability)
(Serviceability)
(Disposability)
Information Flow in Serial Engineering
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Sequential Engineering
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Sequential Engineering
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Concurrent Engineering
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Concurrent Engineering
• An approach used in product
development in which the functions of
design engg., mfg. engg and other
functions are integrated to reduce the
elapsed time required to bring a new
product to market.
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Concurrent Engineering
Inspection
Marketing/
Sales
Manufacturing
Design
Serviceability
Packaging
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Benefits of CE
• Reduction in number of design changes
• Cost of changes in Design is reduced
• Holistic approach to product development
• Robust products
• Reduction in “Lead Time” for product
development
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CIM
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CIM
• To meet competitive pressures
• Shortened Lead Time
• Reduced Costs
• Reduced Inventory
• Improved Quality
• To coordinate and organize data
• To eliminate paperwork
• To automate communication within a factory
• To facilitate concurrent engineering
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Computer Elements of CIM
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Automation
Understand
Analyze
Automate
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Production System
A production system is a collection of people, equipment,
and procedures organized to perform the manufacturing
operations of a company. (3M)
Components of Production System:
• Facilities
• Manufacturing support systems
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Facilities
• Factory
• Production machines
• Tooling
• Material handling equipment
• Inspection equipment
• Computer systems that control the manufacturing
operations
• Plant layout - the way the equipment is physically
arranged in the factory.
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Manufacturing Systems
• Logical grouping of equipment and workers that
accomplish the processing and assembly operations on
parts and products made by the factory.
• Categories of Mfg. systems:
(a) manual work systems
(b) worker-machine systems
(c) automated systems
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Manual Work Systems
One or more workers performing one or more tasks
without the aid of powered tools.
• A machinist using a file
• A quality control inspector using a micrometer
• A material handling worker using a dolly
• A team of assembly workers putting together a piece of
machinery using hand tools
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Worker-Machine Systems
Combinations of one or more workers and one or more
pieces of equipment
• A machinist operating an engine lathe
• A fitter and an industrial robot working together in an
arc–welding
• A crew of workers operating a rolling mill that converts
hot steel slabs into flat plates
• A production line in which the products are moved by
mechanized conveyor and the workers at some of the
stations use power tools to accomplish their processing
or assembly tasks
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Automated Systems
A process is performed by a machine without the direct
participation of a human worker
• Semiautomated 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 (CNC- with bar feeding-load bar)
• Fully automated machine
• Has the capacity to operate for an extended period with
no human attention one or more workers are required
to be present to continuously monitor the operation –
process industry
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Manufacturing Systems
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Manufacturing Support Systems (MSS)
• People and Procedures by which a company
manages its production operations
• It does not directly contact the product, but they
plan and control its progress
• It involves a sequence of activities
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Functions of MSS
• Four functions involving information flow and data
processing
• Business functions
• Product design
• Manufacturing planning
• Manufacturing control
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Functions of MSS
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Production Systems
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Automation in Production Systems
What is Automation?
Automation can be defined as the technology by
which a process or procedure is accomplished
without human assistance.
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Automation in Production Systems
The automated elements of the production system:
Automation of the manufacturing systems in the
factory
Computerization of the manufacturing support
systems
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Opportunities for Automation & Computerization
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Automated Manufacturing Systems (AMS)
• AMS operate in the factory on the physical
product
• Operations:
• Processing
• Assembly
• Inspection
• Material handling
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Examples of AMS
• Automated machine tools that process parts
(CNC)
• Transfer lines that perform a series of machining
operations
• Automated assembly systems
• industrial robots to perform processing or
assembly operations
• Automatic material handling and storage systems
to integrate manufacturing operations
• Automatic inspection systems for QC.
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Classification of AMS
• Fixed Automation
• Programmable Automation
• Flexible Automation
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Fixed Automation (FA)
Sequence of processing or assembly is fixed by the
equipment configuration
• Features:
• High initial cost for custom engineered
equipment (SPM)
• High production rates
• Relative inflexibility of equipment for product
variety
Justification: products that are made in very large
quantities and at high production rates.
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Programmable Automation (PA)
Equipment has the capability to change the sequence of
operations to accommodate different product
configurations.
• The operation sequence is controlled by a program
Features:
• High investment in general purpose equipment (CNC)
• Lower production rates than fixed automation
• Flexibility to variations & changes in product
• Highly suitable for batch production
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Flexible Automation (Fl. A)
• Extn. of PA. Fl.A can produce a variety of parts
with virtually no time lost for changeovers from
one-part style to the next.
Features:
• 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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Types of Automation
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Computerized Manufacturing Support Systems
• To reduce the amount of manual and clerical effort in:
• product design
• manufacturing planning and control
• business functions
• True CIM integrates all these functions in one system that
operates throughout the enterprise
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CAD/CAM/CIM
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Reasons for Automating
• Increase labor productivity
• Reduce labor cost
• Mitigate the effects of labor shortages
• Reduce or eliminate routine manual and clerical tasks
• Improve worker safety – OSHA – 1970
• Improve product quality
• Reduce manufacturing lead time
• Accomplish processes that cannot be done manually
• Avoid the high cost of not automating.
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Automation Principles & Strategies
• Automation is not always the right answer for a given
production situation.
• A certain caution and respect must be observed in
applying automation technologies.
1) The USA Principle
2) Ten Strategies for Automation & Process Improvement
3) Automation Migration Strategy.
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The USA Principle
A commonsense approach to automation and process
improvement
• Understand the existing process
• Simplify the process
• Automate the process.
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Understand the Existing Process
Step 1: Comprehend the current process in all of its details.
• What are 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?
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Methods to Understand the Process
• Traditional industrial engineering charting tools such as
the operation chart and the flow process chart
• Mathematical models of the process to indicate
relationships between input parameters and output
variables.
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Simplify the Process
Prepare checklist of questions about the existing process.
• Is the step necessary?
• Can it be eliminated?
• Does it use the most appropriate technology?
• How can it be simplified?
• Are there unnecessary steps in the process that might be
eliminated without detracting from function?
• Can steps be combined/performed simultaneously?
• Can steps be integrated into a manually operated
production line?
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Automate
• Once the process has been reduced to its simplest form,
then automation can be considered
• The possible forms of automation can be adopted from
the list of ten strategies
• An automation migration strategy might be implemented
for a new product that has not yet proven itself.
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Ten Strategies for Automation & Process Improvement
1. Specialization of operations - use of special-purpose
equipment designed to perform one operation with the
greatest possible efficiency
2. Combined operations – perform more than one
operation at a given machine; reduces the number of
separate machines needed
3. Simultaneous operations - simultaneously perform the
operations that are combined at one workstation;
reduces total processing time.
4. Integration of operations - link several workstations
together into a single integrated mechanism, using
automated work handling devices to transfer parts
between stations.
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Ten Strategies for Automation & Process Improvement
5. Increased flexibility - use the same equipment for a
variety of parts or products; maximum utilization of
equipment for job shop and medium-volume
situations; involves the use of programmable or flexible
automation
6. Improved material handling and storage - automated
material handling and storage systems reduce work-inprocess, shorter manufacturing lead times, and lower
labor costs.
7. On-line inspection - Incorporate inspection into the
manufacturing process so that corrections are made as
the product is being made. (QC-vs-QA)
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Ten Strategies for Automation & Process Improvement
8. Process control and optimization - include a wide range
of control schemes to operate the individual processes
and associated equipment more efficiently.
9. Plant operations control - control at the plant level;
manage and coordinate the aggregate operations in the
plant more efficiently. Needs high level of computer
networking within the factory.
10. Computer-integrated manufacturing (CIM) - involves
extensive use of computer systems, databases, and
networks throughout the enterprise to integrate the
factory operations and business functions.
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Automation Migration Strategy
• A company often needs to introduce a new product in
the shortest possible time. The easiest and least
expensive way is to design a manual production method,
using a sequence of workstations operating
independently.
• The tooling for a manual method can be fabricated
quickly and at low cost. If more than a single set of
workstation is required to make the product in sufficient
quantities, then the manual cell is replicated as many
times as needed to meet demand.
• If the product turns out to be successful, and high future
demand is anticipated, then it makes sense for the
company to automate production.
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Automation Migration Strategy
• A formalized plan for evolving the manufacturing systems
used to produce new products as demand grows
• Phase 1: To introduce a new product, Manual Production
using single-station manned cells operating
independently is used. Reason: quick and low-cost
tooling.
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Automation Migration Strategy
• Phase 2: When demand grows, Automated Production
using single-station automated cells operating
independently is used; reduced labor & increased
production rate. Parts are still moved between
workstations manually.
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Automation Migration Strategy
• Phase 3: Automated Integrated Production - multistation automated system with serial operations and
automated transfer of work units between stations.
Justification: If the product will be produced in mass
quantities and for several years
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Automation Migration Strategy
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Automation Migration Strategy
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Automation & Control Technologies in Prodn. System
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Basic Elements of Automated System
• Power to accomplish the process and operate the
system
• Program of instructions to direct the process
• Control system to actuate the instructions
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Basic Elements of Automated System
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Power for the Process
• For manufacturing processes
• Loading and unloading the work unit
• Material transport between operations
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Power for Automation
• Controller unit. Modern controllers are based on digital
computers, which require electrical power to read the
program of instructions, perform the control calculations,
and execute the instructions by transmitting the proper
commands to actuating devices.
• Power to actuate the control signals. The commands sent
by the controller unit are carried out by means of
electromechanical devices, such as switches and motors,
called actuators.
• Data acquisition and information processing. In control
systems, data must be collected from the process and
used as input to the control algorithms.
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Program of Instructions
Work Cycle Programs
• Set-point control - the process parameter value is
constant during the work cycle (as in the furnace
example).
• Logic control - the process parameter value depends on
the values of other variables in the process.
• Sequence control - the value of the process parameter
changes as a function of time. The parameter values can
be either discrete or continuously variable.
• Interactive program - interaction occurs between a
human operator and the control system during the work
cycle.
• Intelligent program - the control system exhibits aspects
of human intelligence (e.g., logic, decision making,
cognition, learning).
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Control System
• The control element of the automated system executes
the program of instructions
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Advanced Automation Functions
• An automated system should execute advanced functions
that are not specific to a particular work unit.
• The functions are concerned with enhancing the safety
and performance of the equipment.
• Functions:
1) Safety monitoring
2) Maintenance and repair diagnostics
3) Error detection and recovery.
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Safety Monitoring
• Safety monitoring in an automated system involves the
use of sensors to track the system’s operation and
identify conditions and events that are potentially unsafe.
• To protect human workers in the vicinity of the system
• To protect the equipment comprising the system
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Responses of Safety Monitor
• Completely stopping the automated system
• Sounding an alarm
• Light indicator (Red light)
• Reducing the operating speed of the process
• Taking corrective actions to recover from the safety
violation. (Advanced system)
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Sensors & their applications for Safety Monitoring
• Limit switches to detect proper positioning of a part in a work
holding device so that the processing cycle can begin.
• Photoelectric sensors triggered by the interruption of a light
beam; this could be used to indicate that a part is in the
proper position or to detect the presence of a human intruder
in the work cell.
• Temperature sensors to indicate that a metal work part is hot
enough to proceed with a hot forging operation.
• Heat or smoke detectors to sense fire hazards.
• Pressure-sensitive floor pads to detect human intruders in the
work cell.
• Machine vision systems to perform surveillance of the
automated system and its surroundings.
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Maintenance and Repair Diagnostics
• Status monitoring - the diagnostic subsystem monitors and
records the status of key sensors and parameters of the
system during normal operation. On request, the diagnostics
subsystem can display any of these values and provide an
interpretation of current system status, perhaps warning of an
imminent failure.
• Failure diagnostics - is invoked when a malfunction or failure
occurs. Its purpose is to interpret the current values of the
monitored variables and to analyze the recorded values
preceding the failure so that its cause can be identified.
• Recommendation of repair procedure - the subsystem
recommends to the repair crew the steps that should be
taken to effect repairs. Based on the use of expert systems in
which the collective judgments of many repair experts are
pooled and incorporated into a computer program that uses
artificial intelligence techniques.
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Error Detection and Recovery
• Traditionally, equipment malfunctions are corrected by
human workers, perhaps with the aid of a maintenance
and repair diagnostics subroutine.
• Control computer is used not only to diagnose the
malfunctions but also to automatically take the necessary
corrective action to restore the system to normal
operation.
• The term error detection and recovery is used when the
computer performs these functions.
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Error Detection
• Sensors determine when a deviation or malfunction has
occurred, interpret the sensor signals & classify the error
Categories of errors
• Random errors
• Systematic errors
• Aberrations.
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Random Errors
• Occurs as a result of the normal stochastic nature of the
process
• Occurs when the process is still in statistical control
• Large variations in part dimensions, even when the
production process is in statistical control, can cause
problems in downstream operations.
• By detecting these deviations on a part-by-part basis,
corrective action can be taken in subsequent operations.
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Systematic Errors
• Results from some assignable cause such as a change in
raw material or drift in an equipment setting.
• These errors cause the product to deviate from
specifications so as to be of unacceptable quality.
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Aberrations
• Results from either an equipment failure or a human
mistake.
• Examples of equipment failures : fracture of a shear pin,
burst in a hydraulic line, rupture of a pressure vessel, and
sudden failure of a cutting tool.
• Examples of human mistakes: errors in the control
program, improper fixture setups, and substitution of the
wrong raw materials.
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Error Recovery
• Error recovery - apply the necessary corrective action to
overcome the error and bring the system back to normal
operation.
• Design of an error recovery system focuses on devising
appropriate strategies & procedures that will either
correct or compensate for the errors that can occur in the
process.
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Error Recovery Strategies
• Make adjustments at the end of the current work cycle the part program branches to a corrective action
subroutine specifically designed for the detected error,
executes the subroutine, and then returns to the work
cycle program. This action reflects a low level of urgency
and is most commonly associated with random errors in
the process.
• Make adjustments during the current cycle. This indicates
a higher level of urgency than the preceding type. The
action to correct or compensate for the detected error is
initiated as soon as it is detected. However, the
designated corrective action must be possible to
accomplish while the work cycle is still being executed. If
that is not possible, then the process must be stopped.
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Error Recovery Strategies..
• Stop the process to invoke corrective action - the
deviation or malfunction requires the work cycle to be
suspended during corrective action. It is assumed that
the system is capable of automatically recovering from
the error without human assistance. At the end of the
corrective action, the regular work cycle is continued.
• Stop the process and call for help - the error cannot be
resolved through automated recovery procedures.
Situation arises because (1) the automated cell is not
enabled to correct the problem or (2) the error cannot be
classified into the predefined list of errors. In either case,
human assistance is required to correct the problem and
restore the system to fully automated operation.
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Levels of Automation
• Device Level: lowest level; actuators, sensors, & hardware
components; Eg. Feed back control loop of one axis of NC
or one joint of robot
• Machine Level: hardware at device level is assembled into
individual machines. Eg. CNC, Industrial robots, AGV,
Powered conveyors ..
• Perform sequence of steps in correct order
• Mfg. Cell or system Level: operates under instructions
from the plant level.
• Functions: part dispatching, m/c loading, matl. handling
system, collecting & evaluating inspection data
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Levels of Automation…
• Plant Level: Factory or production systems level. Receives
instructions from the Corporate Information System (CIS)
[MIS] and translates into operational plans for
production.
• Order processing, process planning, shop floor control,
QC
• Enterprise level: Highest level consisting of corporate
information system.
• Concerned with all the functions necessary to manage
the company: marketing & sales, accounting, design,
research, aggregate planning & master production
scheduling.
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Levels of Automation…
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Process Planning
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Process Planning
• Process Planning consists of determining the
1. most appropriate mfg. & assembly processes
2.sequence in which they should be accomplished
to produce a given part or product according to
specifications set forth in the product design
documentation.
• Done by mfg./ industrial/ production/ process engineer
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Scope of Process Planning
• Interpretation of detail drawings –
• materials, dimensions, tolerances, surface
finish etc.
• Choice of processes & sequence
• Choice of equipment
• Existing / outsource / New mc / purchase
component
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Scope of Process Planning…
• Choice of tools, dies, molds, fixtures, gauges
• Tool design dept. – tool room
• Analysis of methods –
• layout, small tools, hoist for lifting heavy parts
– IE dept.
• Setting of work standards – time standards
• Choice of cutting tools & cutting conditions
• Standard handbook
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Process Planning for Parts
• For individual parts, the processing sequence is
documented on a form called a route sheet or an
operation sheet
• Operations to be performed in the order in which they
must be
• Describe each operation w.r.t. dimensions & tolerances on
the part dwg.
• Specific machines on which it must be done
• Any special tooling – dies, molds, cutting tools, jigs or
fixtures
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Route Sheet
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Route Sheet
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Route Sheet
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Assignment - 1
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Process Sequence
• Basic Process : starting geometry of the w/p
• Metal casting, plastic molding, rolling of sheet
metal
• Secondary Processes: transforming starting geometry
into final geometry (or close to)
• Sand casting – machining
• sheet metal – punching, bending
• Plastic injection molding – ‘near net shape
processes’
• Impression die forging – ‘near net shape
processes’
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Process Sequence
• Property enhancing processes: geometry not altered;
physical properties are changed
• Heat-treatment; tempering of glass
• Finishing Operations : coating on the work part
surface
• Electroplating, painting
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Process Sequence
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Process Sequence
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Process Planning for Assemblies
• The type of assembly method depends on:
• the anticipated production quantities (small/medium/large)
• complexity of the assembled product, E.g. number of distinct
components
• assembly processes used, E.g, mechanical assembly versus
welding
• For a product with relatively small quantities, assembly is
generally accomplished at individual workstations where one
worker or a team of workers perform all of the assembly tasks.
• For complex products made in medium and high quantities,
assembly is usually performed on manual assembly lines
• For simple products of a dozen or so components, to be made in
large quantities, automated assembly systems may be
appropriate.
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Computer Aided Process Planning -CAPP
• Different process planners have different experiences,
skills, and knowledge of the available processes in the
plant. Hence, the process plan for a given part depends
on the process planner who developed it.
• Routing varies with planner. This leads to variations and
inconsistencies in the process plan.
• Shop-trained people who are familiar with the details of
machining and other processes are gradually retiring and
will be unavailable in the future.
• Hence, manufacturing firms are interested in automating
the task of process planning using computer-aided
process planning (CAPP).
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Benefits of CAPP
• Process rationalization & standardization
• logical & consistent PP
• lower mfg. cost
• high productivity
• Increased productivity of process planners
• Reduced lead time for PP
• Improved legibility
• Incorporation of other programs
• link to cost estimation and work standards
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CAPP - Types
• Retrieval CAPP systems
• Generative CAPP systems.
• Semi-Generative CAPP (Combination of the two)
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Retrieval CAPP Systems
• Based on Group Technology, Parts classification & Coding
• Standard process plan is stored in computers
• An ideal process plan prepared for each family is stored
in computers
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Retrieval CAPP Systems…
Steps:
• Derive GT code number for part
• Search part family file for standard route sheet
• If found, retrieve
• Make modification as needed
• If not found prepare new route sheet
• Process plan formatter – printing
• Also called Variant CAPP system
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Parts Coding Concept
Cylindrical [C] : Turning, Facing, Taper
Turning, Knurling.
Codes for operation: T , F , TP , K
Code for part: CTFTPK
In data base: CTFTP
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Retrieval CAPP Systems
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Generative CAPP Systems
• Process sequence is generated without human assistance
• Works on concept of ‘Expert System’
• Technical knowledge of mfg. & logic used by planners are
coded into computer programs
• Computer-compatible part description
• CAD model
• GT code of the part
• Apply process knowledge and planning logic
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Generative CAPP Systems
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End of UNIT - 1
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