UNIT-IV
Shop Floor Control and Flexible
Manufacturing Systems
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Shop Floor Control
• Shop floor control (or) Production Activity Control Manages the detailed
flow of materials inside the production facility
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Functions of Shop floor Control
• Scheduling
• Follow up
• Dispatching
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Phases of Shop floor Control
• Order Release
• Order Scheduling
• Order Progress
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Order Release
• This phase provides the documentation needed to process a production
order through the factory
• This collection of documents referred as the shop packet
• Shop pocket consists of
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Route sheet- used to list the sequence of operations and tools required
Material requisitions- used to get necessary raw materials from inventory
Job cards- used to report the labour for each operation on the route sheet
Move tickets- used to move the parts between the work centres
Part lists- required for assembly jobs
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Order Scheduling
• It executes the dispatching function in production planning and control
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Elements of Order Scheduling
1.Machine loading- Allocating orders to work centres
2.Job sequencing- Determining priority in which the jobs should be
proceed
Priority Sequencing rules:
• Shortest operating time
• Earliest due date
• Slack time remaining-(Time remaining before due date-Processing time
remaining)
• First come, first served- orders are run in the order they arrive in dept.
• Last come first, first served- orders arrive, they placed on top of the stock
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Order progress
• Monitors the status of the various orders in the plant, work –in progress
and other progress in the shop floor
Types of orders progress reports:
• Work order status progress- indicate the current status of each shop
• Progress reports- indicates the performance of each shop
• Exception reports- indicate the deviations from production schedule
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Factory Data Collection System (FDC)
• FDC consists of various paper documents , terminals and automated
devices throughout the plant for collecting data on shop floor operations
and compile and process the collected data for reference.
Types of data collected by FDC
• Number of Pieces completed at a certain work centre
• Labour time spend on each order
• List and no. of parts that are scrapped
• List the no. of parts required rework
• Time clocks used by employees to punch in and out of work
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Objectives of Factory Data Collection System (FDC)
• To supply status and performance data to shop floor control system
• To provide up to date information
• To enable the management to monitor and implementation of master
schedule
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Types of Data Collection System
• Online data collection system
• Offline data collection system
Online data collection system
• The data are entered directly into the plant computer system and are
immediately available to the order progress module. It always kept the
details in current status
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Types of Data Collection System
Offline data collection system
• The data are collected temporarily in a storage device (or) stand alone
computer system
• Its easy to install and monitor
• It cannot provide up to date information to the shop floor
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Data Input Techniques
1.Manual/Clerical input techniques
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Job traveler- long sheet that travels with the shop packet through the factory
Employee time sheets- daily time sheet is prepared for each worker
Operation tear strips- set of preprinted tear strips
Prepunched cards- Prepunched computer cards to each workers
Disadvantages:
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Its depends on accuracy
Manual errors are highly possible
Delay on submitting the progress data
Delay on compiling data
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Data Input Techniques
2. Data collection terminals- Workers to input data relative to order
progress using simple keyboards (or) conventional alphanumeric
keyboards
EX: Push button keyboards, Workstation etc
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Automatic Identification methods
Automatic data collection is essential for streaming the flow of
information in CIM environments
Types of Automatic identification techniques:
• Bar codes
• Radio frequency systems
• Magnetic stripe
• Optical character recognition
• Machine vision
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Bar code Technology
https://www.youtube.com/watch?v=CFubTQ5p4xk
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Bar cods
Commonly used bar codes are,
• Code 39
• Interleaved two of five (ITF)
• Universal Product Code
• Code 93
• Code 128
• Postnet
• Codabar
• Plessey
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Bar cods
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Radio Frequency systems
https://www.youtube.com/watch?v=MAA9JpGraoU
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Automated data collection systems
1. Data acquisition systems
2. Data logging systems
3. Multilevel scanning
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Data Acquisition Systems (DAS)
DAS is a computer system used to automatically collect data from process
(or) piece of equipment. These perform an analysis of data (or) transfer
the data to another computer for further use
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Data Logging Systems (DAS)
Data logger is a device that automatically collects and stores data for off
line analysis
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Multilevel Scanning
More than one level of scanning
• Low level scan
• High level scan
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Flexible Manufacturing System (FMS)
FMS is highly automate GT machine cell. A FMS is an individual machine
(or) group of machines served by an automated materials handling system
that is computer controlled and has a tool handling capability
(Or)
Multiple Machines that are integrated by an automated material handling
system, whose operation is managed by computerized control system
https://www.youtube.com/watch?v=BBC2oswnrt0
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Components/Elements of FMS
1.Workstations
2.Material handling and Storage systems
3.Computer control systems
4.Human Resources
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1.FMS Workstations
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Load/unload Stations
Machining Stations
Assembly workstations
Inspection Stations
Other processing stations
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Load/Unload stations
• Loading and unloading of parts-either manually or automatically
• Data entry in system
• Soft movement of parts
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Machining Stations
• Automatic tool changing and tool storage
• Use of CNC
• Use of palletized work parts
Machines
• Turning modules
• Milling modules
• Head indexers
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Assembly Workstations
• Replace the manual labour for assembling the parts
• In this workstations, products made of batches –(Robots are used)
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Inspection Workstations
• Inspection carried out for the assembly products
Tools used
• Coordinate Measuring Machines(CMM)
• Special inspection Probes, etc
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Other Processing Workstations
• Sheet metal processing workstations
• Forging process stations,etc
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2.Material handling and storage system
• Part Transportation
• Raw material and finished product transportation
• Storage of Work pieces
• Wastes
• Empty pallets
• Fixtures and tools
1.Functions of material handling system
2.Types of FMS layout
3.Types of handling equipment used in FMS
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Functions of material handling system
• Random, independent movement of work parts between stations
• Handle of variety of work part configurations
• Temporary storage
• Convenient access for loading and unloading work parts
• Compatible with computer control
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FMS Layout
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FMS Layout
Ladder layout
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Types of material handling equipment's
• Conveyors
• Cranes
• Industrial trucks
• Rail guided vehicles
• Automated guided vehicles
• Industrial robots
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Conveyors
• https://www.youtube.com/watch?v=HvFqo_ZOrsU
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Cranes
https://www.youtube.com/watch?v=GwTsLysTtpQ
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Industrial trucks
https://www.youtube.com/watch?v=bmU2CtcGIyQ
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Rail guided vehicle
https://www.youtube.com/watch?v=UdC_Jm7hDs8
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Automated guided vehicle systems(AGVS)
https://www.youtube.com/watch?v=7xvP645fVnI
https://www.youtube.com/watch?v=QKPIOny1AL4&index=4&list=PLQDv5
X70diTwDaucbQ7AyEuzwhQ8Bws0s
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Industrial robots
https://www.youtube.com/watch?v=DYoBUhADU5s
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