Chapter: Integration of Manufacturing System

1
Chapter Integration of Manufacturing System

• Communication
• Material System Handling
• Flexible Manufacturing System (FMS)
• Computer Integrated Manufacturing (CIM)

2
Communication

• Data communication is done by transmitting logic
  0 and logic 1 signals in the form of high and low
  voltages thru wires between 2 interconnecting
  devices
• Typical computing devices in following 2 modes
• Parallel transmission
• Serial transmission
• Parallel transmission involves large numbers of ,
  high rate of data flow
• Serial transmission involves single wire that
  sends data from one terminal to the other

3
Communication Method

• Generally the length of the cable connecting the
  two devices is limited owing to the loss of data
  and the possibility of noise
• When data needs to be transferred for long
  distance, signal will be converted to suitable
  form so that common telephone line could be used
  for transmission
• Modem to be used (modulator demodulator)
• At transmitting end, Modems converts digital data
  into analog oscillation of 2 distinct
  frequencies.
• At the receiving end, the modem demodulates and
  converts to digital signal

4
Direct Numerical Method (DNC)

• DNC is the method used at shop floor to connect a
  number of CNC machine tools together and
  controlled by a PC
• MCU for each CNC machine tool is under control of
  DNC computer
• Individual machine tool is controlled by MCU
• Typical function are as follows
• Communication
• Part program storage
• Ancillary function

5
Direct Numerical Method (DNC) - Communication

• Sending part programs to the CNC machine tool as
  and when required
• Receiving the part programs from CNC machine tool
  after it has been edited (Part Program Uploading)
• Provide a remote control buffer. Part program
  memory size is limited to Imeg. For big size,
  have to split part program
• The tools offset of the tools to be used in the
  current program can be downloaded into the MCU.
  Avoid data entry.
• The CNC machine tool can be operated directly
  from the DNC computer, again operator need not go
  to the MCU
• To bring CNC machine tools to its datum position
  remotely

6
Direct Numerical Method (DNC) Part Program
Storage

• It can store all the part program meant for all
  CNC machine tools
• It is possible to input , edit copy and delete
  programs at the DNC computer
• Editing function can be provided based on blocks
  rather than the paragraph (line feed) as used in
  conventional method
• Removal and renumbering of block numbers can be
  done easily
• Syntax checking
• Calculation facility estimate machining time

7
Direct Numerical Method (DNC) Ancillary
Function

• Integrating the CAD/CAM system or the part
  programming system for the purpose of direct
  transfer of the part programs into the disk
  storage of the DNC computer
• Possibility of integrating with the shop floor
  control system for proper integration purpose
• Getting data from MCU, information about status
  of machine in the form of diagnostic message, to
  be used for predictive/preventive maintenance
• Getting data from MCU, information about parts
  that are competed in terms part number, quantity
  and etc.

8
Direct Numerical Method (DNC) Advantages

• DNC helps in elimination of the local input
  device such as the tape reader. Avoid entry error
  of free part program
• Large storage capacity of the DNC makes it
  possible to store several part programs
• If the same job to be made on different machine
  tools, separate part program entry into
  individual controller are eliminated.
• DNC software helps in managing the part programs
  in a better and easier way
• Because management function of the software, shop
  floor machine, inventories of tool can be handled
  much better
• DNC provides staring point for factory
  integration leading towards CIM

9
Material System Handling

• AGV is a vehicle equipped with automatic guidance
  equipment, either electromagnetic or optical.
  Such a vehicle is capable of following
  pre-described guide paths and may be equipped for
  vehicle programming and stop selection, blocking
  and any other functions required by the system
• Automated Guided Vehicles (AGV) is programmable
  mobile vehicle without human intervention
• Main AGV parts are
• Structure
• Drive system
• Steering mechanism
• Power source, battery
• Onboard computer for control

10
AGVS Type and Guidance

• Type
• AGVS Towing vehicles
• AGVS Unit load vehicles
• AGVS Pallet truck
• AGVS Fork truck
• Light load vehicles
• AGVS Assembly line vehicles
• Adoption of light load vehicles for serial
  assembly process
• Guidance
• Wire Guided
• antenna senses and follow an energized wire on
  the floor
• Infrared
• Infrared transmitted and reflected in the roof of
  facility. Detector relay signal to computer to
  determine position
• Laser
• Laser scan wall mounted and barcoded. AGV can be
  accurately maneuvered

11
Robot

• Computer Aided Manufacturers International
  describes robot as a device that performs
  functions ordinarily ascribed to human function,
  operates with that appears to be almost human
  intelligence.
• ISO describes robot as An automatically
  controlled, reprogramable, multipurpose,
  manipulative machine with several reprogrammable
  axes, which is either fixed in a place or mobile
  for use in industrial automation application
• Success stories of robot application
• Robot performs 98 of the spot welding on Fords
  Taurus
• Robot drills 550 holes in the vertical tail fins
  of F16 fighter in 3 hours

12
Robot Application

• Hazardous or uncomfortable working conditions eg
  in heated, radiated or toxic environment
• Difficult handling workpiece complex or heavy,
  robot perform the job better
• Multi shift operation increasing production and
  reducing costs, robot can work simultaneously

13
Robot Case Study

• A firm has a manual spray line employing 8
  skilled human spray painter. Manual system
  produces 90 units per hour with an operation of 6
  hours per shift. The two hours of lost production
  takes care of breaks, line servicing, maintenance
  and clean-up. The total costs of each human spray
  painter, including salary, benefits and overhead
  is RM80 per hour. Additional maintenance costs of
  the manual system amounts to RM5,000 per month. A
  replacement robotic spray line costs RM5M
  consisting of 10 robots with an production rate
  of 150 units per hour and works full 8 hours per
  shift. Robotic spray line costs the firm a total
  RM1.5M towards the depreciation, amortizing the
  capital investment and salvage value. The robot
  will cause RM150/hr of system operation which
  include the service repair and supervision.
  Compare the two systems costs.

14
Robot Case Study

• Manual system costs of 8 painters
• 8PplRM80/hr8hr/shift RM853.33hr
• 6hr/shift
• Maintenance costs (assume 50wk/yr, 5days/wk
• RM5,000/mth12mth RM40
• 50wk/yr5days/wk6hr/shift
• Hourly prod. costs 853.33 40 RM893.33/hr
• Costs/unit (90unit/hr) RM893.33/hr / 90units/hr
  RM9.92/unit
• Robotic system costs 10 robots (assuming 2000
  annual hours)
• RM1.5M/2000hrs RM750
• Maintenance costs RM150/hr
• Hourly prod. costs RM750 RM150 RM900/hr
• Costs/unit (150unit/hr) RM900/hr / 150unit/hr
  RM6/unit (exp.)
• Operates 2 shifts/day RM1.5M/4000 RM375/hr
• Hourly prod. costs RM375 RM150 RM525/hr
• Costs/unit RM525/hr / 150unit/hr RM3.5/unit
  (favorable)

15
Robot Case Study

• Question Boards of director allows only RM2.5M.
  (5 robots, 70units/hrs. RM0.6M depreciation).
• Calculate costs of running machine against manual
  system and make your costs saving
  reports/recommendation to the Board of Director.
  Include your suggestion to run on additional
  shift.

16
Flexible Manufacturing System (FMS)

• A series of automatic machine tools or items of
  fabrication equipment linked together with an
  automatic material handling system. A common
  hierarchical digital pre-programmed computer
  control, and provision for random fabrication of
  parts or assembly that fall within pre-
  determined families
• A FMS is a group of NC machine tools that can
  randomly process a group of parts, having
  automated material handling and central computer
  control to balance resource utilization so that
  the system can adopt automatically to changes in
  part production, mixes and level of output
• FMS is a randomly loaded automated system based
  on a group technology manufacturing linking
  integrated computer control and a group of
  machine to automatically produce and handle for
  continuous serial processing

17
FMS Automation Benefits

• Automation Machine Utilization
• Basic CNC (Manual) 40
• Basic CNC (Automated) 60
• Complete machine automation 75
• Integration of group no. 3 above 80
• Flexible Manufacturing System (FMS) 90

18
FMS Automation Benefits (cont.)

• FMS are regarded as one of the most efficient
  methods to employ in reducing or eliminating
  problem in industries
• FMS bring flexibility and responsiveness to the
  manufacturing floor
• FMS enable manufacturers to machine a wide
  variety of work-pieces on few machine with low
  staffing levels, productively, reliably and
  predictably
• FMS can handle a wide variety of different parts,
  producing them one at a time in random order
• Machine tools in many manufacturing industries
  are woefully under utilized due to equipment not
  being used on second and third shifts, a
  decreasing availability of skilled personnel and
  day-to-day disturbances
• FMS shortens the manufacturing process through
  improved operational control, round the clock
  availability of automated equipment, increase
  machine utilization and responsiveness, and
  reduction of human intervention

19
FMS Automation Benefits

• Better competitive advantage
• Lower work in process inventories
• Reduced throughput time and its variability
• Improved manufacturing control
• Improved quality and reduced scrap rate
• Reduction of floor space used
• Better status monitor of machine, tools and
  material handling device
• Improves the short run response time to the
  problems on shop floor such as demand variation,
  design and process change, machine unavailability
  (automatically transfer to next machine), cutting
  tool failure can be detected by sensor
• Improve the long term cost-effectiveness by
  supporting changing product volume, allowing
  different part mixers, allowing new part to be
  added

20
FMS Equipment

• Workstation
• CNC Machine tools
• Assembly equipment
• Measuring equipment
• Washing station
• Material Handling Equipment
• Load unload stations
• Robotics
• AGV (Automated Guided Vehicle)
• Tool systems
• Tool setting stations
• Tool transport systems
• Control system
• Monitoring equipment
• Networks

21
Computer Integrated Manufacturing (CIM)

• CIM is the integrations of the total
  manufacturing enterprise through the use of
  integrated systems and data communication coupled
  with new managerial philosophies that improve
  organizational and personal efficiency

22
CIM- History

• Dream period 1950 1970
• Nightmare period 1970 1980
• Realism period 1980 -
• During 1050-1970, many scenarios were proposed,
  however could not materialized
• During 1970-1980, since technologies were
  developing at a faster rate but not enough to to
  provide full capability of CIM at reasonable
  costs
• CIM was realized in 1980 due to the development
  of following
• Machine
• Computers
• Control system
• interfaces

23
CIM- Implementation

• CIM requires a very clear understanding of the
  total information flow within the system
• The structure include all component, system cell,
  workstation and equipment level
• Generally consists of all computer controlled and
  automatic equipment with no manual intervention
• Use of Flexible Manufacturing System greatly
  enhances CIM
• Analysis such as FEA, flow analysis and
  kinematics are used in order to optimize the
  products
• Detailed design here will be used by downstream
  application such as CAPP and CAM
• Transferring of data is crucial to ensure no
  loss, STEP is used
• Local Area Network (LAN) used to access design
  and analysis in database
• Shop floor control (SFC) is used to incorporate
  scheduling, manufacturing, monitoring and
  diagnostic

24
CIM- Benefits

• CIM improves the operational control through
• Reduction in the number of uncontrollable
  variable
• Providing tools to recognize and react quickly to
  deviations in the manufacturing plan
• Reducing dependence on human communication
• CIM improves the short run responsiveness
  consisting of
• Engineering changes
• Processing changes
• Machine down time
• Operator unavailability
• Cutting tool failure
• Late machine delivery
• CIM improves the long run accommodations through
  quicker and easier assimilation
• Changing product volume
• New product addition and introduction
• Different part mixes

25
CIM- Benefits (cont.)

• CIM reduces the inventory by
• Reducing lot sizes
• Improving inventory turnover
• Providing the planning tool for Just In time
  manufacturing
• CIM increases machine utilization by
• Eliminating or reducing machine set-up
• Utilizing automated features to replace manual
  intervention to the extent possible
• Providing quick transfer devices to keep the
  machine in the cutting cycle

26
CIM- Lean Manufacturing

• Pioneered by Toyota, Japan and adopted by many
  manufacturing companies
• Objectives are to reduce costs, satisfy customers
  and increase profitability
• Eliminates non-value added activities
• Process is lean when existing style of
  operations is transformed to entirely different
  which involves process re-engineering, adopting
  new technologies or adding new and different
  equipment
• Involve significant changes in human resources
  such as education, training, practices and
  policies

27
CIM- Lean Manufacturing

• Three steps involves in lean manufacturing
• Define value in term of specifics products or
  services, with specific capabilities, offered at
  specific process with a specific customer. Based
  on concept that providing wrong goods to
  customers is waste
• Identify the value streams , which is the set of
  all actions required to bring a specific product
  or services through the critical management tasks
  of any business. The management tasks are problem
  solving, information management, and physical
  transformation (converting raw material to
  finished product
• Make the value creating steps following the flow
  technology. Conventional thinking and
  manufacturing practices are based to a great
  extent on batch or department concept.
• Batch means a long wait
• Waste in the form of buffer or WIP
• Very large volume manufacturing will benefit
  greatly