automating manufacturing process
TRANSCRIPT
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Automation in Manufacturing
FIGURE 14.1 Outline of topics described in this chapter.
Flexiblefixturing
AssemblyRobotsMaterialhandling
Design for assembly,disassembly, and service
Fixed sequence, variablesequence, playback, NC, intelligent
Manipulators,automatedguided vehicles
ACoptimization
ACconstraint
ComputerNC
Adaptivecontrol
Numericalcontrol
Programming
DirectNC
Computeraided
Manual
Softautomation
Hardautomation
Transfermachines
Automation of manufacturing processes Sensors
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
History of AutomationDate Development1500-1600 Water power for metalworking; rolling mills for coinage strips.1600-1700 Hand lathe for wood; mechanical calculator.
1700-1800 Boring, turning, and screw cutting lathe, drill press.1800-1900 Copying lathe, turret lathe, universal milling machine; advanced mechanical calcu-
lators.1808 Sheet-metal cards with punched holes for automatic control of weaving patterns in
looms.1863 Automatic piano player (Pianola).1900-1920 Geared lathe; automatic screw machine; automatic bottle-making machine.1920 First use of the word robot.1920-1940 Transfer machines; mass production.1940 First electronic computing machine.1943 First digital electronic computer.1945 First use of the word automation.1947 Invention of the transistor.1952 First prototype numerical control machine tool.1954 Development of the symbolic language APT (Automatically Programmed Tool);
adaptive control.1957 Commercially available NC machine tools.1959 Integrated circuits; first use of the term group technology.1960 Industrial robots.1965 Large-scale integrated circuits.1968 Programmable logic controllers.
1970s First integrated manufacturing system; spot welding of automobile bodies withrobots; microprocessors; minicomputer-controlled robot; flexible manufacturing sys-tem; group technology.
1980s Artificial intelligence; intelligent robots; smart sensors; untended manufacturingcells.
1990-2000s Integrated manufacturing systems; intelligent and sensor-based machines; telecom-munications and global manufacturing networks; fuzzy-logic devices; artificial neuralnetworks; Internet tools; virtual environments; high-speed information systems.
TABLE 14.1 Developments in the history ofautomation and control of manufacturingprocesses. (See also Table 1.1.)
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Flexibility and Productivity
FIGURE 14.2 Flexibility and productivity of various manufacturing systems. Note the overlap between thesystems, which is due to the various levels of automation and computer control that are applicable in eachgroup. See also Chapter 15 for more details.
Transferline
Conventionalflowline
Flexiblemanufacturing
line
Conventionaljob shop
Flexible
manufacturingsystem
Increasing productivity
Increasingf
lexibility
Soft automation Hard automation
Manufacturingcell
Stand-aloneNC production
Type of production Number produced Typical products
Experimental or prototype 1-10 All types
Piece or small batch < 5000 Aircraft, machine tools, dies
Batch or high quantity 5000-100,000 Trucks, agricultural machinery, jet engines, diesel
engines, orthopedic devices
Mass production 100,000+ Automobiles, appliances, fasteners, bottles, food
and beverage containers
TABLE 14.2 Approximatea n n u a l q u a n t i t y o f production.
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Characteristics of Production
FIGURE 14.3 General characteristics of three types of production methods: job shop,batch production, and mass production.
Production rate
Production quantity
Plant layoutProcess Flow line
Labor skill
Part variety
General purpose Equipment Special
Mass production
Type of production
Batch productionJob shop
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Transfer Mechanisms
FIGURE 14.4 Two types of transfer mechanisms: (a) straight, and (b) circular patterns.
(a) (b)
Powerheads
Workpiece
Rotaryindexing table
Workpiece
Power heads
Pallet
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Transfer Line
FIGURE 14.5 A traditional transfer line for producing engineblocks and cylinder heads. Source: Ford Motor Company.
Machine 2:
Mill, drill,ream, plunge
mill
Start
Machine 1:
Mill
Machine 3:
Drill, ream,plunge mill
Machine 4:
Drill, bore
Machine 5:
Drill, bore
Machine 6:
Drill, ream,bore, mill
Machine 10:
Bore
Machine 8:
Mill
Machine 7:
Drill, ream, bore
Machine 9:
Mill, drill, ream
Machine 12:
Bore
Machine 11:
Drill, ream,bore
Wash
Wash
Machine 13:
Finish hollow mill,finish gun ream,finish generate
Machine 14:
Ream, tap
Machine 15:
hone, wash, gage,bore, mill
Air test
AssembleAssembleAssemble
End
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Dimensioning Example
FIGURE 14.6 Positions of drilled holes in a workpiece. Three methods of measurements are shown: (a)absolute dimensioning, referenced from one point at the lower left of the part; (b) incrementaldimensioning, made sequentially from one hole to another; and (c) mixed dimensioning, a combination ofboth methods.
(a)
+ + + + +
++
+
+
+
+
(b) (c)
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Numerical Control
FIGURE 14.8 Schematic illustration of thecomponents of (a) an open-loop, and (b) aclosed-loop control system for a numericalcontrol machine. (DAC is digital-to-analogconverter.)
Computer:
Input commands, processing,output commands
Spindle
Work table
Machine tool
Limitswitches
Positionfeedback
Drivesignals
FIGURE 14.7 Schematic illustration of the majorcomponents of a numerical control machine tool.
(a)
Steppingmotor
Pulse train
Work table
Leadscrew
Gear
(b)
Feedback signal
DC
servomotor GearInput 1
2
Work table
Leadscrew
Comparator DAC
Positionsensor
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Displacement Measurement
FIGURE 14.9 (a) Direct measurement of the linear displacement of a machine-toolworktable. (b) and (c) Indirect measurement methods.
(a)
(b) (c)
Rack and pinion
Rotary encoderor resolver Linear motion
Worktable
Rotary encoderor resolver
Ball screw
Machine column
Worktable
Scale
Sensor
Machine bed
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Tool Movement & Interpolation
FIGURE 14.11 Types of interpolation in
numerical control: (a) linear; (b)continuous path approximated byincremental straight lines; and (c)circular.
(a) (b)
Holes
1
2
3
4
Workpiece
Cutter
Workpiece
Cutterpath
Cutter
radius
Machinedsurface
FIGURE 14.10 Movement of tools innumerical control machining. (a) Point-to-pointsystem: The drill bit drills a hole at position 1, isthen retracted and moved to position 2, and soon. (b) Continuous path by a milling cutter;note that the cutter path is compensated forby the cutter radius. This path can alsocompensate for cutter wear.
(a)
x
(b) (c)
1
2
3 4 5
y
y
x
x
Quadrant
Segment
Full circle
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
CNC Operations
FIGURE 14.12 (a) Schematic illustration of drilling, boring, and milling operations with various
cutter paths. (b) Machining a sculptured surface on a five-axis numerical control machine. Source:The Ingersoll Milling Machine Co.
(a) (b)
Point-to-point
Workpiece
Milling
3-axis contourmilling
2-axis contourmilling
Point-to-point andstraight line
2-axis contouring withswitchable plane
3-axis contouringcontinuous path
Drilling andboring
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Adaptive Control
FIGURE 14.13 Schematic illustration of the application ofadaptive control (AC) for a turning operation. The systemmonitors such parameters as cutting force, torque, andvibrations; if they are excessive, AC modifies processvariables, such as feed and depth of cut, to bring them backto acceptable levels.
Spindlemotor
Tachometer
Servodrives
Machinetool
Position
CNC Commands
% Spindle load
Spindle speed
Torque
VibrationAC
Partmanufacturing
data
Velocity
Parameter
limits
Readout
Resolver
FIGURE 14.14 An example of adaptivecontrol in slab milling. As the depth of cut or
the width of cut increases, the cutting forcesand the torque increase; the system sensesthis increase and automatically reduces thefeed to avoid excessive forces or toolbreakage. Source:After Y. Koren.
Conventional
Cutter travel
Adaptive control
Feed
pertooth
(a)
WorkpieceCutter
Variable width of cut
(b) (c)
Variable depth of cut
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
In-Process Inspection
Cutting tool
Final work
size control
Gaginghead
Controlunit
Machinetool
Workpiece
FIGURE 14.15 In-process inspection of workpiece diameter in aturning operation. The system automatically adjusts the radial positionof the cutting tool in order to machine the correct diameter.
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Self-Guided Vehicle
FIGURE 14.16 (a) A self-guided vehicle (Tugger type). This vehicle can be arranged in a variety ofconfigurations to pull caster-mounted cars; it has a laser sensor to ensure that the vehicle operates safelyaround people and various obstructions. (b) A self-guided vehicle configured with forks for use in awarehouse. Source: Courtesy of Egemin, Inc.
(a) (b)
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Industrial Robots
FIGURE 14.18 Various devices and
tools that can be attached to endeffectors to perform a variety ofoperations.
2500 mm 3000 mm
2025 mm1075 mm
1200 mm
(a) (b)
2
3
1
4
5
6
FIGURE 14.17 (a) Schematic of a six-axis KR-30KUKA robot; the payload at the wrist is 30 kgand repeatability is 0.15 mm (0.006 in.). Therobot has mechanical brakes on all of its axes. (b)The work envelope of the KUKA robot, asviewed from the side. Source: Courtesy of KUKARobotics.
Nut driver
(a) (b) (c)
(d) (e) (f)
Small power tool
Deburring tool
Dial indicator
Sheet metal
Electromagnet
Gripper
Object
Vacuum line
Suction cup
Robot arm
Workpiece
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Robot Types & Workspaces
FIGURE 14.19 Four types of industrial robots: (a) Cartesian (rectilinear); (b) cylindrical; (c) spherical (polar); and (d) articulated,(revolute, jointed, or anthropomorphic). Some modern robots are anthropomorphic, meaning that they resemble humans in shape andin movement. These complex mechanisms are made possible by powerful computer processors and fast motors that can maintain arobot's balance and accurate movement control.
(d)(a) (b) (c)
FIGURE 14.20 Work envelopesfor three types of robots. The
selection depends on theparticular application (See alsoFig. 14.17b.)
Rectangular
(a)
Cylindrical Spherical
Workenvelope
Workenvelopes
(b) (c)
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Robot Applications
FIGURE 14.21 Spot welding automobile bodieswith industrial robots. Source: Courtesy of FordMotor Co.
FIGURE 14.22 Sealing joints of an automobilebody with an industrial robot. Source: CincinnatiMilacron, Inc.
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Robots and Transfer Lines
FIGURE 14.23 An example of automated assembly operations using industrial robots andcircular and linear transfer lines.
Circulartransfer line
Robots
Remote center compliance
Torque sensor
Visual sensing
Linear transfer line
Programmablepart feeder
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Advanced End Effectors
FIGURE 14.24 A toolholder equipped with thrust-force and torque sensors (\it smart tool holder),capable of continuously monitoring the machiningoperation. (See Section 14.5). Source: CincinnatiMilacron, Inc.
Toolholder
Chuck
On-board electronicsto process signals
Drill
Strain
gages
Inductive transmitter
FIGURE 14.25 A robot gripper with tactilesensors. In spite of their capabilities, tactilesensors are now being used less frequently,because of their high cost and low durability (lackof robustness) in industrial applications. Source:Courtesy of Lord Corporation.
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Applications of Machine Vision
FIGURE 14.26 Examples of machine vision applications. (a) In-line inspection of parts. (b) Identifying parts withvarious shapes, and inspection and rejection of defective parts. (c) Use of cameras to provide positional input toa robot relative to the workpiece. (d) Painting of parts with different shapes by means of input from a camera;the system's memory allows the robot to identify the particular shape to be painted and to proceed with thecorrect movements of a paint spray attached to the end effector.
(c)
(b)
(d)
(a)
Robotcontroller
Camera
view 1
Cameraview 2
Visioncontroller
Work-piece
Controller
Camera 2Camera 1
Camera
Controller
Good Good Good
RejectRejectRejectReject
Robot
Camera
Workpieces
Visioncontrollerwith memory
Paintspray
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Fixturing
FIGURE 14.27 Components of a modularworkholding system. Source: Carr Lane ManufacturingCo.
FIGURE 14.28 Schematic illustration of an adjustable-forceclamping system. The clamping force is sensed by the straingage, and the system automatically adjusts this force. Source:After P.K. Wright and D.A. Bourne.
Clamp
Amp ADC
Relay Microcomputer
Solenoidvalve
Work table
Workpiece
Hydraulicline
Hydraulic cylinder
Strain gage
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Design for Assembly
FIGURE 14.29 Stages in the design-for-assembly analysis. Source: After G.Boothroyd and P. Dewhurst.
Analyzefor manualassembly
Analyze forhigh-speedautomaticassembly
Analyzefor robotassembly
Select theassembly method
Improve the designand re-analyze
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Indexing Machines
FIGURE 14.30 Transfer systems for automated assembly: (a) rotary indexing machine, and (b) in-line indexing machine. Source:After G. Boothroyd.
(a)(b)
Stationaryworkhead
Completedassembly
Work carriersindexed
Parts feeder
Indexing table
Work carriers
Stationaryworkhead
Parts feeder
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Vibratory Feeder Guides
FIGURE 14.31 Examples of guides to ensure that parts are properly oriented for automatedassembly. Source:After G. Boothroyd.
(a)
(c) (d)
(b)
Cutout rejectscup-shaped parts
standing on their tops
Parts rejectedif laying on side
Bowl wall Scallop Wiper blade
To deliverychute
Bowlwall
Slottedtrack
To deliverychute Slot in track
to orient screws
Screws rejected unlessin single file, end-to-end,
or if delivery chute is full
Screws rejectedunless lying on side
Wiperblade
Pressurebreak
Bowl wallNarrowed track
Widthwise parts rejectedwhile only one row oflengthwise parts passTo delivery
chute
Bowl wallV cutout
To deliverychute
Part rejected ifresting on its top
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Manufacturing Processes for Engineering Materials, 5th ed.Kalpakjian Schmid 2008, Pearson EducationISBN No. 0-13-227271-7
Robotics Example: Toboggan Deburring
FIGURE 14.32 Robotic deburring of a blow-molded toboggan. Source: Courtesy of KukaRobotics, Inc. and Roboter Technologie, GmbH.
Toboggan
Robot
Deburring toolFixture
Cutouts