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AutomatedAutomatedMachiningMachining
Manufacturing Manufacturing ProcessesProcesses
OutlineOutline
Machining CentersMachining Centers
EquipmentEquipmentTool ChangersTool Changers
Centering and ClampingCentering and Clamping
Selection of EquipmentSelection of Equipment
Selection of ToolingSelection of Tooling
Machine Performance MonitoringMachine Performance Monitoring
Manufacturing CellsManufacturing Cells
Manufacturing EconomicsManufacturing Economics
Machining CentersMachining Centers
Machining CenterMachining Center
A computer-controlled machine A computer-controlled machine tool capable of many types of tool capable of many types of cutting operations on multiple cutting operations on multiple surfaces and directions on a surfaces and directions on a workpieceworkpiece
Manufacturing CentersManufacturing Centers
φ
φθ
X
YZ
3-Axis Operation
4-Axis Operation
5-Axis Operation
Components of aComponents of aMachining CenterMachining Center
Example of aExample of aMachining CenterMachining Center
Example of aExample of aMachining CenterMachining Center
Example of a Machining Example of a Machining CenterCenter
Example of a 5-axis CNC machine (the tool pivots instead of the workpiece)
Example of a Vertical Example of a Vertical Machining CenterMachining Center
Example of a Horizontal Example of a Horizontal Machining CenterMachining Center
Examples ofExamples ofManufactured PartsManufactured Parts
Automated Robotic Automated Robotic LoadingLoading
Automated Robotic Automated Robotic LoadingLoading
EquipmentEquipment
PalletsPalletsThe workpiece is placed on a The workpiece is placed on a pallet (module) which can be pallet (module) which can be oriented in different directions oriented in different directions by the machineby the machine
Automatic Pallet ChangersAutomatic Pallet ChangersWhen the workpiece is When the workpiece is finished, automatic pallet finished, automatic pallet changers remove it and changers remove it and replace it with another replace it with another workpieceworkpiece
PalletsPallets
Example of a part mounted on a pallet
Courtesy Toth Industries
Pallet ChangersPallet Changers
EquipmentEquipment
Automatic Tool ChangerAutomatic Tool Changer
Can switch between up to 200 Can switch between up to 200 tools stored in a magazine, tools stored in a magazine, drum, or chaindrum, or chain
Tool Exchange ArmTool Exchange Arm
Picks up particular tools with Picks up particular tools with attached toolholders attached toolholders
Tool ChangerTool ChangerTypesTypes
Automatic (Sequential) SpindleAutomatic (Sequential) Spindle
Turns one increment in one Turns one increment in one direction for each tool change; tools direction for each tool change; tools must be placed in the spindle in the must be placed in the spindle in the order they are usedorder they are used
Indexable (Random Access) SpindleIndexable (Random Access) Spindle
Turns either direction to make a Turns either direction to make a specific tool accessible; tools can specific tool accessible; tools can be placed in any order as long as be placed in any order as long as the computer knows their positionsthe computer knows their positions
Tool ChangerTool ChangerTypesTypes
4
1
2
3
5
6
1
2
3
4
5
6
7
8
Sequential Spindle
Random Access Spindle
Tool Changer SpindleTool Changer Spindle
Tool Changer SpindleTool Changer Spindle
Tool changer spindle capable of holding 60 tools
Courtesy of Toth Industries
Tool Changer ArmTool Changer Arm
Tool Changer ArmTool Changer Arm
Tool Changer ArmTool Changer Arm
Tool Changer –Tool Changer –Live SpindleLive Spindle
Types ofTypes ofManufacturingManufacturing
Cutting From Bulk MaterialCutting From Bulk Material
Starting with a readily available Starting with a readily available shape (rods, ingots etc.) and shape (rods, ingots etc.) and machining the part from thismachining the part from this
Cutting From Near Net ShapeCutting From Near Net Shape
Starting with a pre-formed Starting with a pre-formed (often cast) piece with the (often cast) piece with the general shape of the part and general shape of the part and removing little materialremoving little material
Centering andCentering andClampingClamping
Pre-cast designs should be Pre-cast designs should be made so that the machines can made so that the machines can clamp and orient them quickly clamp and orient them quickly and accuratelyand accurately
Parts to be lathed should have Parts to be lathed should have radially symmetrical outer radially symmetrical outer surfaces and pre-cast holes to surfaces and pre-cast holes to mark the center; they should mark the center; they should also have a center of mass on also have a center of mass on the center line to prevent the center line to prevent vibrationvibration
Orienting andOrienting andClampingClamping
Pre-cast parts should have at Pre-cast parts should have at least three distinct features that least three distinct features that the computer can recognize the computer can recognize and use to orient the partand use to orient the part
holesnotches
Centering andCentering andClampingClamping
Pre-cast parts should have flat Pre-cast parts should have flat parallel surfaces for clamping parallel surfaces for clamping or cylindrical surfaces for or cylindrical surfaces for chuckingchucking
Areas to be clamped or chucked Areas to be clamped or chucked can be ground flat after casting can be ground flat after casting to improve gripto improve grip
Selection ofSelection ofEquipmentEquipment
Various types of parts may require Various types of parts may require various machining centersvarious machining centers
Parts with numerous cylindrical Parts with numerous cylindrical surfaces (or other radially surfaces (or other radially symmetrical surfaces) should be symmetrical surfaces) should be mounted on a machine center mounted on a machine center capable of turningcapable of turning
Specialized machine centers are Specialized machine centers are available for high-speed machining available for high-speed machining and for ultraprecision cuttingand for ultraprecision cutting
Selection ofSelection ofEquipmentEquipment
Example: Pump CoverExample: Pump Cover
Starting with the rough casting, Starting with the rough casting, drill and ream the center hole, drill and ream the center hole, then cut the internal notch with then cut the internal notch with a milling cutter. Mount the a milling cutter. Mount the piece on a mandrel and use piece on a mandrel and use turning operations to cut the turning operations to cut the faces and outer edge. Mill the faces and outer edge. Mill the external notch and drill and external notch and drill and ream the smaller holes in the ream the smaller holes in the plate.plate.
SelectionSelectionof Toolingof Tooling
The proper selection of tools The proper selection of tools depends on the workpiece depends on the workpiece material, size and shape of material, size and shape of holes, radii of the corners of holes, radii of the corners of milling pockets, and various milling pockets, and various other parametersother parameters
The selection of tools affects the The selection of tools affects the cost and time of the operationcost and time of the operation
Machine PerformanceMachine PerformanceMonitoringMonitoring
Machine PerformanceMachine PerformanceMonitoringMonitoring
Y’Y
X’
X
Part Orientation
Cutting Performance
Machine PerformanceMachine PerformanceMonitoringMonitoring
Tool/Part-Checking StationTool/Part-Checking Station
Measures workpieces and Measures workpieces and tools so that the computer can tools so that the computer can compensate for variations and compensate for variations and tool weartool wear
Touch ProbesTouch Probes
Pressed against a workpiece Pressed against a workpiece or tool to measure its exact or tool to measure its exact size and positionsize and position
Touch ProbesTouch Probes
Measurement andMeasurement andAdjustmentAdjustment
Advanced machining software can Advanced machining software can use data from probes to adjust its use data from probes to adjust its coordinate system, ensuring that coordinate system, ensuring that critical distances remain within critical distances remain within tolerances even in deformed tolerances even in deformed workpiecesworkpieces
critical distances
Holes to be drilled
(initial)
Holes to be drilled
(adjusted)
Touch ProbesTouch Probes
probe
tool holder
part
Using a touch probe to measure a part
Courtesy Toth Industries
Touch ProbesTouch Probes
A machining center, being used to measure and determine
the orientation of a part
Courtesy of Toth Industries
Touch ProbesTouch Probes
A machining center, being used to measure and determine the orientation of a part
Courtesy of Toth Industries
tool changer arm probe part
Touch ProbesTouch Probes
To determine the orientation of the part, the machine measures the two large holes and calculates their centers. A line
constructed between the centers serves as a base for the computer’s coordinate system.
Courtesy of Toth Industries
Machine PerformanceMachine PerformanceMonitoringMonitoring
Tool Failure Detection:Tool Failure Detection:- TimeTime
When the total cutting time of When the total cutting time of the tool exceeds the pre-the tool exceeds the pre-programmed tool life, the tool programmed tool life, the tool is replacedis replaced
- HorsepowerHorsepower
Dull tools draw more power; if Dull tools draw more power; if the power exceeds pre-the power exceeds pre-programmed limits, the tool is programmed limits, the tool is replacedreplaced
Machine PerformanceMachine PerformanceMonitoringMonitoring
Tool Failure Detection:Tool Failure Detection:- Acoustic EmissionsAcoustic Emissions
Cutting tools produce Cutting tools produce ultrasonic vibrations and ultrasonic vibrations and weakened ones produce up to weakened ones produce up to five times the normal five times the normal amplitude; when it rapidly amplitude; when it rapidly increases, the tool is increases, the tool is immediately replacedimmediately replaced
Machine PerformanceMachine PerformanceMonitoringMonitoring
Tool Failure Detection:Tool Failure Detection:- Feed ForceFeed Force
Records the feed force of Records the feed force of sharp tools; if the force sharp tools; if the force increase exceeds a increase exceeds a predetermined percentage, the predetermined percentage, the tool is replaced; if the force tool is replaced; if the force suddenly rises, the tool has suddenly rises, the tool has broken and is replaced broken and is replaced immediatelyimmediately
ManufacturingManufacturingCellsCells
ManufacturingManufacturingCellsCells
ManufacturingManufacturingCellsCells
Manufacturing Cells –Manufacturing Cells –ExamplesExamples
Courtesy of Toth Industries
ManufacturingManufacturingEconomicsEconomics
Cost:Cost:
If the cutting speed is too low, If the cutting speed is too low, the cost of cutting increases the cost of cutting increases because of increased power because of increased power consumptionconsumption
If the cutting speed is too high, If the cutting speed is too high, the cost of tool replacement the cost of tool replacement increases because tools wear increases because tools wear out fasterout faster
ManufacturingManufacturingEconomicsEconomics
Time:Time:
If the cutting speed is too low, If the cutting speed is too low, the cutting time increasesthe cutting time increases
If the cutting speed is too high, If the cutting speed is too high, the tool replacement time the tool replacement time increasesincreases
Manufacturing Manufacturing EconomicsEconomics
SummarySummary
Machining Centers allow increased Machining Centers allow increased automation and efficiency, automation and efficiency, especially in large-scale productionespecially in large-scale production
Monitoring, by an operator or the Monitoring, by an operator or the machine itself, is necessary to machine itself, is necessary to prevent damage to the parts prevent damage to the parts producedproduced
Cutting speed can be varied to Cutting speed can be varied to minimize the total cost or time of minimize the total cost or time of the operationthe operation
The EndThe End