Automated Machining

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 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

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 –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


Y’Y

X’

X

Part Orientation

Cutting Performance


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

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)


probe

tool holder

part

Using a touch probe to measure a part

Courtesy Toth Industries


A machining center, being used to measure and determine

the orientation of a part



A machining center, being used to measure and determine the orientation of a part


tool changer arm probe part


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.



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


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


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

Manufacturing Cells –Manufacturing Cells –ExamplesExamples


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

Automated Machining

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