Contents 1 Measurement and Machine Tools An Introduction

Transcription

1 Contents 1 Measurement and Machine Tools An Introduction Why the Need for Accurate and Precise Machine Tools a Brief History The Early Historical Development of a Linear Measurements The Historical Development of the Metre and the International Bureau of Weights and Measures (BIPM) Optical and Laser Length Measurement International Standards Laboratories Why They Are Essential What Is Traceability and Why Is It Necessary? Auditing Metrology: Artefacts, Instrumentation and Equipment National Metrological Research and Calibration Laboratories Machine Tool s Machining Capabilities Metrology Equipment Utilised for Basic Machine Tool Calibration Checks Gauge Blocks Length Bars Combination Angle Gauges Precision Polygons Dial Gauges and Dial Test Indicators Straightedges and Cylindrical Precision Mandrels Precision- and Cylindrical Squares A Concise History of Machine Tool Calibration Notable Chronology in Machine Tool Testing Achievable Accuracy and Precision of Machine Tools Accuracy and Precision Produced by a Machine Tool Designation of Machine Tool Axes and Kinematics Configurations of Machining and Turning Centres xi

2 xii Contents Orthogonal Machine Tools Modular, or Reconfigurable Machine Tools Modular Machine Tool Construction Turning and Machining Centre Configurations CNC Controller Developments Non-orthogonal/Parallel Kinematic Machines (PKM) Major Elements in a Machine Tool s Construction Headstocks for Turning Centres and Spindles for Machining Centres CNC Conventional Drive Systems and Recirculating Ballscrews Machine Tool Bearing Categories Constructional Elements for Machine Tools Linear Motor Drive Systems Linear and Rotary Axis Positioning/Monitoring Systems Finite Element Analysis (FEA) of Machine Tools FEA of CNC Machine Tools Industrial Machine Tool Case Study in FEA for a Machining Centre Basic Construction of Coordinate Measuring Machines (CMMs) Introduction to the CMM CMM Construction CMM Mechanical Probe Recent CMM Probing Systems Micro-Metrology Probes References Laser Instrumentation and Calibration Introduction to Lasers Why Is Calibration so Important? Calibration of Laser Interferometers Laser Calibration Potential Error and Uncertainty Sources Introduction to Laser Machine Calibration Methods of Machine Acceptance Tests The Basis for Verification ISO 230 Machine Tool Standards Previous and Current Calibration Procedures ISO 230 Laser Calibration Procedures on CNC Machine Tools Laser Diagonal Displacement Test Laser Step Diagonal Test Potential Errors In Three Axes Machine Tools ISO for Coordinate Measuring Machine (CMM) Calibration and Verification

3 Contents xiii Coordinate Measuring Machine (CMM) Fundamentals CMM Environmental Conditions CMM Performance Standards Calibration of a Rotary Table With a Rotary Indexer AxisSet Checkup Utilised for Machine Tool Alignments Machine Tool Linear Axes Factors Affecting Their Accuracy and Precision Laser Tracker Instrumentation, Testing and Applications Laser Tracker Calibration Procedures Laser Tracker Frequently Asked Questions Laser Tracker Machine-Based Research Applications References Optical Instrumentation for Machine Calibration Basic Principles of Light Optical Alignment Basic Principles Autocollimation Principles Basic Design of an Autocollimator Autocollimator its Optical Operational Principle Digital Autocollimators Precision Polygons for Angular Measurements Angular Calibration of a Precision Polygon Calibration of a Rotary Table The Micro-optic Dual-Axis Autocollimator, or Angledekkor Optical Squares and Prisms Alignment Telescope Principles of Alignment Targets for Autocollimators Auto-reflection and Autocollimation Calculating Mirror Gradients Effects of the Earth s Curvature and Atmospheric Refraction Precision Spirit Level Optical Instrumentation Clinometers Talyvel Precision Level Software Programs for Precision Electronic Levels References Telescoping Ballbars and Other Diagnostic Instrumentation Telescoping Ballbars Machine Tool Health Checks The Reason Why They Are Necessary Telescoping Ballbars Historical Development and Operation Telescoping Ballbar In More Detail Ballbar Testing Why the Need?

4 xiv Contents Wireless Telescoping Ballbar Telescoping Ballbar A Closer Examination of Machine Tool Inaccuracies Ballbars Other Instrumental Variations Grid Encoders and Linear Comparator Systems Rotary Analyzer System and Calibration Rings Calibration Spheres and Rings for CMMs References Artefacts for Machine Verification Introduction to Artefact Verification For Interim CMM Checks An Introduction to CMM Error Sources ISO and CMM Performance Material Standard of Size and CMM Accuracy CMM Length Measurement and Maximum Permissible Errors Purpose-Made Artefacts Testpieces General Artefacts for CMM Verification Step Gauge Its Calibration Step Gauge For Verification of the Accuracy of CMMs Machine Checking Gauge (MCG) Ball- and Hole-Plates The 3-D Ball-Plates Ball- and Cube-Tetrahedrons Large Reference Artefact For Large-Scale CMM Verification Large Reference Artefact (LRA) Design and Construction Large Reference Artefact Reference Surfaces Large Reference Artefact Artefact Positioning, Alignment and Testing Large Reference Artefact Summary and Concluding Remarks Machinable-Artefacts for Machine Tool Verification Introduction to Machinable Testpiece Standards Artefact Stereometry For Dynamic Machine Tool and Comparative Assessment Stereometric Artefact Conceptual Design Stereometric Artefact Machining Trials Stereometric Artefact Machined and Metrological Results Small Coordinate Measuring Machine (SCMM) Small Coordinate Measuring Machine Design Requirements Small Coordinate Measuring Machine Interferometers, Autocollimators and Probe Design A Novel 3-D-Nano Touch Probe For an Ultra-Precision CMM

5 Contents xv Probing Force and Surface Damage The 3-D-Nano Touch Probe Constructional Details Robotic Arms Industrial Robotics Their Historical Development Defining Robotic Parameters Robotic Calibration Robotic Calibration Devices and Techniques Parallel Kinematic Mechanism (PKM) Equator Gauge Theory of Operation Of the PKM Calibrating This PKM Articulated Arm CMM (AACMM) Articulated Arm CMMs In More Detail Verification of Articulated Arm CMM (AACMM) References Machine Tool Performance: Spindle Analysis; Corrosion and Condition Monitoring; Thermography Machine Tool Spindle Analysis Design Trends in Machine Tool Spindles Machine Tool Spindle Failure Modes Complete Machine Tool Retrofits and Rebuilds Monitoring and Diagnostics of Machine Tool Spindles Spindle Monitoring Instrumentation For Machine Tools Thermal Distortion At the Spindle Spindle Error Motions Spindle Error Analyser (SEA) Instrumentation Spindle Error Analyser The Master Target and Its Fixtures Spindle Hardware Spindle Error Analyser Spindle Software SEA Thermal Drift Resulting from Expansion of Materials SEA Thermal Tests SEA How Spindle Measurement Data is Displayed SEA Spindle Error Plots: For Analysis and Rectification of Bearings Corrosion Basic Concepts Understanding Metallic Corrosion In Brief Machine Tool Spalling of Bearings and Gears Bearing Failure Modes With Hard Particle Lubricant Contamination Bearing Contamination Condition Monitoring Of Machine Tools Condition Monitoring Historical Perspective Types of Condition Monitoring Systems Condition Monitoring Systems Establishing a Programme

6 xvi Contents 6.6 Thermographical Inspection Electromagnetic Spectrum A Brief and Introductory History Thermography Further Information Thermal Imaging Cameras Emissivity Thermal Radiation Advantages and Limitations of Thermography Effects of Temperature Variation in Machine Tools Controlling Component Part Temperatures Minimising Heat Sources Temperature Control Strategies References Uncertainty of Measurement and Statistical Process Control Conformance, Traceability and Measurement Uncertainty Task-Specific Measurement Uncertainty Traceability Reporting Conformance Rules for Metrological Equipment Measurement Uncertainty Typically Relating to Machine Tools and CMMs Statements of Compliance The Effect of Uncertainty Uncertainty Issues Statistical Measures In Uncertainty Calculations Origins of Uncertainties Calculation of Measurement Uncertainty Analysis of Uncertainty: Uncertainty Budgets Reducing Measurement Uncertainty Statistical Process Control (SPC) In Production Output on Machine Tools What is Statistical Process Control? Control Chart Functions Control Chart Background Information Control Chart Limits Reading Control Charts Computerised SPC Charts Machine and Process Capability Studies Machine and Process Capability Studies Typical Procedure Machine Capability Study In Detail Machine Tool Capability Study Practical Example Final Concluding Remarks References Appendices Index

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