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Explore traditional, optical, and digital alignment tools and their pros and cons. Learn how new technology, such as laser trackers, can improve efficiency and accuracy in alignment processes.
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Alignment Techniques – Traditional, Optical, Digital Warren Wagstaff – Digital Precision Metrology Inc. October 2014 WELCOME TO
Traditional Tools • Plumb bobs • Precision Levels • Straight edges • Piano wire • Wire mics • Tape Measures
Traditional Tools - Pros • Used since the Egyptians • Proven methods • Inexpensive • Reliable (can always go back to it) • Keeps people working • Comfort (widely accepted)
Traditional Tools - Cons • Labour intensive • Opinion / feel • Human error • Resolution • Accuracy • Repeatability • Susceptible to drift • Wire sag in horizontal applications
Optical Tools • Optical Transits • Scales • Precision Levels (standard and optic) • Targets • Laser tools
Optical Tools - Pros • Accurate • Comfort (people accept it) • Portable • Relatively inexpensive
Optical Tools - Cons • Labour intensive • Susceptible to environmental conditions (lighting, dust, heat, vibrations) • Allows for human error (transposing numbers) • LOS (line of sight) • Not easily moved and tied in (device move) • Fragile
Digital Tools • CMM (coordinate measuring machines) • Laser Trackers • Arms • SMR’s (spherically mounted retroreflectors) • Probes • Target holders
Digital Tools – Cont’d • CMM (coordinate measuring machine) • A coordinate measuring machine (CMM) is a device for measuring the physical geometrical characteristics of an object. This machine may be manually controlled by an operator or it may be computer controlled. Measurements are defined by a probe attached to the third moving axis of this machine. Probes may be mechanical, optical, laser, or white light, amongst others. A machine which takes readings in six degrees of freedom and displays these readings in mathematical form is known as a CMM. • http://en.wikipedia.org/wiki/Coordinate_measuring_machine
Digital Tools - Pros • Accuracy (0.0004” over 24’) • Fast (real-time) • 3D data (XYZ coords) • Adapts to environment • Data digitally recorded • Can easily be moved and tied in (check drift) • Allows for GD&T Measurements (flatness, concentricity, roundness, parallelism, etc.)
Digital Tools - Cons • Expensive (unit and tooling) • Expensive software • LOS (line of sight – Laser Tracker) • Warm-up or acclimatization time • Requires a skilled operator
Why Laser Trackers? • It’s Todays Technology • Laser beams don’t sag, not affected by gravity • Not effected by shaft run-out or eccentricity • Can Monitor distance travelled over time (troubleshooting) • Built in temperature compensation (weather station – pressure, temp, humidity) • Traceability to NIST (National Institute for Standards and Technology) • Calibrated and certified to accuracies stated • Provide XYZ coordinates and/or deviations in real-time • www.digitalprecision.ca
Setting a bedframe for a turbine 84% savings just on one part of the project!! Let alone project completion time!! Less chance of safety incidents due to man hours!!! ETC.
Cost Benefits of taking a leap of faith • Time --- up to 14x faster than traditional methods when setting bases or doing new builds/layouts (setting turbine bases, cases, rotors, etc.) and less manpower required • Time --- up to 3x faster than optical methods on new builds/layouts
Where Traditional and Optical Tools Trump CMM’s • - Tight spaces • - Smaller applications (shaft coupling) • - Low accuracy requirements
Where Digital Trumps Optical and Traditional • Building or aligning to CAD/drawings • Field machining, verification of flatness and/or machined heights to drawings (pump and motor base plates/sole plates) • Alignment of shafts that are cumulative or through walls • Verification of gear case alignments, sheave alignments • New builds • Mapping existing conditions of parts
Benefits of a good alignment • Less fatigue on parts • Potentially can increase the speed of the machine • Potentially reduce frequency of alignment
www • www.digitalprecision.ca
Conventional Alignment • Clamps, straight edges & • Indicators; • Time consuming • No hard copy available • Labour intensive • Costly • www.digitalprecision.ca
Vertical Alignment • Four wire method; • costly? • slow tedious process? • difficult to use? • Inclinometer; • digital with output? • Optical; • limited to distance or range? • www.digitalprecision.ca
Strategies • Roll Measurement as 2 circles • Circularity – Point collection • Cylinder method – Scanning of Rolls • Tangent method – High points of Rolls
Important • Drift Check – Has anything moved? • Contributors • Sunlight • Vibration • Truck traffic
Laser Tracker • Increased quality of alignment • Increased speed of machine • Reduced frequency of alignment • Greater speed of alignment • Shorter shutdowns
To summarize Benefits of using new technology • Speed, Accuracy and Traceability • Up to 3x as fast as an Optical system • Data and reports saved automatically, leaves a digital footprint • Export in Excel, PDF, CSV, or to CAD. • Consistent error free process
Warren Wagstaff – Consultant – 3D Metrology Digital Precision Metrology Inc. Ph: 778-833-3276 Email: warren@digitalprecision.ca