3 Strategies for Using a Laser Tracker to Measure Difficult Spaces

08 June 2023 · 3 min read

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The paradox of modern manufacturing is that as designs of machined parts become more complex and difficult to navigate, they require more intricate and precise three-dimensional measurements. Cockpit assemblies, vacuum chambers, turbine housings and railroad cars are just some of the examples of objects that require very precise measurements in their construction but also have large dimensions, hidden angles and tight spaces that complicate the process.

Due to the difficulty of these measurements, manufacturers often resort to time-consuming and expensive practices like multiple tracker repositionings or traditional CMM readings. By using the full advantages of the Laser Tracker, however, many of difficult spaces can be managed with a single, inexpensive measurement setup.

Here are three strategies for improving Tracker use in complex manufacturing.

1) Take Advantage of the Tracker’s Range

API’s Radian Laser Trackers are accurate to a range of 80m, and the SMR targets boast an accuracy down to ± 2.5 microns at that range. It’s easy to view that 80m as a sheer linear distance, but it can be advantageous to use that range three-dimensionally. Mounting the tracker at a high level can provide unobstructed angles of the entire manufacturing area and a bird’s-eye view inside intricate parts that may remove obstacles presented to head-on measuring.

Many bottling plants, for instance, install laser trackers near the ceiling. In other cases, such as compressors set up in the open air, trackers are placed on maintenance platforms up to 6m high, depending on the size of the machines. And a temperature sensor, weather station, and autolock target tracking ensure that measurements stay accurate, even at long distances.

2) Use the Tracker’s Portable, Flexible Mounting Capabilities

When measuring large components, it is often essential to install the laser tracker inside the system itself, as some of the measurement points cannot be reached from the outside. Often in these confined spaces, the tracker cannot be setup at a point far enough from the object to pick up these measurement angles. This is common in vacuum chambers, where conventional trackers are rearranged up to 10 times.

As with our first strategy, however, many of these setups can be eliminated by using the tracker’s flexibility in three dimensions. The Radian Laser Trackers can be mounted vertically, horizontally, and in inverted positions, and at <11kg each, they are the lightest on the market. Additionally, they have a vertical scanning range of 138° (-59°-+79°), allowing virtually any point that is not directly above or below the Tracker to be measured.

3) Use the Full Range of the vProbe to Reach Hidden Points

Regardless of Tracker position, there are many manufactured parts whose intricate features and characteristics are not all within the Tracker’s line-of-sight for a single measurement setup. For many of these parts, however, the Tracker’s line of sight can be extended far enough with a tactile probe to complete the measurement in a single setup.

Tactile probing can be used for parts and locations of various sizes. API’s vProbe has multiple probe mount orientations, allowing for measurements inside, behind, and underneath parts. And with styli lengths of up to 500mm, the vProbe has a probing circumference of over 3m without having to change its position in relation to the Tracker. And the dynamic scanning ability of the vProbe allows for expanded functions beyond part inspection and quality management to reverse engineering.

Manufacturing environments and their machined parts are becoming increasingly more complex over time. Proper use of the Laser Tracker and all of its features is essential for maintaining accuracy and efficiency in these difficult locations.

For more information about API’s Radian Laser Tracker Series, click here.

Interested in training on all of your Tracker’s features, contract our Services Team here.

radar vs lidar vs ladar

 – Radar

Radar (Radio Detection and Ranging) emits microwave pulses and measures the time for echoes to return. Because radio waves have long wavelengths, radar devices can detect objects at great distances and through fog, rain or dust. They are widely used in aviation, weather monitoring and speed‑enforcement. Radar systems provide a long range but lower spatial resolution compared with LiDAR . This lower resolution arises from the larger wavelength and beam divergence; as a result radar cannot pinpoint features smaller than several centimetres.

(source:wevolver.com)

 – LiDAR

LiDAR (Light Detection and Ranging) uses pulsed laser light to measure distance. Because it operates at optical wavelengths, LiDAR can produce very high‑resolution 3D point clouds. It is the backbone of autonomous vehicles and aerial mapping. LiDAR systems generally have a shorter to medium range but offer high spatial resolution, enabling detailed 3D mapping

LiDAR’s ability to capture millions of points quickly makes it ideal for applications such as autonomous driving and surveying. For manufacturing metrology, LiDAR is useful for creating digital twins of large objects or structures. However, typical LiDAR accuracy (millimetre to sub‑millimetre) is not sufficient for tight‑tolerance inspections that require micron‑level precision. Therefore, LiDAR still falls short for high‑precision metrology in aerospace and automotive manufacturing.

– Laser Radar

Laser radar is often used to describe high‑precision laser time‑of‑flight systems. It uses a narrow, focused laser beam and measures not only the time of flight but also the angles of the incoming beam to compute precise coordinates. Laser radar systems can achieve micron‑level precision but typically operate over shorter ranges and at slower scanning speeds compared with LiDAR. Laser radar system steers a focused beam, reading the return signal directly from the object without a retroreflector, and is engineered to provide precise, industrial measurements with tolerances of thousandths or even tenths of thousandths of an inch. However, the speed of data collection is sacrificed for resolution—laser radar scans smaller areas more slowly to achieve high accuracy

(source:eastcoastmetrology.com)

– LADAR (Dynamic 9D LADAR by API)

LADAR (Laser Detection And Ranging) is sometimes used interchangeably with LiDAR, but API’s Dynamic 9D LADAR is a novel system that blends interferometry with laser scanning. LADAR is an interferometry‑based non‑contact measurement system that provides fast and accurate data acquisition. It overcomes several limitations of conventional measurement methods by delivering micron‑level resolution and eliminating issues such as limited accuracy, slow data acquisition speeds and sensitivity to surface reflectivity. LADAR technology uses fast data acquisition to deliver rapid, real‑time data collection, significantly reducing measurement and analysis time compared with traditional methods. It also functions effectively in noisy production environments and at various incident angles. The technology delivers rapid, real‑time data collection, making it suitable for in‑line production measurements where conventional laser radar is too slow.

To learn more about how LADAR can preform in line inspection, click here.

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