Laser tracker
Everything worth knowing about the instrument PHYSTECH MB works with: what it can do, what it is used for, and how it works internally.
What a laser tracker is
A laser tracker is a mobile 3D coordinate measuring machine for large components and plants — for everything a tape measure and spirit level can no longer handle.
It is used wherever more than a rough estimate is needed:
- Assessing the flatness of surfaces and components
- Establishing the geometric condition of a machine or plant
- Detecting wear and belt-tracking deviations before they cause failure
- Checking and realigning machine bearings
- Checking components against a drawing or CAD model (nominal/actual comparison)
The real benefit shows up afterwards: the measurement itself often takes only a few hours to a few days, while the subsequent trial-and-error search for the cause can, in my experience, cost weeks. This always requires the plant to be shut down but ready to operate, in a largely vibration-free and temperature-stable environment — what that means in detail is set out under Services.
Depending on accessibility, the tracker can be set up upright, on its side, or overhead. For recurring control measurements on the same plant, permanent reference points can also be set — such as floor sockets or wall nests — which later measurements can use without having to rebuild the reference system from scratch.
The technical figures of the Leica AT401 in use — measuring range, accuracy and repeatability — are listed in the Measuring range and accuracy section on the Services page.
Where the laser tracker is used
Wherever components or plants need to be positioned precisely relative to one another.
- Parallelism and level of rollers in a single measuring pass
- Support during set-up and adjustment of rollers and belt systems
- Inspection of bearings, frames and wear strips
- Monitoring and adjustment of jigs and fixtures
- Component surveying against drawing or CAD (nominal/actual comparison)
- Crane runway surveying for gauge, level, straightness and inclination
- Inspection of drive units and robotic arms
Industries where these tasks typically arise:
Your task doesn't fit any of these categories? Get in touch — the full list of applications shows further examples.
How does a laser tracker actually work?
The basic principle resembles a classic total station measurement — except that the tracker continuously follows its target instead of sighting it point by point.
A head mounted firmly on a tripod rotates about two axes, measuring the horizontal and vertical direction of the emitted laser beam. The beam is reflected back by a precision reference sphere (SMR) at the object being measured — the exact distance to it is determined by the absolute distance meter. From the two angles and this distance, a spatial coordinate results for every point probed.
These coordinates are then transformed into the reference system of the component or plant — for example via the centre of a measured circle or a previously determined machine axis. A roller, for instance, can be defined as the reference axis, with the deviations of all other rollers reported directly against it. This is exactly the principle shown in the video on the homepage as a short animation.
For large plants, or ones that must be measured from several sides, the tracker is repositioned. A network adjustment mathematically ties the different stations together into one common coordinate system, so that all measured values remain consistently comparable.
Why the environment matters: the laser beam covers the measuring distance through air at the speed of light. Temperature stratification, dust or humidity slightly change this propagation speed — and that has a direct effect on the measured distance. That is why a stationary, temperature-stable and largely dust-free environment is a precondition for the stated accuracy, not merely a recommendation.
Terms such as absolute distance meter, reflector, reference system or network adjustment are each explained in the Glossary.
Questions about the laser tracker or your specific task?
A brief description of the plant and the observed problem is usually enough for an initial assessment.