Faro Laser Tracker Accuracy: Best Practices

With your FARO® Laser Tracker, obtaining the most accurate readings requires setup, warm-up, compensation, and frequent checks while taking long-duration readings.

In the field of metrology, where even the smallest mistake can have serious repercussions, precision and accuracy are crucial.

To maximize the efficacy of the Faro Laser Tracker, following a set of recommended procedures is essential. This includes meticulous setup and compensation procedures, among others.

In this post, we explore the fundamental best practices for the Faro Laser Tracker accuracy. It can be a useful tool for anyone learning how to use the Faro Laser Tracker for accurate measurement, regardless of their experience level. Whether you’re a seasoned metrologist seeking to refine your techniques or new to this field.

Warm-up of the Tracker

It takes time for your tracker to warm up and stabilize its laser in order to get the greatest performance. The Tracker temperature will determine how long this takes, which can range from 45 to 80 minutes. Poor overall reproducibility or CompIT failures in the early stages of measurements are frequently caused by inadequate thermal stabilization.

It is possible to skip the warm-up if an instant measurement is needed. If so, then regular compensation should be run.

Notice that some environmental factors, like excessive vibrations, mounting stability, and temperature-related effects such as gradients, air turbulence, or varying air temperatures along the laser beam’s path, might produce errors and make it difficult to measure precisely.

In order to follow Faro Laser Tracker accuracy best practices, it is recommended to get rid of all of these sources that might influence errors.

For details, refer to this post: Vantage S6: Understanding Measurement Accuracy

Full Pointing Compit

CompIT pointing enables you to verify the tracker’s accuracy and make adjustments as needed. The typical Pointing CompIT requires six points to make up for lost time and three intermediate test points to ensure accuracy. The Tracker will meet specifications at all ranges thanks to the compensation points, which are located at 2, 4, and 6 meters.

Pointing CompIT can be adjusted to employ the greatest range necessary for the measuring task in order to achieve the best accuracy at distances greater than 20 meters.

It is best to run Pointing CompIT right before beginning a measurement job. If the tracker is within specification, the intermediate test will report on it. Even if the interim test is successful, the adjustment can still be carried out for optimal accuracy. If the tracker is not being brought in by the pointing compensation.

Long Duration Measurements

Long-duration observations or tasks that take longer than two hours frequently experience global drift. Vibrations or variations in the surrounding temperature may be the source of this drift. Temperature variations can have an impact on the floor, the tracker stand, the tracker, and the part being monitored. Drift needs to be monitored throughout the life of a measurement operation due to these environmental impacts.

Periodically performing backsight checks or pointing interval tests is a good way to ensure accuracy during long-term measurement jobs. In case the checks are not up to par, it is recommended to conduct a 5-minute Pointing Compit.

Front-back sight averaging

The process of measuring points in frontsight and backsight modes and averaging them is known as frontsight-backsight averaging. This method can only be applied to tasks that involve measuring individual points; it is not suitable for measuring features. Every point needs to be measured in both frontsight and backsight when measuring frontsight-backsight work. This technique works best when applied to uncompensated trackers.

Surveys

Surveys are used to continuously measure a set of objectives. Utilizing relocation between each cycle and frontsight/backsight averaging on each point (insight only) yields the most accurate results when conducting a survey. The front and rear sights cancel out beam and gimbal faults, and relocation eliminates part, environment, and tracker drift during the survey.

Compensations

Basic Compensation

Using the Basic Compensation feature is advised when measuring in a small area and without intending to use the tracker’s full range (Quick Compensation and Angular Accuracy Check).

The laser tracker’s accuracy is increased through quick or self-compensation, which modifies many parameters. Its goal is to deliver angular accuracy results that, for the system’s current working range, are either within the laser tracker’s specifications or, based on the published specifications, lower than the laser tracker’s maximum permissible error (MPE).

For most applications, Quick/Self Compensation is the best option; however, when the system needs to operate over its whole range or at greater distances, Pointing Compensation from CompIT’s Advanced tab can produce better angular accuracy results or less back sight error.

Full Pointing Compensation