Best Practices for Laser Trackers and Portable Arms: Get the Accuracy You Paid For

Laser trackers and portable arms are powerful tools in dimensional metrology. However, without the right processes in place, even the most advanced system can deliver inaccurate or inconsistent results. Whether you're a seasoned quality engineer or just starting to integrate these tools into your workflow, following the best practices below will help you maximize accuracy, reliability, and efficiency.

1. Start With the Right Setup

Laser Trackers

• Stable Mounting: Use certified tripods or magnetic bases. Avoid placing the tracker near vibrating equipment or in high-traffic areas.

• Line of Sight: Clear any obstructions, especially reflective or translucent surfaces that could interfere with the laser beam.

• Warm-Up Time: Allow 15–30 minutes of warm-up for internal temperature stabilization before performing critical measurements.

Portable Arms

• Mounting Surface: Use a heavy-duty granite table or vibration-isolated cart if operating on the shop floor.

• Reference Features: Use certified fixtures or repeatable features to reduce variability between measurement sessions.

Pro Tip: Standardize each session with a pre-use checklist that includes warm-up time, cleaning optics and probes, and quick calibration verification.

2. Environmental Factors Matter—A Lot

In most cases, measurement issues are caused by environmental conditions, not the equipment itself. Be mindful of the following:

• Temperature Fluctuations: Even a 2°C change can affect metal expansion and compromise tight-tolerance measurements. Use thermally compensated devices and minimize exposure time in uncontrolled environments.

• Airflow: Avoid direct airflow from fans or HVAC vents, which can deflect laser beams and introduce instability.

• Surface Cleanliness: Dirt, oil, and residue can affect probe consistency and part reflectivity. Always clean parts and surfaces before scanning or probing.

Case in Point: One client improved measurement consistency by over 30% simply by relocating their tracker away from a floor-mounted air vent.

3. Calibration and Drift Checks

A measurement system is only as reliable as its last calibration.

• Daily Checks: Most portable arms require a daily probe calibration routine—this should never be skipped.

• Drift Monitoring: Use certified artifacts (e.g., length bars or spheres) periodically throughout the day to verify system stability.

• After Relocation: If a system is moved, recalibrate it immediately. Even small shifts can alter reference frames.

Leapfrogging Tips (Laser Trackers)

• Use multiple common points or SMR nests when measuring across large volumes.

• Avoid leapfrogging with a single SMR—this can amplify alignment errors.

  
  

4. Train Your Team for Consistency

Variability in user technique is one of the leading causes of inconsistent results.

Train your team on:

• Using consistent probe angles and scanning paths

• Following structured workflows from startup to reporting

• Proper care and handling of probes, SMRs, and accessories

• Utilizing checklists to ensure no steps are missed

Pro Tip: Develop a visual SOP (standard operating procedure) for each station, with photos and step-by-step instructions. This minimizes reliance on tribal knowledge and improves repeatability.

5. Optimize Your Software Settings

Metrology software is just as critical as the hardware—and often more overlooked.

• Filtering and Smoothing: Many programs apply mesh filters or smoothing by default. Understand how these affect data accuracy.

• Alignment Methods: Selecting the right alignment method (3-2-1, best-fit, RPS, etc.) is crucial. Poor alignment affects every subsequent measurement.

• GD&T Interpretation: Ensure your team understands GD&T symbols and how your software interprets them. A profile tolerance calculated from raw points can differ significantly from one applied to a smoothed mesh.

Real-World Insight: One manufacturer resolved a months-long issue with inconsistent flatness results by identifying a change in mesh smoothing settings made by a single operator.

6. Documentation and Traceability

For compliance with ISO 17025, AS9100, or internal QA standards, every measurement must be traceable and reproducible.

• Save raw measurement data—not just the final reports.

• Use version control for inspection templates and plans.

• Attach metadata (e.g., operator, date, device serial number, calibration status) to each job.

• Keep a logbook for each device documenting usage, issues, calibrations, and drift checks.

  
  

Bonus Tips: Get More From Your System

• Use Accessories Wisely: Use magnetic bases, nesting spheres, and storage racks to streamline setup and protect sensitive components.

• Maintain Redundancy: Keep spares for SMRs, probe tips, batteries, and calibration tools on hand to avoid downtime.

• Automate When Possible: Many systems support scripted workflows or automated routines, which reduce variability and increase throughput.

  
  

Bring the Experts to You

Whether you're performing routine inspections or just getting started with laser trackers and portable arms, the difference between average and excellent results often comes down to setup, training, and process control.

At SS Metrology Solutions, we offer:

• On-site metrology clinics

• Hands-on training with your team and equipment

• Workflow audits to help you implement best practices and boost efficiency

Book a On-Site Visit today, and ensure your system delivers the accuracy you paid for.