Certificate ISO Veritas

Common Misconceptions of Laser Calibrations

Calibrations are a common requisite for ensuring that accuracy levels for any equipment are maintained. There are various tools in the market which help in measuring the values of an instrument for aiding the calibration process. Of these tools, the laser interferometer is the most widely used tool and is popular among technical experts due to its high accuracy capabilities. However, not all are quite familiar with laser calibration process and due to this lack of familiarity, they end up getting inaccurate results. Most of the times, they are not even aware of the kind of outcomes that they should expect during a laser assisted calibration routine. Here are some of the common misconceptions of laser calibrations. This should help you to distinguish between facts and perceptions.

Perception 1: Lasers are used for aligning the machine tools.

The Fact:

The lasers are already aligned to the machine. When the setup has been done perfectly, the measurements are derived from the axis of the plane to which the laser has been aligned. This clearly shows that with such a configuration, lasers cannot be used for aligning machine tools. Laser tools are used to measure the following common metrics in the calibration process:

  • Perpendicularity of the central axis.
  • Angular yaw
  • Angular pitch
  • Degree of straightness of the axis along both planes (horizontal and vertical)
  • Backlash error
  • Linear error of ball screw 

Perception 2: You only need to calibrate the machine’s ball screw

The Fact:

The actual calibration requirement involves a single step. But there are other factors that need to be given due importance in order to ensure that the readings obtained from the instrument are accurate and are in compliance with static accuracy tolerances. The machine tool needs to be in perfect alignment, adjustment and compliance with the stated ISO standards for static tolerance levels. If these configurations are inaccurate, then the measured values will not be ISO compliant and this will make the entire purpose of the calibration process ineffective.

Perception 3: Its takes just one measurement to calibrate the axis.

The Fact:

If you were to go by the book, you need at least 7 measurements for the axis before you begin analysing the extent of calibration required in it. One of the key requisites that are required for taking such measurements is to ensure proper thermal expansion of the axis as any expansion in dimensions during the measurement could give false indications of calibration requirements.

Perception 4: Any Technician with a laser can perform calibration of machine tools.

The Fact:

While it may seem fairly easy to set up the instrument and take appropriate readings with the laser tool, the interpretation and analysis of the data is what makes the difference in the quality levels. This is where the skill level of the technician plays an important role. One needs to be experienced in understanding the indications that are provided by the obtained data in order to arrive at the most appropriate and accurate calibration modifications.