Laser micrometer
A laser micrometer as a special type of laser scanner is used to determine the diameter of relatively small objects (fractions of a millimeter up to a few centimeters). Unlike for example in the micrometer as diameter can be measured accurately within a few microns.
functionality
The laser micrometer consists of a transmitter and a receiver side. With the usual design, the laser beam on the transmitter side first hits a rotating mirror, where it is fanned out. A collimator lens turns it into a light curtain made of almost parallel laser beams. The measuring object must be at a specified point in the beam path in order to obtain exact measurement results. As a rule, the measurement object must not be transparent. The beam scans the entire measurement cross-section and is interrupted by the test object. A lens focuses the parallel laser beams on a photodiode . In the course of time, this means that the measurement object provides a shadow for a certain time. This time is now converted into a diameter by the processor. A mean value is calculated from 100 to 1500 measured values per second. This prevents disruptive influences (air currents, dust particles, extraneous light, etc.) of the individual measured value from interfering with the result. The measured value is usually displayed digitally. If necessary, it can be read into a computer for further processing.
Instead of a photodiode with a collecting lens, an imaging lens and a line camera can also be used on the receiver side.
If you move the measuring object along the longitudinal axis or rotate it around it during the measurement, not only the diameter but also other geometric parameters such as roundness, cylindricity or runout as well as taper can be measured.
Areas of application
Laser micrometers are used in a wide variety of industries and areas (selection):
- In injection technology in the automotive industry, small tolerances of 0.5 µm are the order of the day. There are control piston manufactured so precisely that they without further sealing their task in the control hole meet.
- When manufacturing medical products, laser micrometers measure the diameter of cannulas and catheters.
- Copper or aluminum wires must be insulated with enamel to prevent short circuits. With the help of a laser micrometer, you can check the diameter of the wire and how thick the lacquer layer is within a few seconds .
- Many companies use sets of dowel pins in production. These are used to check bores and wear out due to daily use. The test equipment manager must therefore check all locating pins at regular intervals in order to replace worn locating pins.
- In the manufacture of dowel pins, the diameter of the dowel pins is checked randomly, which is ground by cylindrical grinding machines in a continuous process.
- Another application is the measurement of waves . If, for example, a gear is to be pressed onto a shaft , the diameter must not be too small, otherwise the gear will not be firmly connected to the shaft.
- Laser micrometers are also a suitable tool for measuring pistons. For example, they determine the diameter of piston rods that are built into gas pressure springs .
- With additional software it is possible to B. cutting tools to determine the flight circle (effective cutting diameter), which is used when grinding tools.
Individual evidence
- ↑ a b Heinz-Peter Hippler: Optical diameter determination. Retrieved May 26, 2020 .
- ↑ Z-Mike Lasermesstechnik: Traceable optical measurement . Retrieved May 26, 2020 .
- ↑ AEROEL: What is a laser measuring device? Retrieved May 26, 2020 .
- ↑ Laser micrometer. Retrieved May 26, 2020 .