Optical Micrometers and Laser Micrometers Information
Laser micrometers measure extremely small distances using laser technology. Laser micrometers are used in both laboratory and production settings. In production setting, CCD or shadow based laser micrometers provide accurate results when gaging high speed wires, fibers bar stock or webs. Laser micrometers that use the scanning or rastoring of a laser beam combined with position sensitive detectors (PSD) provide accurate results especially in laboratory applications where the measured part is stationary.
Types of Laser Micrometers
Laser micrometers are available in four main types. These include automatic or inline, benchtop or floor, handheld or portable and machine mounted. Automatic or inline micrometers have the part automatically presented to the gage and measured without operator intervention. Inline designates that the automatic gages are applied in a production line. Usually, shadow type or CCD based laser micrometers are used in these applications. These laser micrometers can maintain high accuracy levels during production gaging of moving products such as wire, webs, or bar. In a benchtop, table-based or floor mounted micrometer the part is both manually loaded and measured. Laser scanning or rastoring type micrometers are commonly applied and provide sufficient accuracy in most stationary or benchtop applications. With a handheld micrometer the device can be operated while being held in the hand. A machine mounted micrometer is mounted within, or on, a machine tool or process equipment for tool setup or travel measurement. Test indicators, dial indicators or micrometer heads are example of gages that are often machine-mounted.
The laser micrometer can be configured as either a dual or single head. On a dual head configuration the transmitter and receiver are independently positioned in two separate units or heads. On a single head micrometer the transmitter and receiver are tied together on a single structure.
Parameters to Consider
Important parameters to consider when specifying laser micrometers include range, resolution, speed, T/R separation and laser and visibility type. The range of the micrometer is the total range length or dimensional range that the gage can measure. The resolution is the best or minimum resolution for gages with digital displays. Speed refers to either ultimate response speed for CCD type micrometers or to scan speed for laser rastoring type micrometers. Scan speed is the same as '1 / (response time)'. T/R separation is the distance between the transmitter and receiver heads in the laser micrometer. There are several laser or visibility types available for laser micrometers, including, visible laser light (680 nm), infrared laser light (> 680 nm), laser class I, laser class II, and laser class III.
Measurement units for laser micrometers can be either English or metric. Some laser micrometers are configured to measure both. The display the micrometer can be non-graduated meaning that the micrometer has no display, digital display, column or bargraph display, or remote display. Electrical output options for laser micrometers include analog current, analog voltage, serial, parallel, and digital or GPIB, IEEE 488, or HPIB.
Laser micrometers may have additional measurement features including averaging, diameter, edge, gap, machine travel, segmentation, and SPC capability.