Selecting by Scale Unit
1 mm Units
The ruler is the most popular measuring instrument that can be used to measure at a scale of 1 mm units. Steel and glass rulers are generally used at manufacturing sites. Tape measures are also commonly used, and plant engineers can usually be seen carrying one around.
Gauge blocks are often seen at metal processing plants and other manufacturing sites. Block gauges are rectangular solids made of steel whose dimensions and parallelism are guaranteed on the order of 0.1 μm. They are highly valued for their use in dimensional measurements of processed products. One of the advantages of gauge blocks is how they can be combined to create a variety of different lengths.
0.1 mm Units
Vernier calipers are measuring instruments generally used to perform measurements in units of 0.1 mm. Their smallest scale is 0.02 mm or 0.05 mm. Height gauges can be used to measure heights at this size as well.
0.01 mm Units
Micrometers are frequently used to perform measurements in units of 0.01 mm. Based on Abbe’s principle, these instruments are designed to perform measurements with high accuracy. Dial gauges are also used quite frequently. Optical comparators can be used to precisely measure multiple measurement points.
0.001 mm Units
Indicating micrometers are used to perform measurements in units of micrometres. The type most commonly seen today displays measurements digitally. Precautionary measures must be taken to prevent dust and dirt from entering the micrometer during measurement.
Using a digital measuring instrument makes it possible even for inexperienced users to perform measurements in units of micrometres.
0.0001 mm Units
Mechanical measuring instruments may be capable of measurements up to units of 1 μm, but such devices are unable to measure units smaller than micrometres. Laser length measuring instruments, electronic micrometers, and microsensors can be used for such applications. Recently developed measuring instruments such as image dimension measurement systems have also made it easy to perform highly accurate measurements.
The measurement environment is an important factor for achieving correct measurements with such instruments. For example, a metrology lab must be kept at a constant temperature of 20°C.
