For those who can learn the basic knowledge such as the features and precautions of measuring equipment, but do not know which measuring equipment to choose. In this post, we introduce how to select measuring equipment from various items such as objects and costs.

Select According To the Measurement Object

Select a measuring instrument that meets the conditions of the object

Is the Shape Simple or Complex?

Of course, the simpler the shape of an object, such as a rectangular parallelepiped or a circular object, the easier it is to measure the dimensions. In addition, it is possible to use various measuring devices such as calipers and micrometer, as well as rulers and tape measures. For height measurement, use a set with a height gauge or dial gauge.

On the other hand, it is difficult to measure the dimensions of objects with complex shapes such as polygons and stars. The measuring instruments that can be used are also limited. Projectors and image dimensional inspection instruments are especially effective for measuring the dimensions of complicated shapes. In recent years, there are models that can instantly measure the dimensions and angles of complex shapes simply by placing the object on the stage.

Is the Material Hard or Soft?

Objects with high hardness, such as metals and ceramics, have a small rate of deformation when sandwiched between calipers and micrometer measuring parts, and it can be said that it is easy to measure using any measuring instrument.

On the other hand, soft objects such as synthetic resins are difficult to measure because they deform when scissors with a measuring device. In such a case, a non-contact measuring machine is useful. For example, an image measuring machine can measure the dimensions of an external shape without contact by using laser light, which is very convenient.

Choose by Size

A measuring microscope is effective for targeting extremely small objects of submicrons. The principle is the same as that of a microscope, and since it can be measured without contact, it does not damage the object.

On the other hand, for objects of several meds such as automobiles, a long scale is used for simple measurement. In addition, a large CNC coordinate measuring machine is useful for precise measurement.

Choose between transparent and non-transparent

Non-transparent objects can be measured with various measuring instruments. However, it is necessary to devise an object with high light transmittance such as the thickness of a transparent film. Although contact-type devices such as micrometer can be measured with transparent objects, they are not suitable for accurately measuring soft objects such as film. In that respect, measuring machines that use laser light, such as laser displacement meters, can measure accurately without contact.

Choose According To Scale Units

1mm unit

The ruler is the most popular measure with a scale of 1 mm. Steel and glass are used at the manufacturing site. In addition, tape measures are also common, and plant technicians can be seen carrying them without exception.

Block gauges are often seen in manufacturing sites, including metal processing. It is a rectangular cuboid made of steel, and its dimensions and parallelism are guaranteed on the order of 0.1 µm, which is useful for measuring the dimensions of workpieces. One of the merits is that you can create various lengths by combining multiple block gauges.

0.1mm unit

When measuring in units of 0.1 mm, calipers are commonly used. The minimum scale is 0.02 mm or 0.05 mm. In addition, a height gauge may be used to measure height.

0.01mm unit

Micrometers are often used to measure 0.01 mm units. Because it is based on the so-called Abbe principle, it is possible to measure with high accuracy. Dial gauges are also often used. In addition, the projector can accurately measure a large number of measurement points.

0.001 mm unit

To measure the unit of micron, use an indicator micrometer. Recently, the type that displays the measured value digitally has become common. At the time of measurement, it is necessary to pay attention to the adhesion of dust.

In addition, by using a digital measuring machine, it is possible to measure in micron units even if you are not an expert.

0.0001 mm unit

Mechanical measuring equipment such as a micrometer can handle up to 1 µm, but it is difficult to use in submicron units. Laser type length measuring machines, electron micros, microsense, etc. are used. Recently, image dimensional measurement has been introduced, making it easy to perform high-precision measurement.

For correct measurement, the measurement environment is important, such as performing in a measurement room with a constant temperature of 20 ° C.

Choose According To Measurement Environment

Manufacturing site

In addition to metal processing, what you often see in manufacturing sites is calipers, micrometers, block gauges, etc. Block gauges are rectangular shapes made of steel and are guaranteed in dimensions and parallelism on the order of 0.1 μm, which is useful for measuring the dimensions of workpieces.

Measuring room

Micrometers are often used to measure 0.01 mm units. Because it is based on the so-called Abbe principle, it is possible to measure with high accuracy. Dial gauges are also often used. Sub-micron measurements include laser length measuring machines and image dimension measurements, making it easy to perform high-precision measurements.

The room temperature is usually controlled in the measuring room, but if the object is metal, there is a risk of thermal expansion. For precision measurement, it is essential to pay attention to keeping the object at room temperature in advance and not to hold it with bare hands.


Although the risk of contamination is lower than at a manufacturing site, it is difficult to make precise measurements like those performed in a measurement room. In addition, since multiple people may perform measurements, there is a risk that correct measurements cannot be made if the measurement equipment is not managed. Therefore, it is necessary to establish equipment managers and management standards.

Choose According To Applications

Length measurement

Measuring length on the shop floor typically involves the use of yardsticks, tape measures, and block gauges. For objects that span several meters, use a long scale. For more precise measurements, calipers, dial gauges, micrometers, etc. are used.

Measuring angles

For units of degree, a semicircular protractor is useful. In units of minutes, a bevel tractor or projector is used. In addition, in units of seconds, there is a measuring device called a sign bar. In addition, by using an angle gauge or an autocollimator, measurement in seconds is possible. Tools for checking the right angle include skoya (square) and a perpendicular measuring machine.

Hole diameter measurement

To measure the hole diameter of an object, a caliper is active. There is also a dedicated inner diameter measuring machine.

To measure a large-diameter ring-shaped object, a rod-shaped micrometer, cylinder gauge, a small diameter measuring machine, or a stopper gauge are useful. For more precise assumptions, use electronic micro and air micro.

If you need to measure optically and precisely, a projector, a factory microscope, an image dimension measuring machine, etc. are useful.

Coordinate measurement

To measure coordinates such as the position of holes in a workpiece, use an off-center caliper, hole pitch gauge, height gauge, or pin gauge.

Projectors, factory microscopes, 2D / 3D measuring machines, image dimension measuring machines, etc. are useful when optical precision measurement is required. For ultra-precision measurements such as semiconductors, a light wave interference standard measuring machine is used.

Choose According To Measurement Speed

Reliably by hand

Although calipers and micrometer are time-consuming, they can be measured reliably. It is necessary to measure multiple times for more accurate measurement. It takes time to measure a large number of objects, which makes it unsuitable.

Automatically quick measurement

By using an image dimension measuring machine, it is possible to instantly measure the dimensions of complex objects in multiple places. There is no need to re-measure many times, and even a large number of objects can be measured automatically and quickly.

Choose According To Cost (Price)

The cheaper ones are the ruler and tape measure. It can be said that it is an indispensable item in the field of manufacturing. Nogisu is also a relatively low-cost measuring device, which is useful for measuring in units of 0.1 mm.

Although the dial gauge and height gauge are slightly higher, it is possible to measure in units of 0.01 mm.

Micrometer ranges from thousands of yen to hundreds of thousands of yen, and can be used according to the purpose and accuracy of measurement.

Furthermore, as a precision measuring machine that can measure in units of 0.001 mm, the price range is mainly in the price range of several million yen or more, and it is called “non-contact optical equipment” such as projectors and measuring microscopes. , It is roughly divided into “contact type measuring machines” such as gate type 3D measuring machines.

There are various lineups from those that measure manually to those that measure automatically by creating a program, and if it is a high-performance model, the price is about 10 to 20 million yen. Since there are many, it is necessary to select the appropriate one according to the object to be measured, the application, and the accuracy.