In some cases, when measuring objects, a high accuracy of the results is required, which cannot be obtained using a conventional ruler. In such situations, special micrometric instruments are used. What is a micrometer and how is it used, described in this article.
What is a micrometric device
It is a tool designed to accurately measure small parts. The micrometer allows you to determine the thickness, depth, outer and inner diameters of the products. To perform these measurements, micrometer depth gauges, calipers, and other micrometers of various designs are used.
All varieties of this measuring tool work on the same principle: the use of mutual movement of the nut and screw. Among all micrometric mechanisms, the most common are conventional micrometers.
A micrometer is a small metal tool that consists of a screw, a retainer and a tip. It allows you to measure objects with a high degree of accuracy. The error of the tool is very small and ranges from 2 to 9 microns. It should be noted that 0.1 mm = 100 ΞΌm, that is, 1 ΞΌm is a millionth of a millimeter. The maximum screw travel is 25 mm. This length contributes to maximum measurement accuracy. If the length of the micrometer screw were longer, the measurement results would not be true. Some models of micrometers allow measuring products with sizes up to 100 mm due to the use of interchangeable heels.
There are strict technical requirements that a micrometer must meet. GOST determines that all models of the measuring device must have an accuracy of 0.01 mm. Also, according to standards, micrometers can be produced with the following measurement limits: 0β25, 25β50, 50β75, 75β100, and so on up to 300 mm, and then 300β400, 400β500, 500β600 mm.
History of occurrence
For many centuries, mankind has known what a micrometer is. According to historical facts, they began to use a screw measuring mechanism in the 16th century in the sighting mechanisms of artillery weapons. A little later, the tool began to be used in geodetic devices. But he did not give the required accuracy of the results. And only in 1867, American engineers created a micrometer that allows you to get high-quality measurements.
Types of micrometers
A micrometer is the most versatile measuring mechanism. Lightness and ease of use have made it virtually indispensable in many industrial fields. Due to the variety of measuring objects, the following types of micrometers are produced:
- sheet - designed to measure the thickness of flat sheets made of metal or other material;
- lever - differ from other micrometers by the presence of a lever-toothed head, which allows to produce complex products or repair them with high accuracy;
- smooth - devices of this type are equipped with a bracket and ratchet, which allow you to measure objects with a smooth surface; smooth micrometers are the most common and are used in almost all industrial sectors;
- universal - designed to fence the internal and external sizes of different parts;
- pipe - used for measuring pipe walls;
- thread and wire gauges - make it possible to measure the thinnest products, for example, an optical cable ;
- digital - measuring with a micrometer of this type provides additional advantages: data recording and the possibility of instant processing on a computer.
As for production, two types of micrometers are most used here - mechanical and digital. Let us dwell on them in more detail.
Mechanical micrometers
A mechanical type micrometer is a traditional measuring instrument and is widely used in various sectors of the national economy, despite the presence of a more advanced electronic analogue.
The mechanical micrometer device consists of two parts:
- handles (ratchet, stem and drum);
- a semicircular recess with a support stand for fixing the measured object.
To measure a part, you need to follow this scheme: first you need to place the object on a support stand and tighten the micrometer screw with a handle. After that, you need to scroll the ratchet to adjust the measurement. When it starts to scroll, then the measurement has already been taken. The last step is to take the values ββfrom the scale located on the drum and the stem.
There are models of micrometers that are equipped with a locking mechanism. It allows you to keep the ratchet in place so that the recorded value does not go astray while the result is recorded in a special book or journal.
Micrometer digital
An electronic device is an advanced form of a simple mechanical micrometer. It is more modern and convenient to use. So, a digital micrometer allows you to take measurements with an accuracy of 1 ΞΌm and an error of up to 0.1 ΞΌm. Many models have built-in calibration.
Externally, the electronic device differs from the mechanical model by the presence of a digital display. The user can select any of the possible calculation systems. For example, inches or millimeters. The scoreboard also displays other important information. So, at any time, you can view the battery level.
To reduce energy costs, the device can be programmed to turn off automatically. This mainly occurs after 5 minutes of inactivity.
There are technical requirements that a digital micrometer must meet. GOST denotes the scale of division, permissible errors and other important features of the device.
How to use the device
- Tool check. Immediately after purchase you should check the device for suitability and absence of defects. If the micrometer is working, then you need to adjust the scale. To do this, in conjunction with the tool is a special key. If everything is done correctly, the scoreboard of the digital device when closing the measuring planes without a part should show 0. In a mechanical micrometer, the drum should close the stem, and the zero value of the drum scale should coincide with the longitudinal stroke on the stem. It is advisable to do such manipulations periodically in order to be able to identify malfunctions in time and adjust the micrometer. This will allow in the future to exclude incorrect measurements.
- Fixation of the part. This stage is very responsible and requires the observance of important recommendations. So, first place the object between the measuring planes and simple rotations of the drum to bring the screw to the part. After a short rotation, an emphasis should be felt. Then you should shift the handle and continue to twist the ratchet, until you hear three clicks. This will be a signal that the part is securely locked.
- Micrometer measurement. After fixing, the digital device will show the measurement result on the display. As for the mechanical device, a little tinkering is required here. The result should be read from large numbers and end with small ones. First you need to look at the notes of the stem. There are two scales on it. The upper divisions are 0.5 mm, and the lower ones are 1 mm.
Industrial application
Micrometric instruments are indispensable in modern industry. This is especially true for industries that work with small parts. So, almost all instrument-making enterprises use a micrometer. This allows the production of parts with a high degree of accuracy. Also, a measuring device is used in the jewelry industry to measure the size of stones.
It is impossible to do without a micrometer at many stages of the automotive industry. That is, the micrometric instrument is used wherever production is associated with small and medium parts.
Micrometer cost
Today, a wide variety of micrometers are on the market. A large selection of tools due to the active increasing demand for the micrometer. The price for different models of the device can vary significantly. It depends on functionality, material strength, reliability. A great influence on the cost of the tool is provided by the manufacturer. As a rule, a micrometer of a well-known brand is much more expensive than regular Chinese. In this case, the buyer himself decides what is more important - to save on the device or to have a high-quality measuring mechanism. So, the price of a smooth digital micrometer is in the range of 90-200 euros. And an ordinary mechanical device can be bought for only 19 euros. More complex models with integrated digital displays, levers, interchangeable measuring elements are much more expensive.
Important Tips
- Before using the micrometer, it is necessary to withstand it and the measuring object for 3 hours in one temperature mode.
- The markings on the scale in different micrometers may vary. Therefore, before counting measurements, you should read the instructions and carefully understand the values ββof the divisions.
Now you know what a micrometer is, and you can use it in practice.