Along with the micrometer, the chuteomer and other tools for more accurate measurements, use the caliper. This is not just a ruler, but more accurate than it, a tool, measuring the distances between the edges of parts with an accuracy of 0.1 mm.
Features and destination
The caliper allows you to more accurately determine the outer and inner diameter of the gaps and holes, the length and depth of parts in various projections. Special purpose caliper also allows you to measure the distance in the grooves, the holes of the small diameter, the distance in the flow-in definitely details, the distance between the axes, the thickness of the pipe walls and T. D.
The classic caliper can be finalized and enhanced with the help of additional scales and elements of its design, allowing to expand the area and the scope of its use.
In the simplest version, the main part consists of a fixed base with the left sponge. Right moves along with a movable guide – barbell, and is connected to her hard. This pair of sponges serves for external measurements. The second pair is deployed 180 degrees with cutters and moves similarly to the first pair, it serves to measure internal diameters and distances. On the rod is located the second scale, which helps more accurately measure the desired distance. At the end of the ruler there is a depth procedure that allows you to count the distance for the depth of the holes. To fix the readings taken from the part or holes, so as not to move the rod, the retaining screw with the handle is provided.
But the mandatory attribute of the digital caliper is a digital module with a display.
The rotation sensor, rolling through the rod, is located inside – it considers it, for what distance the moving part has come to, and focuses on the main scale.
The accuracy of the digital caliper – up to 0.01 mm, which brings it closer to the analog micrometer. The mechanical micrometer also has accuracy of up to 10 microns, but the range of measurements is limited to 2.5-10 cm, and the caliper is a significant distance significantly more – 15-130 cm. Electronic caliper – in fact, the simplest microcomputer with a processor, ADC, RAM.
If there is no special requirements for the error (“how much I saw – as much as I noted”), then the digital, according to GOST and international standards, the error should not be more than 10% of the division price.
If you caught a high-precision caliper, in which accuracy approaches micrometric (0.01 mm), then the error has one micron. With a significant deviation from this indicator, the caliper after the product is sent from the conveyor to be re-calibrated or selected.
Scope of the application of the caliper – metalworking production, Auto industry and auto repair, repair of all sorts of equipment and products, construction.
Principle of operation
The principle of operation of any caliper is based on the coincidence of the desired scale marks on stationary and retractable parts. But the digital device has its own characteristics. Here use a capacitive matrix with an encoder. Simply put, The scheme operates a pair of simple capacitors included one through another, and the upper plate of each of them is a general conclusion. To create a capacitive combination, several capacitor plates are applied.
Such a system has a sensitive reaction to the motion of the sensor. The rotating part in this system is the slider. The fixed part is placed in the steel line. The digital block with the slider is fixed on the moving part of the caliper. When spreading the sponges of the calipers, the movable part is not simply shifted, and the slider rotates, pulling it out in the desired side.
In the microcircuit of long-term memory, or the ROM, “sits” the firmware loaded into the processor each time the digital module is turned on and its organizing operation. It interprets the data taken from the caliper sensor through the ADC, in the testimony, and displays them on the display.
Advantages and disadvantages
The advantages of digital caliper.
- Increased accuracy and small error, which is extremely important with accurate measurers, where the slightest inconsistency in a certain part will immediately cause unstable operation in the whole mechanism or installation.
- Simplified verification (or calibration) – when it is necessary to check the operation of several calipers at once.
- The speed of perception and transmission of received data. It is extremely important in production, where the conveyor has a controller that determines the accuracy and loyalty of certain sizes of the outputs and detecting a production marriage. The instrument readings are issued instantly – the calculation on the scales here is not required.
- Newcomers have no reason to study how measurements are made – they will make a sensor and a digital module for them.
- The ability to switch from one type of measurement to another – on multidisciplinary details that have different approaches to measurement of one or another interval.
- The ability to easily translate inches into centimeters and back, as well as transfer data using the built-in interface for external communication with PC and mobile devices.
Disadvantages of electronic device.
- Availability of a battery – forgetting it on time to replace, you will face the need to do “in the old man”.
- Sensitivity to high humidity, shaking, shocks and vibrations – because of this, the electronic module is easy to damage.
- Software malfunctions due to strong interference nearness, static electricity sensitivity. Hence the inoperability of both individual functions and the whole device as a whole. Maybe the indication – most calipers have no highlighting, and guess that the device is still working and is operational (with an extinct display), it is impossible.
Rating the best models
Wide well-known manufacturers The following firms are:
- “Microtech” (Ukraine);
- INTERTOOL, MIOL, UKC, VEMER and WENZHOU SANHE MEASURING INSTRUMENT (China);
- Came To, Digital (South Korea).
However, the best models today were lined up as follows (starting with the most universal).
- Holex 412805 150 – Self-holder for 150 mm stroke and microUSB interface to transfer data to a PC, smartphone or tablet.
- Yato Today is a record holder for sales of such devices. They have high quality performance, measurement accuracy – 25 microns. Warranty – half a year. For 1.5 milliseconds it will measure. Suitable for people with the need for high-precision measurements. This Polish model is distinguished by reliability, the best in the plan of everyday tasks in which these measurements are included.
- Fit Digital Caliper – Devices having unsurpassed design quality and electronic module, limit clarity and speed of work on small parts. Weak place – plastic case electronic part. Measses the same quickly as the previous model, but the accuracy reaches 10 microns. Canadian product perfectly combined in quality with its value and is suitable for small production or at home.
- IP67 Filetta Series 907 – The device gives consistently high accuracy. You can make measurements under water, as it is designed for immersion duration up to 20 minutes. Has 300 mm stroke.
- Krun Shtsz-1-125 / 150 0.01 Posses up to 250 mm long, accuracy – up to 10 microns.
- Matrix 31611 – measurement range up to 200 mm, accuracy – as in the previous. Equipped with depth size. Increased speed (up to 1.5 ms). Works at a temperature of 5-40 degrees.
- Models Shtsz-1 / 2/3 Also contain a digital reading device – their length ranges from 15 cm to 1 m, they are professional devices.
- “Ermak” MT-027 – measurement range up to 150 mm, the same accuracy – 0.01 mm.
- Qstexpress 150 – accurate device, but its quality is medium, justified only by price. Small discrepancy scale on the carrier part with testimony on the screen. Protected from moisture, convenient to use.
- Qstexpress 008 – related previous model, but has its design. Plastic Case of the electronic module, accuracy – only 0.1 mm, but it will be suitable for infrequent use. No shut-off screw. The speed is all the same – 1.5 ms.
The carrying construction of all these calipers – from a stainless steel, there is support for both measures, auto power in the inactivity of the user (after a minute).
How to choose?
When buying a calipers, check the accuracy, the range of measurements (in length), the presence of a digital meter, a depthioner pin and a locking screw, the integrity of the claw and the entire carrying structure as a whole.
It is not recommended to buy a caliper with a relaxed or poor-quality body of a digital module – it will be easy to break, and only analog component will remain on the best case (scale marking) from the calipers.
At worst – the device can fully fail.
The housing of the diginodule must be made of aluminum alloy or high quality composite. He should not be peeling and creaked. Bright scale can rush in the eyes if you left the tool somewhere, but it is only a pleasant bonus to it. The caliper must be performed by itself at least from aluminum or alloy based on it. But the best choice is the instrumental stainless steel device.
Checking the caliper – an important aspect before purchasing it. At home to get the technologies of calibration close to factory, extremely difficult. Check out the data from the process.
It should not have any inaccuracies and passes in the device description.
- With an external inspection, the integrity and purity of the “ferrous” mechanism is performed. The fuzziness in the notation, markup and movement – a sign of poor quality of execution, do not waste your time and money in this case.
- Check, “sits” if the moving frame is zero in the initial position (before measurement).
- Make sure that when measuring thickness, for example, a flat board or smartphone, the light does not pass through the line of contact. If this is not the case – the tool should be cleaned of dust and sand, extraneous particles (if they are detected). His sponges should clearly contact, again, not missing light through the closure line.
If the selected model has passed the test and suits you in all respects – you can stay on it.
How to use?
According to the instructions for use, before starting work, clean the tool sponge from extraneous particles. Randomly having a hair between them, a pork from upholstered furniture and other can lead to exceeding the readings more than the value to which the declared error of the device is equal.
The use of digital calipers differs from the use of analog certain additional features.
- Using the “Inch and Millimeters” button, select the measured unit.
- If the readings at the beginning of work are not zero – click “Reset to Zero”. Loosen the shut-off screw holding the rolling part of the tool.
- Slide the sponge, the pointed faces of which are directed inside.
- Place the measured item or pipe between sponges.
- Twist them so that they come closely to the details, slightly tighten the holding screw.
- Check, opposite what division is the pointer (line). The device will immediately show the desired value on the display.
- If you need to calculate the difference between the two items in the same projection, click the “Reset to Zero” button, loosen the shut-off screw and measure the same site on another similar detail. The caliper will show the difference from the previously obtained value.
The value obtained and will be the size of the part. If you need to measure the internal dimensions, insert another pair of sponges, the faces of which are bred outward, in a hole or groove, and dive them, then fix the screw. They are located so that the sizes are measured outside and from the inside were equal.
If this is not the case – the device is considered a fake under the caliper.
In the next video you will learn the main differences in the cheaper and expensive electronic calipers.