What Is an Inside Caliper?

A caliper is a measuring tool used to measure length, inside and outside diameter, and depth. It has the functions of measurement and inspection.

Gages are instruments for measurement and inspection.

The principle of a caliper is to use the difference between the engraved line distance (line distance) on the main ruler and the line distance on the vernier ruler to read the decimal part. Grid with a line spacing of 0.9 mm. When the zero scale of the two coincides, if the vernier ruler moves 0.1 mm, its first engraved line coincides with the first ruler of the main ruler; if the vernier ruler moves 0.2 mm, its second engraved line The line coincides with the second engraved line of the ruler. By analogy, the decimal part of the value can be read from the overlap of the ruler and the ruler on the main ruler. The difference between the main ruler and the vernier line distance of 0.1 mm is the minimum reading of the vernier caliper. Similarly, if the difference between their line spacing is 0.05 mm or 0.02 mm (there are 20 or 50 divisions on the vernier scale, respectively), the minimum reading value is 0.05 mm or 0.02 mm, respectively.

The cursor principle was proposed by the Frenchman P. Venier in 1631. It is commonly used in subdivision reading mechanisms for length and angle measurement tools. For details, please refer to national standards (GB / T21388, GB / T21389, GB / T21390). ^[2]

1. The main ruler and measuring claw of the lightweight Digimatic caliper are CFRP (carbon fiber reinforced plastic).

2. Durable and easy to operate.

3. The application range can be expanded by options.

4. The internal diameter measurement value can be read directly from the LCD screen (press the offset key to easily set the offset value).

5. The required starting point can be set by the preset function.

6. With SPC data output.

7. Special model with ceramic measuring claw, suitable for measuring magnetic products; calipers have a simple and basic design; calipers can measure outer diameter, inner diameter, depth and step; Easy to read; caliper sliders are equipped with locking screws; calipers are available with hard alloy head measuring jaws.

The calipers are mainly

1. Outer diameter measurement (lower / outer measuring jaw)

Calipers: Caliper (American English); Calliper (British English)

Digital Caliper: Digital Caliper

Vernier Caliper: Vernier Caliper

Depth Ruler: Depth Gauge

Height caliper: Height Gauge

Vernier calipers commonly used can be divided into three types according to their accuracy: 0.1 mm, 0.05 mm and 0.02 mm. Their working principle and method of use are the same as the vernier calipers with an accuracy of 0.1 mm described in this article. The vernier caliper with a precision of 0.05 mm has 20 division marks on the vernier, with a total length of 19 mm. When measuring, if the 11th scale line on the vernier is aligned with the main ruler, the decimal part reading is 11/20 mm = 0.55 mm. If the 12th scale line is aligned with the main ruler, the decimal part reading is 12/20 mm = 0.60 mm.

In general, there are n division marks on the cursor, and their total length is equal to the total length of the (n-1) division marks on the ruler. If the minimum scale length on the cursor is x, the minimum scale length on the main ruler is y, then:

The difference x between the minimum scale of the master ruler and the cursor is:

y / n is the accuracy of the vernier caliper, which determines the number of digits in the reading result.

It can be seen from the formula that improving the measurement accuracy of the vernier caliper consists in increasing the number of scales on the vernier or decreasing the minimum scale value on the main ruler. In general, y is 1 mm, and n is 10, 20, or 50. The corresponding accuracy is 0.1, 0.05 mm, and 0.02 mm. The mechanical vernier caliper with an accuracy of 0.02 mm is limited by its structural accuracy and the resolution of the alignment of the two scribe lines by the human eye, so its accuracy cannot be improved.

1. Vernier calipers are relatively precise measuring tools. Handle them gently and do not bump or drop them underground. Do not use it to measure rough objects during use, so as not to damage the measuring claws. When not in use, they should be placed in a dry place to prevent corrosion.

2. When measuring, loosen the fastening screws first. Do not use excessive force to move the cursor. The contact between the two measuring claws and the test object should not be too tight. Do not move the clamped object in the measuring claw.

3. When reading, the line of sight should be perpendicular to the ruler surface. If the reading is to be fixed, the vernier can be fixed on the ruler with fastening screws to prevent sliding.

4. In actual measurement, the same length should be measured several times, and the average value should be taken to eliminate accidents.

1. Operation check Before using every day, first check whether the zero scale of the vernier caliper is aligned, whether the scale is clearly visible, and whether the movement is smooth. If so, the caliper can be used normally, otherwise the caliper needs to be repaired or replaced with a new one.

General calipers will be used in conjunction with a data acquisition instrument. The data acquisition instrument can be directly connected to the caliper for automatic data collection without the need for the operator to manually record data, saving labor costs; many calipers are connected to the QSmart data acquisition instrument for automatic data collection and data analysis. Connect calipers for efficient mobile data collection.

Application background: At present, the internal quality inspection method of the factory is to measure one data and record it manually on the paper by the surveyor, or measure it by one person and record it by the other person. When analysis is needed, it is entered by the operator. To the computer's EXCEL form; the problems caused by this method are low efficiency and easy to remember the data. At the same time, some operators are not aware of the product's measurement specifications. The operator cannot take timely measures for products that exceed the specifications. When data analysis is needed, it needs to be entered into the computer repeatedly.

The main goal: to achieve paperless measurement, improve the accuracy of measurement and improve the efficiency of detection, and to promptly remind when the specifications are exceeded.

Collector connected to calipers to collect data