A level is a common measuring tool for measuring small angles. In the mechanical industry and instrument manufacturing, it is used to measure the inclination Angle relative to the horizontal position, the planeness and straightness of guide rail of machine tool equipment, the horizontal position and vertical position of equipment installation, etc. Next, I will explain the knowledge of level in detail.

1. A brief introduction to the level

A level is a common measuring tool for measuring small angles. In the mechanical industry and instrument manufacturing, it is used to measure the inclination Angle relative to the horizontal position, the planeness and straightness of guide rail of machine tool equipment, the horizontal position and vertical position of equipment installation, etc.

2. Principle of level

The leveling pipe of the level is made of glass, the inner wall of the level pipe is a curved surface with a certain radius of curvature, and there is liquid in the pipe. When the working principle of the level gauge is inclined, the bubbles in the leveling pipe will move to the raised end of the level gauge, thus determining the position of the horizontal surface. The larger the curvature radius of the inner wall of the leveling tube, the higher the resolution; the smaller the curvature radius, the lower the resolution; therefore, the curvature radius of the leveling tube determines the accuracy of the level. Horizontal instrument is mainly used to check the flatness, straightness, verticality of various machine tools and workpiece and the horizontal position of equipment installation. In particular, when measuring perpendicularity, the magnetic level can be attached to the vertical working surface without manual support, thus reducing labor intensity and avoiding the measurement error brought to the level by human thermal radiation.

The bottom and side length of the level are 200mm rectangular structure, the accuracy is generally (0.02-0.025) mm/m, if the user has special requirements, can be customized. The zeroing structure of level gauge has its own characteristics, which are different from the conventional structure:

(1) Zero setting is easy.

(2) After adjustment, the zero position is not easy to change. When the v-groove surface of the bottom of the level is rotated around the core axis for 5, if the bubble moves, the requirements can be met by adjusting screw 2, which has been adjusted at the time of delivery and generally remains unchanged.

3. Type of level

Bubble level has three types: box level, strip level and image level. Box level and strip level are mainly used to test the flatness of various machine tools and other equipment, the correctness of horizontal and vertical positions installed, and to test the micro inclination Angle. Bar level is suitable for horizontal operation, vertical operation accuracy is not high.

4. Use method of horizontal instrument

The scale value of the level is expressed by the Angle (second) or the slope, which means the Angle at which the bubble deviates one working inclination, or the height at which the bubble deviates one working surface and tilts one meter in length. Since the inclination Angle of the level is very small, tg, such as tg4 4 radians =0.02mm/1000mm, can be used to make the working face of the level close to the surface under test, and the reading can be made after the bubble is stable. If the actual tilt value of length L is to be measured, it can be calculated by the following formula. Actual tilt value = deviation lattice of nominal index value L; For example: the nominal indexing value is 0.02mm/m, L=200mm, and the deviation grid number is 2, then the actual tilt value =0.02/1000*200*2=0.008mm. In order to avoid the measurement error caused by the inaccurate zero position of the level, the zero position of the level must be checked or adjusted before use.

Level zero check and adjustment method, will be the school level on the level of tablet, close to the locating piece, after waiting for bubble stability for bubble readings at the end of the a1, then modulates level 180 bearing, accurately in the original position, according to the first write down the side of bubbles at the other end of the reading for a2, two reading half of poor as zero error, namely = (a1, a2) / 2. If the zero error exceeds the red limit, the zero mechanism needs to be adjusted.

5. Inspection and adjustment of level

Horizontal instrument is used to check the irregularity of guide rail of various machine tools and other mechanical equipment, the parallelism of relative position of machine parts and the horizontal position and vertical position of equipment installation. Level is the most basic inspection tool in machine tool manufacture, installation and repair.

Horizontal gauge is a commonly used instrument to measure the straightness of machine guide rail, which is used to check the straightness of guide rail in the vertical plane and the straightness in the horizontal plane. Before using a level gauge to adjust the straightness of the guide rail, the level of the whole guide rail should be adjusted first. Place the level gauge in the middle and both ends of the guide rail and adjust it to the horizontal state of the guide rail so that the bubbles of the level gauge can be kept within the scale range in all parts. Then the guide rail is divided into a number of equal whole sections for measurement, and the head and tail are smoothly connected, check and read section by section, and then determine the movement direction of the bubble of the level and the actual calibration pass number of the level.

Guide straightness error < curve line >, what is said in the textbook has no actual basis, and it is very inconvenient and inaccurate to apply in the production site. It misleads people’s ability to identify, in the actual work can not be applied, often give the staff to create an illusion. According to this check guide straightness error, can not get the correct precision value.