Learn what a flatness meter is through an article
Flatness means that when processing or producing something, the surface is not absolutely flat. The difference between the unevenness and the absolute level is the flatness.
Characteristics
When processing a blanket, the thickness uniformity of each point is required, that is, the processing thickness must have a certain precision. Offset blanket is used for lithographic offset printing. The compression of the blanket cylinder and the impression cylinder is only 0.1~0.2 mm during printing. Therefore, the flatness of the blanket must be determined properly, and the flatness error should not exceed 0.04 mm. If it exceeds 0.04 mm, the ink color of the printed matter will be uneven, and the shape of the dot will also change. Sometimes you have to use the adhesive on the back of the blanket to fill it. Therefore, the flatness is especially important for offset blankets. (the smaller the value, the better)
Measurement methods
3 meter ruler method continuous flatness meter method
significance
Road surface flatness is one of the main technical indicators for assessing road quality. It is related to the safety and comfort of driving and the impact force and service life of the road surface. The uneven road surface will increase the driving resistance and make the vehicle add-on. The vibration effect. This vibration will cause the car to bump, affect the speed and safety of the driving, affect the smooth driving and passenger comfort. At the same time, the vibration will also exert impact on the road, thus aggravating the damage of the road and the car parts. And tire wear and increase the consumption of oil. Moreover, for the uneven water surface in the water network area, it will accumulate rainwater and accelerate the water damage of the road surface. Therefore, in order to reduce the vibration impact force, increase the driving speed and increase the speed. Car comfort, safety, road surface should maintain a certain degree of flatness.
The factors affecting the smoothness of the road surface can be related to design, construction, natural conditions, etc. Excellent road surface flatness depends on excellent construction equipment, fine construction technology, strict construction quality control and regular and timely maintenance to ensure the impact. The factors of the flatness of asphalt concrete pavement are: uneven settlement, paving process, rolling process, transverse joint treatment, mix design, underlying layer disease and so on.
The flatness directly reflects the comfort of the vehicle and the safety and service life of the road. The detection of pavement flatness provides important information to decision makers, enabling decision makers to make optimal decisions for the repair, maintenance and renovation of pavements. On the other hand, the detection of pavement flatness can accurately provide information on pavement construction quality and provide an objective indicator of quality assessment for pavement construction.
Measuring instrument
There are two main categories of instrumental measurements for pavement flatness:
The first type is longitudinal section measurement (direct detection type), that is, the profile curve of the pavement profile is measured, and then the measured longitudinal section curve is mathematically analyzed to obtain the flatness index.
The second type is the vehicle's response to the road surface (response detection type), that is, the mechanical response of the vehicle to the longitudinal section of the road surface is measured, and then the mathematical analysis of the measured mechanical response is performed to obtain the flatness index. The conversion of the pavement flatness index is mainly obtained by calibrating the results measured by standard instruments.
Generally, the first and second types of detection methods can be used for the acceptance and evaluation of pavement construction quality and the periodic evaluation of pavement. The second type of testing equipment generally requires calibration by means of a first type of testing instrument. Direct and responsive pavement flatness meters are essential for pavement construction, acceptance, maintenance, evaluation and management.
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