Ultraviolet transmission type plastic film thickness on-line measurement method

Abstract

The invention discloses an ultraviolet transmission type plastic film thickness on-line measurement method. The method comprises the following steps: emitting ultraviolet rays to the surface of a testsample to be measured to obtain data of ultraviolet transmissivity of the test sample in an ultraviolet waveband range; detecting a batch of samples in advance to obtain ultraviolet transmissivity values corresponding to samples under different ultraviolet wavelengths, and drawing a ultraviolet transmissivity value change curve of the samples with different thicknesses in the ultraviolet band; and measuring in real time to obtain the ultraviolet transmissivity y of the sample to be tested with a thickness value, substituting the value into a pre-obtained fitting formula between the thicknessand the ultraviolet transmissivity, and directly calculating to obtain the thickness value x of the sample. The method is low in measurement cost and convenient to operate; and real-time thickness testing on a film production line is achieved in the method for achieving non-contact type thickness online measurement of the plastic film material through the ultraviolet transmission principle, so technological parameters can be adjusted in time, the product quality requirement is guaranteed, and the production cost is effectively saved.

Description

technical field [0001] The invention relates to the technical field of physical optics measurement, in particular to an ultraviolet transmission type online measurement method for plastic film thickness. Background technique [0002] In recent years, with the continuous update of modern scientific research technology and the rapid development of the polymer industry, the research and application of plastic film materials have shown a rapid growth trend. At present, the common film products on the market include high temperature resistant polyester film (PET), polypropylene film (BOPP), polyethylene film (PE), based on their excellent properties such as acid and alkali resistance, electrical insulation, high transparency, etc., have been Benefits to food packaging, aerospace, pharmaceutical chemicals, agricultural film and other fields. Moreover, according to the market policy of my country's national economy and the adjustment and transformation of rural production structur...

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Problems solved by technology

Among them, the X-ray thickness measurement technology is mature. However, due to its shortcomings such as strong electromagnetic radiation, high instrument maintenance costs, and unclear diffraction images of amorphous polymer materials, it is generally not considered in the thickness test of plastic film materials. The method; the capacitance thickness measurement method is based on the principle that the dielectric constant between the capacitance of the capacitive sensor and the pole plates will vary with the thickness of the medium. When the film material is between the capacitive pole plates, the measurement of the film thickness is realized. It is suitable for dynamic online testing, but distributed electricity is likely to cause nonlinear output, which affects the measurement accuracy, and requires extremely high parallelism of the test rails, which adds difficulty to the thickness test; the infrared thickness measurement method uses the plastic film material to The difference in infrared characteristic absorption wavelength, the thickness information of the film can be obtained by monitoring the change of infrared light intensity, the infrared method has no radiation and low cost, but the change of film temperature and haze caused by infrared thermal effect will directly affect the thickness measurement result

[0006] Ultraviolet light refers to electromagnetic waves with a wavelength range of 10-400nm. The frequency is between visible light and X-rays. The photon energy it carries is greater than that of visible light, but its radiation effect is much lower than that of X-rays.

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