An ultraviolet transmission type online measurement method for plastic film thickness

Abstract

The invention discloses an ultraviolet transmission type online measurement method for the thickness of a plastic film. The steps are as follows: on the surface of a sample to be tested, emit ultraviolet rays to the sample to obtain the data of the ultraviolet transmittance of the sample within the range of the ultraviolet wave band; Detect a batch of samples in advance to obtain the corresponding UV transmittance values ​​of the samples at different UV wavelengths, so as to draw the change curve of UV transmittance values ​​of samples with different thicknesses in the UV band; real-time measurement to obtain a thickness value to be The ultraviolet transmittance y of the test sample is brought into the fitting formula between the pre-obtained thickness and the ultraviolet transmittance, and the thickness value x of the sample is directly calculated; the invention has low measurement cost and is easy to operate In the present invention, the non-contact online thickness measurement method for plastic film materials using the principle of ultraviolet transmission realizes real-time thickness testing on the film production line, thereby enabling timely adjustment of process parameters, ensuring product quality requirements, and effectively saving production costs.

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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