Study On The Method Of The Deformation Evaluation Of The Pattern&Color On The Film Forming

In Mold Decoration(IMD)is a surface-decoration technology that thermoforms printed films and then ends up with injection molding.It is with great market value mainly used in the fields of electronics,household appliances,communication equipment,automobile and so on.However,in the process of real production,the product surface is often disqualified due to the change of the pattern color of the IMD film.In this paper,aimed at the changes of pattern color in IMD film during the forming process,a method is proposed to accurately and quantitatively evaluate pattern color changes.The specific work and achievements are as follows:(1)By studying the changes in pattern shape,color and thickness in terms of the stretch deformation of film,an evaluation method for the pattern color change of IMD film was constructed.This method can quantitatively evaluate the variation of pattern color in various areas on the surface of the diaphragm.(2)A new color measurement system was established,which was aimed at the examination of IMD film.The color of each region on the diaphragm was collected with a special color measuring instrument,and the pattern color change in each region of the diaphragm was comprehensively analyzed under two independent color measuring systems.(3)In terms of the color value fluctuation of the film pattern,this paper established the mathematical model and the python language respectively for the purpose of collecting data and further analysis based on the change of film thickness and patch acquisition area.(4)The paper also established the corresponding relation between the color difference extreme value and the color instrument system.When the ink color difference is at the critical points of 3 and 5 respectively,the corresponding color of extreme values would change from yellow(2.07NBS),blue(4.34NBS),green(4.35NBS)to black(4.13NBS).The innovative of this paper is to study the difference of ink color in film forming by grid method,and get the corresponding relation of ink color difference in two independent color measuring systems.However,this paper only studies several kinds of color ink,and therefore the evaluation parameter is the approximate planar area ratio.In the further research,the color evaluation system can be extended to other colors,or even to a different surface area ratio.In order to independently realize the evaluation and application of film color under the color measurement device constructed in this paper,the printing grid pattern of unformed film shall be remoulded,and then the corresponding relationship of color distortions obtained in this paper can be used to evaluate four distortions of color ink in each molding area to some extent.