Views:93 Author:Site Editor Publish Time: 2019-08-05 Origin:Site
The following improvements can be taken when assembling the windshield of the bonded bus windows.
A) Increase the strength of glass . The dimension accuracy and quality control of the windshield glass assembled with bonded structure are stricter than those assembled with adhesive tape. In order to further improve the strength of the glass, manufacturers have adopted to strengthen the curing process around the large-size windshield glass after forming, so that the surrounding glass in the range of 100 mm can be tempered locally to increase the strength. With this method, the number of self-cracking of glass can be greatly reduced.
B) Increase the skeleton strength. In order to effectively withstand the load, ensure the shape of the window and avoid the damage of the glass due to the deformation of the window hole, the skeleton must have enough rigidity and strength, and the skeleton sections are designed to be closed. The size of the skeleton support beam, the thickness of the skin inside and outside the mouth, the depth of the mouth and the height are all analyzed for strength. In order to increase the strength of the mouth, the outer skin of the mouth can be bent and the inner skin is formed into a triangular structure. In addition, the method of intentional welding should be adopted to ensure the welding strength.
C) Develop a strict and meticulous bonding process to ensure the quality of bonding. At present, the commonly used bus window adhesives in China are Tyrone 8590 glue from Hangao Company of Germany or Sikaflex 265 glue from Sika Company of Switzerland. The suppliers provide detailed instructions when using them, and the operation should be carried out according to the instructions. In addition, the following points should be paid attention to:
(1) Cleaning of the bonding surface. The above two kinds of glues are high-grade elastic polyurethane two-component compounds, which have high requirements on the surface of the substrate, and the bonding surfaces (including glass) must be dry, free of oil, grease, dust and other impurities. The cleaning agent can be selected with alcohol or FL cleaning agent and wiped with cotton gauze.
(2) Brushing method of primer. The primer should be brushed all the way. Any bonding surface including the glass vertical edge should be brushed. Second, the brush should not be brushed back. Try to be thin as possible, otherwise the bonding strength will be reduced.
(3) Guarantee the full curing of the adhesive. The reaction between two-component polyurethane binder and air moisture will be accelerated with the increase of air temperature and relative humidity. Under these conditions, the time between gluing and glass assembly should be shortened correspondingly. On the contrary, the time between gluing and glass assembly should be longer correspondingly. Surface curing of polyurethane adhesives will seriously affect the adhesion of polyurethane adhesives. Therefore, when the surface of polyurethane adhesives has been cured before assembly, it is necessary to re-gel.
D) Improve the consistency between the skeleton and glass, and improve the assembly process. In order to achieve the same plane between the outer surface of glass and the outer surface of skeleton, besides the requirement of minimizing the tolerance of coincidence when making glass, one layer of positioning rubber plate is added to the frame checker one week, so that the sum of the thickness of the checker and the rubber plate equals the depth of the windshield stop. Thus, there are strict standards when modifying the skeleton, with emphasis on ensuring the skeleton. The glass surface and the skeleton surface can be smoothed when the surface and the outer surface of the frame checker are on a plane. In addition, it should be noted that the underlying plate should be removed before the adhesive is completely cured.