mailbox
Adhesives are widely used in Metro, light rail, EMU and other rail transit vehicles, such as the sealing of automobile windshield and side window glass, the bonding of ground cloth, the bonding of top plate and side wall panel, the bonding of interior trim, etc. Different bonding positions and bonding substrates, such as cold resistant materials, require different adhesive types and processes. Only by selecting the appropriate adhesive and following the correct construction process can the bonding effect be maximized. Take floor cloth bonding as an example, as follows:
PVC or synthetic rubber is the common base material of rail transit floor cloth, aluminum honeycomb is the main base material of vehicle floor, and there are also a few wood floors or carbon fiber composites. The bonding area of the floor cloth is large. If the bonding fails, the appearance of the whole vehicle will be affected and it is difficult to repair. Therefore, it is very important to strictly follow the bonding process. Among them, the expansion and warpage of the floor cloth is the most common phenomenon.
Cause analysis:
There are many reasons for floor cloth bulging, which can be divided into two categories.
(1) External factors, such as loose rivets at the bottom of the train during long-term operation, seat rotation, honeycomb panel collapse, etc., cause the floor cloth to bulge or open edges.
(2) There are problems in the bonding process, such as the bonding surface is not cleaned, the gluing is uneven, the ambient temperature and humidity are inappropriate, there is air inside, the glue drying time is not enough, etc.
Solution:
(1) Remove sundries and oil stains on the surface of the substrate, and polish the surface of the aluminum plate to prevent poor adhesion caused by oxides on the surface of the aluminum plate.
(2) PVC floor cloth or rubber floor shall be laid in advance in the construction environment to ensure the memory recovery of the floor cloth and prevent poor bonding caused by internal stress concentration.
(3) Ensure that the construction environment is appropriate. For example, the temperature shall not be lower than 15 ℃ and the humidity shall not exceed 85%. If the humidity is too high in summer, dehumidification can be carried out.
(4) According to the requirements of the process documents, ensure the uniform construction of the glue solution within a certain range of glue application amount. Meanwhile, the glue drying time shall be reasonably arranged according to the current construction environment. If the time is too long, the bonding strength may be reduced. If the time is too short, the water will volatilize incompletely, resulting in later expansion.
(5) A reasonable pressing method shall be adopted to avoid that the air stored inside cannot escape due to improper pressing, resulting in bulge.
Error report description