Glass cannot be gilded directly. Usually, the gilding layer is silk-screened on the glass surface, and then gilding is performed. The process is briefly described as follows:
silk screen
The bronzing process itself is not complicated. It uses heat and pressure to transfer the metal layer on the bronzing paper to the surface of the product. There are two conditions that must be met to be qualified: one is that the metal layer can be completely separated from the PET base film. , the other is that the separated part can be tightly covered on the surface of the product. Adhesives that can produce adhesion with paper and plastic are easy to coat on the surface of hot stamping paper, so direct hot stamping is easy to understand. The hot stamping of glass must be done by means of coating technology, and the process of realizing this coating on the surface of glass is screen printing.
In order to form a strong bronzing layer on the surface of the cup, the coating of the silk screen must reach a certain thickness, so the mesh number of the silk screen should not be too high.
glass varnish
Some ink manufacturers tell us that UV glass varnish can be used, but we have not seen this trade company use it, they use solvent-based glass varnish, which needs to be baked at high temperature. The adhesion of solvent-based varnish is very good.
The workers will put the cups on a plate next to the screen printing machine and wait for printing. Their screen printing machine is a common circular printing machine that is easy to see in the market. I looked at the jig they made, it's a jig on four wheels, it's a bit difficult to adjust, but once it's adjusted, it's easy to print. Such a fixture is also very adaptable. Even if the glass cups with different diameters and tapers are replaced, the angle is only adjusted. In addition, the cup itself has a certain tolerance, and the four wheels themselves can also consume some of the diameter tolerance of the cup.
After the workers have finished printing, they put the cups one by one in another tray. The drying process is to ensure that the surface of the varnish is dry, that is, it cannot stick, otherwise, the thickness of the coating will change.
Hot Stamping and Thermal Transfer
Silk screen glass varnish is only for bronzing preparation, whether it can achieve exquisite bronzing effect depends to a large extent on the bronzing process.
With the advancement of automation, the automatic bronzing machine for glass cups also came into being. The automatic glass bronzing machine integrates silk screen printing, UV curing and bronzing technology, which greatly improves the production efficiency. The automatic glass bronzing machine adopts a flat turntable. Structure, with the improvement of users' requirements for precision, more and more production factories design and manufacture servo-controlled automatic hot stamping machines.
