Home » Service » Industry Knowledge

The Details of the Processing Techniques of Hot Melting Glass Mosaic
Hot melting glass, also called hot melting three-dimensional sound-absorbing glass, is heated in hot furnace to molten state (the heating temperature is generally 750 degree Celsius) so that the glass can get to the natural or required form and three-dimensional patterns. With sound-absorbing effect, this glass is in dazzling and elegant style, which combines color and technique to provide a hazy feeling and imagination. Its precious artistic value is unmatchable for other similar products. When used in departments and large entertainment venues and combined with high-grade decoration materials, it can play a finishing touch on the decoration works.

Heating Temperature
As glass produced by each glass manufacturer has different melting point temperature, the processing of hot melting glass shall use glass from the same manufacturer as far as possible. If the manufacturer is switched, the temperature curve shall be adjusted as well.

Temperature Curve
The temperature curve is the process of temperature changes in annealing after the glass is melted to molten state. A furnace with temperature curve can control the whole hot melting process by computer without any manual control. But the simple furnace do not have a temperature curve, so the temperature has to be adjusted manually.

The annealing is the cooling process after the glass is melted and molded. Without proper annealing, the glass can burst in the furnace or crackle after melting, because the incomplete annealing can make the stress of the glass change. Glass annealed to 300 degree Celsius is most likely to burst, so when the temperature approaches 300 degree Celsius, the annealing process must be divided into several phases of cooling and heating. When using furnace with temperature curve, the process will be automatically performed according to the curve, but if the furnace does not have a temperature curve, you have to pay attention to the manual adjustment on the annealing temperature.

Hot Melting Molds
The Molds used in hot melting glass process is generally made of heat-resistant materials with no changes in thermal expansion such as thermal insulation cotton and board or materials whose expansion coefficient is close to the one of glass, such as quartz sand, cast iron and stainless steel cotton, etc.

Coefficient of Thermal Expansion
The coefficient of thermal expansion is the shrinkage of the material in heating and cooling process. The expansion coefficient of the molds used in hot melting glass production is nearly the same as the one of glass. Otherwise, the glass may burst or hard to demold.

Glass Tin Side Detector
The glass tin side detector is an instrument to detect the front and back of glass. In the float glass molding process, high-temperature glass floats on the melted tin surface, so a certain amount of tin will permeate into the lower surface of the glass. This surface with permeated tin has some special properties, and has obvious effect on the further processing of the glass. Silk screen printing has to be applied on the non-tin side, or there will be color deviations. Coating shall not be performed on the tin side, and when bent tempering, the tin side shall be the convex surface to avoid the rainbow effect. If the tin side is not set properly in hot melting glass process, the glass produced will have a low transparency.

Moiré Glass
The moiré glass is a kind of hot melting glass. After heated in hot melting furnace, a lot of long, wavy glass are naturally bonded together to make this decorative glass. The process of moiré glass doesn't need any mold, and the processing steps are as follows:
1. The glass shall be of the same batch from the same manufacturer. (This is very important. As mentioned before, glass from different manufacturers has different melting point temperature. In hot melting process, because of the difference between coefficients of thermal expansion, glass will likely to burst.) The glass is cut straight in one side and wavy in the opposite side, or both wavy according to the requirements.
2. The glass bars are adhered together with UV glue or 502 glue. The glue doesn't need to be applied on a large area, we just need to bond the glass bars together. If the moiré glass processed is not large, they can be bonded together before sent into the furnaces. If the moiré glass is very large, we can directly bond them in the furnaces or bond them into several parts and then bonded together in the furnaces.
3. Spontaneous explosion may occur on glass in the furnaces. The reason is the NiS impurities interfused during the manufacturing of the glass. The NiS has two forms of crystallization, namely alpha phase in high temperature and beta phase in low temperature. During the annealing process, if the temperature drops too fast, leaving no enough time for the alpha phase to turn into beta phase, the glass will explode spontaneously.

The transformation time for NiS has a strong relationship with temperature. When it is 280 degree Celsius, the transformation time is only 1 hour, but when it is 250 degree Celsius, it becomes 100 hours. So the temperature controlling is critical. Sometimes the transformation process is not completed after several hours, and that becomes totally a waste of time.

Main Products
  • Mesh Belt Glass Decorating LehrThe mesh belt glass decorating lehr is suitable for continuous large-scale production of high-temperature logo printing and metal printing and low-temperature glass paint drying for domestic glass such as glass bottle and cup and art glass. The whole lehr measures 18m to 60m. It has maximum service temperature of 650℃ and production cycle of 30 to 40 days.
  • Glass Hot Bending Hot Melting Production LineThe glass hot bending hot melting production line comprises of glass cleaner, shaped glass cutting machine, mesh belt electrothermal tunnel calcining kiln. Baseplate, namely 5mm to 8mm thick plate wavy glass, is heated, bent, and melted in stainless steel or fireproofing material molds into glass fruit plate, glass ashtray, and lighting glass. It can also be tempered.