Raw materials that we primarily use in the manufacture of glass bottles are sand, soda ash, limestone and cullet.These materials are mixed in a specific ratio to make soda lime glass. Other types of glass bottles may, however, require additional inputs. For instance, dyes and chemical compounds may be added in the manufacturing process to produce colored bottles or heat-resistant borosilicate glass.
Once the raw materials are gathered and prepared, they are placed in a hopper machine for mixing. The mixture is then put into batching compartments in measured portions. It is from these compartments that it is fed into the melting furnace through a conveyor belt.
Batching is an important phase of glass bottle manufacturing. The mixture portions have to be accurate to ensure consistent quality. Their mixing ratio are determined by the design and the number of bottles to be made.
The melting phase takes place in a heating furnace where the raw materials are subjected to high temperatures of about 1600°C. The water content evaporates and organic matter is burned off while the remainder of the mixture melts to form molten glass. Finally, the molten glass is cooled to achieve viscosity in readiness for the formation stage.
All our furnaces are fully automated. Their temperatures settings are controlled by our engineers from an integrated control room using special software.
Glass formation involves the molding of molten glass into the desired bottle shapes. First, the viscous mixture is cut into gobs of equal size using a timed blade. The gobs fall into separate slots of an individual section machine. Each slot contains a shaping mold.
The final shape is achieved by either Blow and blow method or Press and blow method.
In the Blow and Blow method, compressed air is used to shape the bottle. It is blown onto the molten gob and pushes it to take the shape of the mold. This initial shape is referred to as a parison. The parison is then flipped to an upright position, reheated and injected with more air to fully define its shape.
This method is used for narrow glass bottles such as beer glass bottles, wine glass bottlesor soda glass bottles.
The Press and Blow method involves the use of both a plunger and air to shape bottles. When the molten gob falls into the individual section, a plunger pushes it to fit the mold. This action defines it into a parison which is then transferred to a blow mold. There, it is reheated and blown with air until it is properly shaped.
This method is preferred for wide-mouth glass containers such as glass vases, glass candle jars or milk bottles.
After formation, the glass bottles are allowed to cool before entering an annealing furnace. This is a long kiln with controlled temperature settings. In it, the glass bottle is slowly reheated and then gradually cooled again to a temperature below the glass strain point.
This process makes the inside of the bottle more resistant to chemicals. It also ensures uniform settling of the glass material.
Surface treatments are performed on the exterior of glass bottles when they are complete. They can be used for decoration, labeling and even protection against abrasion. We have specialized equipment and know-how in performing various treatments, including: