(1) Cracks are the most common defect of glass bottles. The cracks are very fine, and some can only be found in reflected light. The parts where they often occur are the bottle mouth, bottleneck and shoulder, and the bottle body and bottom often have cracks.
(2) Uneven thickness This refers to the uneven distribution of glass on the glass bottle. It is mainly due to the uneven temperature of the glass droplets. The high temperature part has low viscosity, and the blowing pressure is insufficient, which is easy to blow thin, resulting in uneven material distribution; the low temperature part has high resistance and is thicker. The mold temperature is uneven. The glass on the high temperature side cools slowly and is easy to blow thin. The low temperature side is blown thick because the glass cools quickly.
(3) Deformation The droplet temperature and the working temperature are too high. The bottle ejected from the forming mold has not yet been fully formed and often collapses and deforms. Sometimes the bottom of the bottle is still soft and will be printed with the traces of the conveyor belt, making the bottom of the bottle uneven.
(4) Incomplete droplet temperature is too low or the mold is too cold, which will cause the mouth, shoulder and other parts to be blown incomplete, resulting in gaps, sunken shoulders and unclear patterns.
(5) Cold spots The uneven patches on the glass surface are called cold spots. The main reason for this defect is that the temperature of the model is too cold, which often occurs when starting production or stopping the machine for re-production.
(6) Protrusions The defects of the seam line of the glass bottle protruding or the edge of the mouth protruding outward. This is caused by the incorrect manufacturing of the model parts or the inappropriate installation. If the model is damaged, there is dirt on the seam surface, the top core is lifted too late and the glass material falls into the primary mold before entering the position, part of the glass will be pressed out or blown out from the gap.
(7) Wrinkles have various shapes, some are folds, and some are very fine wrinkles in sheets. The main reasons for the wrinkles are that the droplet is too cold, the droplet is too long, and the droplet does not fall in the middle of the primary mold but adheres to the wall of the mold cavity.
(8) Surface defects The surface of the bottle is rough and uneven, mainly due to the rough surface of the mold cavity. Dirty lubricating oil in the mold or dirty brush will also reduce the surface quality of the bottle.
(9) Bubbles The bubbles generated during the forming process are often several large bubbles or several small bubbles concentrated together, which is different from the small bubbles evenly distributed in the glass itself.
(10) Scissor marks The obvious traces left on the bottle due to poor shearing. A drop of material often has two scissor marks. The upper scissor mark is left at the bottom, affecting the appearance. The lower scissor mark is left at the mouth of the bottle, which is often the source of cracks.
(11) Infusibles: Non-glassy materials contained in glass are called infusibles.
1. For example, unmelted silica is converted into white silica after passing through the clarifier.
2. Refractory bricks in batch or cullet, such as fireclay and hight Al2O3 bricks.
3. Raw materials contain infusible contaminants, such as FeCr2O4.
4. Refractory materials in the furnace during melting, such as peeling and erosion.
5. Devitrification of glass.
6. Erosion and falling of AZS electroformed bricks.
(12) Cords: Inhomogeneity of glass.
1. The same place, but with great composition differences, causes ribs in the glass composition.
2. Not only is the temperature uneven; the glass is quickly and unevenly cooled to the operating temperature, mixing hot and cold glass, affecting the manufacturing surface.