Several reasons for defective glass bottles

After a long period of production experience, the production and quality departments of the company have summarized ten types of defective products and their causes in the glass bottle production process for colleagues and customers to use. They are cracks, uneven thickness, deformation, incompleteness, cold spots, protrusions, wrinkles, surface defects, bubbles, and scissor prints. Below we will introduce them one by one.

1. Bubble

The glass bottle body allows for the presence of individual bubbles, and the number of bubbles allowed for glass bottles of different capacities varies. If the quantity is too large, it is not a qualified product. The bubbles generated during the forming process are often several large bubbles or concentrated small bubbles, which are different from the uniformly distributed small bubbles in the glass itself.

2. Wrinkles

Wrinkles come in various shapes, some are thin patches of wrinkles, while others are creases. The main reason for wrinkles is due to the material droplets being too cold and too long, which do not fall into the middle of the initial mold and adhere to the mold cavity wall.

3. Deformation

If the operating temperature and droplet temperature are too high, the bottles ejected from the forming mold may not have fully formed and often collapse and deform. Sometimes the bottom of glass bottles is not even marked with conveyor belt marks, resulting in uneven bottle bottoms.

4. Uneven thickness

This refers to the uneven thickness of the glass bottle wall. Mainly because the temperature of the glass material droplets is uneven, and the viscosity of the high temperature parts is low, making it easy to blow thin; The part with low temperature has high resistance and is relatively thick. The temperature of the model is uneven, with the lower temperature side blowing thicker due to faster glass cooling, and the higher temperature side blowing thinner due to slower glass cooling.

5. Not full

If the model is too cold or the droplet temperature is too low, it will cause the mouth, shoulders, and other areas to be blown incompletely, resulting in defects such as gaps, flattened shoulders, and unclear patterns.

6. Cold spots

The uneven spots on the surface of a glass bottle are called cold spots. The main reason for this defect is that the model temperature is too cold, which usually occurs when production starts or stops.

7. Highlight

Defects in glass bottles where the stitching line protrudes or the edge of the mouth protrudes outward. If the model is damaged, there is dirt on the joint surface, or if the top core is lifted too late and the glass material falls into the initial mold before entering the position, it will cause some glass to be pressed out or blown out from the gap. This is due to improper manufacturing or installation of model components.

8. Crack

Cracks are a common drawback of glass bottles and jars. It is sometimes very fine, and some can only be found in reflected light. The common areas of occurrence are the bottle mouth, neck, and shoulders, and cracks often appear on the bottle body and bottom.

9. Scissor printing

Due to poor cutting, there are obvious traces left on the bottle or can. A drop of material often has two scissor marks, with the scissor mark on top remaining at the bottom, affecting the determined appearance. The scissor print below is left at the mouth of the bottle, often the source of cracks.

10. Surface defects

The surface of the glass bottle is rough and uneven, mainly due to the uneven surface of the mold cavity. The lubricating oil of the mold is not clean or the brush used for oiling is too dirty, which can also cause a decrease in the surface quality of the glass bottle.