8 Reasons That Affect the Quality of Glass Bottles

8 Reasons That Affect the Quality of Glass Bottles


By understanding the factors that affect the quality of glass bottles, we can largely avoid buying inferior products. This article will share with you some reasons that affect the quality of glass bottles.

 the advantages of glass bottles

There are many types of glass bottles on the market now, and many consumers do not know how to judge their quality and choose relatively inferior products, which can easily be damaged during use.
We can first understand the production process of glass bottles. First of all, we must design and manufacture the mold. The glass raw material uses quartz sand (property: silicate mineral) as the main raw material, and other auxiliary materials are melted into liquid at high temperature, and then injected into the mold, cooled, cut, and tempered to form a glass bottle.

According to the manufacturing method, the molding of glass bottles can be divided into three types: manual blowing, mechanical blowing, and extrusion molding. In the molding process, if the following conditions occur, the quality of the glass bottle will be poor.


Cracks are the most common shortcoming of glass bottles. It may be very thin, and some can only be found in reflected light. Frequently produced parts are the bottleneck and bottleneck, and the bottle body and bottom of the bottle often have cracks.

Uneven thickness

This refers to the uneven distribution of glass on the glass bottle. The main reason is that the temperature of the glass gob is uneven, the part with high temperature has low viscosity and is easy to blow thin; the part with low temperature has high resistance, and the glass will be thicker.

The temperature of the model is not uniform. The glass on the higher temperature side cools slowly and is easy to blow thinly, and the lower temperature side is thicker because the glass cools quickly.


The temperature of the gob and the action temperature are too high, and the bottle ejected from the forming die is not completely shaped, and tends to collapse and deform. Sometimes the bottom of the glass bottle is still soft and will be printed with the marks of the conveyor belt, making the bottom of the bottle uneven.
The bottle design is not full

If the gob temperature is too low or the model is too cold, the bottle mouth and bottle shoulders will not be full-blown, resulting in defects such as gaps, shrunken shoulders, and unclear patterns.
Uneven spots

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

Protruding suture line of glass bottle or protruding edge of the mouth

This is caused by the incorrect manufacturing of the model parts or the inadequate installation. The model is damaged, there is dirt on the joint surface, and the top core is lifted too late before entering the position. The glass frit has fallen into the preliminary mold, which will cause a part of the glass to be pressed or blown out of the gap.

Surface defects

The surface of the glass bottle is hairy and uneven, mainly due to the non-smooth surface of the mold cavity. The model's lubricating oil is not clean or the oiled brush is too dirty, which will also degrade the surface quality of the glass bottle.


The bubbles produced during the forming of the glass bottle are often several large bubbles or several small bubbles concentrated together, which is different from the evenly distributed small bubbles of the glass itself.

If the glass bottle is improperly handled during the production process, these phenomena will easily occur, which will seriously affect the performance and service life. If you want to know more about glass bottles after reading the above, please contact DAS Packing for professional advice.

We are a leading glass container and packaging manufacturer, focusing on providing high-quality glass bottles and jars for the personal care and food and beverage industries. We have a professional production team and strict quality inspection system, which can carry out comprehensive quality control on the quality of products. At the same time, we can also turn your creative concept into a real product to achieve personalization and branding. If you want to buy our glass bottles, please contact us immediately!