Cracks are the most common defect of glass bottles. It can be very fine, some of which can only be found in reflected light. The bottle mouth, bottle neck and shoulder are often found, and cracks are often found on the bottle body and bottom.
Ⅱ Uneven Thickness
This refers to the uneven distribution of glass on the bottle. The main reason is that the temperature of glass droplet is uneven, the part with high temperature has small viscosity and is easy to blow thin; the part with low temperature has large resistance and thick. The temperature of the model is not uniform. The high temperature side of the glass cooling slow, easy to blow thin, the low temperature side, because of the glass cooling fast and thick.
When the temperature of droplet and action temperature are too high, the bottle released from the forming die has not yet been fully shaped, and it often collapses and deforms. Sometimes the bottom of the bottle is still soft, which will be printed on the conveyor belt lines and make the bottom of the bottle uneven.
If the temperature of droplet is too low or the model is too cold, the mouth and shoulder will not be fully blown, resulting in defects such as notch, shrunken shoulder and unclear pattern.
The uneven patches on the glass surface are called cold spots. The main reason for this defect is the supercooling of model temperature, which often occurs when the production is started or stopped for reproduction.
The defect of protruding suture or protruding mouth edge. This is due to the incorrect manufacturing or installation of model parts. If the model is damaged, there is dirt on the joint surface, and the top core is lifted too late, the glass frit has fallen into the parison mould before entering the position, and a part of glass will be extruded or blown out from the gap.
There are various shapes of wrinkles, some are creases, some are thin wrinkles. The main reason of wrinkle is that the droplets are too cold and too long, and the droplets do not fall in the middle of the parison mould and adhere to the cavity wall.
Ⅷ Superficial defects
The surface of the bottle is hairy and uneven, which is mainly caused by the unsmooth surface of the mold cavity. If the lubricating oil of the model is not clean or the oiled brush is too dirty, the surface quality of the bottles and cans will also be reduced.
The bubbles produced in the forming process are usually several large bubbles or a number of small bubbles concentrated together, which is different from the small bubbles uniformly distributed in the glass itself.
Ⅹ Scissors marks
Obvious traces left on the bottle due to poor shearing. A droplet often has two scissor prints, the upper scissors print remains at the bottom, affecting the appearance. The scissor print on the bottom of the bottle is often the source of the crack.
Post time: Nov-17-2020