About the annealing of glassware after molding

As we all know, the main raw material for glassware production is quartz sand, which is one of the second largest storage resources on the planet besides water. There is an extremely complex process for glassware from quartz sand to molding to various forms of glassware. There are many small defects in the production process, and some products sometimes explode without reason. These phenomena are mainly related to the annealing after molding of glassware, So how important is the annealing step? Next, we will popularize some knowledge about annealing of glassware after molding.

[Benefits of annealing purposes]

After molding, glassware must undergo thermal processing, which is mainly due to the thermal stress generated by the temperature difference during the production process of blown glassware. If it is not annealed and allowed to naturally cool in the air, cracks will eventually occur. In order to eliminate the thermal stress of the product, it is necessary to anneal the glass, which is simply controlled within a certain range of temperature for thermal treatment, Prevent the cracking phenomenon of later products during use due to excessive permanent stress or uneven stress distribution. Appropriate annealing temperature can improve the strength and physical and chemical properties of glass.

Annealing time

All glass factories have their own annealing furnace. In fact, different molding methods produce different glassware, and the annealing principle is the same. Although there are some differences in annealing equipment, this is mainly due to the different types of glassware produced. Conventional manually blown glassware generally has a relatively thin wall thickness, and the annealing time can be shorter. Therefore, conveyor belt type annealing furnaces can be used for batch production, The annealing time is generally 4-6 hours, but for a small amount of products, it is more economical and cost-effective to use a batch annealing furnace.

For large products with complex shapes manufactured by hot melting, the annealing time needs to be longer, some of which can even reach more than a week. Even so, cracks often occur due to poor returns. Because intermittent annealing furnaces are small equipment, also known as annealing furnaces, intermittent annealing cannot ensure the continuous stability of the annealing temperature, so they are also prone to cracking.