History and Manufacturing of Glass

The word glass comes from the Teutonic term “Glaza”, which means amber. Although the origin of glass production line is still uncertain, the Mesopotamians from the 5th century BC discovered an ash by chance when they fire to melt clay vessel to use for glazing ceramics or when copper was smelted. In Egypt, greenish glass beads were excavated in some of the Pharaohs’’ burial chambers dating from the early 4th century BC, and this has been referred to as intentional glass manufacture. From the second century BC, the production of rings and small figures by using core-wound techniques began to appear. The oldest blueprint for glass was made on clay tablets in 669-627 BC, which read: “Take 60 parts sand, 180 parts ash from marine plants, and 5 parts chalk”. This blueprint is now held in the great library of the Assyrian king, Ashurbanipal, in Nineveh. [1]

The invention of the Syrian blowing iron around 200 BC by Syrian craftsmen enabled the production of thin-walled hollow vessels in a wide variety of shapes. Excavations have revealed that in the Roman era glass was used for the first time as part of the building envelope of public baths in Herculaneum and Pompeii. These panes could have been installed in a bronze or wood surround or without a frame. In the middle ages, this technique spread to the northern Alpine regions, and utensils like drinking horns, claw beakers, and mastos vessels started to be produced; in addition, the use of glass increased in the building of churches and monasteries. [2]

Blown cylinder sheet glass and crown glass were invented in the 1st century AD and the 4th century AD respectively. In both, a blob of molten glass was drawn off with a blowing iron, performed into a round shape, and then blown into a balloon. Blown cylinder sheet glass and crown glass remained two of the most important production techniques for producing glass furnace until the early 20th century. From the 17th century, the glass melt left the crucible in portions and passed through two cooled roller to form a glass ribbon. In this way, a glass pane with the dimensions of 3 x 6m could be produced. In the 1950s, the Englishman Alastair Pilkington developed the hot end glass equipment, wherein viscous glass melt was passed over a bath of molten tin floating on the surface. Tin was used because of the high temperature range of its liquid physical state (232 to 2270°C) and having a much higher density then glass.

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Another process for the production of flat glass is the cast process. In this process, cold end glass equipment is poured continuously between metal rollers to produce glass with the required thickness. The rollers can be engraved to give the required surface design or texture and produce patterned glass. The glass can be given two smooth surfaces, one smooth and one textured, or two textured sides, depending on the design. In addition, a steel wired mesh can be sandwiched between two separate ribbons of glass to produce wired glass. Wired glass can keep most of glass pieces together after breakage, and it is therefore usually used as fire protection glass.