6.1 Ancient Drilling Machines – The “bow†drilling technique has a long history. Archaeologists have now discovered that in 4000 BC, humans invented devices for punching. The ancients placed a beam on the two columns, and then suspended a rotatable awl from the beam, and then used the bowstring to drive the awl to rotate, so that the wood stone could be punched. Soon, people also designed a perforating tool called "辘轳", which also uses a flexible bowstring to make the awl rotate.
6.2 The first drilling machine (Whitworth, 1862) By around 1850, the German Martignoni was the first to make a twist drill for metal punching; at the International Fair in London, England, 1862, UK Whitworth exhibited a drill press with a power-driven cast iron frame, which became the prototype of a modern drilling machine.
In the future, various drilling machines appeared one after another, including a radial drilling machine, a drilling machine equipped with an automatic feeding mechanism, and a multi-axis drilling machine capable of simultaneously punching a plurality of holes at the same time. Thanks to improvements in tool materials and drill bits, and the use of electric motors, large, high-performance drill presses were finally built.
Tempered or toughened glass is a type of safety glass processed by controlled thermal or chemical treatments to increase its strength compared with normal glass. Tempering puts the outer surfaces into compression and the interior into tension. Such stresses cause the glass, when broken, to crumble into small granular chunks instead of splintering into jagged shards as plate glass (a.k.a. annealed glass) does. The granular chunks are less likely to cause injury. Toughened glass is a kind of safety glass.
Toughened glass can be made on customer's request, clear toughened glass, ultra clear toughened glass, colored tinted toughened glass, printed toughened glass, back painted toughened glass, frosted toughened glass, toughened Laminated Glass, toughened Insulated Glass, toughened Vacuum Insulated Glass and so on.
Toughened glass can be used for furniture, buildings, doors, windows, walls, table tops, fence, partitions, railings, balcony, balustrade, shower room and so on.
toughened glass, clear toughened glass, color tinted toughened glass, ultra clear toughened glass, back painted toughened glass, silk printed toughened glass
Shanghai Lead Glass Co.,Ltd , https://www.leadglazing.com