Tempered glass, or heat strengthened glass, is glass that has been heat-treated to make it stronger, more resistant to heat and break in a way to prevent injury. The first patent on a whole process to make tempered glass was held by chemist Rudolph A. Seiden who was born in 1900 in Austria and immigrated to the United States in 1935
Today, tempered glass is made all over the world including at our OEM & Distribution facility in Neenah. How does annealed glass become tempered glass? We’ll take you through the steps.
Step 1: Pick The Glass. We have sheets and sheets of glass that are 8 feet by 11 feet. We can store more than 1,000 sheets of glass in our warehouse at time. The thickness ranges from 5/32 to 1/2 inch. We have everything from clear glass to frosted glass to clear mirror.
Step 2: Cut the Glass into the Desired Shape. The sheet of glass gets move by a machine and placed on the CNC Cutting Machine. The CNC machine is programmed to cut the desired shape. Afterwards, the employee breaks the excess glass manually.
This has to be done before the glass is tempered, as the tempering process will weaken the glass if it is cut or etched afterward and may increase the likelihood of breakage.
Step 3: Seaming Machine, Glass Edger, CNC Mill or Water jet. Depending on the type of order, the sheet of glass can go several different ways either to the seaming machine, glass edger, CNC mill or water jet.
The seaming machine is used to take the sharp edge off of the glass. The glass edger creates a ground or high polish on the edge of the glass. The CNC Mill is used to make or edge custom and DOT patterns. It can cut, seam, or even high polish shapes and holes. Like drilling, milling uses a rotating cylindrical cutting tool. Abrasive water jet cutting technology is a great method for cutting glass because it allows for contours and shapes that cannot be achieved or achieved easily with other cutting machines at a reasonable cost.
Step 4: High Speed Washer. This removes any tiny grains of glass deposited during the other processes, as well as any dirt that may interfere with the tempering process.
Step 5: Heat the glass in the tempering oven. The oven reaches temperatures of over 600 degrees Celsius (1,112 degrees Fahrenheit), with the industry standard being 620 degrees Celsius (1,148 degrees Fahrenheit). The temperatures changes depending on the thickness of the glass, color of the glass or even the temperature outside. The tempering process takes about 2-25 minutes.
Step 6: Quench the glass to cool it. The heated glass is subjected to seconds or minutes of high-pressure blasts of air at various angles. The rapid cooling causes the outer surfaces of the glass to cool and contract faster than the center, giving the tempered glass its strength.
Step 7: Label, Package & Delivery. The glass is off to the customer.
Stay tuned to our Facebook page as we post videos of the processes.