Question 1

What special requirements apply to the tempering process for side window glass with plastic encapsulation edges?

Accepted Answer

Tempering must be completed prior to edge encapsulation (typically plastic injection molding). Plastics cannot withstand the ultra-high temperatures inside tempering furnaces. After tempering, the cleanliness, surface temperature and primer coating treatment of glass edges are critical factors that directly affect the adhesion and sealing performance of subsequent injection-molded encapsulation.

Question 2

Why are side windows generally made of tempered glass while windshields use laminated glass?

Accepted Answer

This is determined by both safety regulations and functional requirements. Windshields must stop occupants’ heads from being thrown out in collisions and retain partial visibility after breaking, hence laminated glass is used. Side and rear windshields need to be breakable to create escape access for rescue operations while avoiding flying sharp fragments, so tempered glass is the mainstream choice. Nevertheless, some high-end vehicles equip side windows with laminated or tempered-laminated glass to boost safety (penetration resistance, anti-theft performance) and sound insulation.

Question 3

Why is tempered glass adopted for automotive sunroof and panoramic roof glass?

Accepted Answer

A sunroof is a movable component. When tempered glass breaks, it crumbles into granular pieces free of sharp angles, which effectively prevents vehicle occupants from being cut or struck by large glass shards.

Question 4

I plan to fabricate tempered insulated glass with Low-E glass. Should I choose on-line Low-E or off-line Low-E glass? What is the correct processing sequence?

Accepted Answer

On-line Low-E glass: Its coating film is hard, allowing storage, cutting and tempering just like ordinary glass with flexible processing workflows. However, it offers average energy efficiency (especially solar heat gain coefficient) and limited color options. Off-line Low-E glass: It delivers superior energy-saving performance and diverse aesthetic colors, yet its coating film is soft. It must be tempered after cutting and edge grinding. In addition, the tempered off-line Low-E glass needs to be assembled into insulated glass units promptly after tempering to prevent coating oxidation.

Processing sequence for off-line Low-E glass: Raw glass cutting → edge grinding → cleaning → coating → tempering → IGU assembly. Southtech tempering furnaces can efficiently temper Low-E glass with an emissivity (e) of no more than 0.01.

Question 5

Can tempered glass be used as base lites for insulated glass units (IGUs)? What are its advantages?

Accepted Answer

Absolutely, and it is the preferred base glass for IGUs. Its benefits are as follows:

Higher safety: If one side of the insulated glass breaks, the tempered layer provides reliable safety protection.
Enhanced structural strength: It improves the overall wind load resistance and anti-deformation performance of the insulated glass.
Improved durability: The high mechanical strength of tempered glass reduces breakage risks caused by uneven stress during transportation, installation and service.
Better airtightness for gas-filled IGUs: Tempered glass has minimal deformation, which helps maintain the tightness of the insulated cavity and prolong the retention rate of inert gases such as argon.

Question 6

What benefits does glass gain after tempering?

Accepted Answer

Tempered glass features high strength, 3 to 5 times that of standard glass, enabling excellent resistance to impact and deformation. It delivers superior safety, breaking into tiny fragments without sharp edges upon damage, and boasts outstanding thermal stability. It serves as the core raw material for manufacturing safety architectural glass and heat-resistant home appliance glass.

Question 7

If brand logos or patterns need to be printed on the glass surface, should printing be done before or after tempering?

Accepted Answer

Printing must be completed prior to tempering. Ceramic ink for glass requires sintering at high temperatures (usually over 600°C) inside the tempering furnace to achieve permanent curing, resulting in a hard, wear-resistant and corrosion-resistant finish. Therefore, the printing procedure must be finished before glass tempering, and the tempering process doubles as the ink sintering process.

Question 8

Are tempered glass viewing windows heavier than ordinary glass?

Accepted Answer

No. Glass tempering is a physical strengthening process that does not alter the glass’s density or thickness, so there is nearly no difference in weight. The superior strength of tempered glass over regular glass stems from pre-stress formed inside the glass, rather than added material.

Question 9

Why is tempering treatment required for home appliance glass?

Accepted Answer

Tempering home appliance glass can greatly boost the safety and durability of household appliances. Tempered glass boasts drastically improved strength to withstand impacts during cooking, drastic temperature fluctuations and daily bumps. Even if tempered glass breaks accidentally, it shatters into safe granular fragments without sharp edges, effectively preventing lacerations. Meanwhile, the outstanding thermal stability and resistance to low-temperature impact deformation of tempered glass are essential guarantees for the safe operation of home appliances such as ovens, cooktops, stoves, refrigerators and freezers.