In the process of processing toughened glass, various parameters are unreasonable, which may cause toughened glass bending and other appearance quality. In this paper, some common bending reasons and how to solve the quality problems of toughened glass are summarized.
1. Upwarping: reason: when the glass comes out of the furnace, the upper surface temperature of the glass is higher than the lower surface temperature, the upper surface temperature of the glass is too high, the lower surface temperature is low, and the upper wind pressure is lower than the lower wind pressure.
The solution is to increase the bottom temperature of the furnace and reduce the upper temperature properly. If the furnace temperature is stable, the air gate pressure can be adjusted, and the upper pressure is greater than the lower pressure when the height of the nozzle is constant.

The so-called glass white road refers to a white trace in the longitudinal middle of the lower surface of the glass in the process of production.
This phenomenon is very easy to appear at the beginning of production, which is normal. Generally speaking, with the progress of production, Baidao will gradually reduce until it completely disappears.
So how to reduce and eliminate the occurrence of white road phenomenon?

As a preventive maintenance measure, roller cleaning is the most ideal.
Periodic cleaning depends on the quality requirements of the glass, the thickness of the glass and the amount of SO2.
Usually 4 to 8 weeks or 6 months.

Please note: this document comes from the internationally renowned roller manufacturing company Vesuvius. Due to the progress of technology and the improvement of process level, the SO2 device mentioned in the document may not have been configured in the production of glass toughened equipment in recent years!
The maintenance of all tempering furnaces includes the replacement of heating elements, insulators, old insulation layers, thermocouples, and component protective covers.
Furnace lining is very important, especially for furnaces with refractory fiber lining, because dust from the fiber lining deposits on the surface of the roller, causing imprints on the lower surface of the glass.

In recent years, there have been incidents of self-explosion of toughened glass at home and abroad. When the glass fragments after self-explosion are scattered, it has caused harm to the people walking on the street.
Through statistics, it is found that the self-explosion of toughened glass is mainly caused by nickel sulfide stones existing in the original glass sheet. By homogenizing the toughened glass, the local stress concentration caused by the stone is reduced.
It can effectively reduce the harm of self-explosion of toughened glass.
For homogenization treatment, a homogenizing furnace with convective heating should be selected, and each piece of glass should be uniformly heated through air circulation. Even if the glass is damaged, the air flow in the furnace should be parallel to the surface of the glass, and the air flow in the furnace should be parallel to the surface of the glass.
The air inlet and outlet should be designed to ensure that glass fragments do not clog it.
It is best to place the glass vertically, not completely fixed, should ensure that the glass can expand freely.
At the same time, the glass should be separated in a way that does not affect the air flow, the spacer can not hinder the air flow, the glass spacing is recommended as 20mm.

The rupture of glass in the toughened furnace, commonly known as the furnace, is an abnormal situation in the production of toughened glass.
Because the glass is broken in the tempering furnace, it usually needs to cool and wash the furnace to clean up, which usually means thousands or even tens of thousands of electricity losses for deep processing enterprises.
At the same time, because the tempering furnace cooling, cleaning and washing, re-heating recovery of production generally takes at least 24 hours, so the toughened blast furnace will often affect the implementation of production plans and order delivery.

Flat glass is generally divided into toughened glass, semi-toughened glass and annealed glass according to the difference of surface compressive stress.
According to the American ASTMC1048-1997b standard, the surface compressive stress range of all kinds of glass is toughened glass > 69MPa (10000psi), and the semi-toughened glass is 24MPa (3500psi) ~ 52MPa (7500psi).
The national standard of toughened glass and semi-toughened glass for curtain wall issued in China also has clear requirements for stress. The semi-toughened glass is 24 to 60 MPA and the toughened glass is more than 90MPa.

PLC is formed with the continuous development of electrical control technology, combined with electronic technology, computer technology, communication technology and automatic control technology.
It is widely used in all kinds of automation equipment and industrial production process control.
Compared with conventional electrical control, it has obvious advantages, save a lot of relays, reduce a large number of wiring, high reliability of system operation, communication ability, easy to network to achieve intelligent control of the system.
However, the use of PLC, like most electronic products, requires the conditions to ensure normal operation. The main environmental factors affecting the work of PLC are temperature, humidity, noise and dust, as well as corrosive acids and bases.
Therefore, the maintenance of PLC should pay attention to the following problems:

In general, there are 8 kinds of reasons for motor heating: (1) the air gap between motor stator and rotor is very small, which leads to the collision between stator and rotor, (2) the abnormal vibration or noise of motor causes the heating of motor.
3. Abnormal operation of the bearing, resulting in motor heating; 4. High power supply voltage, increased excitation current, excessive heating of the electrical opportunity; 5. The power supply voltage is on the high side, the excitation current is increased, and the electrical opportunity is overheated. 5.
Winding short circuit, turn-to-turn short circuit, interphase short circuit and winding open circuit; 6, material leakage into the interior of the motor, so that the insulation of the motor is reduced, so that the allowable temperature rise of the motor is reduced; 7, caused by the lack of phase operation of the motor;
8. Other causes of non-mechanical and electrical faults.

In the process of toughened glass, if the furnace door is not opened in time, the heating time is too long, the transmission stops and other equipment failures, the glass may stick to the ceramic roller. The correct treatment of this phenomenon is as follows: 1. Equipment shutdown,
Cut off the heating power supply, open the heat dissipation valve, raise the front and rear furnace doors, and lower the temperature.

When the glass first enters the tempering furnace, due to the contact with the roller table, the expansion speed of the lower surface of the glass is greater than that of the upper surface, and the glass will bend upward. The glass plate is suspended around and only the middle part of the roller table is in contact with the roller table.
As a result, the glass in the contact roller part heats up faster than the suspended part (the cause of heat conduction), and the surrounding suspended part will not continue to absorb heat until the glass plate is completely softened.
At this time, the heat in the middle part of the glass plate is much larger than that in the edge of the glass, which results in the serious deformation of the middle part of the glass plate because of the high temperature, thus forming the light distortion.
At this time, the rotating speed of the upper convective fan should be properly opened or the temperature of the upper and lower furnace should be adjusted so that the glass can be quickly flattened in the reheating furnace to correct this problem.

The production line of double-chamber tempering furnace is mainly composed of upper stage, preheating furnace, heating furnace, tempering section, slow cooling section, lower stage and control system.
The low temperature range is generally between 450 and 500 degrees, and the high temperature range is about 700 degrees.
The furnace can be used to process toughened low radiation coated glass (i.e. toughened off-line LOW-E glass) and high grade ordinary glass.
The radiation heat transfer efficiency of glass is relatively low in the low temperature section, and the LOW-E glass has a strong reflection on the radiation heat, that is to say, the radiation heating efficiency in the low temperature section is lower, and the forced convective heat transfer is used to solve this problem.
It can greatly improve the heat transfer efficiency and shorten the heating time effectively.
In the high temperature section, because of the high furnace temperature, the effect of radiative heat transfer is obvious, but the reflection of LOW-E glass to radiative heat can not be ignored. At the same time, in order to further improve the high temperature heating of ordinary glass, it is more uniform and effective.
Therefore, the heating system in the high temperature section still adopts convective heating, so that the configuration of the equipment is most strengthened and the product quality is significantly improved.

The control system of the tempering furnace can automatically set the heating temperature, convective intensity and toughened wind pressure, and automatically match the shape of the glass in the heating to open the effective heating area, so that the heating of the glass is more accurate and the energy consumption is more saved.
Secondly, combined with the previous processing experience, the experience of the existing operators will be transformed into production data and retained to the greatest extent, and the parameters will be analyzed automatically in the process of glass processing.
And distribute the relevant data in order to achieve the optimal combination, and real-time monitor the relevant data to make automatic adjustment to improve production efficiency.

When the fuse is electrified, the temperature of the melt will rise because of the heat converted by the current. When the normal working current or the allowable overload current is loaded, the heat generated by the current and the heat emitted through the melt shell and the surrounding environment can be balanced step by step.
If the heat dissipation rate fails to keep up with the heating rate, this heat will gradually accumulate on the melt, causing the melt temperature to rise, and once the temperature reaches and exceeds the melting point of the melt material, it will liquefy or vaporize it, thereby disconnecting the current.
It plays a role in the safety protection of the furnace circuit and the person.

The principle of glass cooling is that the glass heated to a certain temperature enters the grate from the tempering furnace, and the cooling air ejected from the grate nozzle is in close contact with the glass surface, and the heat on the glass surface is transmitted into the cooling air.
So that the glass temperature decreases and the cooling air temperature increases, and then the cooling air that increases the temperature diffuses to the periphery along the glass surface, and spreads out through the gap between the small bellows of the grate of the tempering furnace and the space around the grille.
Take away the heat from the glass to reduce the temperature of the glass;
The air grid nozzle continuously ejects cooling air to the glass surface, and the glass temperature continues to drop until the set time.

(1) the glass surface can be kept clean when the tempering furnace is cooled, (2) the toughened cooling rate of the glass can be easily and accurately controlled by changing the toughened air pressure, (3) the toughened cooling effect of all parts of the glass is the same.
(4) the tempering fan of the tempering furnace is a simple and reliable equipment.

Embossed glass, mainly used for residential interior decoration, partition, bathroom, doors and windows of the ground floor house, etc., with the characteristics of transparent and impermeable.
The surface of embossed glass is uneven, the general embossed glass is one-sided embossing, when toughened, the embossing surface (concave and convex surface) is facing up, the smooth surface is placed downward, and then heated into the furnace to avoid damage to the quartz roller surface.
Due to the decrease of the reflection of heat and the increase of absorption of the uneven embossing surface, the temperature of the glass rises faster, and the heating time is about 5% less than that of the ordinary white glass.
At the same time, due to the non-uniformity of the thickness of embossed glass (the thickness difference can reach 0.8mm), the quenching pressure will be reduced.
For example, when toughened 5mm thickness embossed glass, quenching pressure is lower than ordinary flat glass 10~20mmHg.

Frosted glass (frosted glass) is a kind of uniform woolen glass formed by mechanical sandblasting or hydrofluoric acid solution.
Sand masking technology can also be combined with screen printing technology to produce a variety of patterns and patterns on the glass surface for decoration, resulting in hazy, noble and elegant decorative effects.