13 min read
15 Dec

As an energy-saving material, insulating glass has a wide range of uses. It belongs to a class of glass deep-processing products. In recent years, some special products that are only favored by high-end buildings have rapidly become popular in ordinary buildings, air-conditioned passenger cars, trains, display cabinets, refrigerators, and other fields. Coupled with people's increasing awareness of environmental protection, energy saving, and energy-saving policies, As well as the mandatory implementation of environmental protection standards in some developed countries, the insulating glass market is developing rapidly and quality requirements are getting higher and higher. This article briefly introduces the composition and process flow of insulating glass and discusses the development direction of complete sets of insulating glass processing equipment based on understanding what complete sets of equipment are needed for insulating glass processing.

1. The composition and basic manufacturing process of insulating glass

1.1 Composition of insulating glass

The composition of any kind of insulating glass includes the following three parts:

  1. The original piece of glass that makes up the insulating glass. These original glass sheets can be ordinary float glass, or laminated glass, solar control glass, Low-E glass, colored glazed glass, fireproof glass, etc. Different original pieces of glass are used, and their functions and usage locations are also different. According to different needs, 2 layers, 3 layers or even multiple layers of original glass and composite insulating glass can be used;
  2. Space separation layer and gas. This is a key factor in ensuring the performance of insulating glass. Aluminum/steel partition frames are commonly used with pins and bends. There are three commonly used gases in the spacer layer, namely argon, air, and vacuum. To ensure the dryness of the gas and prevent the occurrence of dew points, molecular sieves with extremely strong hygroscopicity are filled in the spacers. The needs of glass buyers are different, and the thickness of the insulating glass spacer layer and the selection of internal gas are also different;
  3. Insulating glass edge sealing system. There are currently two types of insulating glass edge sealing systems recognized in the international market: the traditional cold edge sealing system (trough aluminum type) and the warm edge sealing system (composite strip type). The warm edge sealing system is improved based on the traditional method. , which greatly improves the heat insulation and sound insulation performance of insulating glass, including single-component insulating glass hot melt adhesive, two-component silicone insulating glass sealant, two-component polysulfide insulating glass sealant, butyl sealant, etc., and Double sealing can extend the service life of insulating glass.

1.2 Basic manufacturing process flow of insulating glass

The thickness of the original glass is generally 3~12mm, and it is cut by hand or a fully automatic cutting machine to ensure that the size meets the requirements. Workers should avoid scratches on the glass surface during operation, and choose original pieces without obvious defects such as bubbles, slag inclusions, uneven inner quality, color difference, and peeling. The entire manufacturing process of insulating glass is: washing, closing the sheets, pressing and applying glue; cutting the spacers, cutting the curved frame or pins, filling the glass with molecular sieve, and applying butyl extruder sealant.

(1) Glass washing and drying

This process must be washed by machine, manual washing cannot guarantee the cleaning quality. 5MΩ deionized water is used to ensure the bondability of the sealant and glass, and the water can also be filtered for recycling. Use light to check whether there are residual water drops, water stains, etc. on the glass surface. If there are any, you can adjust the machine's operating speed, brush gap, air volume, and heating temperature before checking. After cleaning, the insulating glass assembly should be completed within 1 hour.

(2) Assembly of strip type insulating glass and aluminum strip type insulating glass

First, stick and cut the tape. Assembling strip-type insulating glass requires that the processing temperature of the laminating room should be in the range of 10 to 20°C in winter and 20 to 30°C in summer. When filling molecular sieves, the desiccant of strip-type insulating glass is in powder form and must be mixed with the glue. It works slowly after uniformity, so relatively low humidity should be ensured in the assembly area of the strip. The required processing temperature for assembling aluminum strip insulating glass is in the range of 10 to 30°C, and the relative humidity is normal. However, a qualified desiccant should be selected and used within 24 hours after opening. To strengthen the sealing, double-layer glue is often used for sealing, with butyl rubber as the first seal and polysulfide glue as the second seal.

(3) Glass lamination

When pressing strip-type insulating glass, pay attention to aligning the edges of the sheets. When pressing, leave a small opening at the back to allow the dried gas to escape from the small opening. You can also fill it with inert gas and then seal it.

(4) Manual or automatic sealant application

For aluminum strip-type insulating glass, there should be a distance of 5 to 10 mm from the outer edge of the aluminum frame to the edge of the glass after the sheets are combined, which is used to apply the second sealant. The polysulfide glue should be applied evenly along one side to prevent air bubbles from being included in the middle. After application, the residue on the glass surface should be scraped off. At this point, the processing of aluminum strip insulating glass is completed.

(5) Placement of insulating glass

Whether the insulating glass is placed correctly or not will also have an impact on the final quality of the insulating glass. Whether it is in production, transportation, or construction site storage, the design requirements of the stacking rack must take into account the characteristics of the insulating glass, and the stacking rack must have a certain inclination. degree, but the bottom plane and the side should always maintain a 90° angle to ensure that the two bottom edges of the insulating glass can be placed vertically on the stacking rack. In addition, ensure that the bottom of the glass is not stained with substances such as lime oil stains, so as not to corrode the second sealant and affect the sealing performance of the insulating glass.

As insulating glass continues to be promoted and applied, the requirements of glass buyers and end users are getting higher and higher. Therefore, we should continuously improve the insulating glass processing technology, vigorously improve the technical level and product quality, and strive to promote the development of insulating glass in the direction of automated and intelligent glass deep processing.

2. Complete sets of insulating glass processing equipment

As mentioned before, the main raw materials for insulating glass production mainly include glass, aluminum spacers, angle bolts, butyl rubber, polysulfide rubber, desiccant, etc. The main complete sets of processing equipment required for the production of corresponding insulating glass include: Aluminum-type insulating glass equipment is equipped with a butyl glue machine, simple auxiliary equipment, cleaning and drying machines, etc.; large-scale processing plants should be equipped with glass chamfering machines, cleaning and drying machine, butyl glue coating machine, two-component glue machine, auxiliary equipment, insulating glass automatic laminating and plate pressing production line. The composite strip-type insulating glass equipment is equipped with a strip assembly table, a heating roller press, a lightweight installer, a washing and drying machine, a strip assembly table, a glass joining table, a heating roller press, a lightweight installer, etc.; large-scale configuration There are glass chamfering machines, wash ing and drying machines, strip assembly tables, glass laminating tables, heating roller presses, glass conveying tables, and lightweight installers. Based on the main testing indicators of insulating glass, the research and development direction of complete sets of insulating glass processing equipment is discussed.

2.1 Main testing indicators of insulating glass

(1) Initial dew point: Test whether the air inside the insulating glass is dry. International industry standards stipulate that the dew point is ≤-40℃.

(2) Ultraviolet irradiation: Test whether the insulating glass sealant contains organic volatiles that affect vision. After the insulating glass sample is continuously irradiated with a 300W ultraviolet lamp for 168 hours and stored at a temperature of 23±2°C for one week, there should be no fog, oil, or other contaminants on the inner surface of the insulating glass.

(3) Sealing inspection: Test the hardness and softness of the insulating glass sealant and whether there is leakage. The sample is maintained at a pressure 10±0.5 kPa lower than the ambient pressure for 2.5 h, and the thickness growth deviation should be <15%.

(4) High temperature and high humidity test: It mainly tests the adhesive force of the sealant, the water vapor permeability, and the effective adsorption capacity of the molecular sieve. The samples were subjected to 224 cycles under high temperature and high humidity test conditions (humidity >95%, temperature changing regularly between 25 and 55°C). The gas in the insulating glass undergoes expansion and contraction in each cycle, which places higher requirements on the adhesive strength of the sealant. In addition, due to the high humidity, the water vapor transmission rate of the sealant should be low, and the molecular sieve should have strong adsorption capacity.

(5) Climate cycle test: Testing the anti-aging ability of insulating glass is an examination of the comprehensive performance of insulating glass. It simulates the climate of the four seasons of the year (cold, hot, wind, rain). Each cycle goes through 3 stages of heating, natural cooling, and forced cooling, with a total of 320 cycles. A common problem during the inspection is the explosion of the insulating glass. , glue opening, and final dew point increase. As a deep-processed glass product, insulating glass is relatively expensive. Once it is damaged after installation and use, replacement is difficult and expensive. Therefore, the raw materials of insulating glass must be carefully selected, and the production process must be strictly carried out by operating procedures. Only in this way can the overall production quality level of insulating glass be further improved.

2.2 Development direction of complete sets of insulating glass processing equipment

The good performance of insulated glass is gradually recognized by glass buyers, and its popularity is getting higher and higher. Insulated glass deep processing equipment should develop in the direction of high automation, stable product quality, good energy saving, heat insulation effect, and long service life.

(1) Online film removal machine

Given the large number of coated glasses such as Low-E glass and solar glass control film currently used in the insulating glass market, the glass film layer must be removed at the butyl extruder coating point, otherwise the service life will be affected, so the surface film must be removed mechanically. The recommended parameters for the film removal wheel of the Low-E glass film removal automatic machine are air pressure 0.8~1.2 MPa, rotation speed 900 r/min; and the grinding wheel is made of emery or stainless steel wire below 0.15mu (100 mesh). No traces remain on the surface after film removal. The development direction is to set the grinding wheel pressure according to different film systems.

Figure 1 The Low-E glass online film removal machine

Figure 1 The Low-E glass online film removal machine

(2) Online chamfering machine

At present, many insulating glass are embedded inside the window frame, and the glass edge grinding requirements are not high. However, in order to prevent edge cracks and residual stress, it is necessary to grind and remove the corners on both sides. The online chamfering machine is characterized by its high speed and efficiency. Quickly be applied to the hollow wire group line. The chamfering speed should be strictly controlled, usually using variable frequency speed regulation. The speed of the high-speed chamfering machine can reach more than 10,000 r/min, and the chamfering size is 0-6 mm, which is adjustable. Currently, there are two main types of grinding wheels and abrasive belts, each with its own advantages. The key is how to extend the service life of the grinding wheel and realize adjustable chamfering angle and online special-shaped chamfering at high speeds.

(3) Vertical washing and drying machine

It is required that Low-E Glass, thin-film photovoltaic glass, and ordinary float glass can be cleaned. It is an efficient glass washing and drying equipment that integrates glass washing and drying. It can be used for washing and drying before insulating glass manufacturing to ensure that the insulated glass wash surface. During research and development, attention should be paid to the material, diameter, pure water conductivity, parallelism, and material of the roller brush, and it should be equipped with electric heating and hot air devices. During treatment, 5 MQ or more deionized water must be used, heated to 30°C for use, and issues such as the speed of the roller brush, air duct pressure, angle, outlet return water, etc. must be controlled in detail.

Figure 2 The vertical glass washing and drying machine

Figure 2 The vertical glass washing and drying machine

(4) Automatic bending frame loading, online butyl extruder coating, molecular sieve filling

The automatic strips frame loading equipment involved in this process should meet the needs of both aluminum frames and stainless steel frames. Online two-component sealant application is mainstream, and attention should be paid to glue material, pressure, electric heating, etc.

Figure 3 The automatic bending strips frame loading equipment

Figure 3 The automatic bending strips frame loading equipment

(5) Pressing equipment

There are two methods of internal and external pressing. The external pressing is more flexible, and the flatness and pressure of the pressing are the key. The plate pressure equipment should have the function of vacuuming or adding inert gas online or offline.

Figure 4 The plate pressure function of insulating glass production line

Figure 4 The plate pressure function of insulating glass production line

(6) Online Low-E glass sealing machine

Generally divided into two types: single-component and two-component gluing machines, which mainly use polysulfide glue, the pressure is generally 0.5~0.8MPa, and the gluing depth is 5~10 mm. The two-component sealant sealing applicator generally adopts digital simulation PLC control, and uses manual on-site input of numbers according to different insulating glass. The key to research and development is the stability of glue pressure, corner control of glue pressure and glue amount, improvement of glue application speed, automatic recognition of width and depth, automatic glue application and identification of unequal sides and special-shaped hollows.

Figure 5 The automatic insulating glass online sealing robot machine

Figure 5 The automatic insulating glass online sealing robot machine

(7) Front and rear hanger suction cups

Used for glass edge grinding machines, glass adsorption, and transportation tools. There are single-claw suction cups, double-claw suction cups, three-claw suction cups, etc. The suction capacities of the front and rear hanger suction cups loading lifter equipment are 500 kg and 1000 kg respectively, which can reduce the operator's handling labor intensity and reduce the number of workers.

Figure 6 The front and rear hanger suction cups loading lifter equipment

Figure 6 The front and rear hanger suction cups loading lifter equipment 

(8) Fully automatic control

It should focus on the research and development of the combination of centralized signal control of the whole line and on-site control: automatic recognition of film system and detection of glass position; automatic detection of insulated thickness and aluminum strip width; automatic adjustment of sheet closing pressure according to insulated size; automatic sealing, automatic identification of sealing depth and width, automatic adjustment of glue pressure and flow, program optimization of online frames and automatic adjustment of lamination pressure.

Figure 7 The combination of centralized signal control of the insulating glass production line

 Figure 7 The combination of centralized signal control of the insulating glass production line 

3. The conclusion

Insulating glass is currently the most widely used deep-processed glass in the construction market. Its manufacturing equipment, the insulating glass production line, is gradually being promoted, but most of them are semi-automatic production lines with low stability, efficiency, and quality. Therefore, a truly fully automatic line can not only save a lot of labor, increase production capacity, and improve product quality, but can also upgrade equipment online (such as adding functions such as insulating glass gas filling, vacuuming glass, etc.), which is a great addition to the fully automatic insulating glass production line. R&D and manufacturing are of great significance.

For more information about LIJIANG Glass insulated glass production line and insulated glass producing machine, please click here to learn more. 

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