9 min read
A brief discussion of the production details and improvement suggestions for architectural insulating glass.

1. The preface

Insulating glass refers to a product in which two or more pieces of glass are evenly spaced bonded and sealed with effective support so that a dry gas space is formed between the glass layers. Insulated glass has many properties superior to ordinary double-glazed glass. It has the functions of sound insulation, heat insulation, anti-condensation, and energy consumption reduction. It is widely used in construction, transportation, and other fields. In recent years, triple-glass and two-chamber insulating glass, laminated glass composite insulating glass, and vacuum composite insulating glass products with better energy-saving performance have appeared on the market. However, insulating glass has always been unqualified, with unqualified dew point, ultraviolet radiation resistance, and water vapor sealing durability all appearing, and the reasons involved include all aspects of production. This article adopts the concept of analyze the production and production of insulating glass from aspects such as "man, machine, materials, methods, environment" and efficiency enhancement, and make relevant suggestions.

2. The personnel capabilities

The impact of personnel capabilities on quality exists in all aspects of insulating glass production. Management, purchasing, production, and quality inspection personnel all have an important impact on product quality. Training and assessment should be conducted for personnel in different positions. Procurement personnel should assess raw material suppliers promptly, collect the supplier's qualifications, inspection reports, certificates of conformity, and other relevant materials, and evaluate the suppliers based on raw material inspection conditions, quality stability, and timely supply. Production personnel should understand the relevant knowledge of the process and make effective process inspections for the transfer of the previous process. Production management personnel should master the processes and methods of key processes to conduct assessments and supplementary training for operating workers. Inspection personnel should inspect raw materials according to relevant standards, master the routine inspection methods before leaving the factory, and conduct dew point inspection on insulating glass before leaving the factory according to the frequency of national standards. Managers should arrange each link according to the actual production situation to avoid unnecessary errors in the production process. At the same time, they should pay attention to whether the procurement, production, and inspection links are working according to the process regulations.

3. The inspection and maintenance of equipment

Insulating glass production equipment includes spacer bending machines, desiccant filling machines, butyl extruder coating machines, external sealant sealing robot machines, etc. Equipment should be inspected, maintained, and maintained by regulations, and should be adjusted and repaired promptly according to problems in production.

3.1 Desiccant filling equipment.

Pay attention to whether the filling outlet is blocked, and control the amount of filling desiccant by adjusting the time and flow rate.

3.2 Butyl extruder dispensing machine.

Pay attention to whether the temperature control meter indicates an accurate value and whether the sealant head is consistent and evenly dispensing sealant. Inaccurate temperature indication will cause the temperature of butyl extruder to be too high or too low, which is not conducive to the uniform coating of butyl extruder and the bonding with spacers or glass. The sealing outlet should be cleaned and adjusted in time to avoid uneven butyl extruder coating or butyl extruder breakage caused by blockage of the glue outlet and angle deviation.

3.3 Washing section and plate pressing section.

The insulating glass production line should pay attention to the washing section and plate pressing section. The washing section should be washed and dryed in time to avoid excessive oil stains that may affect the bonding between butyl extruder and glass. In the plate pressing section, it is necessary to regularly observe whether the pressure plate is flat, so that the glass, butyl extruder, and spacer strips are fully pressed together. At the same time, pay attention to whether the pressure indication value on the back of the plate pressing section is accurate to ensure the pressure of the plate pressing.

 3.4 Sealant dispensing machine.

The sealant head and sealant dispensing pressure gauge of the outer sealant dispensing machine are the parts that need attention. You should observe whether the filling of the outer sealant is full, and judge whether it is necessary to clean the sealant head and adjust the sealant dispensing pressure.

3.5 Low-E film removal machine.

When making insulating glass composed of offline-coated glass, a film removal machine is usually required. It should be observed in time to see whether the glass in the film removal area is evenly removed and whether the grinding wheel used for film removal is flat and at the correct angle. When the film removal effect is not good or the grinding wheel is uneven, the grinding wheel needs to be trimmed, adjusted, or replaced.

3.6 No one for inert gases.

To obtain superior energy-saving parameters, many insulating glasses will be filled with inert gas. Inflating equipment needs to regularly pay attention to the inflation pressure gauge, whether the gas nozzle is unobstructed, and the timing control device to ensure that the specific gravity of the inert gas filled reaches the design standard.

Figure 1 Dew point frost and sealant bleeding

Figure 1 Dew point frost and sealant bleeding

3. Selection and inspection of raw materials

Safety glass or vacuum glass, exterior sealant, butyl extruder, desiccant, etc. used in making insulating glass should be inspected before use, and raw material suppliers should be evaluated promptly.

3.1 Various types of glass used.

For safety glass (tempered glass, laminated glass) or vacuum glass, its safety performance should be considered. Outsourced safety glass suppliers should provide CCC certificates, certificates of conformity, or factory inspection documents, and coated glass suppliers should provide third-party inspection reports or factory inspection reports of energy-saving parameters. Its size, appearance, etc. need to be inspected, and when applicable, safety performance incoming inspections should also be conducted (such as tempered glass to randomly check its fragmentation status, etc.).

3.2 External channel sealant.

Currently commonly used are silicone sealant and polysulfide sealant. The exterior sealant supplier should provide an inspection report on the full performance of the product. Not only incoming inspection is required, but also a butterfly test and pull-off test should be conducted before production to ensure the uniformity of sealant mixing and bonding strength.

3.3 Butyl extruder sealant.

Butyl extruder sealant factories usually do not have inspection equipment. Generally, they only inspect the diameter and appearance of incoming materials. Butyl rubber has poor aging resistance is easily affected by external conditions and causes aging. It is usually not used alone in the edge sealing system of insulating glass and requires external sealant to provide protection. At the same time, butyl extruder, as a single-component plastic sealant, has poor corrosion resistance to low-molecular mineral oil substances and is prone to swelling and dissolution. This requires that the outer sealant is pure and compatible with butyl extruder and can prevent the use environment. Migration movement of medium and low molecular weight mineral oils.

3.4 Desiccant inspection.

Insulating glass manufacturers may purchase Class A desiccant (3A molecular sieve) or Class B desiccant, and should require the desiccant manufacturer to provide an inspection report of the product. The incoming inspection of desiccant usually requires a temperature rise test, and the order needs to be paid attention to during the test. At present, the market is full of fake and inferior desiccants mixed with lime. During the temperature rise test, because the lime generates heat when exposed to water, the temperature rise rate is very fast and can meet the requirements. However, this type of desiccant will cause great corrosion damage to the aluminum strip and cannot meet the drying requirements in the insulating glass cavity.

3.5 Spacer strips.

When inspecting spacers (aluminum bars, rigid warm-edge spacers) upon arrival, attention should be paid to whether the air holes are unobstructed. Select any part of the spacer, block one end of the spacer, and inject water (or other liquid) or smoke into the other end for inspection. When water (or other liquid) or smoke cannot flow out or emerge smoothly from the pores, the pores may be closed or narrow, and the desiccant cannot play a corresponding role.

4. Control of the production process

The production of insulating glass should be as stable as possible under the premise of determining the production parameters.

4.1 Selection of different types of glass.

For safety glass or vacuum glass that constitutes insulating glass, when the sizes are different, attention should be paid to matching the sheets before joining them to avoid mismatching of the inner and outer sheets. For the case where there are one or more pieces of coated glass, the direction of the coated surface and the order of joining the pieces should be distinguished in advance.

4.2 Spacer production process.

When making spacers, the depth of the outer sealant should be considered, and the size of the spacers should be determined and reviewed before proceeding with relevant operations.

4.3 Desiccant filling process.

Whether it is manual filling or automatic filling, to ensure that the desiccant can fully absorb the moisture in the hollow glass cavity, the filling volume of the desiccant in the spacer should be maintained at more than 70%, but the desiccant cannot be filled. The entire spacer strip causes insufficient contact between the desiccant and the moisture in the hollow glass cavity. In addition, it should be noted that the spacers filled with desiccant should be closed as soon as possible to minimize the absorption of moisture in the air by the desiccant filled in the spacers. The closing should be completed within 45 minutes.

4.4 Butyl extruder sealing process.

Confirm the operating temperature of the product with the butyl extruder sealing manufacturer, and pay attention to distinguishing the temperature of the glue tank and the temperature of the glue outlet. After determining the temperature of the butyl extruder, the sealant discharging pressure should be adjusted so that the butyl extruder meets the bonding conditions. When applying glue, you should observe whether the butyl extruder is continuous and full, and pay special attention to the corner parts.

4.5 Washing section and plate press processing.

The glass of the combined segments should be fully cleaned and dried. Before joining the pieces, the cleaning quality and drying degree of the glass need to be checked, especially the side of the inner cavity of the insulating glass. After ensuring that the glass is clean and dry when bonding the spacer strips coated with butyl extruder, ensure that the distance between the spacer strips and the edge of the glass is as even as possible. The pressure in the pressing section should ensure that the butyl extruder is fully bonded to the glass.

4.6 External channel sealant sealing process.

Make sure the sealant is filled. It should be noted that the viscosity of the sealant varies depending on the operating temperature, and the glue discharging pressure needs to be adjusted in time.

5. Control of the production environment

The insulating glass production process should be carried out in a clean environment. In areas with high relative humidity, try to build a closed room in the desiccant filling, butyl glue machine, and spacer storage location after filling the desiccant to prevent the desiccant from absorbing moisture and becoming ineffective. For areas with four distinct seasons and a large temperature difference between day and night, the temperature will affect the viscosity of the outer glue. The ambient temperature should be monitored, and the local temperature (such as the area where the silicone glue is placed) should be controlled when necessary.

6. The quality and efficiency control

Due to the special parts for glass deep-processing, as well as the complexity of the insulating glass production process and the influence of internal and external environmental factors, the quality and efficiency control of insulating glass should be paid more attention to.

6.1 Raw material selection

The performance and quantity control of key materials is not only the key to ensuring the quality of insulating glass but also one of the control points for cost reduction and efficiency improvement. Quality problems and increased costs due to improper material and process control often occur. According to the particularity and life cycle requirements of insulating glass, the use of desiccant, butyl sealant, etc. with appropriate performance and quantity has become a matter of concern.

6.2 Performance and structural configuration

First of all, the performance of the final product should at least meet the national standard requirements (dew point, UV radiation resistance, water vapor sealing performance test qualified). Secondly, the dosage should be accurately controlled. Taking silicone glue sealing groove aluminum double-pass sealed insulating glass as an example: Preparation steps for initial calculation values: Calculate the cross-sectional area of the aluminum strip, assuming it is S1; Calculate the sealant depth + aluminum strip height, assuming it is H; Calculate the perimeter of the glass, assuming it is L glass; the thickness of the inner sealant, assuming it is L thick; the thickness of the gap, assuming it is L; the width of the inner seal, assuming it is LJ; the width of the outer seal, assuming it is WJ. The calculation method is as follows: Inner channel sealant amount = L thickness * L glass * inner channel sealant density Outer channel sealant amount = {[L glass * (L space + L thickness) * (WJ + LJ)] - (S1xL glass)} * exterior sealant density desiccant dosage = S1 * L glass * desiccant density * 85%

6.3 Stable quality control and cost control

Key materials have been accurately calculated, and process monitoring has been carried out to determine whether the required usage has been achieved under the condition that they meet the requirements of national standards. The suitability of process control and usage of key materials has been confirmed through tests to achieve stable and controlled product quality and avoid unnecessary mistakes. Cost expenditure and material waste.

7. The conclusion

Insulated glass is widely used in construction and other fields, but the quality on the market varies, and substandard conditions such as frosting inside the cavity and leakage of sealant often occur. When such a situation occurs, the unqualified insulating glass needs to be replaced, which is very costly. Insulating glass manufacturers should ensure stable and controlled product quality in all aspects and processes of production to avoid unnecessary losses.

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