With the development of China's construction industry, aluminum alloy doors and windows have also developed rapidly in recent years. At the same time as the rapid development of aluminum alloy doors and windows, its quality problems have become increasingly prominent. The main problem is the quality of the profile itself, the insulation strips, the hardware and the corner strength and sealing of the doors and windows. Today, we talk about the problems that are often encountered with the corner reinforcement and sealing of aluminum alloy doors and windows that use corner joints.
At present, many people mistakenly believe that the production of aluminum alloy doors and windows as long as the cutting equipment has a high cutting precision, the corner code is properly matched, and the corner angle of the group angle unit is fixed, so that the corner strength and sealing of the aluminum alloy door and window can be achieved. Claim. In fact, most of the aluminum alloy doors and windows that use corner joints are produced by this process. This simple mechanically fixed connection is a rigid connection that is difficult to adapt to the various forces encountered in the production, transportation, installation and long-term use of doors and windows without being damaged.
First of all, we need to understand the physical properties of aluminum alloy profiles.
Aluminium profiles have the same temperature differential stress as any other material. Temperature difference stress refers to the stress caused by a change in temperature of a material, usually a linear expansion/contraction coefficient.
We can calculate the dimensional change of the aluminum alloy profile within the normal operating temperature range, that is, the linear expansion/contraction rate formula is as follows: L=L0(1ΑΔT) where: L: the length after the change L0: the original length Α: the expansion/contraction coefficient For aluminum alloy profiles, in the range of -40 ° C and 50 ° C, the value is 2.4 × 10 -5 / ° C ΔT: for the temperature (Celsius) change value calculation example: the original length of the aluminum alloy profile is 1 m, The temperature change value is 50 ° C -40 ° C = 90 ° CL = 1 M (12.4 × 10 - 5 ° C × 90 ° C) = 1.00216 M which means: 1 m long aluminum alloy profile at 90 ° C temperature change It will produce a length change of 2.16MM. For the corner strength of aluminum alloy doors and windows with only rigid joints, this change will have a devastating effect, causing the mutual position of the parts at the corners of the door and window to be disorganized or deformed, which is undoubtedly a fatal flaw in the corners of the doors and windows. . This kind of defect is that there is no way to make up for any bolt or angle machine with a rigid connection.
Secondly, in the production and installation process of aluminum alloy doors and windows, due to the movement error during handling, transportation, installation and construction, and the completion of the installation of doors and windows, the aluminum alloy doors and windows have to bear their own weight for a long time, and the window hole and the wall of the building are deformed. Stress errors, switching windows, wind pressure, ambient sound waves and other spike impacts and vibrations of varying frequencies. Such vibrations sometimes induce resonance in doors and windows, affecting the overall strength of the doors and windows.
All of the above reasons will cause the gap between the corners of the door and window to gradually increase and dislocate with time, resulting in airtightness, watertightness, sound insulation, dust-proof performance of the door and window, and serious deformation of the door and window, which has adverse consequences. At present, there are more and more engineering disputes arising from this, which seriously affects the overall reputation and image of aluminum alloy high quality doors and windows.
In fact, the corner strength and sealing of aluminum alloy doors and windows can be used only with special aluminum alloy doors and windows, but unfortunately most door and window factories as well as developers, administrative departments and related architectural design, supervision and other units do not really know. The role of special-purpose corner glue in improving the overall quality of doors and windows. Some door and window assembly factories do not use a set of corner glue or mistakenly use glass glue, structural glue, epoxy glue, etc. as a special set of corner rubber for aluminum alloy doors and windows. At present, there are three types of glues that are often used to fill the corners on the market:
1. Glass glue is also known as silicone sealant; it has poor adhesion to aluminum alloy, poor weather resistance, easy aging, low hardness, too much elasticity, and the gel does not swell when solidified, so the corner code can not be closely adhered to the cavity. Connected into one.
2. The structural adhesive has poor adhesion to the aluminum alloy, the curing time is long, the product has many odors, does not swell when solidified, and cannot produce high strength.
3. Epoxy adhesive is inelastic after curing, can not adapt to the micro-shock of the form, easy to crisp and broken, long-term strength after the group angle is not enough, it will crack and slag phenomenon.
Why do we advocate the use of special sets of corner glue? Because the special aluminum alloy door and window set angle glue has the following characteristics:
1. The colloid is a modified polyurethane-based adhesive that does not contain solvents and meets environmental protection requirements.
2, the initial curing time is short, about 10 minutes, which is conducive to improving production efficiency. It is divided into single and double components, which is more suitable for the requirements of the two processes of “corner glue insertion and corner injectionâ€.
3, after curing, the hardness is very high, but not brittle, with low elasticity and excellent waterproof performance, so that the corner code and the wall of the profile cavity are connected by toughness, thereby making up for and reducing various deformation and cracking of the window corner. Effectively solve the leakage problem at the corners of doors and windows.
4. After the single-component glue group is fully cured, the shear strength of the effective bonding part of the corner code and the inner cavity of the profile can reach 10.3N/MM2, and the shear strength of the two-component group can reach 18N/MM2. Greatly improve the window corner strength. That is to say, the shear strength of the ordinary 60 series profiles in China can be exceeded.
5. The colloid is slightly foamed and expanded during the curing process to form an elastic pad between the metal and the metal, which effectively weakens the conduction of various forces and acts as a shock absorber and a cushion.
6, strong weather resistance, can withstand temperature changes of -40 ° C 80 ° C, the colloid is white or translucent, the gel produced will not turn yellow in the short term. The two-component gelatin can withstand 30 minutes at 230 ° C, suitable for post-processing needs such as powder coating.
7. Cooperate with special cleaning agent, a small amount of overflow glue is easy to clean, never damage the coating and paint surface of the profile surface, and is environmentally friendly and non-toxic. 
Editor in charge: Wang Zhen
Drill Bit Sharpener,Drywall Taping Tools,Sharpener Grinding Stone,Drill Bit Sharpener Grinding
SHAOXING SUNWAY TOOLS & HARDWARE IMPORT & EXPORT CO.,LTD , https://www.sunwaytools.com