Discussion on Quality Problems of Aluminum Insulation Bars

According to the large-scale non-ferrous net reprint: With the enhancement of environmental protection and energy saving requirements, many advanced energy-saving products and energy-saving technologies have gradually been used in China's construction industry. Energy-saving insulation issues are very important for buildings, because they are related to thousands of thousands of million. Households are closely related to people's lives. Doors and windows occupy a crucial position in the house's energy-saving system.

As a key component of heat-insulating aluminum alloy doors and windows and curtain walls, heat insulation strips also create a brand new product area with the application of heat-insulating aluminum alloy doors and windows and curtain walls. In short, the heat insulation aluminum alloy divides the original one-piece shape into two parts on the basis of the traditional aluminum alloy, and then the two heat insulation strips connect the two separate parts together by mechanical composite means.

The use properties of the heat-insulation bar determine that it must have high strength and low conductivity at the same time. Otherwise, there is a significant quality risk for the heat-insulating aluminum alloy doors, windows and curtain walls. (The lack of strength will cause the heat-insulation aluminum profile to be insulated from the heat insulation bar. If the connection is broken, the thermal insulation effect is lost (high thermal conductivity can not guarantee the thermal insulation effect), so the material selection and manufacturing process of the thermal insulation strip are very important.

First, how to do

1, appearance

Under natural scattered light, visual inspection was performed at a distance of 0.5 m with normal vision (without magnifying glass). The appearance of the heat-insulating bar should be smooth, flat, uniform in color, and the surface should not have appearance defects that affect the use. Straight lines are not allowed to break. The number of breaks in the strip is no more than two.

2, cut off the experiment

Random sampling of the manpower breaking experiment, nylon insulation bar can feel good toughness and strength when bending, bending to the two ends together and will not break, even if the fracture is slowly broken; some nylon insulation bar or brittle Obviously, when the bending ends to a certain distance, multiple cleaving phenomena occur, or the toughness is obvious, and the bending is repeated many times; the PVC heat insulation bar is very soft, basically no strength, and the repeated bending will not break.

3, the dimensional accuracy.

Using the vernier caliper (micrometer more precise) to inspect the dimensional precision of the thermal insulation strip's external precision, it can be found that the nylon thermal insulation strips have a dimensional deviation of less than 0.1mm regardless of the batch or the same thermal insulation strip, and the parallelism standard; Some nylon insulation bars or PVC insulation bars in different batches or the same thermal insulation strip at different parts of the size of the deviation of at least 0.1mm.

Second, the impact of substandard insulation bars on production

1. Changes in the heat-absorbing strip after absorbing water and its effect on wearing

Insulation bars saturated after water absorption will have a more obvious impact on the re-spray of the profile. As the re-spray temperature of the profile reaches approximately 200°C, the moisture in the insulation bar is hardly volatilized instantaneously. Bubbles cause unqualified profiles. Therefore, the amount of water absorbed by the insulation bar is strictly controlled for the re-injection process.

Absorption is the inherent characteristic of nylon 66 insulation strip, so wear it as soon as possible after entering the warehouse, and do the required amount of first-in, first-out, excessive water content will affect the efficiency of the strip or aluminum in the re-injection Foaming phenomenon, it is recommended that the optimum temperature for the insulation strip is 20°C-30°C and humidity ≤55%. Due to the brittleness of nylon 66 in cold weather and dry conditions, it is recommended to open the outer package of the product 3 days before wearing. The product can absorb certain moisture, reduce brittleness, and improve toughness.

2. The relationship between the placement time and dimensional change of insulation bars

The effect of water absorption on the dimensions of nylon 66 insulation products is still quite significant, although the effect of dimensional changes on the insulation bars is not significant for open-toothed, rolled insulation profiles (adjustment of the wear bars, rolling only Pressure process parameters).

3, insulation bar twist

In the production, there are often encountered twisting of the wire rod, which is mainly due to the fact that the heat-insulated strips are too tight during the completion of the bundling, and then the heat-insulating strips are piled up during the transportation, resulting in the twisted strips, which has an impact on the efficiency of employees in the actual production. At the same time, it also brings trouble to production.

4, the influence of transverse tensile strength

When used in winter and summer, there is a large temperature difference between the inner and outer two-cavity profiles of the heat-insulating profile that forms the insulated aluminum window. This temperature difference will cause different deformation trends between the inner and outer two-cavity aluminum materials. In summer, the temperature of the outer cavity profile is high, causing the outer arch to shrink. In winter, the temperature of the outer cavity profile is low, causing the inner arches to shrink outwards. This non-stop arching stress will cause the heat-insulating profile to produce a larger horizontal pull in the middle. If the heat-insulating strip has low transverse tensile strength, cracking will occur, leading to quality problems in the heat-insulated section.

Third, the risk of fake nylon insulation strip

If the mechanical strength of the heat insulation strip is not enough, the wind pressure resistance performance cannot be guaranteed, which directly affects the safety of the building; if the heat resistance is not good, some surface treatment processes in the production process of the heat insulation aluminum strip are directly affected; The chemical corrosion not only affects the chemical treatment process during the process but also hinders the cleaning work during the subsequent use; if the linear expansion coefficient differs greatly, the creep resistance is poor or the dimensional stability is not high, it will lead to thermal insulation and The deformation between the aluminum alloy profiles is loosened, and the airtightness, sound insulation effect, and heat insulation of the energy-saving doors and windows are reduced.

Fourth, high-quality insulation

1. High-quality heat-insulating strips The surface smooth heat-insulating strips are black matt-colored, and the whole is smooth and smooth, no shrinkage holes, no looseness, no scratches and die-extrusion marks, and the minerals have unique luster. There is no parting line marking on the end face of the hot strip head;

2. The longitudinal tensile strength reflects the mechanical properties of the thermal insulation strip in the longitudinal direction. At the same time, the elastic modulus is one of the indexes that best characterize the performance of the material. In engineering, the elastic modulus is called the stiffness of the material and it is characterized. The greater the resistance of the material to the elastic deformation, the smaller the elastic deformation produced under the same stress and the more rigid the material.

3. When the product is subjected to dynamic load, the impact strength (toughness) performance index of the material is required. The level of impact strength also indicates the toughness of the material. It is one of the performance indicators of the material. A good toughness can ensure that the heat insulation strip is assembled. With a relatively high yield.