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Thermal Insulation Strips in Broken Bridge Aluminum Profiles


The word "broken bridge" is a word that consumers hear more frequently when purchasing door and window products, and in broken bridge aluminum door and window products, thermal insulation strips are the key to the performance of this type of products.

The thermal insulation bridge breaking process of aluminum profiles is a method of embedding thermal insulation strips in the middle of aluminum profiles through special machining to enhance the thermal insulation performance of aluminum door and window profiles for construction.
There are two kinds of common insulation strips, PVC insulation strip and PA66 insulation strip

PVC thermal insulation strip

The full name is polyvinyl chloride insulation strip. PVC insulation strip has the advantages of beautiful appearance and low price, but it has poor heat resistance, and PVC insulation strip is easily deformed when the temperature changes greatly.
The safety of the processed heat-insulating aluminum material cannot be guaranteed, and the PVC material is prone to produce substances that are harmful to the human body. In some areas, PVC heat-insulating strips have been disabled.

PA66 thermal insulation strip

The full name is reinforced polyamide nylon thermal insulation strip, which is widely used in broken bridge aluminum profiles. Compared with PVC thermal insulation strip, PA66GF25 has stronger thermal insulation and can play a better thermal insulation effect. Nylon material has a certain degree of brittleness and high hardness, and is not easy to deform. Therefore, PA66 thermal insulation strips are more favored by consumers in the door and window market.


The biggest use of thermal insulation strips is the thermal insulation of building doors and windows, but the role of thermal insulation strips in doors and windows is much more than that.

bear the load

The thermal insulation strip is the core component of the threaded thermal insulation aluminum profile. While reducing the heat transfer in the aluminum profile, it also makes the three parts of the thermal insulation profile become a whole through its connection to jointly bear the load.

prevent condensation

The temperature of the inner surface of the broken bridge aluminum door and window profiles with thermal insulation strips is close to the indoor temperature, which reduces the possibility of indoor moisture condensing on the surface of the profiles due to oversaturation.


When many owners choose doors and windows, due to the regulations of the property, they can only choose the specified or similar outdoor colors for the windows, and the indoor colors need to meet the interior decoration effect and the owner's own preferences. It can be made of two colors inside and outside, while ensuring the decorative effect of indoor and outdoor.

Noise reduction

The hollow glass structure with different thicknesses and the heat-insulating broken bridge aluminum profile cavity structure can effectively reduce the resonance effect of sound waves, reduce the transmission of noise, and reduce noise by more than 30dB.

threading process

Rolling type threading is to combine the outer aluminum alloy profile, the inner aluminum alloy profile and the nylon 66 heat insulation strip with reinforced glass fiber through mechanical processing. After the partition material is melted, the glue-like partition material is injected into the profile, which is a glue injection process.

The glue injection type has large equipment investment and low production efficiency. The rolling type has a production capacity of about 50% higher than the glue injection type, and is superior to the glue injection type in terms of tolerance control, shear force and thermal insulation performance. . Therefore, the rolling type has become a more common threading method at present.

The rolling production process is generally divided into three processes: tooth opening → threading → rolling and shear force detection.

open teeth

Use mechanical equipment to roll out evenly arranged tooth gaps on the inner surface of the aluminum profile slot. The tooth opening can remove the coating formed by the surface treatment of the aluminum profile in the slot, increase the roughness inside the slot, increase the friction between the profile and the heat insulation strip during shearing, and the protruding part of the tooth gap is rolled At times, it is partially embedded in the thermal insulation strip to improve the bonding force between the thermal insulation strip and the aluminum material. The tooth opening should not be pressed too deep, so as not to damage the card slot.

wear strips

Threading is a relatively simple process in the whole process of thermal insulation and bridge breaking. In some improved equipment, tooth opening and threading can be completed simultaneously. The purpose of threading the strips is to quickly and accurately insert the two heat insulation strips into the corresponding card slots of the aluminum profile.

When threading, pay attention to:

1. Check the directions corresponding to the upper and lower profiles to avoid wrong directions;

2. Check the length of the profile, avoid the uneven length of the upper and lower profiles, and control the error of the threading process;

3. The heat insulation strip should be two parallel lines.


Rolling is the most critical step in the processing of thermal insulation and broken bridges of aluminum profiles.

Three sets of rollers are used to continuously squeeze and roll the slot with uninterrupted and balanced force. The rolled profile should be visually inspected first, lay the profile flat on the platform, and observe whether the profile is twisted, whether the end or tail is lifted, and whether the bottom of the profile slot is cracked.

Visual inspection of qualified products and then shear force testing.


Each profile produced by rolling must be tested for shear force.

Cut off a section of about 10cm from the end of the heat insulation profile, fix a part of the profile on the testing machine, apply 420N pressure to the other part of the profile through the pressure device, observe whether the profile has shear dislocation, and make appropriate adjustments to the rolling machine according to the test results. .