With the development of lightweight car bodies, aluminum is widely used in various positions of the car body. Die-cast aluminum is used in the front cabin, rear floor, A-pillar, CD-pillar and other areas, which can effectively realize the connection between the car body and other systems and meet good strength.

Wire thread insert installation process

Drill the hole and put the wire thread insert into the installation tool, so that the installation handle is embedded in the guide rod groove and the installation tool handle is turned to screw the wire thread insert into the screw hole. For wire thread inserts with broken grooves, the installation handle should be removed after screwing into the screw hole.

Wire thread insert application selection

It is common for the vibration of the car to damage the threaded hole. When removing the over-tightened bolts, the thread slips. Frequent assembly, removal and corrosion can all cause the thread damage on the parts. Based on the above reasons, in order to have a better fastening method for the car, major domestic and foreign automobile companies use threaded sleeves as original fastening, which are used in threaded holes made of lightweight materials and important positions. Using thread sleeves for fastening can make the thread stronger and more durable, and can also reduce the impact of corrosion.

Due to its structural characteristics, the thickness of the steel thread at the corresponding position of the vehicle body needs to be greater than the length of the thread sleeve (if the corresponding position is a through hole, the bottom hole depth must be 3P deeper than the thread sleeve) to meet the needs of thread sleeve installation and meet the strength of the corresponding position of the vehicle body. Die-cast aluminum can achieve local thickness increase, which is mainly used in the connection between die-cast aluminum and seats, suspensions, fuel tanks, batteries and other components. (Die-cast aluminum material: ADC12, A356, A380, ALSi10MnMg)

Common problems with thread sleeves

If the steel thread sleeve is found to fall off, the fallen steel thread sleeve cannot be put back in place. It is necessary to check whether the base thread is damaged. If not, a new thread sleeve needs to be installed. Because the fallen thread sleeve has removed the tail end used for installation after installation, it means that the installation tool can no longer put the old thread sleeve back in place. After removing the tail end during installation, the locking force formed by the thread sleeve and the base no longer exists. When the screw is removed again, the thread sleeve is very likely to fall off again.

If the installation process of the wire screw sleeve is found to be too tight, it is necessary to check whether there are debris in the bottom hole. You can use air blowing or high-pressure water gun to flush, check whether the tap is worn, check and replace the tap through the bottom hole plug gauge, check whether the sleeve is deformed, and check by reducing the installation speed.

If the installation process of the wire screw sleeve is found to be too loose, check whether the hole diameter is too large, check whether the appropriate drill bit is selected, and ensure that the tap is not skewed by selecting the correct tapping method and lubrication method. Check whether the sleeve is standard and small in size.

During the installation process, ensure that the thread sleeve is perpendicular to the parent material to avoid skew. The installation and connection of fasteners require high precision in each step. If one step is wrong, all steps will be wrong.

Because aluminum alloy is lower in strength than steel screw sleeves, the threads on the bottom hole of the parent material are often completely damaged. When reworking, only two methods can be used to solve the problem, namely, reinstallation after repair welding or tapping into special-shaped steel screw sleeves after expanding the hole. The time consumed is at least several times that of normal operation, and the second method is not conducive to maintenance. At the same time, if the steel screw sleeve is loose during vehicle operation, the parts will fall off, causing traffic safety accidents.

Wire thread sleeve test

After the wire thread sleeve is installed, an experiment is required to verify the performance.

Load holding capacity:

M8 guarantees a load of 38.1KN, M10 guarantees a load of 60.3KN, and M12 guarantees a load of 88.5KN.

Repeated disassembly test:

Use a 12.9-grade bolt through the fixture and the embedded thread sleeve structure to repeatedly disassemble the bolt 10 times. After the experiment, the wire thread sleeve thread is tested to have no damage, and the thread sleeve has no rotation or falling off.

The wire thread sleeve can improve the strength and durability of the aluminum alloy threaded hole because its steel wire has a higher hardness and wear resistance than aluminum alloy, and can achieve repeated screwing in and out of the bolt without damaging the internal thread. It is mainly used in parts of the die-cast aluminum process in the car body, and the application area is mainly in the front cabin and the rear floor. The thread sleeve can solve the problem of weak local connection strength of die-cast aluminum to the greatest extent, and it is also a necessary connection process for thick parts.

Chuangtuo Jinggong (Jiangsu) Co., LTD is profession manufacturer of various types of Hexagon Nuts, everything is customized in our factory, Should you have any questions please feel free to come back to us.

Contact: Lorena
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