OEM Reusable Brass Insert M4*6*7 Knurled Metal Brass Heat Stake Heat Set Insert

Information

Plastic inserts, commonly known as copper nuts, are usually embedded in the plastic to provide threads that can be removed and assembled repeatedly. Since plastics are divided into crystalline and non-crystalline types, four different installation types of plastic inserts have been derived, such as hot-melt ultrasonic embedded copper nuts (for example: QT), cold-pressed embedded copper nuts (SP ), self-tapping embedded copper nuts (for example: DG), injection molding embedded copper nuts (for example: DIN16903).

For different types of plastics, the principle of choosing plastic inserts is roughly as follows:
1. The crystalline plastic is relatively insensitive to stress, so all kinds of nuts can be applied
2. Amorphous plastic is very sensitive to stress. When choosing the nut type, avoid sharp knurling. Special care should be taken for those plastic parts that need to be electroplated for the screen. Pickling of the plastic parts with embedded nuts will cause serious cracking. It is best to first electroplating and embed the nuts.
3. Thermosetting plastics are not suitable for hot-melt and ultrasonic implantation of nuts. If necessary, you can choose precise and sharp knurled nuts to press in.

Specification

Embedding method

1. Hot melt/Ultrasonic type

2. In-mold injection type

3. Press-in type

4. Self-tapping

Cold pressed nuts refer to directly pressed into plastic without heating (at room temperature). This concept is relative to hot pressed nuts, and does not refer to nuts that are pressed into plastic "after cooling".

There is no unified national standard or industry standard for cold-pressed nuts. According to some commonly used styles of users and their own manufacturing habits, these standards (or styles) can be organized for users as a reference when designing products and selecting specifications.

Why not use hot melt, but need the classification style of cold pressed nuts?

We know that some thermosetting plastics (such as phenolic plastics, epoxy plastics, amino plastics, unsaturated polyesters, alkyd plastics, etc.) use thermosetting resins as the main component, combined with various necessary additives to form plastics through a cross-linking and curing process. Products, this kind of material cannot be hot melted or softened again once it is solidified. Obviously, hot melt (hot, ultrasonic, etc.) nuts are no longer suitable for this plastic. In this scenario, it is suitable for cold pressed nuts.

Application

1. Improve the connection strength between plastic parts.

In general, the screw connection between plastic parts is usually connected by self-tapping screws. The inner hole of the plastic screw column can be formed by injection molding at one time, and the subsequent self-cutting of the self-tapping screw is used to generate the threaded connection, which is convenient and fast; however; When the connection strength between plastic parts needs to be improved, the screw must be tightened with sufficient torque to generate sufficient axial tension between the main part and the screw thread to prevent loosening. However, the inner hole of the plastic screw column If the thread cannot withstand a large enough load, slippage or looseness will occur, which naturally cannot meet the required connection strength.

The metal thread can prevent the thread from deforming under the entire load, so the copper nut can significantly improve the connection strength in the plastic part.

2. The plastic parts need to be disassembled many times.

Some products require maintenance or require frequent disassembly and assembly of certain parts. The use of copper nuts embedded in the plastic parts can achieve repeated disassembly and assembly without losing the integrity of the thread. This is also self-tapping. The screw column is incomparable.

3. Replace metal parts with plastic parts.

Although metal parts are easy to obtain high-strength threaded connections, their processing and material costs are high, and their specificity is high. They are not suitable for cost-required and lightweight products. Therefore, copper nuts can be embedded in the plastic parts. Meet this demand.