What causes exposed iron in silicone hardware products?

The occurrence of exposed iron in silicone hardware products is a complex problem involving multiple links and factors. This phenomenon not only affects the aesthetic appearance of the product, but may also have adverse effects on its performance and service life.

1、 Improper surface treatment

1. Incomplete cleaning
Before production, the surface of silicone coated hardware products must be kept clean and free of oil stains. If the cleaning is not thorough, residual oil stains, impurities, etc. will seriously affect the adhesion between silicone and hardware, leading to the occurrence of exposed iron phenomenon. Therefore, thoroughly cleaning with alcohol or professional cleaning agents is a crucial step.
2. Insufficient sanding
Proper sanding of the surface of hardware can increase its roughness and help improve the adhesion between silicone and hardware. If the sanding is insufficient, the surface of the hardware will be too smooth, and the silicone will be difficult to firmly adhere, which can also easily cause exposed iron.

2、 Insufficient chemical treatment

The use of specific chemical substances such as acid washing or phosphating treatment can further enhance the bonding effect between hardware and silicone. If this step is ignored or not adequately addressed, it will directly affect the adhesion between silicone and hardware, increasing the risk of exposed iron.

3、 Improper selection of adhesive

Choosing the appropriate adhesive is the key to preventing exposed iron in silicone coated hardware products. Adhesive specifically designed for bonding silicone and metal should be selected and used correctly according to the manufacturer’s instructions. If the adhesive is selected improperly or used incorrectly, it will directly affect the bonding effect and lead to iron exposure.

4、 Mold design and injection molding process control issues

1. Unreasonable mold design
The design of the mold should be able to accurately fix the position of the hardware and ensure that the injection of silicone does not leak out. If the mold design is not reasonable, such as inaccurate positioning of hardware components, poor sealing of the mold, etc., it may cause silicone to overflow from the gap between the hardware components and the mold during the injection molding process, forming exposed iron.
2. Improper control of injection molding process
The temperature, pressure, and speed during injection molding need to be strictly controlled. If the temperature is too high, the pressure is too high, or the speed is too fast, it may cause silicone to overflow from the gap between the hardware and the mold under high pressure. In addition, the flow of silicone should be closely monitored during the injection molding process. Once any abnormalities are found, parameters should be adjusted immediately or production should be stopped to check the cause.

5、 Insufficient follow-up processing and quality control

1. Insufficient heat treatment
After injection molding, appropriate heat treatment of the product can enhance the bonding strength between silicone and hardware components. If the heat treatment is insufficient or not carried out, it will affect the bonding effect and increase the risk of exposed iron.
2. Poor quality control
Establishing a strict quality control process is crucial throughout the entire production process. Comprehensive inspection of raw materials, production processes, and finished products to ensure that every step meets standards can effectively prevent the occurrence of exposed iron. However, if quality control is not strict or there are loopholes, it may lead to missed inspections or failure to detect and solve problems in a timely manner.
In summary, the occurrence of exposed iron in silicone hardware products is the result of multiple factors working together. In order to effectively avoid this phenomenon, it is necessary to start from multiple aspects such as surface treatment, chemical treatment, adhesive selection, mold design and injection process control, as well as subsequent processing and quality control. Scientific methods and meticulous operations should be adopted to ensure the quality and performance of the product.