What are the reasons for missing glue in the production of liquid silicone products?

The problem of missing glue in the production process of liquid silicone products is a complex and common technical challenge, which may be caused by multiple factors working together. The following is a detailed analysis of the reasons for missing glue in the production of liquid silicone products:

1、 Raw material factors

1. Insufficient weight of silicone raw materials: This is one of the direct reasons for the lack of glue. In the production process, if the amount of silicone raw materials added does not meet the design requirements, or there are errors in the batching process, it may lead to a shortage of glue after the product is formed.

2. Long storage time of raw materials: During the storage process of liquid silicone raw materials, if the time is too long, the flowability may deteriorate due to changes in physical and chemical properties. This change will make it difficult for the raw materials to flow evenly in the mold, leading to a shortage of glue.

3. Unstable quality of raw materials: The quality of raw materials is crucial for the production of liquid silicone products. If the quality of raw materials is unstable, such as impurities, high moisture content, or ineffective curing agents, it will directly affect the flowability and curing effect of silicone, leading to a shortage of adhesive.

2、 Process control factors

1. Uneven mixing and stirring: Liquid silicone gel needs to be mixed and stirred before production to ensure that each component is fully and uniformly mixed. If the mixing is not uniform, it may cause inconsistent flowability of silicone in the mold, and some areas may experience missing glue.

2. Insufficient injection pressure: Liquid silicone requires sufficient pressure during the injection process to ensure that the raw materials can fill every corner of the mold. If the injection pressure is insufficient, the raw materials cannot fully flow into the fine structure of the mold, resulting in a lack of glue.

3. Improper mold temperature control: Mold temperature is one of the key factors affecting the fluidity of liquid silicone gel. If the mold temperature is too high, the silicone raw material may undergo early vulcanization during the flow process, resulting in a decrease in fluidity; If the mold temperature is too low, it will affect the curing speed of silicone and may also cause glue shortage problems.

4. Inaccurate control of vulcanization time: vulcanization is an important process for the solidification of liquid silicone gel. If the vulcanization time is not accurately controlled, such as too short or too long, it may lead to missing rubber or other quality problems in silicone products.

3、 Equipment and mold factors

1. Unreasonable mold design: The structure and size design of the mold have a significant impact on the molding effect of liquid silicone products. If the mold design is not reasonable, such as improper flow channel design, unreasonable exhaust hole position, etc., it may lead to poor flow of silicone in the mold, thereby causing glue shortage problems.

2. Mold wear or damage: Molds may experience wear or damage during use, which can affect the fluidity and molding effect of silicone in the mold. For example, scratches or dents on the surface of the mold may cause silicone to accumulate in these areas and cannot flow smoothly.

3. Injection equipment malfunction: Injection equipment is one of the key equipment for the production of liquid silicone gel. If the equipment malfunctions, such as insufficient injection pump pressure or inaccurate measurement, it will directly affect the injection effect and product quality of silicone gel.

4、 Human operational factors

1. Improper operation: The production process of liquid silicone requires strict operating procedures to ensure product quality. If the operator does not follow the specifications for operation, such as too fast or too slow injection speed, improper mold temperature control, etc., it may lead to the problem of missing glue in silicone products.

2. Insufficient skill level: The skill level of operators has a significant impact on the production quality of liquid silicone products. If the operator’s skill level is insufficient and their understanding of equipment and processes is not deep enough, it will be difficult to detect and solve problems that occur during the production process, thereby increasing the probability of quality problems such as missing glue.

​In summary, the reasons for the lack of glue in the production of liquid silicone products are multifaceted, including raw material factors, process control factors, equipment and mold factors, and human operation factors. In order to effectively avoid and solve the problem of glue shortage, production enterprises need to start from multiple aspects, strengthen the quality control of raw materials, optimize production processes and equipment maintenance, improve the skill level of operators, etc., to ensure the production quality and stability of liquid silicone products.