Die casting is an important process in the manufacturing of mobile phone frames, which accounts for a large proportion of the manufacturing process due to its advantages of high output and low cost. According to reports, improved new processes in die casting, such as bimetallic die casting, may further reduce the manufacturing cost of mobile phones. The use of die-casting release agents is an important means to ensure the yield of die-casting. Choosing the right release agent is extremely important for die-casting manufacturers.
1、 What is silicon free release agent
Silicon free mold release agent is a functional substance between molds and finished products, which is a type of processing aid that prevents metal molded products from sticking to molds and makes die-casting parts easy to detach. Due to the rapid development of die-casting technology, the amount of mold release agent has also significantly increased.
2、 Classification of release agents
1. Classified by composition
According to their composition, commonly used release agents include inorganic substances, organic substances, and high polymers.
(1) Inorganic release agents, such as talcum powder, mica powder, clay, and white clay, are mainly used as composite materials for rubber processing film and semi-finished product release agents.
(2) Organic release agents, including fatty acid soaps (potassium soap, sodium soap, ammonium soap, zinc soap, etc.), fatty acids, paraffin wax, glycerin, Vaseline, etc.
(3) High polymer release agents, including silicone oil, polyethylene glycol, low molecular weight polyethylene, etc., have much better release efficiency and thermal stability than organic release agents.
2. Classified by physical state
According to the physical state of silicon free release agents, they are usually classified into powder, semi-solid, and liquid. Powdered and semi-solid materials can be applied to the surface of the mold like wax, using a brush or by hand; The liquid can be painted on the surface of the mold with tools such as spray or brush to form an isolation film; Spraying is preferred for liquid release agents.
3、 How to choose release agent
It is crucial to choose a high-quality die-casting release agent during the die-casting process of the phone frame/shell. Due to poor release agents, defects such as mold sticking, porosity, scaling/carbon deposition inside the cavity, cold insulation, and white spots may occur.
The key points for selecting release agents are:
1. Good demoulding performance. For spray release agent, the surface tension should be between 17-23N/m;
2. Has heat resistance and does not undergo carbonization or decomposition when heated;
3. Stable chemical performance, no chemical reaction with molded products;
4. Does not affect the secondary processing performance of die-casting;
5. Non corrosive molds, non polluting products, low odor and toxicity;
6. Smooth and aesthetically pleasing appearance;
7. Easy to apply, high production efficiency.
