Silicone molds, which are made of polymer and are non-sticky with high flexibility can simplify work and be used in various fields. To produce any number of silicone molds in different models and colors, you can leave it to Temco Rubber Industrial Group to do it in the best way for you.
In general, silicones are divided into several categories according to their application, which is based on the sanitary and non-sanitary level and the industrial application that they have due to the inexhaustibility of these materials in the fatigue process. Due to their hardness, silicones can be widely used in medical, automotive, petrochemical, cooking, toys, etc.
Silicone rubber is a type of rubber material that has a mineral base and for this reason, its flammability and temperature resistance is higher than natural rubber, and due to its non-reactivity with other materials, it is a widely used material in the food and health industries by adding the necessary additives.
In order to produce silicone parts, after the detailed design of the product, the silicone shrinkage factor should be applied to the product and the molding process should be done. Finally, the production of your silicone parts is done by baking the mold.
Manufacturing Silicone Mold
Silicone is a strong choice for mold making; Because it offers a wide range of benefits. You can easily create custom designs such as chocolates, ice shapes, sweets, etc. using silicone molds. The molds themselves are also quite durable So you can use them repeatedly without fear of breakage. Silicone’s inorganic makeup compared to its organic counterpart, rubber makes it highly resistant to heat and cold, chemical exposure, and even fungus.
Work Samples of Manufacturing Silicone Mold
Silicone molds advantages
- Flexibility: The flexibility of silicone makes it easy to work with and silicon molds are flexible and lightweight compared to more rigid materials such as plastic and once a piece is fully formed, it is also easier to separate them.
- Durability: In most cases, you will have a lot of fallout from the silicone mold however, it is important to note that the lifespan of molds varies greatly. To maximize the life of your silicone molds, clean them with mild soap and water, dry thoroughly, and keep them flat without clumping.
Silicone mold making process
First, it should be understood that silicone casting technology is 180 degrees different from previous molding and casting technologies. Silicone rubbers are synthetic polymers with an alternating Si-O backbone. Its molecules are bonded by adding a catalyst, such as catalytic silicones. Then, the two parts are mixed in a predetermined ratio to form a ready-made mixture.
First, the thermoplastic resin is heated in a barrel and injected into a cold mold. Typically, silicone castings require the liquid rubber to be cooled (5 to 25°C). Then it is injected into a hot mold (170 to 210 degrees Celsius).
Designing and making a silicone mold is also different from thermoplastic. For example, tolerance, discharge, partial discharge and installation of a vacuum system are among its differences. Although tool design varies, optimization of processing variables such as temperature, pressure, and time is essential in thermoplastic molding and silicone casting.
Now, according to the process that was explained, one of the challenges of mold design is the double-sided casting system or cold deck. This system allows for equal distribution of material to each cavity at the same hydraulic pressure and consistent temperature profile.
Classification of silicone molds and its types
The methods used in preparing and making this sample of molds have placed them in three different categories.
- Air baking silicone mold: The flexibility and resistance of these molds against heat and the high elasticity of these molds are widely used in the industry.
- HTV molds: These samples of silicone molds are also known as heat-baking samples. Due to their high resistance to heat and cold, they are used in industrial production.
- Liquid silicone: This example of silicone mold is used to produce special products. Among their features, we can mention high stability and high resistance to heat.
Necessary equipment for the production of silicone parts
Several mechanical components must be in place to perform the molding processes of silicone parts. The existence of a single fabric and strong system makes the production process of parts to be done in a single fabric with more precision and efficiency. The components of a molding machine are:
Injectors: The injection device improves the injection of the material inside the pumping section by creating pressure on the liquid silicones.
Measurement: The measuring unit pumps the primary liquids of the catalyst and base silicone and then releases both liquids at fixed ratios simultaneously.
supply cylinder: They use this cylinder to mix ingredients together. This cylinder is connected to the main pumping system.
Mixer: After the materials leave the measuring unit, the mixer mixes them with each other, and after mixing by using pressure, they transfer the materials into the pre-determined molds.
Nozzle: So that the mixture is easier to put inside the mold. A nozzle is used. This nozzle has a shut-off valve that prevents leakage or overfilling the mold.
Hook clamp: This clamp holds the mold during the entire molding process and is separated from the mold after the process is finished.
Silicone compression molding
The simplest method is compression molding, which is ideal for smaller parts. This process begins with material selection, the appropriate grade must be carefully selected or custom formulated. This grade provides processing specifications for the physical properties and industrial approvals required for that application.
After mixing, the silicone rubber compound is cut into pieces of appropriate size and weight. This process is called blanking or flaking. Then, the blanks are placed directly over each of the tool holes and the silicone molding process begins.
Compression mold design
Oftentimes, thanks to the high elongation percentage of liquid silicone, simple parts, even parts with small and slight cuts, can be demolded from double-sided compression molds. Parts with complex geometry usually require a pick-apart die, which may consist of three to eight or more different parts.
The plates and cores are mounted together to form the liquid silicon and the part is molded. This process may increase the demolding time compared to injection molding.
One of the least expensive methods of making a silicone mold is the extrusion method. This method is used to produce different silicone parts. However, silicone extrusion molding has lower precision. Normally, the extrusion molding method is used to make hollow bottles or containers.
In this method, silicone rubber is usually shaped by pressing it into a mold called an extruder. Then, the mold is heated to bake the material. In this way, the desired shape and cross section is obtained. One of the significant advantages of making a silicone mold is its very high lifespan as well as the variety of colors.
Industrial silicone mold
Compared to the expensive metal molds that are made, there is a silicone mold that has high flexibility and a more affordable price. Of course, this mold model is not very durable compared to the metal mold, but it is very easy and convenient to make. Another strong point about molds made of silicone is that the material does not stick to these molds at all and is easily removed from inside them. Many factories and manufacturing industries need mold making machines in order to be able to produce the parts they need in small and large sizes. A very high cost should also be taken into account for the preparation of the molding machine. But on the other hand, the silicone mold is made at a very low cost and at a very high speed and can meet your needs.