The possibilities of rubber, plastic and silicone molding unfold with extensive wideness, it will overwhelm all materials you are searching for. It can be anything from rubber O-rings, sealing strips, to tiny computer components in aerospace. Normally, we require these components to complete some missions and project, or accomplish business goals. You can find that these molding products are precise to fit any need or application. Some types of molding are literally found everywhere, ranging from household items and appliances to industrial components and manufacturing lines. We can find molded products in our cars, homes and daily products.
What is Molding?
Molding is a process to make materials of rubber, plastic or silicone compound into different required forms. Sometimes, the molding can contain two or more different elements, because there are endless possibilities of material mixture.
Elastomer molding typically starts with uncured rubber materials, and applies heat in most vulcanization processes. We call these materials as thermoset, rubber and elastomer are synthesized in various process and formula additives.
Silicone has abundance and easily altered chemical structure. It can be modified and processed in different ways, including thermoplastics and metals unison. Furthermore, silicone is especially appreciated for its water repelling and heat resistance properties, some patented formulas are specific for unique applications.
Types of Molding
We determine different molding technologies by specifications of part, components and projects. The rubber, plastic and silicone molding are generally manufactured by these processes. There are several common molding techniques as following.
Blow Molding
Blow molding is similar to glass-blowing. Firstly, the heated tube or other implement will insert into materials. Then blown air though to enlarge rubber, plastic or silicone to fit the molds. Finally, remove objects once cool down. We normally apply this technique to produce high volume hollow objects. It is suitable for hollowed shape requirement in projects.
Compression Molding
Compression molding uses high pressure to squeeze a preformed material piece into a mold between 2 or more plates. The preformed material pieces must be more weight than molded parts, in order to expel all air from the mold under high pressure. Then we will cut away excess materials, and cure shaped products by heat or more pressure. This curing process is vulcanization. Normally, compression molding is suitable for large cross-section parts with low quantity volume.
Compression molding normally has a longer cure time than other techniques. However, it is idea for materials with high density or high hardness level. The automotive industry always apply compression molding products, in reason of its superior strength.
Compression tooling makes low cost than other tooling, it is idea for medium and large size parts without high volume quantity. It is able to process any rubber materials without any limitation of challenging.
Extrusion Molding
Extrusion molding is usually used for long and hollow products, like pipe, straw or tube. Different with other methods, extrusion molding places materials through a die directly and determines the form. Then cool down the formed long tube, and cut for different applications. Such as drinking straw. It is the unique tube shape production method.
Hot Runner Injection Molding
Hot runner injection molding apply screw nozzles to inject molten thermoplastics through the hot runner system. Molten materials will pack the mold cavities full via gate, runner, and sprue system. Then cool and solidify the formed parts before ejection from the cavities.
Injection molding is the most efficient molding process, it is suitable for small to medium size items with high quantities. It is able to produce components with requirement of high uniformity, complex inserts and tight dimensional tolerance.
Injection molding is widely applied in medical, electronic, and automotive industries. Its application have grown vastly and cover all industries over time. Hot runner injection molding eliminate pre-forming and human-operator handing process. Its unit cost is general low in high volume.
Cold Runner Injection Molding (Thermoset)
Cold runner injection molding is specific for thermoset like liquid silicone rubber. It applies a closed thermoset mold. Liquid silicone rubber is divided into two parts, mixing-metering pump combines them together and delivers to the injection device. Then inject these mixtures into the mold chamber. After that, in heated mold, platinum catalyst in LSR materials will compel the rapid curing process.
Liquid Silicone Injection Molding is the best choice for medical industry, the whole production process involves a closed system without human contact and contamination. It is most suitable for micro-components with different object sizes accommodation. Otherwise, LSR injection molding is idea for high-volume production, it also can add color by pigment.
Rotational Molding
Rotational molding (Rotomolding) rotate the mold to coat materials inside, and create the desired products. This process is relatively slow and only suited for large, hollow objects. Such as liquid or gas tank. There is littler material waste because of even coated walls by centrifugal force in rotational motion. However, it is only economical for certain applications.
Transfer Molding
Transfer molding apply a piston or plunger to push rubber materials from containers into the mold through gate, runner, sprue system. Then cure injected rubber materials by heat and pressure in mold. Transfer molding has lower unit cost than compression molding, rubber materials are injected into closed mold cavities with exact quantities.
This technology still require litter pre-forming process, it has tighter dimensional control than compression molding, especially for micro-component production. In addition, we also can add different color to final products. All molding projects are different from size, complexity, quantity, purity and other factors. The final products may have marks of indentation, lip, ridge, hole, groves, notches or other cavity kinds. All these molding technologies can manufacture components with various properties to satisfy customer specification demands.
Liquid Silicone Rubber Molding
Liquid silicone rubber molding produces multitude application for different industries. It is the cutting edges of molding technologies, it continues to improve as new developments of polymers and formulas.
Miwo, as the silicone industry leader in China, focus on extraordinary solutions for Liquid Silicone Rubber(LSR), including LSR injection molding, LSR over-molding, LSR 2-shot molding. This expertise enables us to develop versatile components for various specifications.
LSR excels in many electrical applications due to its insulation and conductivity. Consider LSR fire resistance, it is good for construction and building applications. In addition, its water repelling and resistance make it a popular choice for marine-oriented devices.
Professional Manufacturer to Refine Production
In conclusion, Miwo manufacture custom designed LSR parts with high-quality. Our capability can satisfy different requirements in various industry. Since 2000, we have produce billions of components, we have served clients from medical tools to specialty items. We invite everyone to understand the molding process, and provide guidance t no matter what they need for their specific projects.
In addition, you also can contact us for professional advice in your LSR projects.
