Plastic Injection Mold and Plastic Injection Molding Process
What is injection molding?
Plastic injection molding is a rapid manufacturing process used to produce custom plastic injection molded parts in low or high volume for commercial or industrial use. Plastic injection molding applications span a wide range of industries from complex auto safety parts to simple parts like card holders. At TEAM Rapid, we combine skilled mold designers, software technology with CNC machinery to create injection molds to produce top quality plastic injection molded parts. Our team of engineers are happy to work with every customer on their injection molding projects.
Plastic injection molds builds
At TEAM Rapid, all of customer plastic injection molds are built in house. Our factory is staffed with experienced designers and machinists by the most advanced CNC machines and software. Once customized part designs are finalized and approved for production, we will build plastic injection molds for their production.
Producing high quality plastic injection molded parts begins with injection mold. Our engineers work with every customer closely to make sure they are familiar with different types of molds for injection molding. Below is a understanding of basic injection mold construction types and their advantages.
Insert molds
Insert molds have a cavity side and core side insert which fit inside of customized molds base. Insert molding is a good way to provide customers with inexpensive tooling at a short lead time. The design of insert style of suitable for parts in small and medium size in low volume. Insert molds are inexpensive but they are made with the same high-quality materials and part as free standing plastic injection molds. Insert molding process also provides the same high quality part. Lead time for insert molding is around 5-15 days. Insert molding is good for one cavity molds and low volume orders.
Free standing molds
Free standing molds are known as stan alone molds. It offers an all in one design. Free standing molds include mold base, inserts, and all parts needed to be completely functional alone. Stand alone molds are expensive, they are a great choice for multi cavity production and high quantity orders. Lead time for free standing molds is around 3-8 weeks. Free standing molds are the best methods for parts which will not fit into insert molds. Free standing molds are the great choice for multi cavity molds to lower the product cost.
What is plastic injection molding process?
There are three main parts involved in plastic injection molding process. They are injection molding machines, molds, raw plastic materials. Plastic injection molds are made from high strength aluminum and steel parts which have been machined to operate in two halves. The two halves come together inside the injection molding machines to produce custom plastic injection molded parts.
Injection molding machines inject molten raw plastic material into the mold, it solidifies to form the end parts. The plastic injection molding process is a complex process with many different speed, time, temperature and pressure. The whole plastic injection molding process cycle for produce custom plastic injection molded parts ranges from a few seconds to several minutes. Here are the four main steps of plastic injection molding process.
l Clamping
Before the molten raw plastic is being injected into the injection molds, the injection machines close the two halves of the plastic injection mold with force which prevent the molds from being opened during the plastic injection molding process.
l Injection
Raw plastic material which is in the form of small pellets is fed into the reciprocating screw feed zone area of injection molding machines. Temperature and compression heat the raw plastic material. The amount of plastic material which is conveyed to the front of the screw. It is a dosage which is controlled strictly as the amount of plastic material which will turn into the end parts after injection. When the correct dosage of plastic material meets the front of the screw and the mold is completely clamped, the injection machine injects into the mold, pushing it to the end points of the mold cavity by high pressures.
l Cooling
Once the molten plastic material arrives at the internal mold surface, it starts to cool. The cooling process solidifies the shape and hardness to the injection molded plastic parts. The thermodynamic properties of the plastic, the wall thickness of the injection molded parts and the dimensional requirement of the end parts will affect the cooling time requirement of each plastic injection molded parts.
l Ejection
When the plastic injection molded parts are cooled in the mold. And the screw prepares a new shot of plastic for the next unit, the injection machine unclamps and opens the plastic injection mold. The injection molding machine is equipped with mechanical provisions which work with features designed with the injection mold to eject the parts. The injection mold parts are pushed out of the mold and when the new parts are completely ejected, the injection molds are ready for the next unit.
Most plastic injection molded parts are done after they are ejected from the mold. And some plastic parts additional processing treatment after they are molded. Each custom plastic injection molding project is different.
Plastic injection mold is expensive
If you want to produce high quality plastic injection molded parts, you must build high quality injection molds. Plastic injection molds consist of precise machined parts which made from metal like aluminum or hardened mold steels. Plastic injection molds are designed and built by skilled and well-paid mold makers. Professional mold makers spent many years in mold creating industry. Expensive tools are needed to create plastic injection molds, for example, high cost software, CNC machinery, tooling, fixture. Depending on the complexity and size of the final parts, it will take around a few days or even several weeks to complete a plastic injection mold.
Construction requirement of injection molds to function in the plastic injection molding process is astounding. Injection molds are summarized as halving two halves, a cavity and a core, there are many precise parts which make up every half.
The design of plastic injection molds will impact on the mold cost. Plastic injection molding process need high pressure when the plastic material injected into the mold by the machine. If there is no high pressure, the surface finishes of the injection molded parts are not good and the parts won’t be dimensionally right.
To withstand the pressure, injection molds must be made with high quality aluminum and steel. The injection molds have to be designed to withstand clamping and injection forces.
At TEAM Rapid, no matter what type of plastic injection molds customers build, our engineers understand that customers’ injection mold purchase is a significant asset to their business. So, warranty the life of custom injection molds for our customers for the life of their requirements. Let us to give you an instant free quote for your next injection molding projects. Our team will work closely with you to make your next project a success.
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