Injection molding is the manufacturing process of obtaining molded components or products by injecting molten plastic, rubber, metal or glass into a mold, then solidifying the product through a cooling process. This method provides many benefits to the automotive, medical and consumer electronics industries, including mass production, low waste and the ability to develop complex parts.

If you’re asking yourself, “What is plastic injection molding?” this blog post jumps into the many details of the process, benefits and industries listed above.

What is plastic injection molding?

In 2020, the global injection molded plastics market was valued at USD 265.1 billion. Between 2021 and 2028, the value is expected to expand at a CAGR of 2.6 percent. The growing demand for plastic products and components primarily comes from end-use industries including automotive, electronics, medical devices, home appliances and packaging. Additionally, modern innovations in technology have minimized the rate of faulty production and enhanced the mass production process of complicated plastic shapes. 

What are the benefits of plastic injection molding?

Before jumping into the industries and processes, it is important to know why plastic injection molding is so widely used:

  • Mass production. Because it is one of the fastest production processes, plastic injection lends itself well to mass production. The cycle time takes between a few seconds to a minute and can produce multiple parts, which makes the output significant. 
  • Low waste. Some processes, such as CNC machining, cut away plastic, which can produce waste. Plastic injection molding is more efficient: On average, only 20g out of 100g of plastic material is wasted. 
  • Complex parts. One of the great benefits of this method is its ability to produce intricate parts without the need for secondary processes, thereby cutting down overall production time. 
  • Low cost. Wasting less material means a less expensive process. Plus, plastic tends to run cheaper than other injection materials, such as metal and rubber. With a predicted CAGR of 6.5 percent in the plastics recycling market, manufacturers can either recycle waste into another cycle or sell it to a factory that manufactures plastic parts. 
  • Consistent quality. Because of the reliability of the molds and repeatability of the process, thousands of plastic parts can be produced in a single day at a similar quality. The rejection rate tends to be very low, so if consistency is important for your project, plastic injection is an ideal method. 

Which industries benefit most from plastic injection molding?

Because of the versatility and adaptability of the method, plastic molds can produce smaller components at a high rate and with precision and flexibility. The primary industries that use plastic injection molding include the following: 

  • Consumer electronics. The majority of electronic devices rely on plastic components, especially casing within electronics, which must be resistant to moisture, dust and other external influences to provide the electrical components with a high level of protection to extend the durability and performance of the device. 
  • Pharmaceutical and medical devices. Plastic injection molding offers a high level of quality and precision, two factors that are important for these two industries. Custom plastic parts are commonly used for pharmaceutical components, test kits, X-ray components and more. Additionally, these products are produced with a high level of design and application flexibility, allowing them to have a high level of durability and resistance to high temperatures. 
  • Automotive components. Automotive component manufacturers are able to create lightweight, highly durable components through the plastic injection molding method. Because the automotive industry is held to such a high standard for safety regulations, plastic components are precisely designed. Proper design begins with prototyping to test plastic components to ensure the design is at the required standards. 

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What is the process of plastic injection molding?

Plastic injection molding can be divided into six steps:

  • Clamping. An injection molding machine consists of two units: A clamping unit and an injection unit. Much like die casting, the clamping unit can open and close a die to hold and eject the product. There are two types of clamping methods: The toggle type and the straight-hydraulic type in which the mold is opened and closed with a hydraulic cylinder. 
  • Injection. The injection unit melts the plastic to then inject the molten plastic into a mold. While the molten plastic flows into the mold, the machine controls the injection speed and dwell pressure after the mold is filled.
  • Mold. A mold is a hollow metal block that the molten plastic is injected into. There are several holes drilled into the mold for temperature control by way of water, oil and heaters. After the cooling process, the mold is opened and the ejector rod pushes the ejector plate to release the component. 
  • Molding. Moldings consist of sprues, which introduce molten plastic, runners to lead the molten to the cavities, and products. Molds are usually designed to have multiple cavities so that many products can be made by one shot. 
  • Using reprocessed materials. The sprues and runners can be reground and reused as materials for molding new products, which helps cut down on cost of materials. 
  • Molding condition. The molding condition includes the cylinder temperature, injection speed and mold temperature. In addition to the conditions, the appearances, dimensions and mechanical properties can affect the molded products. 

Partner with a versatile OEM supplier.

Now that we have answered the question, ”What is plastic injection molding?” consider the capabilities of your OEM supplier. At VPIC Group, our plastic injection molding services have short lead times and high-quality results. Inevitably, your service needs will adjust. With VPIC, you will have access to technicians who can provide any number of primary and secondary services.

Ready to take that first step to working with VPIC Group? Contact us today!

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