Injection molding is a popular technique used in the manufacturing industry to inject molten materials into molds, solidify them in different shapes, and create spare parts. It is a mass-production technique to create identical plastic parts. A range of components can be manufactured using this technique, be it electronics, automobile components, toys, kitchenware, and more.
Let’s read more about injection molding in this blog.
Injection molding is the process of injecting molten/ liquid plastic into a mold and clamping it until the liquid cools down and solidifies. Materials like plastic, ceramics, metal, and glass are melted on high heat to turn them into a liquid state. This hot liquid is injected into various molds, which are clamped shut and left to cool down. The molds are then cooled, and the material inside them solidifies, taking their shape. They are then removed from the molds and tested for quality before packaging and delivery.
Creating the mold is the first step of injection molding. Once you have the mold ready, it can be used multiple times to create a huge batch of products. A mold is a hollowed-out block in the shape, size, and dimensions of the final product you want. Additives like color, sparkles, etc., can also be added to the molds while injecting molten plastic into them.
Injection molding has become a popular technique due to its cost-efficiency and ease of use. It is a convenient technique to mass produce large batches of final products in quick time. It also offers flexibility in designs. Additionally, manufacturers can also choose different types of injection molding machines based on their requirements.
Molding has been a well-known technique since the Second World War days. It is a great method for mass production, which became a necessity during the war. However, the actual history dates back to 1872, when American investors John Wesley Hyatt and his brother Isaiah developed the first machine for injection molding. The machine had a simple design where a piston pushed hot and molten plastic into a mold through a cylinder. This machine was used to produce buttons, combs, etc., in large batches.
A few years later, in 1919, German chemist Arthur Eichengrün created an injection molding press and filed a patent application in 1939 for molding plasticized cellulose acetate. This raw material was less inflammable compared to other materials used back then.
With the onset of World War II, there was an increase in demand for cheap products manufactured in mass production. Since metal was expensive, plastic was used to create spare parts for weaponry and other products. Even after the war ended, plastic continued to be popular among the common public and became a standard product in the global market.
However, the modern-day injection molding machine traces its roots to the gas-assisted unit developed in the 1970s by James Watson Hendry. He also made the first screw injection molding tool during WWII. Nevertheless, the gas-assisted machine made it easier to manufacture intricate parts and reduce the cooling time. This led to faster production.
The latest injection molding machines rely on the same old technique but are powered by computer software to design molds and automate the process. They also improve the quality and accuracy of the end product.
Injection molding is a multi-stage method where every step is crucial. An error or lapse at any step can lead to defective products.
Step 1: The raw material (plastic pellets) is added to a hopper and sent to a cylinder.
Step 2: The cylinder is heated for the plastic pellets to melt and turn into a hot liquid.
Step 3: The nozzle at the other end of the cylinder injects the molten plastic into the mold channel. It works much like a syringe.
Step 4: The mold channel (also known as sprue) will be cooled for the material inside to harden and solidify in its shape.
Step 5: The sprue is removed from the part after cooling down. Finishing touches will be added to the final parts before sending them to the quality check.
Even though injection molding has many advantages and is a reliable technique for mass production, it is not without a few issues. Not taking proper care during the production cycle can lead to the following defects and affect the overall product quality.
Over the years, a plethora of plastics have been used by manufacturers to create components using the injection molding technique. The following plastics are more commonly used:
The injection molding technique offers many advantages, such as the following:
Applications of Products Made Through Injection Molding
As mentioned earlier, a variety of products can be made using injection molding. This technique is widely used in the following industries:
Automotive (creating spare parts and components for vehicles)
Toys (the parts for dolls, action figures, etc., are made through this process)
House and Kitchenware (plastic curtains, hangers, hooks, spatulas, bowls, glasses, cups, and many more)
Electrical Components (plugs, switches, screw holders, etc.)
Medical Devices (stethoscopes, syringes, etc.)
Food and Beverage Containers (instant noodle cups, yogurt cups, bottles, etc.)
Tools (screwdrivers, hammers, wrenches, etc.)
Sporting Items (tennis balls, hockey pucks, etc.)
Injection molding is a versatile, precise, and reliable technique to mass-produce numerous products in different industries. Work with a reputed partner to access state-of-the-art injection molding equipment powered by the latest technology.
Contact Trumold for customized injection molding services with greater precision, accuracy, and cost-effectiveness.