Injection Molding
Roughly 32% of all plastic processing applications utilize injection molding. Injection molding is the most common plastic processing method today; it enables manufacturers to fabricate plastic products in configurations that vary in complexity.
Quick links to Injection Molding Information
Applications of Injection Molding
In almost every industrial or consumer industry, injection molded parts are used to some extent.
The injection molding process can be used to fabricate items such as:
- Automotive Parts
- Computer Parts
- Medical Equipment
- Toys
- Tools
- Office Supplies
- Screwdriver Handles
- Video Game Cartridges
- Mop Buckets
- Monitors
- Contact Lens Containers
- Catheters
Materials Commonly Used in Injection Molding
Thermoplastic is the most common material used for the injection molding process. However, elastomers, biodegradable plastics, and thermosets can also be used. More specifically, materials that can be used for injection molding include ABS, polycarbonate, and polypropylene. Some materials are more expensive than others. To keep costs low, manufacturers may find an alternative type of plastic for the fabrication process.
Process of Injection Molding
The injection molding process remains the same regardless of which machine is ultimately used. In the first step, the barrel section of the machine is heated. The next step involves placing the pellets, or granules, into a hopper. Inside the hopper, a screw mechanism forces the granules into the heated barrel, where the granules are melted down. The molten plastic is injected into a split die chamber mold cavity. Once the cavity is full, it is clamped shut. Additional fluids, such as water, circulate through the mold’s cooling system and remove the heat. The part is held in the mold under a high amount of pressure until it completely hardens. Finally, upon the solidification of the part, it is extracted from the mold.
Hydraulic oil machines are the most common type of injection molding. These machines use hydraulic fluids to propel the mold through the machine. Toggle injection molding comes in at a close second in terms of popularity, Toggle injection molding machines move the mold through the machine using mechanical links. In recent years, hybrid hydraulic and toggle machines have emerged into the injection molding industry and are increasing in popularity due to their ability to eliminate the problems that the other machines may have, such as rapid wear and tear of the equipment, as well as slow processing rates for parts.
Rapid injection molding is another process that can be utilized. It is the same as normal injection molding, using the same materials and the same type of molds, but it is quicker and has a lower production cost. Because the molds go through the process at a much quicker rate, they need to be of the utmost quality. In the early stages of developing a new product, a company will need to develop a prototype before production of that item can begin. Alternatively, they may request that a product be made in a limited quantity as opposed to it being mass produced. Therefore, rapid injection molding is a recommended process for prototyping and small-scale production. Toys, gears, and enclosures are common items that undergo prototyping. Industries that frequently utilize rapid injection molding for prototyping include appliances, aerospace, electronics, automotive, and medical.
Benefits of Injection Molding
The injection molded process itself comes with a variety of advantages. The process has a high production rate and little to no need for further processing upon completion of the injection molded part. Despite the high tooling cost, the injection molding process has a very low production cost per part. Injection molding is the process of choice to produce highly complex items that no other process can create. Additional advantages include energy efficiency, precision in forming parts, and the small amount of waste produced.
Factors to Consider When Using Injection Molding
Researching the pros and cons of various types of plastic can keep costs at a minimum. For example, not all plastics can be recycled but materials such as polystyrene, polyethylene, and nylon can be. One of the best ways to save money during the production process is recycling and reusing plastics. Many manufacturing companies have representatives that will help customers in choosing the right product the first time, which will fulfill the needs of the customer quickly and save the company money.
Additionally, injection molding machines are made up of a network of motors, heaters, and moving parts that require an extensive amount of energy to carry out their functions. Over the years, research has been done to make injection molding machines more energy efficient. One method that has been developed is a labeling system, which displays the rate of energy that is used by the machine. Regulated consumption of energy can help save a company money in production costs, and a labeling system is anticipated to assist in making that happen.