Injection molding is used to manufacture various products from plastic, resin, or other components. Like every other production method, injection molding has benefits and drawbacks. Injection molding has several advantages. It minimizes molding costs and is a highly repeatable way of producing plastic or elastomeric parts with high precision. Once set up, it can manufacture a large volume of parts per hour, from a wide range of plastics plus other materials such as liquid silicone rubber.

However, like any manufacturing process, it does have some disadvantages, and if these prove significant to the success of your project.

We shall go over the advantages and disadvantages of the injection molding method in this extensive post.

What is Injection Molding? 

Injection molding is a manufacturing technology for the mass-production of identical plastic parts with good tolerances. In Injection Molding, polymer granules are first melted and then injected under pressure into a mold, where the liquid plastic cools and solidifies. The materials used in Injection Molding are thermoplastic polymers that can be colored or filled with other additives.

• Mold design: Mold design is the initial and most crucial stage. It takes a very accurate mold that exactly matches the desired shape. Steel and aluminum are common metals used for molds since they can endure high pressure and temperatures.
• Materials selection: Injectable thermoplastics come in a wide range of strengths, flexibility, and heat resistance qualities. The use of your finished product determines the material choice completely.
• Molding process: The plastic or other thermoplastic material is heated in a barrel till it melts. Then, a plunger forces the molten plastic into the mold cavity under high pressure. The plastic takes on the necessary shape inside the mold as it cools and solidifies.
• Part ejection: Once cooled to the design temperature, the mold opens, and the finished part is ejected. After the removal of any extra material—like sprues and runners, which are conduits that carry plastic into the cavity, the process repeats for the next production.

The effective automated method enables the bulk manufacture of identical plastic components.

Advantages of Injection Molding 

Manufacturers choose injection molding because of its various strong benefits:

• 1) High Precision and Repeatability: 

• Parts produced by injection molding are extremely accurate and have close tolerances. Applications needing exact fit and function, such as medical equipment or electrical components, depend on this uniformity.

• 2) Mass production: 

• High-volume manufacturing is where injection molding shines. For high-demand products, the mold is perfect. You can produce identical components quickly and accurately.

• 3) Extensive Material Options: 

• Inject molding provides a large range of materials to meet various requirements. Starting from standard plastics like ABS and polypropylene to specialized resins with particular specifications, any material is suitable for the injection molding process.

• 4) Fast Cycle Times: 

• Based on the product complexity, injecting a part can produce a part in 10 seconds. This process is the most suitable one for satisfying tight deadlines.

• 5) Design Flexibility: 

• Parts with complex shapes can be produced using injection molding. Most often, injection molding can manage moderate to complex designs.

• 6) Low Material Waste: 

• Injection molding produces less scrap than conventional techniques. Waste of materials is reduced even by reusing unused runners and sprues.

• 9) Surface finish: 

• The mold itself can impart specific surface textures or finishes onto the parts. Separate painting is also not necessary because pieces can be colored directly during the molding process.

Disadvantages of Injection Molding 

Though there are several benefits, injection molding has certain limitations.

• 1) High Initial Cost: 

• The biggest challenge is the initial investment cost. Particularly for intricate items, the cost of designing and producing the mold is significant. Such high expenditures are not practical for low-volume production.

• 2) Long Lead Times: 

• Mold design and manufacture require time. Perhaps injection molding isn't the best choice if you need parts quickly.

• 3) Design Restrictions: 

• Even though injection molding provides flexibility, there are certain design restrictions. Manufacturing products with extreme undercuts or very thin walls could be problematic. Successful molding requires careful design.

• 4) Material Restrictions: 

• Not every material can be injected. Some high-performance materials or those with high melting points might not be compatible with the process.

When Should You Use Injection Molding? 

When complex pieces or bulk manufacturing of resin or plastic components are required, injection molding performs admirably. If you can afford a large initial outlay and require a large number of similar parts at a fair price, this method could be the best option. Other methods, such as 3D printing or CNC milling, might be more suited for smaller items, low-volume jobs, or situations requiring a quick response.

Injection molding is an excellent manufacturing technology for producing mid- to high-volumes of parts in plastic and liquid silicone rubber. It is evolving over time so it is worth exploring new ideas which could help you reduce your part cost for smaller production runs. Explore Mech Power’s Injection molding service and our team of experts can guide you through the entire production process. Inquire with us today!