Extrusion and injection molding are two ways to make plastic products. Injection molding is good for making 3D items, while extrusion molding is for 2D items.
Plastic manufacturing is a domain of production that employs multiple methods of manufacturing. Owing to the high popularity of plastic products, it is important to pay attention to its manufacturing process. Injection molding and extrusion are two of the most popular manufacturing processes employed by plastic manufacturers. It happens to be true that due to slight similarity in the output, these techniques are pitted against each other. This post gives insights about the difference between extrusion & injection molding.
DIFFERENCES INJECTION MOLDING & EXTRUSION
While the final shape required for a part often dictates the process used, both extrusion and injection molding have their own advantages.
INJECTION MOLDING typically has a higher, initial design cost due to the complexity of the mold structure. Its cyclical production, however, typically creates a finished piece that often does not require further assembly or secondary processing.
The EXTRUSION method can create complex cross-sections such as multi-lumen tubing used in medical devices or food processing. The surfaces of extruded materials are smooth and do not require post-production “clean-up.” Extrusion is ideal when a variety of lengths of the same profile shape is required. By producing a stock product with a continuous production process and cutting to length post-process per demand, setup and die/design costs are reduced for similar items.
Principle:
Injection Molding: Melts plastic into a liquid, injects it into a mold, cools, and gets the product.Extrusion Molding: Uses pressure to push plastic through a die, creating continuous shapes like plates or tubes.Advantages of INJECTION MOLDING
Injection molding is a higher quality product manufacturing process than CNC or 3D printing that can maintain intricate precision and eliminate the need for post-processes. Furthermore, it’s highly repeatable and gets affected by economies of scale. Thereby making it an effective choice for industrial production.
There are numerous other advantages of the injection molding process. Some of the most important ones are:
Excellent Precision: One of the key advantages of injection molding is the repeatability and precision it offers. The average tolerance of injection molds is around +/- 0.005 inches but it’s possible to further reduce it and enhance the overall precision of the part.Compatibility With Various Plastics: Another capability that makes injection molding excellent is its almost universal compatibility when it comes to plastics. The process is suitable for almost all kinds of plastics which makes it unique and allows greater versatility from a product development perspective.Consistent Performance: Building on to the previous point of precision, the consistency of injection molding machines is another factor that makes this process so great. The injection molding process generally creates hundreds to thousands of the same parts and all of them will have the same geometric properties as long as the mold is correct. Enhanced Productivity: There are two factors to this quality. Firstly, injection molding machines can handle multiple parts in the same cycle, which means better economies of scale and more efficient production. Secondly, most injection molded parts don’t need any post-processing, which means that they are ready for the market as soon as they are ejected. Thereby enhancing overall productivity by delivering ready-for-market products sooner.Advantages of Extrusion
Extrusion is among a few processes that are remarkably similar for both metal and plastics. Plastic extrusion has a plethora of advantages, and the following are a few of the main ones:
Low Cost: The best part about the plastic extrusion process is the overall effect on the costs. The process is an ideal choice for non-complex 2D parts as it delivers consistent, quick, and quality results in the shortest time.Excellent Surface Finish:Plastic extrusion doesn’t require any post-processing. Plastic is forced through a limited opening with a lot of pressure, which doesn’t let any air bubbles or other deformities remain inside. Thus, the surface finish it delivers remains great.Versatility:No matter what kind of 2D design it is, extrusion molding can handle it like a charm. Furthermore, the process can handle many types of plastics with simplicity. Therefore, it is quite common across the industry.Process:
Injection Molding: Feeds plastic into a machine, melts, compresses, and injects it into a mold for cooling.Extrusion Molding: Involves plasticizing, molding, and cooling in a continuous process.Materials:
Injection Molding: Works for almost all thermoplastics.Extrusion Molding: Suitable for most thermoplastics and some thermosets.Differences in Materials:
Liquidity: Injection molding needs high fluidity, while extrusion is more relaxed.Melt Strength: Extrusion requires higher melt strength.Outlet Expansion: Extrusion has strict requirements for exit expansion.Applications:
Injection Molding: Various shapes and sizes.Extrusion Molding: Films, nets, tubes, plates, sheets, and more.Conclusion
Veejay Plastic possesses many years of experience in working on various plastic material for injection molding. Our plastic experts will work with you to identify the polycarbonates, which are best suited for your industrial applications. They will explain you how each polycarbonate will contribute to your application. For more information on our PC injection molding expertise, or to get started with your plastic injection molding project, contact us today. They have been dealing with automotive, electronics, aerospace, defense, and packaging industries for a long time. Although plastic injection molding and extrusion molding services are widely available, it is important to partner with an experienced company. Veejay Plastic has been providing various types of plastic molding services. They have well-equipped work stations and experienced staff since 1970.
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