The Plastics Comeback- GIT for Plastic Reduction
Our society has long procrastinated on solving the “plastics dilemma.” Pollution from plastics has reached epidemic proportions, from microplastics present in our food supply to plastic waste stashed in the deepest parts of our oceans. Despite mitigation efforts like recycling, we have more plastic waste on Earth today than we have ever had in history, and we are manufacturing more plastics every minute.
In this article, we will discuss the negative impact of plastics on our planet, and promote a unique and efficient plastic part production process known as Gas-Assist Injection Molding (GIT). GIT is good for both the consumer and the plastics producer because it requires less resin to create plastic parts. GIT results in a stronger product than conventional methods, using less resin, which both saves money for the producer and creates less plastic waste in the environment. With this exciting technology, it isn’t too late to help our planet, so long as society acts quickly with an eye for innovation!
I. Negative Environmental Impact As a Result of the Plastics Lifecycle
Plastic has been found in all major ocean basins, and an estimated 4-12 million metric tons of plastic waste entered the marine environment in 2010 alone. Since then, 14 million more tons have been leaking into the seas every year. In fact, plastics in the ocean will soon outweigh, pound for pound, the gross weight of all of the fish in the sea.
It isn’t just oceans that are full of harmful plastics, either. Plastics are estimated to last hundreds or even thousands of years without decomposing, and thusly will remain in landfills for the indeterminate future. Between 1960 and 2005 alone, the percentage of plastics in solid waste grew over 10 times.
One problem is the sheer inefficiency in the plastics lifecycle. Even though 30% of all plastics ever produced are currently in use, recycling plastic can only delay its final disposal, rather than eliminating the toxic materials. Non-recycled plastics will end up in landfills, where they either eventually enter the ocean or add to the enormous amounts of solid waste on our planet, thereby contributing to global warming. Since plastics cannot decompose like organic materials, natural elements like sunlight will only reduce them down into tiny shards in the form of microplastics or nanoplastics (which new research has found could infect food and water, and potentially even stick to human stomach linings).
II. Utilizing GIT Technology to Reduce Plastics Production
There are two ways to address the inefficient lifecycle. We could find a way to safely and sustainably get rid of plastics, but there are millions of tons of plastics scattered across our planet. It will likely take humanity decades to properly gather and dispose of plastics. The more practical and quick response is to reduce plastics production in the first place.
Modern-day plastic parts which include intricate weaves and gaps in their design require a process called “injection molding.” In injection molding, molten-hot plastic resin is injected into a metal mold. This method ensures that the plastic will be in a customized shape once it cools to create a solid part. However, in conventional injection molding, the plastic resin is fed into a screw and barrel where it is first melted, then injected into the mold until it completely fills the cavity. Once the cavity is filled with the melted plastic resin, the screw continues to apply pressure by forcing more material into the part through the runner system and material feed gates. The conventional packing method can result in very high pressure near the gates, with much lower pressure in the areas of the part that are farthest away from the gates. As a result, the final product could be full of stress and warp, while thicker sections of the part may not be sufficiently packed out enough to prevent sink marks.
Gas-Assist Injection Molding (GIT), on the other hand, uses nitrogen pressure to pack out an injection molded part during the cooling phase of the process. The gas is injected into thick sections of the part, or into gas channels that are added to the part design to distribute the pressure as equally as possible. The cavity is not completely filled with resin before the gas is injected. Once the gas is introduced, it displaces the molten resin in the thick areas or gas channels, thusly creating hollow sections. The resin that is displaced is used to finish filling the mold cavity, or it is expelled into a spillover pocket. The GIT packing method leads to much lower internal gas pressure flowing through the part. Lower pressure distributed more equally throughout the part results in less stress and warp, with fewer sink marks.
Excitingly, the main environmental benefit of GIT is that it can reduce the amount of plastic material which is needed to produce parts by as high as 50%. This is in part because of the more efficient cooling process, which uses less plastic to create a lightweight part with a higher quality and increased strength over the conventionally molded part.
III. Technology Which Improves GIT
Various companies have created technology that can improve GIT and incentivize its usage across plastics facilities. For example, BAUER Compressors, Inc. manufactures GIT control systems with True-Track Ramping, a technology that accurately controls the rate of pressure increase or decrease during the gas injection cycle. The BAUER gas control system makes it easier for companies to adopt GIT solutions, as they can precisely measure and control the internal pressure flowing through the part, to ensure more efficient packing and increased part performance. BAUER’s OXYPURGE can also purge oxygen from the mold cavity before the molten plastic resin is injected, which prevents burning in the plastic material.
Plastics aren’t going away for a while – and this isn’t a bad thing. By correctly harnessing new technologies to reduce the production of plastics, we can more easily enjoy the durability and convenience of this important material without furthering its over distribution in our ecosystem.