Plastics are found everywhere in our lives, you find them as bottles of water, toys, and in tiny objects like cell phones or medical devices which can be implanted in the body.
Have you ever wondered how each product we use is manufactured? It is all thanks to plastic injection and injection molding, do you know what they are about?
Do not worry! The experts at Precision Group bring for you this article to learn more about the plastic injection molding process in San Antonio. If you are looking for a company that supports you in the creation of products, the mold manufacturing for your business, or simply to know more about the topic, we invite you to read it!
What is plastic injection molding?
Before going into details, let’s start by clarifying what plastic injection is: In engineering, it is a technique that consists in molding a plastic product through the pressure injection of plastic polymers.
In other words, we have a mold with the shape of the final product; this product has a nozzle through which hot resins enter filling each cavity of it, and when it cools, the product is ready to use.
Later on, we’ll discuss the manufacturing process of plastic products thanks to plastic injection in San Antonio.
What type of polymers are used for plastic injections?
Plastic injection is a process that needs to be precise; that is the reason prior to the manufacturing of plastic injection molding in San Antonio the characteristics of the product and the client’s specifications are considered to determine the best materials for the creation of the product.
At this point, it is explained some of the most common plastic resins used in plastic injection. However, it is necessary to clarify that any type of polymer is viable for this process, it depends on the needs of each person and product.
- Polyethylene (PE): Household products are manufactured of this type of plastic. It is used not only for plastic containers, bottles, bags, but also for bulletproof vests by using a different treatment.
- Polypropylene (PP): This type of polymer is not toxic, therefore it is used to manufacture children’s toys and different medical tools for example syringes.
- Polyvinyl Chloride (PVC): It is one of the most popular plastics due to its use in pipes since it is highly resistant to chemicals.
- Polyethylene Terephthalate (PET): This polymer is widely used in the manufacture of plastic bottles and containers.
- Polystyrene (PS): This type of plastic resin is used in the manufacture of household appliances, toys and the automotive industry.
Plastic injection process
Once you know the most common types of plastic resins, it is the moment for you to learn more about the plastic injection process; it has four stages and the second one has two phases.
1.- Mold closure
The first stage consists on placing the mold in the press and closing it under pressure and, once the plastic injection cycle begins, the material won’t come out. Likewise, the product’s specifications and the mold will determine the amount of pressure that needs to be applied.
There are pieces that require a pressure of over 2,000 tons to produce them. To have an idea of the power of this process, a diver swimming in the deepest earth’s ocean trench would have to withstand 10 tons of pressure.
The second stage of plastic injection has two phases: The filling phase and The sustaining phase.
2.1.- The filling phase
After the mold is already closed, the screw or spindle rotates to drive the plastic resins into the injection chamber, and when it is full, the heaters will melt the plastic. When it comes in contact with the mold, it does not cool down so fast, and you can get the desired shape.
2.2. The sustaining phase
In this phase, pressure is maintained to keep the same temperature in the plastic before the plastic injection process begins.
3.- Plasticization or dosage
Once the mold is closed and the chamber full, the plastic resins are injected into it, then, the screw rotates to transport the material forward and fill all the mold cavities. This stage is performed at the same moment the plastic is cooled to optimize the processing time and to have the plastic product ready more promptly.
4.- Mold opening
When the mold temperature and the plastic piece are at the extraction point, the mold is opened and the product is removed from the interior to close it again and restart the process.
Advantages of the plastic injection
Plastic injection is a simple process for those who have the experience and knowledge to select not only the plastic polymer, but also the ideal pressure for each type of mold. Additionally, it has several advantages for companies and entrepreneurs with the objective of optimizing costs in the development of their products.
1.- Mass production
The plastic injection molding is a process that allows the creation of plastic parts and products in mass. A single mold can be used hundreds, thousands, and millions of times without affecting the dimensions.
At the moment a plastic injection mold is manufactured, the dimensions should be very well analyzed since the equipment is complex and highly precise to avoid having to re-manufacture a plastic part.
3.- No finishing processes
Finally, with the plastic injection molding you avoid detailed processes because it’s not needed. The product is finished and ready to be sold at the market.
3 Industries using plastic injection molding
The three industries that incorporate plastic parts created from injection molding are the following:
- Consumer: This may not seem new to you. Consumers in general are full of products that are created thanks to plastic injection as they develop different containers, from plastic bottles to cookie bags or refractories to storage food or even household appliances.
- Automotive: In the same form, the automotive industry uses plastic injection molding to create pieces and components for the correct functioning of vehicles, ranging from the caps that cover the elements of the hood to the bumper or the dashboard.
- Medical: Finally, the medical industry implements plastic injection molding, as it is mentioned before, from the manufacturing of syringes to more specialized medical devices with the necessity to have better plastic quality, to mention an example: the rapid test for the detection of the SARS-COV-2 (COVID-19)
Now, you know more about what plastic injection molding is, how it works, some advantages, and the process to follow and get these types of products. Don’t forget to share this post on your social media.
Stay tuned for updates in our blog because the Precision Group is developing more content for you about plastic injection.