Products made of plastics are part of our daily life. Their presence can be seen everywhere we go like in school, at work in our offices, and especially in our home. We know how to use different shapes and forms of plastic products but do you know what are the different types of plastics and how to manufacture plastic products? Read until the end because this article will give you information about plastics and you will learn some tips for better manufacturing plastic products.
Table of Contents
- 1 Different Types Of Plastics
- 2 Plastic Manufacturing Process
- 3 Different Methods for Plastic Products Manufacturing
- 4 Tips for Better Manufacturing Plastic Products
Different Types Of Plastics
There are various types of plastics having different derivatives, base chemistries, and additives that are formed to be used by humans. The two main types of plastics are thermoplastics and thermosets.
Thermoplastics are the most common type of plastics that are being used. It can have numerous melting and solidification cycles without having significant degradation. These are the following thermoplastics that we normally used: the first is Polyethylene Terephthalate (PET) which is strong, lightweight, transparent, and commonly used in fabrics and food packaging. Examples are food bottles, beverage bottles, and polyester clothing. We also have Polyvinyl Chloride ( PVC or Vinyl) which are hard plastics that are usually used for building and construction applications. PVC is the most dangerous plastic for human health but this is widely used in medical applications. Common examples are credit cards, human pet toys, oxygen masks, plumbing pipes, and rain gutters. The most common plastic in the world is Polyethylene and is classified into three: High-Density, Low-Density, and Linear Low-Density. Milk cartons, toys, cereal box liners, pipes, park benches, and detergent bottles are examples of High-density Polyethylene. The most durable type of plastic is Polypropylene (PP). It is more resistant to heat which is ideal for food storage and food packaging. Examples are bottle caps, straws, packaging tape, disposable diapers, hot food containers, and prescription bottles.
Thermosetting plastics or thermosets will remain in a permanent solid object after the curing process. Instead of being melted, thermosets will decompose after when heated and when cooling, they will not reform again. Common examples of thermoplastics are epoxy, polyester, silicone, vulcanized rubber, polyurethane, and cyanate ester.
Plastic Manufacturing Process
Manufacturing procedures depend on what type of manufacturing process is being used. There are 8 different types of manufacturing processes namely: 3D Printing, Polymer Casting, Vacuum Forming, CNC Machining, Extrusion, Blow Molding, Rotational, and Injection Molding in which these processes use additive manufacturing technologies. But for the conventional one, this type of process involves changing the different shapes of raw materials so that model will be created by using hand tools or molds to mechanize material. This is the Conventional Manufacturing technology process: molding, extrusion, calendering, and subtractive manufacturing. During molding, it will produce plastic pieces with a mold by casting and injecting. Then by having extrusion, you need to gradually melt the plastic and mix it inside an extruder. In calendering phase, plastic materials are forced to pass in two-counter rotating rolls and it will transform into a thin film. Lastly, in subtractive manufacturing, materials are being cut away from a solid block so that a 3D model will be constructed. There are also four steps in the manufacturing process of extrusion molding works. First, plastic is heated and by having a heated chamber, plastic will push through using a screw. Second is the molding in which plastic is being forced through a die to create the final shape of the part. Then it is being cooled and the last one is the cut or spool in which the shape is being cut into lengths.
Different Methods for Plastic Products Manufacturing
Most of us use different plastic objects in our everyday living but do not know how these products are being manufactured. Let us discover then the six different methods used in manufacturing plastic products.
Plastic Injection Molding
Plastic injection molding is the most popular manufacturing plastic process used by companies because it can produce thousands of plastic parts at once. This process uses die or molds from stainless steel or aluminum so that plastic will be formed. The mold is being placed in the injection molding machine and plastic material is being injected and molted into the mold. The plastic parts are being ejected from the mold once they are cooled and become hardened under great hydraulic pressure.
Reaction Injection Molding (RIM)
RMI is the best manufacturing process in producing hard plastic parts. It is commonly used by automotive industries in creating plastic parts of a vehicle like bumpers, stepping boards, and dashboards. It undergoes a chemical reaction inside the mold using thermosetting plastic so it will expand. The plastic part takes in its final form after the chemical reaction is being complete. This can be the most expensive one because of the materials being used and the intensive complex labor applied.
Injection Blow Molding
This is normally used so that plastic bottles will be created. To force molten plastic into the mold, manufacturers of plastics use gas pressure with injection blow molding. Polyethylene terephthalate (PET) and Polyether-ether-ketone (PEEK) are the plastic materials being used in this process that are safe to use for its consumers.
Extrusion Blow Molding
This method uses a parison which is a molten plastic in a balloon formed and is being placed in a dual-piece mold. The parison is inflated until it will fill the empty mold cavity once it is being sealed. The plastic can easily be injected and it quickly hardens because the sides are water-cooled. This is good to use in making plastic cups, bottles, and small-sized plastic containers.
Casting was used before in producing metal products but now, it is being used for making plastics. It is a craft process and is good for low-production needs. It is used for producing rods, sheets, tubes, jewelry, and radio housings. Casting employs Phenol-Formaldehyde, Polymethyl Methacrylate, and Polyurethane. This is poured in an open mold and once cooled, it will solidify to form the product.
Vacuum casting is the best use in making plastic parts without having enough capital for plastic materials and tools. A 3D product prototype will be placed in a sealed box with silicone. Once the 3D image is being removed, a cavity is formed and it can be filled with plastic resin so that the original model will resemble. To take the air out of the mold, vacuum pressure is being applied.
Rotational molding is a plastic manufacturing method and is commonly known as Roto Molding which uses mold with a core and cavity side. Plastic materials are being poured into an empty cavity and heated in an oven. The mold will be constantly rotated by two axes and by having enough gravity, the plastic will remain on the tool walls so that the right amount of thickness will be built up. Before the tool gets open, the part is allowed to cool and have it removed.,
Tips for Better Manufacturing Plastic Products
To develop strong products from plastic materials, injection molding is the most commonly used process but it is only productive in industrial ecosystems that are large wherein there is high demand. For low-volume production and intermediate demands, casting, rotational molding, and fabrication are the three efficient methods being used. Some of the tips or recommendations for better manufacturing products aside from those methods being mentioned, maintaining order and cleanliness is important. You must keep production areas as always clean. There might be stains on machines, pellets spilled, oil, dust, and spilled water everywhere that might complicate defect detection. Disordered production areas will cause delays and might generate more failures. Your cabinet with tools and inputs must be organized. If each important tool is in place and each tool corresponds to each job well, then the job becomes faster and more output will be produced. Screws, barrels, and other machine parts must be cleaned inside and out. If all machines are always clean and have regular and proper maintenance, equipment will perform at its best. During production, there must be appropriate cleaning to avoid having contaminants and to maintain the quality of the product. Once the production is finished, you need to clean the cavities’ molds and also the casts. Before you enter the tools in a warehouse for safekeeping, do this proper cleaning first. Auxiliary equipment like chillers or heating elements must be kept clean at all times.
Knowing how to manufacture plastic products is important for us to know and give importance to plastics wherein for others this junk thing has no value or is just worthless that is thrown in the trash. Manufacturing plastic products is complex, time-consuming, and it needs keen knowledge, interest, and human efforts so that end users can fully use the new plastic being newly manufactured. Let us conserve and reuse those plastics especially those that are not or seldom being used. They have pure value and are needed by individuals. So use, reuse, and recycle plastics well not just for us but for our next generation as well.