Fabrication of plastics enjoys wide applications in various industries. It is an essential process to bring a new plastic product to the market. An in-depth look at plastic fabrication techniques, applications, and future trends is provided in this article.
Plastic is made from monomers joined together to form a polymer. It can maintain its shape and has flexibility between cloth and rubber. Plastic is mainly composed of resin, with additives to enhance properties. Some plastics, like acrylic and polystyrene, are made mostly from synthetic resins with few additives.
Types of Plastics
There are different classifications of plastics. According to their properties, plastics can be classified into two types: thermoplastics and thermosetting plastics.
Thermoplastic plastics are a type of plastic that can be molded when heated to a certain temperature and solidified again when cooled. This process can be repeated, and it is a purely physical change.
Some typical thermoplastics are:
- Polyethylene (PE)
- Polypropylene (PP)
- Polyvinyl chloride (PVC)
- Polystyrene (PS)
- Polyethylene terephthalate (PET)
- Polyamide (PA/Nylon)
- Acrylonitrile butadiene styrene (ABS)
- Polycarbonate (PC)
- Poly methyl methacrylate (PMMA/Acrylic)
- Polyvinylidene fluoride (PVDF)
2. Thermosetting plastics
Thermosetting plastics are made mainly from thermosetting resins, along with necessary additives. They are formed into products through a curing process involving crosslinking. These plastics start as a liquid during manufacturing or shaping, but once cured, they become solid and cannot be melted or softened again.
Some typical thermosetting plastics are:
- Epoxy resins
- Phenolic resins
- Polyurethane (PU)
- Melamine formaldehyde (MF)
- Urea-formaldehyde (UF)
- Unsaturated polyester (UP)
- Silicone resins
Properties of Plastics
The reasons why plastics can be applied to nearly all industries are the benefits they offer by their excellent properties.
1. Strength and durability
Plastics can show high strength and durability, making them able to withstand various mechanical forces and impacts. They can be engineered to have different levels of strength depending on the intended application.
2. Flexibility and elasticity
Plastics can be flexible and elastic, enabling them to bend, stretch, and return to their original shape without breaking. This property makes plastics suitable for applications that require flexibility, such as packaging materials and plastic films.
3. Heat resistance and insulation
Many plastics have good heat resistance. So they can withstand high temperatures without deforming or melting. Additionally, plastics are often excellent insulators, both electrically and thermally. It makes them useful in electrical and electronic applications, as well as in building insulation.
These characteristics, along with chemical resistance, lightweight, and ease of processing, have made plastics widely used in industries like automotive, construction, packaging, electronics, etc.
Common Fabrication Techniques
Injection molding is a widely used technique where molten plastic is injected into a mold cavity and cooled to form a solid part. With a long history, injection molding is a very mature technology. It offers fast production, high efficiency, automation, diverse colors, complex shapes, and precise dimensions. Injection molding is suitable for large-scale production and complex products.
Blow molding creates hollow plastic parts, such as bottles or containers. Plastic is melted and then air pressure is used to expand it into the shape of the mold. The types of blow molding techniques are extrusion blow molding, injection blow molding, and stretch blow molding. This technique of fabrication of plastic finds applications in various industries, including packaging, automotive, consumer goods, and healthcare.
In extrusion, plastic is melted and forced through a die to create continuous shapes such as pipes, tubes, and sheets. It is a continuous process and can be used for both simple and complex profiles. According to the different desired shapes, the different types of extrusion are profile extrusion, sheet extrusion, film extrusion, coextrusion, wire and cable extrusion.
Extruded plastic products often have good strength, durability, and weather resistance, and can be tailored to meet specific requirements such as flame retardancy or UV resistance.
Computer Numerical Control (CNC) machining involves using computer-controlled machines to precisely cut and shape plastic parts from a solid block or plate of material. General CNC machining techniques include milling, turning, drilling, and routing.
With high precision, accuracy, and repeatability, CNC is suitable for producing prototypes or low-volume production runs.
Vacuum casting involves creating a flexible mold around a master pattern using silicone rubber. It can produce complex parts with a good surface finish, using a wide range of materials. However, vacuum casting is limited to smaller-sized parts, longer lead times, and fewer material options than other methods like injection molding.
Advanced Fabrication Techniques
In rotational molding, powdered plastic is placed in a mold, heated, and rotated to create hollow parts. It offers advantages such as seamless construction, design flexibility, and cost-effectiveness. It makes products like storage tanks, automotive components, and outdoor furniture.
A heated thermoplastic sheet is shaped using vacuum, pressure, or mechanical force during thermoforming. It is applied to produce lightweight parts with complex shapes at a lower cost. Typical types include vacuum forming, pressure forming, and twin-sheet forming. Thermoforming finds applications in packaging, automotive, aerospace, and healthcare industries, but material selection and structural considerations are vital.
Compression molding is a technique of fabrication of plastic where pre-measured polymer material is heated and compressed in a mold to take the shape of the cavity. It is suitable for producing large and high-strength parts with good surface finish but has restrictions on design flexibility and cycle times. Many industries use it, including automotive, aerospace, electrical, and appliance manufacturing.
Emerging Trends in Plastic Fabrication
An emerging trend is the integration of innovative techniques such as additive manufacturing (or 3D printing). The advantages of aster iteration, complex geometries, and reduced waste make it an ideal tool for prototyping and low-volume production. The combination of CNC machining and 3D printing is one of the most prominent examples.
Another trend is increasing sustainable plastic fabrication methods to minimize environmental impact. Through recycling and upcycling, using renewable materials, and reducing energy consumption, eco-friendly fabrication methods contribute to a more environmentally friendly and resource-efficient future.
Selecting the Most Suitable Plastic Fabrication Method for Your Product
You may be confused by so many fabrication methods of plastic. Turning to an insider with industry expertise and rich experience would save you time and money. X Rapid Technologies is always available to help you choose the right material and production method. Just send us an email today!