Plastic manufacturing is the design, manufacture, or assembly of plastic products by one of several methods. Some manufacturers prefer to make plastic over working with other materials (such as metal or glass) because of the advantages of the process in certain applications.
Plastic bottles: products used to manufacture plastic
Image source: Tezzstock / Shutterstock
Plastic manufacturing methods
The malleability and cost effectiveness of plastic make it a versatile and durable material for a number of different products.
As with metal welding, plastic welding uses heat to fuse two or more workpieces together. This method is effective in handling thermoplastics that are not suitable for bonding. Individual parts are often fused with a filler material in between, especially if the plastics have very different melting points. Welding can be done by a variety of methods including hot gas emissions, high frequency vibration, spinning, or contact welding. The equipment used in plastic welding depends on the process chosen and the type of plastic used.
Compounding (or mixing) plastic Manufacturing techniques
Compounding is a type of manufacturing that involves combining two or more plastics into an amalgam before forming them into a single part. Melted plastics are mixed according to precise specifications and then shaped with a mold, die or other shaping tool.
Compounding is often used to improve the ease of processing of a given material or to improve product performance. By combining the advantages and disadvantages of several types of plastics, the process can result in a unique material that compliments a specific application. Some common types of plastic compounds are:
- Polymer fillers
- Base resins
- Pigment masterbatches
- Flame retardants
- Purge connections
The plastic lamination creates a barrier along the surface of another material. This process is most commonly used to improve the durability, styling, or aesthetic quality of a product. It can also be an inexpensive measure by shielding a delicate or susceptible material and reducing its potential maintenance needs.
Film and resin are the two most common types of lamination. Both methods apply heat and pressure to a manufactured film to allow it to adhere to a moving substrate. Foil lamination is more effective for forming a plastic barrier on the outside of a product, while resin lamination is more commonly used to create an adhesive layer between two substrates. Paper, fabrics, sheet metal and flexible foam are common base materials for lamination.
In plastic molding, plastic is brought into a certain shape by allowing the heated, flexible workpiece to cool and harden around or in a mold. There are numerous plastic molding processes including injection molding, blow molding, and rotational molding. Blow molding is widely used to make containers such as bottles or fuel tanks, while injection molding is useful in applications that require a higher melt index, such as making tableware. Rotomolding leads to hollow plastic products such as canoes, toys, buoys, and automotive parts.
Plastic extrusion can be used to make pipe, pipe, or film components. It is also used to increase the effectiveness of further forming or processing steps. For example, plastic extrusion is often a precursor to adhesion or lamination processes.
Profile extrusion and sheet extrusion are the most common forms of processing. to Briefly describe the plastic extrusion process: pProfile extrusion uses a single screw extruder to melt plastic pellets, move the molten plastic through a pressurized screw mechanism, and force it into an annular die. The plastic then solidifies around a calibration sleeve to create a pipe or pipe component of a specific diameter. Unsurprisingly, sheet extrusion uses a similar technique to make thin plastic sheets.
Foam products can be formed into a variety of different shapes. Common foam configurations include round, sheet, film, solid plank, rod, and roll material. To achieve the desired properties, polymer composites are typically formed by a physical or chemical blowing process. As with compounding, additives such as pigments, antioxidants and flame retardants can be incorporated into the base material to optimize product performance for the user.
Choosing a plastic manufacturing process
Product functionality and ease of manufacture are important factors to consider when choosing a plastic manufacturing process. Some methods are inefficient at making certain types of plastic and therefore may not be helpful for your particular project. Some other issues to be aware of include:
- The need for individual plastics versus plastic compounds
- The intended ratio of plastic to non-plastic material in the product
- The role of plastic in your manufacturing process (as an adhesive, lamination or base product)
- The dimensions and use of the final product.
- Plastic definitions
- Types of plastic
- Plastic production for life sciences