The most common methods are:
- Plastic extrusion
- Injection molding
- Rotational molding
- Plastic extrusion & injection blow molding
- Vacuum casting
- Thermoforming and vacuum forming
- Compression molding
What are these methods, let’s analyze it
MANUFACTURING PROCESSES FOR PLASTICS
During this process, plastic powder or pellets are fed into the extruder through the hopper. The polymer is heated inside the barrel at a controlled temperature. A screw pushes molten plastic through a metal mold, which is then cooled to give the plastic a constant, fixed shape while it is continuously pulled and shaped into its final shape. The product can be shortened or cut to the desired length.
This is a prevalent method for manufacturing plastic products. High-volume production of various types of products, such as pipes, door and window frames (for example hollow doors), seals, or other construction products like ventilation, is facilitated by the plastic extrusion process.
A hopper feeds plastic polymers into a heated and screwed barrel. During meltdowns, the screw melts the plastic and injects liquid polymer into a temperature-controlled split molding tool to achieve the desired shape. Injection molding is used for high-volume production and many parts can be produced in a short period of time, from small parts to large parts such as bumpers and pans. Unlike extrusion, molten plastic is forced through a die to take its final shape.
EXTRUSION AND INJECTION BLOW MOULDING
Plastic extrusion and injection molding share similarities, except for the hollow plastic created by air pressure expansion in the mold or extrusion form, which causes the object’s interior to become hollow. This process is used to mass-produce inexpensive containers such as bottles, cups, and beakers.
PLASTIC ROTATIONAL MOULDING
This is the second option for manufacturing hollow plastic products. In this process, plastic polymers are placed into a mold before heating. The closed mold goes into the oven and rotates, allowing the plastic polymer to evenly coat the entire inside of the mold.
Upon heating the material, it is melted into a single layer that conforms to the mold cavity’ interior and creates ductile hollowness. A jet of water cools the mold as it rotates, solidifying the polymer. The rotation stops, the mold opens and the plastic part is removed.
Suitable for short run, economical production runs and not suitable for precision shaping due to part finishing.
Method of manufacturing low-volume, high-quality prototypes from small functional plastic parts. Vacuum molding is a highly versatile technology for elastomers that uses a vacuum to draw liquid raw materials (e.g., polyurethane resin, molded nylon, and wax) into a mold.
This process is used when air trapping is a problem, if there are intricate details or recessed surfaces, or if the material is reinforced with fibers or wires (e.g., glass-filled nylon). The raw material is poured into a two-part silicone mold and the vacuum is released.
The mold is removed from the chamber and the casting is hardened in the furnace. The mold is then removed to release the casting. Molds can be reused.
After extruding a plastic sheet, it is heated to flexibly shape it into a shape that will precisely fit your desired outcome’, before being die-cutting.
These machines can quickly produce thousands of parts. Products such as disposable cups, containers, lids, trays, blister packs, and other products are available in the food industry, medical industry, or general retail. A simple version of thermoforming is vacuum plastic forming.
This method is commonly used in thermosetting polymers (which become irreversibly hard when heated). The raw material is preheated and placed into the open mold cavity. The mold is closed with a lid and pressure is applied to force the material into all areas of the mold.
The material is kept under heat and pressure until it becomes hard. Once hardened, the product formed can be removed. This plastic molding method is frequently used in the production of automotive parts such as hoods, fenders, and spoilers, as well as smaller, more complex parts. It is also widely used to create sandwich structures such as honeycomb or polymer foams.
It is a subtractive process that uses computer-controlled cutting tools including milling machines, lathes, and drills to create plastic parts. Unlike additive manufacturing, the material is gradually removed from a block, commonly known as a blank, to create the finished part.
There are two primary types of CNC machining: milling, which involves spinning tools and fixtures, and turning, which uses fixed tools and a rotating part.
This process uses CAD designs and models to create three-dimensional parts by adding manufacturing materials layer by layer until the part is completely formed.
Compared to most other manufacturing processes, 3D printing has few restraints on design making it an extremely economical way of generating components that have complicated shapes.
Unlike CNC machining, for example, where engineers may need to consider how the milling head will reach tight spots, as well as the size of the tools needed to create fine details of the shape of the part, 3D printing allows for complex work design features: for example, curved internal channels – crafted without any assistance.
Additives have the ability to create complex designs that are difficult or impossible to achieve efficiently with other manufacturing processes. This also allows a part to be made as a single block, rather than multiple parts then being reassembled.
Factors to consider when manufacturing plastic parts
Because there are many different manufacturing processes available, it is important to choose the process that best suits the part.
Here are some considerations to keep in mind.
A part’s application is a key consideration when selecting possible materials, and determining the physical properties that are most beneficial to the part in question can help narrow down the options choose materials. However, it is important to note that certain materials are better suited to specific manufacturing processes.
For example, low-stiffness, elastic polyurethane parts are easily produced using urethane casting but are extremely difficult to machine when 3D printing. In some cases, desired material properties can even be enhanced by strategic selection of manufacturing methods.
By considering Model Factors like tight tolerance requirements, unique internal characteristics, or high levels of geometric complexity, determining which manufacturing process is most cost-effective and efficient can help. If the part requires a specific process, a design for manufacturing (DFM) review may be necessary to optimize manufacturing profitability.
As such, one critical consideration for identifying the ideal manufacturing method is to anticipate production time for the final part since several production time rates could differ. Some of these 3D printers print whole, working parts within a few hours depending on how they have been set up and what kind of part or machine it is. However, for instance, at the opposite extreme, although the injection molding procedure may be quite efficient, involving cycle times occasionally only minutes long, the final molding might still take many months to finish. , prolonging production progress.
Volume and cost
The final major factor to keep in mind is the required production volume. Injection molding systems require high upfront costs, which tend to be economical when running high volumes but are inefficient when prototyping. Other processes, such as CNC machining, have lower upfront costs but can easily result in higher costs per part depending on the amount of manual labor involved. It is essential to find the right balance between production volume and profits.
Start ordering plastic parts
Plastic comes in so many different forms because it is very versatile and there are various ways of making different types of plastic. There are various parameters that would determine the right process for any particular part. They include the part’s application, design, production scale, and delivery schedule.
Since we are working with our clients to achieve quality products manufacturing at UEW is by far among many others.Are you willing to commence with the manufacturing process? Get in touch with us if you require clarifications on how we operate together.