Plastic fabrication is a crucial CNC plastic machining process used in manufacturing all sorts of plastic products. However, with so many different plastic fabrication methods available, it can be hard to know which process is best for specific applications. This complete guide will help explain the most common plastic fabrication processes and factors to consider when selecting one.

Injection Molding

Injection molding is one of the most commonly used plastic fabrication processes. It involves melting plastic pellets or resins and injecting them into a mold cavity under high pressure. This allows the plastic to take the precise shape of the mold.

Injection molding can produce large volumes of accurate, consistent plastic parts very quickly. It is well-suited for mass production applications.

Molds are usually made from metal like aluminum or steel. Steel molds offer more durability but aluminum molds conduct heat more efficiently.

Blow Molding

Blow molding begins by extruding melted plastic into a hollow tube called a parison.

The parison is then clamped inside a mold and air is injected inside to expand the plastic against the mold walls. This produces hollow plastic containers and bottles.

Common blow molded plastics include polyethylene (PE), polyethylene terephthalate (PET), and polyvinyl chloride (PVC).

Thermoforming

Thermoforming involves heating flat plastic sheets and then forming them to a mold using pressure, vacuum forming or other methods.

Once softened, the plastic easily takes on the mold shape and then cools to retain its new form.

Thermoforming produces things like food packaging trays, plastic medical products, and more using materials like polycarbonate and polystyrene.

Factors to Consider When Selecting a Plastic Fabrication Process

Beyond just the type of parts being made, several factors must be weighed when determining the best plastic fabrication process:

• Volume needed - High volume processes like injection molding are best for mass production while low volume options allow for smaller batch sizes.
• Part design and tolerances - More complex or precise geometries may limit suitable processes.
• Material used - Different plastics are better for certain fabrication methods.
• Budget - Process costs including tooling, labor and equipment should factor in.
• Timelines - Some methods have longer setups but faster cycles times than others.

Other Plastic Fabrication Processes

While injection molding, blow molding and thermoforming are among the most common, other plastic fabrication options exist such as:

• Vacuum forming: Similar to thermoforming but uses a vacuum to draw the plastic sheet tightly over a mold.
• Rotational molding: Plastic powder is fused inside a mold rotated in a heated oven.
• Compression molding: Heated plastic is compressed in a mold by pressure and cooling.

Casting: Molten plastic is poured or injected into molds like die casting.

Selecting the Right Process

With knowledge of the various plastic fabrication methods and considerations, manufacturers can determine the most suitable process for their specific application and production needs. Prototyping services are also helpful when first developing new designs to test different manufacturing approaches.

Plastic fabrication enables the mass production of an enormous variety of plastic products through tailored processes. Careful evaluation of factors such as part design, materials, production volumes and schedules ensures the optimal plastic forming technique is applied. Following this comprehensive guide provides insight towards selecting plastic manufacturing processes for both short and large scale product runs.