In the same way that uses for plastics are varied, so are their production methods. Low volume plastics refer to those niche or small-sized plastics whose customized production demands specialized manufacturing methods.
For instance, you may have wondered how dispensable drinking cups or brand-specific water bottle designs are manufactured on a small scale. Even more intriguing, is how clamshell packaging is achieved (packaging that completely surrounds and conforms to the shape of the packed item).
You might even be tempted to wonder whether the manufacturers of such items necessarily have the packaging infrastructure installed on their production lines to cater to these needs.
If you have a new plastic project to do, you will be happy to learn that you can conveniently outsource plastic parts production and that most expert fabricators offer a variety of low volume plastic production methods. The following are the three most effective low-volume plastic parts production techniques you can deploy for the large scale manufacture of different components for your projects.
Rapid Injection Molding
Rapid injection molding is the most popular low volume plastic parts production method because it allows you to create virtually any design.
It is a rapid tooling method that delivers fast and quality prototypes of your quality plastic parts.
Primarily deployed at the research and development stage of production, rapid injection molding is a pre-production process. It involves the sending of a computer-assisted design (CAD) file of the desired product to a fabricator who then mills the desired mold.
As a tooling method, it enables the quick and affordable production of a prototype from aluminum and allows a client to quickly discern the viability of their design.
It is an affordable method that also allows the manufacturer to test run the parts using a production-grade prototype and where necessary, effect changes.
Due to its ease of production, rapid injection molding also enables the manufacture of plenty of parts within a short period.
To determine whether a particular design can be manufactured using this method, the fabricator considers several factors.
One of these is whether the proposed design has a consistent wall thickness. Designs with inconsistencies in their walls are usually likely to end up with distortions and warps, which will in turn impact the integrity of the part.
When put to use, distorted or warped parts tend to perform dismally and might not render the desired results.
Another point of consideration that fabricators bear in mind is the part’s geometrical design. An ideal design is one that avoids unnecessary use of material while maintaining its strength and stability.
Rapid injection molding is done with materials that offer decent resistance against heat, UV rays, fire, and chemicals.
Extrusion blow molding
Extrusion blow molding is the easiest and most affordable way to make disposable plastics on a massive scale.
Some of the items manufactured using this method include disposable cups, soap and detergent bottles, and other small commercial product containers.
While versatile and quick to produce, this method cannot be deployed in the manufacture of complex designs.
Extrusion blow molding involves the use of a water-cooled mold. The mold is constituted of two halves placed opposite each other in a clamshell design.
Molten plastic (or parison) is blown into the cavity of the water-cooled mold, which is then closed. Air is then blown into the cavity, forcing the molten plastic to attach to the walls of the mold and cool into a rigid container.
The product is then ejected from the mold and any excess material is trimmed off.
Some of the advantages of extrusion blow molding include the capability of having multiple necks on one container, inclusion of handles, labels, and embossments.
Also, this fabrication method allows a manufacturer to inexpensively produce a large quantity of items within a short period.
Products developed through extrusion blow molding are also easily recyclable compared to some of the other low volume plastic parts production methods.
The most commonly used materials in extrusion blow molding are thermoplastics and polypropylene (PP), polyethylene, and nylon.
Unlike extrusion blow molding, thermoforming works with a one-sided cast or mold.
To achieve the desired result, a plastic sheet is exposed to heat until it becomes pliable. It is then stretched over the single sided mold and manipulated to conform to the mold design.
The method relies on the use of heat, and the application of vacuuming pressure to transform a plastic sheet into a three dimensional item.
Thermoforming plastics are used in the production of clamshell packages for different kinds of products.
Typically, with clamshell packaging, thermoforming renders a three-dimensional wrap design. On one half of the pack, the packaging will take the shape of a particular product while maintaining a flat surface on the opposite side.
Due to its asymmetrical design, thermoforming is also deployed in the manufacture of automotive interior door panels, air ducts, dashboards, and other accessories.
For most manufacturers, thermoforming offers an affordable way of ensuring that the packaging of their products is safe. That is because products packed using this method are insulated against damage from improper handling.
It is also a flexible tooling design that can be manipulated to produce a variety of product designs including complex shapes and sizes.
The polymers used in thermoforming designs are of a light weight, thus ideal for most product applications.
Also, compared to other plastic molding methods in use today, thermoforming plastics have a longer shelf life and are thus ideal for products that need to stand the test of time.
Some of the most commonly used plastics in thermoforming include polypropylene (PP), polycarbonate, polymethyl methacrylate (PMMA), HDPE, and ABS.
Lastly, due to its quick lead time, thermoformed plastics are ideal for companies that use the ‘just-in-time’ (JIT) inventory management method.