Injection Molding of Large Plastic Parts

By Blog-manager

What are the benefits of injection molding large plastic parts?

  1. Short cycle time
  2. Minimal scraps
  3. Can include inserts
  4. Ideal for high-volume production
  5. Variety of design
  6. Good surface finish

Are you in need of injection molding of large plastic parts? Richfields Plastics does 100% injection molding for various sizes of plastic components. They have large, 2100-ton tooling machines that can accommodate up to 11 kg by weight of injected parts, with dimensions of 1.5 meters by 2 meters. 

For smaller products, Richfields has also the right machines to manufacture parts that weigh between 2 kg to 6 kg. This is ideal for any everyday household items, automotive components, sound system parts, gaming machine casings, and a variety of custom-built plastic products that you can use for your prototypes. 

Injection molding is the most ideal technique to produce these types of products due to its ability to eject multiple parts in a short cycle time, produce minimal scraps, and a variety of designs. Continue reading to learn more.

Short Cycle Time


Injection molding is the suitable choice for manufacturing large parts due to the relatively short cycle time. This is simply the time it takes for the plastic part to be ejected from the machine, after the resin pellets have been poured into the hopper, and the non-return valve has injected the molten resin into the steel or aluminum mold.

With a short cycle time, manufacturers are able to produce a great number of injection molded products in a short amount of time. While the time may vary depending on the appearance and the form of the product, large-size plastic models typically take around 1 hour to finish. This will be done in a suitable machine, such as a 2200-ton or 1300-ton injection molding equipment — both of which are also available from Richfields.

Minimal Scraps

Compared to CNC machining, injection molding produces far less waste plastic or scrap materials after a cycle time has been completed. This means that there is a minimal need for any post-processing or secondary processes on the ejected plastic product, simply just to cut off any excess plastic material from it. Minimal scraps are cost-efficient because manufacturers are not wasting plastic resin in the process. 

Although some resins can be recycled — i.e. processed into pellets once more before being fed back into the hopper for another injection molding cycle — the low scrap rates means that all of the resin used during manufacturing has been optimized. 

Waste production is relatively common in any injection tooling mold that contains runners and sprues, but this amount is greatly reduced in a hot runner system. 

Can Include Inserts


Injection molding is primarily done in the manufacturing of single-part plastics for a variety of uses. However, it can also be used to combine two wholly different materials together, like metal or plastic. This is possible through a process known as insert molding.

In insert molding, another kind of resin is injected onto a base component or a substrate. The substrate is typically made out of metal, while the injection molded resin is a rigid plastic — an example of which is HDPE or polypropylene (PP). The inserts can also sport a threaded figure that can be found in consumer electronic goods, pipes, knobs, bottle caps, dials, and the like. 

Ideal For High-Volume Production

Although large part injection molding requires a need for larger machines and a greater volume of plastic resins, it is still a great choice for high-volume production. If you belong to an industry that is in need of high-volume parts in a moderate time period, the injection molding technique is your best choice.

An injection molding machine can produce thousands of plastic components before the machine is due for maintenance. This involves making sure that the mold is free from any defects that can negatively affect the injection molded part. 

Since injection molding does not really produce too much waste, the tooling also doesn’t require immediate inspection for excess waste that can cause deformations on the ejected product. Even after the tooling die has been used in multiple cycles, the plastic component still maintains its structural integrity and quality. 

Variety Of Design

Variety of design

Almost any kind of large part molds can be possible through injection molding. This is useful for industries that are looking to make use of either aftermarket or OEM-grade components that are in excellent quality.

For construction, large part injection molding can be used to create hardware tools, HVAC parts plumbing components, electrical conduits, and many more. Other industries also benefit from large-size molding. Casino gaming machines in the US are one good example, while the automotive industry uses injection molded parts for fenders, grills, hoods, panelling, door covers, and many more. 

Good Surface Finish

As mentioned before, injection molded parts rarely have to undergo further processing and other secondary manufacturing techniques. This is due to the fact that injection molding takes place in a highly-controlled environment in the machine. The pressure, temperature, clamping unit, and tooling die are consistently inspected to ensure that there are no defects that can affect the ejected product.

This results in a large plastic part that is durable and also sports a good surface finish. Cooling is controlled to avoid warping. Furthermore, any discoloration on the product is also avoided, resulting in a uniform product that is ready to be distributed for various industries

Key Takeaway

There are several benefits to injection molding of large plastic parts. As discussed in the guide above, this process involves a short cycle time, which is cost-efficient in high-volume production. Large part injection molding also produces less plastic waste, results in products that have an excellent surface finish, and can include complex designs that are also durable.

Richfields Plastics has all the machines and expertise required to produce a range of large parts by injection molding. Click here to view our products and services! You may also get in touch with us and learn more about how we can meet all your injection molding requirements for OEM, aftermarket, or custom-built parts.