Roto Molded Vs Injection Molded Coolers

Home Roto Molded Vs Injection Molded Coolers

What goes into creating an Elite Cooler? To ensure high ice retention, there must be a lot of insulation. However, the insulation must go someplace. The best bet is between the cooler’s tough plastic walls. So, what is the best method to go about building those walls? It’s time to weigh the pros and drawbacks of roto molded vs. injection-molded coolers. 
If you’re thinking about making a plastic product, you’ve probably wondered what the distinctions are between injection molding and rotational molding. How then do they compare in terms of cost, consistency of manufacturing, materials, and design flexibility? Before we can compare the benefits of injection molding with roto-molding, we must first evaluate both methods.

What is Roto-Molding?

An illustration of the advantages of roto-molding
Source: Pinterest

Roto-molding is a manufacturing method used to create hollow components of any size. Roto-molding may be used to produce large plastic pieces at a low cost. Initially, resins or polymers (in powder form) are injected into a hollow-shaped mold. The mold is then heated and carefully turned in vertical and horizontal planes. Because of the continual heating and turning, the resin melts and distributes uniformly throughout the inside surface of the mold.

This method yields a pre-designed component with consistent wall thickness. Since more material tends to gather at the edges and corners of the mold, the corners of a rotomolded item will have denser walls. The original iteration of Elite Coolers had all been rotomolded. The rotomolding method gave these coolers exceptional durability, and the 2″ of polyurethane insulating foam gave them outstanding ice retention.


  • The mold is being filled with a thermoplastic polymer substance.
  • Melting material by heating the instrument in an oven.
  • The tool is being cooled to firm the component.
  • Taking the plastic component out of the tool.

Advantages of Rotomolding

  • Complex geometry is possible due to design flexibility.
  • The cost of tooling is lower than that of other plastic molding processes.
  • Production has a short lead time.
  • Parts’ weight might be reduced.
  • Parts provide strength, resistance to corrosion, rigidity, and longevity.
  • Reduced labor hours increased throughput.

Limitations of Rotational Molding

Rotational molding elements are more confined to poly-based resins, such as polyethylene, polycarbonate, polyurethane, and polyamides, to mention a few: Nylon and plastisols are other materials that can be utilized. Before they can be utilized, these polymers must be crushed to a very fine powder. In terms of constraints, some forms and features are difficult to include, thus anything more complicated than a simple design may impede manufacturing.

What is Injection Molding?

Plastic injection molding
Source: Pinterest

Injection molding is the process of injecting a molten plastic mixture into a firmly held mold cavity. Once injected, the plastic is heated and cools to adopt the shape of the mold. The mold may be created and built to fit any form or size of the finished object that you are attempting to make. Creating a mold is a complicated, high-skilled procedure.

The mold is made of either aluminum or steel. Molds can be constructed to make identical copies of a single item or to produce numerous pieces that fit together. Injection molding is utilized when identical copies of the same object must be produced in huge quantities.

Advantages of Injection Molding

  • Complex mold designs are possible using injection molding.
  • Injection molding also allows for a wider choice of materials to be used with the mold.
  • Furthermore, the polymers used in injection molding are less expensive than the additions used in rotomolding resins.
  • In the injection molding process, compounds can be employed to reclaim some of the physical characteristics that might have been destroyed during the molding process.

Injection molding is a more cost-effective method for mass manufacturing. Injection molding allows for more products to be produced on the manufacturing line.

Differences Between Roto Molding and Injection Molding

A man holding rotational molded products
Source: Pinterest
  • Cost; When it comes to production, the initial cost is a major concern. Because roto-molding is done under low pressure, less costly materials may be utilized to make the molds. Injection molding necessitates high pressure, which necessitates tougher (and more costly) molds. This round is won through roto-molding!
  • Design complexity: Both of these approaches apply to a wide range of designs. Due to the tremendous pressure that guarantees plastic occupies every nook and crevice in the mold, injection molding narrowly edges out roto-molding. This round is won through injection molding
  • Production time: If items can be manufactured and sold more rapidly, costs can be offset. Because of the high pressure utilized, injection molding is rapid. Rotomolding just takes more time for each item. This round is won through injection molding
  • Manufacturing stress: Excessive stress during the molding process might produce discoloration in the plastic or other stress signs. These sorts of stress mark practically never occur because of the low pressure required for rotomolding. This round is won through rotomolding
  • Waste: When considering rotomolding vs. injection molding coolers, the best part is that disposal is minimal in both techniques. Excess plastic, also known as flashing, can be extracted from the product and reused in the production of another item. This round is a toss-up
  • Weight: As previously stated, rotomolding utilizes more plastic and produces a heavier item than injection molding. Each round is dedicated to injection molding

Making the Choice Between Roto-molding and Injection Molding for Coolers

Man cleaning the inside of a cooler
Source: Unsplash

Why Choose Roto-Molding?

Rotomolding results in a more uniform distribution of the plastic substance. As a result of this technique, the finished product is tougher, more versatile, and more durable. Products designed for usage in harsh conditions or at high temperatures will be less likely to shatter or fracture if the roto-molding process is employed. The reason for this is that larger thickness walls at the corners and edges eliminate stress areas in a rotomolded object.

The producer can obtain a uniform wall thickness by using roto-molding. Injection molding depends on pressure to drive molten plastic through, therefore the wall thickness is not as consistent. There will be no separating lines or weld lines on the exterior of a rotomolded product. Injection molding, on either hand, will produce surface flaws that cannot be prevented.

Just before the roto-molding process has begun, it is possible to add elements such as threads and subsurface pipes to the mold. Instead of attaching labels after the forming process, serial numbers and barcodes could be molded further into a product’s shell. Rotomolding allows for the production of complicated forms in a single piece. With injection molding, it is possible to create several parts of the same item and then assemble everything.

Why Choose Injection Molding?

Complex mold designs are possible using injection molding. As a result, injection molding may be used to create items with complicated forms and patterns. Injection molding is widely used in the manufacture of toys, bottle caps, handles, and some kitchen appliances.
Injection molding also allows for a wider choice of materials to be used with the mold. Rotomolding is often limited to poly-based polymers and polyamides. These materials must be crushed to a powder.  Furthermore, the polymers used in injection molding are less expensive than the compounds used in rotomolding resins.

The Bottom Line

Now, judging by the information above, one would conclude that injection molding takes a higher position than rotomolding in the production of coolers. However, we strongly advise against choosing a particular process over the other, without gauging the needs of your project. So consult a professional injection mold manufacturer for proper processes to find one that suits your project’s needs.

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