Injection Molded Cases vs Roto Molded Cases

Injection Molded Cases vs Roto Molded Cases

One of the questions we are often asked by our customers is for an explanation of the differences between a case that is manufactured using injection molding and one created using roto molding.

Most customers are familiar with injection molded cases, as these are the Pelican cases that we all buy to hold everything from camera equipment, sportsman’s guns and just about everything else we want to take out into the great outdoors.

Our B2B clients will use these cases to transport their company’s equipment around the world whether travelling to and from trade shows or as part of a turnkey solution for getting their products to clients. These cases are legendary for their toughness and ability to survive the harshest conditions.

Are there circumstances in which roto molded would be better, and what are they? Read on to find the answer.

Injection Molded Cases – Great Strength, Less Weight

Pelican injection molded cases, as the name implies, use a standard mold for each particular size of case, e.g. 1200, 1510, 1660 etc. The plastic used in these cases is typically a proprietary combination of homo- and co-polymers. This combination allows for a stronger yet lighter case; features we all are looking for.

These cases end up with very even corners and single walls and are typically watertight with numerous standard military certificates behind each model. Typically most models come with plastic catches, air valves and gaskets. At this time the largest Pelican injection molded case is the 0550 case, with just over 20 thousand cubic inches of interior space.

An injection molded case has single wall construction that offers great strength while keeping the weight light.

A roto molded case has double-wall construction in the corners that makes it heavier.

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Roto Molded Cases – Extra Toughness When You Need It

Roto molded cases will always be heavier than their injection molded size equivalent. One of the main reasons for this is that roto (short for rotationally) molded cases actually have double walls in the corners of the case. This is where you need additional strength especially when a loaded case is dropped accidentally, or in a conventional 19” rack case where payload stress is created against the shock absorbers.

Case molds are placed on a giant robotic machine which rotates on both the vertical and horizontal axis (you can see this in action in the image at the top of this article). Heat, speed and cooling are some of the main the factors which determine the outcome of each case.

Pelican-Hardigg roto molded cases may reach sizes over 10 feet long and most come with military grade hardware, including optional black metal twist catches. Most roto molded cases take longer to order as typically they are custom made to the customer’s required features (although there are now some models that are a “quick ship”).

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Making the Right Choice

For most applications injection molded cases will more than do the job and can typically be delivered within a day or two. There may be times, however, when you need a larger size case or the additional strength and features only found in a roto molded case. Whichever one you choose, you’ll get the same great quality. This video has some great visuals of the manufacturing process:

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