Rotational molding (rotomolding) and blow molding are two popular manufacturing processes used to create hollow plastic parts. Both processes have their advantages and disadvantages, and the choice between them depends on various factors such as cost, design flexibility, production volume, and the desired end-product. In this blog post, we will compare and contrast these two processes to help you determine which one is best suited for your needs.
Rotomolding
Rotomolding is a manufacturing process that involves the creation of hollow plastic parts. It involves heating plastic resin in a mold while rotating it around two perpendicular axes. This creates a uniform coating of plastic on the mold’s interior, which cools and solidifies into the desired shape.
The process is versatile and can be used to create a wide range of products, from large tanks to small toys. Rotomolding is ideal for creating parts with complex shapes and designs, as it allows for the creation of parts with varying wall thicknesses and intricate details.
Pros and Cons
Pros:
- Ideal for creating large, hollow, and complex parts that require uniform wall thickness and excellent strength
- Customizable among many sizes and materials
- Versatility
Cons:
- Long cycle times
- Limited material options
- High costs of raw material
Blow Molding
Blow molding is a process that involves heating plastic resin and then blowing it into a mold to create a hollow object. The process can be divided into three types: extrusion blow molding, injection blow molding, and stretch blow molding. Blow molding is often used to create bottles, containers, and other small to medium-sized objects.
Blow molding can be used to create a variety of plastic products, including bottles, containers, and automotive parts. The process is often used for producing large quantities of parts quickly and efficiently. It is also known for its ability to create parts with consistent wall thickness, which can be important for certain applications.
Pros and Cons
Pros:
- Low cost
- Speed
- Versatility
- Wide range of resins and colors to choose from
Cons:
- Highly dependent on petroleum
- Limited material options
- Complex geometry of the components is difficult to achieve
- Not ideal for mass production of small disposable containers
Important Factors When Deciding Between Rotomolding and Blow Molding
When deciding between rotomolding and blow molding, there are several factors that need to be taken into consideration. These factors can help determine which method is better suited for a particular application.
- Cost: One of the primary factors to consider when choosing between rotomolding and blow molding is cost. Blow molding typically requires more expensive molds, which can make it more expensive than rotomolding for smaller production runs. However, for larger production runs, blow molding can be more cost-effective due to its faster production times.
- Cycle Time: Blow molding is a faster process than rotomolding, with cycle times often less than 1 minute, whereas rotomolding cycles can stretch past 30 minutes. If speed is a priority, blow molding may be the better choice.
- Tooling: Rotomolding has lower tooling costs than blow molding, making it a more cost-effective process for low-volume production runs. However, blow molding produces products on a shorter cycle time and can be up to 40% cheaper than rotomolding if the output volume is high enough.
- Porosity: Blow molding reigns when it comes to part weight and porosity. Rotomolding, on the other hand, produces no weld lines or pinch-off seams, resulting in a finished product without the use of secondary processes.
- Part Weight: Blow molding is ideal for simple tanks, while rotomolding is best suited for large, single-piece hollow parts or double-walled open containers like kayaks, oil tanks, and coolers. As a consequence of the manufacturing process, rotationally molded products are often substantially heavier than their blow-molded counterparts.
Count On Us for Your Blow Molding Needs
Both rotomolding and blow molding have their advantages and disadvantages. The decision should be based on a careful evaluation of the product’s requirements and the capabilities of each process.
For all your blow molding needs, contact us, Blow Molded Products. We will deliver the results you need with 100% satisfaction guarantee.