Rotational moulding or injection moulding: Which technique suits your project best?
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Daan Buitenhuis
Communication
At Pentas, we are passionate about rotational moulding. However, we understand that not every product can be produced using this technique. In this blog, we outline the differences between injection moulding and rotational moulding, making it easier to determine which method best fits various projects.
Table of contents
What is injection moulding?
Injection moulding is a process in which molten plastic is injected under high pressure into a metal mould. This allows for the rapid and precise production of large quantities of identical products. The process is particularly suitable for components with complex shapes and high precision, such as electronics casings and automotive parts. Additionally, injection moulding accommodates a wide range of plastics, from thermoplastics to thermosets.
A drawback of injection moulding is the high start-up cost. The moulds are expensive to produce, making the process less suitable for smaller production runs. Producing very large parts is also challenging due to the high pressure and material usage required. Moreover, injection moulding is less suitable for creating hollow products, such as tanks, without additional processing. Designs with undercuts can also be more complex. Despite this, injection moulding is the perfect choice for projects requiring large volumes of consistent, high-quality products.
Examples of injection moulding applications include:
What is rotational moulding?
Rotational moulding, also known as rotomoulding, is a versatile technique in which plastic powder is poured into a mould. The mould is then heated and slowly rotated along two axes, causing the powder to melt and adhere to the inside of the mould. This results in seamless, hollow products. Examples include storage tanks, kayaks, and large play structures.
What makes rotational moulding unique is the low cost of the moulds and the flexibility in design. The process is ideal for small to medium production runs and offers the ability to create very large products, something often unachievable with injection moulding. Rotational moulding is also well-suited for complex designs, such as double-wall structures. While the process is slower than injection moulding, the design freedom and suitability for unique, large shapes more than make up for it.
Examples of rotational moulding applications include:
When to choose which technique?
The choice between injection moulding and rotational moulding depends on the project goals. When a product requires tight tolerances, a high level of detail, and large production volumes, injection moulding is often the best solution. Examples include bottle caps, phone casings, or handles.
For products that need to be large, hollow, or complex in shape, and where smaller production runs are preferred, rotational moulding is the ideal choice. This process not only offers cost advantages for small series but also unmatched design freedom. From innovative playground equipment to durable storage tanks, the possibilities are diverse and widely applicable.
A world of possibilities
At Pentas, expertise in rotational moulding is at the core of what we do. Whether it’s producing storage tanks, playground equipment, or decorative objects, we are ready to bring these ideas to life. With a strong focus on customization, we work with you to find the best solutions for your product, always prioritizing quality and efficiency.