At a time when demand for flexible plastic packaging is rising, driven by the need to reduce material waste, and develop sustainable solutions that are as robust as they are cost-efficient to produce, a new method of injection moulding has come to light.
A request for examination has been submitted to the German Patent and Trademark Office (DPMA), and the patent is currently under review to assess its novelty, inventiveness, and industrial applicability.
A new way to manufacture thin-walled plastic parts
Traditional plastic manufacturing techniques, such as thermoforming and conventional injection moulding, have certain limitations. Thermoforming, for example, is an energy-intensive process, which results in a high volume of material waste, and restricts the freedom of design engineers. Conventional injection moulding, on the other hand, requires extremely high clamping forces, especially for large components, making production both costly and inefficient.
The innovative thin wall cascade injection moulding (TWC) process offers a breakthrough solution. By combining the high flowability of thin-wall injection moulding with the controlled, multi-point injection system of cascade moulding, the technique significantly reduces material usage, shortens cycle times, and is capable of precision-making components with irregular or complex shapes.
How does it work?
The published patent describes a process where highly flowable polypropylene (PP) is injected into a mould using a series of sequentially controlled injection points. This ensures an even distribution of the material, minimises weld lines, and enables ultra-thin wall thicknesses whilst maintaining structural integrity.
The drawings included in the patent illustrate the core elements of the process. One of the key innovations is the melt distribution system, which consists of a network of interconnected injection points, which allow the mould cavity to be filled in a controlled fashion. This system reduces the required clamping force dramatically— for example, for a component with a projected area of 1800 mm × 600 mm, the required force can be lowered from 4500 t to approximately 1600 t.
Figure 1 of the patent shows this process in detail, highlighting the thin-walled structure (1), the distributor channel (2), the main channel (3), and the side channels (4), ensuring an optimised flow of material. The strategic placement of injection points (5) plays a critical role in achieving uniform distribution and ensuring the structural stability of the moulded part.
Sustainability and efficiency
The benefits of this new injection moulding technique are significant. Lower energy consumption is achieved through reduced cycle times and optimised material flow, which lowers the energy required per unit. Less material waste is another advantage. Unlike thermoforming, where up to 40% of material is wasted, the patented process helps to minimise offcuts. Greater design flexibility is also a key benefit, as the technique allows for sharp contours, variable wall thicknesses, and complex geometries that are difficult to achieve by conventional methods.
Potential applications
The patent highlights a wide range of potential applications, including industrial packaging and trays, logistics and transport containers, lightweight components for various industries, and customisable designs for high-precision manufacturing. By securing patent protection, the inventors are well-positioned to bring this technology to market, either through in-house production or by licensing it to manufacturers in the plastics industry.
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