Waste bin with minimal warpage

Brabantia recently introduced the SortUp: a new recycling bin with two stacked compartments to make the most efficient use of available space. Like the rest of Brabantia’s product line, it is a high-end product that must excel in functionality, ease of use, and aesthetics. BPO analysed Brabantia’s final design for injection moulding feasibility and recommended design improvements prior to the start of production.

The SortUp recycling bin consists of multiple components, seven of which were subjected to a comprehensive analysis by BPO. These parts are made of polypropylene, which benefits the product’s recyclability. BPO assessed the manufacturability of these components, including the possible injection mould design and gate locations for each part.

A key focus area in the design was warpage. Due to shrinkage and orientation effects during the injection moulding process, unwanted deformation can occur. The design was intended to ensure that the components could be produced with minimal deformation; otherwise, the components would no longer fit together properly. In the worst-case scenario, components could interfere with one another or fail to fit altogether.

Initial Moldflow simulations indicated that several components would indeed experience too much deformation. Through a series of steps, BPO optimised the design and recommended design improvements. The process took into account the possibility that adjustments would need to be made to the moulds, in case the warpage needed to be slightly adjusted after the first test samples. After the trial production, it turned out that one part did indeed still have slightly too much warpage. By implementing a solution that had already been prepared in advance, the time required to modify the mould was minimised. A local increase in wall thickness successfully ensured that this component also remained within specification.

After optimising all seven components, the design was approved for production. The result is an injection-moulded solution with excellent dimensional stability, while maintaining the sleek design of the SortUp recycling bin. This project is an excellent example of a design that could only be realised through effective warpage optimisation, and demonstrates significant time savings compared with products developed solely through a trial-and-error approach.