en.Wedoany.com Reported - The UK BEC Group has supported Cornwall-based custom earplug specialist Moulded for your Ears in developing an overmoulded acoustic filter and cable retention system, which incorporates recycled plastic recovered from discarded fishing nets. Collaborating with product design consultancy VitalSpark, BEC Group provided manufacturing design expertise, tool development, and material evaluation to help commercialise the new filter assembly. This assembly combines hydrophobic mesh technology with precision overmoulding to prevent water ingress while maintaining acoustic performance.
Moulded for your Ears aimed to enhance the performance and manufacturability of acoustic filters in its custom watersports earplugs. The filter design allows sound and air to pass through while preventing water from entering the ear canal, requiring a careful balance between permeability and repellency. VitalSpark generated the initial CAD concepts, after which BEC Group optimised the design for injection moulding and high-volume manufacturing, and designed and built a dedicated two-cavity overmoulding tool for filter production, along with another tool for the cable retention system.
A key challenge during development was the selection and integration of the filter media. The mesh specification needed to meet hydrophobic performance requirements while allowing sufficient acoustic transmission. Several mesh grades were evaluated during development; initial trials using finer mesh provided effective water resistance but limited sound transmission below acceptable levels. A coarser mesh was ultimately selected, offering a more favourable balance between acoustic transparency and water repellency.
The finished filter is manufactured using a precision overmoulding process, where the mesh is manually positioned onto the mould core prior to moulding. During injection, the polymer encapsulates the mesh perimeter, forming a strong mechanical bond without compromising the open structure of the filter media. Mike Tharme, Tooling Director at BEC Group, stated that the filter development process required balancing several competing performance criteria: the mesh must effectively repel water while remaining acoustically transparent, and the overmoulding process must secure the media without affecting its functional properties. Achieving consistent mesh positioning and encapsulation was critical to the success of the final design.
Sustainability was also a primary objective. Moulded for your Ears and BEC Group evaluated recycled polymers supplied by Waterhaul, which recovers discarded fishing nets from marine environments. Initial moulding trials used recycled HDPE from discarded fishing gear, but processing limitations related to the material and tool geometry prompted the development team to adopt Waterhaul's recycled polypropylene grade, which offered better flow characteristics and greater process stability.
Chris Roynon, co-founder of Moulded for your Ears, stated that from the outset, the goal was to improve the filter design while maximising the use of recycled materials. Collaboration with VitalSpark and BEC optimised acoustic performance and manufacturing processes, resulting in a stronger, more sustainable product. This project demonstrates the combination of filter media selection, polymer processing, and precision overmoulding technology to develop compact filter assemblies that meet demanding performance requirements, and also highlights the growing potential of ocean-recovered recycled polymers to be integrated into technically challenging moulded components without compromising functionality.
