Advanced TechnologyMarine

Breaking the mold – Substituting metal for plastic in the development of anti-vibration solutions

By August 12, 2015 No Comments

HD Cushy Float

As a company who designs and produces sustainable anti-vibration and suspension mounts, we’ve traditionally used the method of bonding rubber to steel and other metals in our installations. The rubber provides a high load bearing capacity, whilst the metal provides a structural interface suited to the harsh environments in which we operate. The process is so integral to our company it in fact lends its name to the one of our most popular brands, Metalastik® – the sticking of Metal to Elastic.

Now, the substitution of metal with plastic is not a new concept. For many years the auto motive industry has been replacing metal interiors with plastic counterparts due to their protective function and ability to reduce the danger of injury. However, the consideration of using plastic in our anti-vibration products has been approached at arm’s length, and tended to default to a situation where the material simply acts as a space filler – despite the inclusion of glass filled nylon and other higher performance materials.

Some of our reticence to use plastic was driven by the need to include these materials within our own molding process, where high temperatures (160-180⁰C) and pressures are applied when filling the product with rubber. We have found to our peril that thermo plastic and thermosetting materials behave very differently in this environment. Similarly potential suppliers do turn somewhat paler when we declare our molding conditions…

It wasn’t until a few years ago during a visit to a local plastic molding company, a colleague and I noticed an engine inlet manifold made from a short fiber polyamide on display. First thought – it must have exceptional heat properties to withstand the engines environment, and further scrutiny concerning physical strength also looked promising. And so the seed was sown… This chance encounter presented new development opportunities for our anti-vibration products, and not long after the Mini HD Cushyfloat was born – a hybrid of our most popular engine mount the Cushyfloat®.

The original Cushyfloat was developed for small marine engines, where apart from the vibration isolation, the operating environment of (salt) water, oil and other fluids are highly demanding. To protect against this the product is coated in a Trivalent plating (however, on some installations our customers test this finish to its limit!). We found that by replacing the metal with plastic the product delivered additional benefits such as weight saving, internal processes and environmental capability. To our customers of course the service performance, including environmental, was key.

The Mini HD Cushyfloat is made with the same grade of short fibre Polyamid as the inlet manifold we originally saw.  Developments to validate its suitability for internal manufacturing processes, and application environmental performance have all been completed, in addition to fatigue and durability tests as an anti-vibration mount. In all situations this product has passed with flying colors. Perhaps like my bike frame, metal is not always the only answer to the problem after all…

 

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Bill Mortel

About Bill Mortel

Having started with the company as an apprentice 45 years ago, Bill has held a wide variety of roles in both Technical and Commercial functions. A member of the Rubber in Engineering Group within the Institute of Materials, Minerals and Mining (IOM3), Bill has a broad depth of knowledge with respect to product design, testing, and application performance. He is currently Director of Material and Development.

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