Tecni-Form moulding technique completes iPad device rollout to Clarks’ shoe stores
Innovative plastics specialist, Tecni-Form Ltd, re-imagined the scope of rotational moulding to produce a design company’s iPad-enabled measuring device, which has now rolled out to each of Clarks’ shoe stores in the UK, supplied from its Staffordshire manufacturing site.
The award-winnning Clarks’ iPad foot gauge was designed and developed for the precise measurement of children’s feet by Designworks Windsor Ltd. They initially challenged Tecni-Form to produce the device’s main body in white, medium density polyethylene (MDPE), specifying an exceptional surface finish to complement the appearance and feel of the iPad case.
Although rotational moulding, using relatively low cost tooling, makes good sense for a large component produced in sub-five-figure quantities, the technique is not conventionally prescribed to achieve a flawless, gloss finish and very high dimensional accuracy. The Tecni-Form team, however, was keen to demonstrate its advances in the process, such that surface finish limitations are now a perception from the past.
Expert in rotomoulding and reaction injection moulding (RIM) for clients including Bentley, Aston Martin, Volvo, JCB and Caterpillar, Tecni-Form mobilised its experience in mould tool design, precision process control and machining techniques to meet the specification in full. The company also drew on knowledge it gained in a previous project for Designworks, a Gunnebo security safe with a style and finish to appeal to high-street consumers.
Material suppliers worked with Tecni-Form to formulate a specific, high brightness, white MDPE rotomoulding powder. The tailor made formula assisted with the complexity of the moulding shape and the final gloss of the product.
With the surface finish achieved, Tecni-Form also had to be able to manufacture to a ±0.5mm machining tolerance to ensure a clearance fit between the main body and a steel footplate insert. This eliminated a potential dirt trap on the upper face of the assembled device. In production the component is moulded fractionally oversize and a CNC 3D machining station is used to create the correct recess profile to accept the steel plate.
A combination of uniform wall thickness and very low residual stress promote high strength in rotational mouldings. When Designworks tested production samples, the strength of the mouldings reached the 350kg load limit of the test rig – more than twice the specified minimum failure load for the component.
The cost of the rotational mould tools for the main body was between one tenth and one twentieth that estimated for a pair of imported injection moulding tools for the same product.
Charged with the complete assembly and distribution of the Clarks foot gauge, Tecni-Form convinced Designworks they were right in their choice of both moulding technique and manufacturer. The company is well advanced in terms of manufacturing automation and supply chain management, having developed a bespoke Enterprise Resource Planning (ERP) system that encompasses the entire operation, from RFQs to SOPs.
Tecni-Form has completed the delivery of 2,500 units for Clarks’ domestic stores and has already begun fulfilling orders to equip Clarks’ branded outlets across Europe and beyond.