Precision Component Manufacturer Installs Acid-etching Process Facility

Phil Black - PII Editor 13/01/2015

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A dedicated and highly versatile acid-etching process facility and associated effluent plant have now been fully installed by Jacquet Weston Engineering (JWE) for one of the world’s major manufacturers of precision components. The factory at American-owned Symmetry Medical’s plant in Sheffield focuses on a range of products – from aerospace components to surgical instruments and implants – and is at the heart of a newly constructed building on the site.

“The Symmetry facility produces both cast and forged components, primarily on a subcontract basis for customers worldwide, using special performance metals including stainless steel, cobalt chrome and titanium,” says Nick Weston, JWE’s Managing Director. “Our installation is dedicated to the full range of components produced via the forging operation, addressing the removal of an excess coating – ‘the boundary layer’ – that is invariably created by the production process. The control capability of the acid-etching method used means, for example, that just 0.0003” is removed from titanium components.

The installation comprises two cantilever transporter lines with a framework manufactured from 316 ST/ST, due to the aggressive process chemistry. Separated by a walkway, each line comprises 13 individual stations – an unload/offload facility and 12 individual process tanks. These provide the appropriate number of acid baths – either heated or at room temperature – together with both hot and cold water rinses. “The acids used include hydrofluoric, hydrochloric, ferrous sulphide, nitric and ferric chloride, some of which are noted for their aggressive properties,” adds Nick Weston. “The health and safety considerations at site, particularly the handling processes, were therefore a prime consideration with the installation design.”

“We load loose components into Progalvano PVDF process barrels that are lifted and positioned by the transporter mechanism which then lowers them into the individual tanks to match the appropriate sequence and timing requirements of each component treatment process,” comments Russell Robinson, Director at the Symmetry site. “Manual handling operations are therefore kept to a minimum, which is a factor that could be further enhanced as the JWE design would enable automatic operation to be readily introduced if required in the future. From the etching process, components are then moved on to either machining, NDT inspection or directly back to the customers.” He points out that the service also benefits from three key NADCAP approvals applicable to aerospace, orthopaedic and general manufacturing operations held by Symmetry.

Significantly, a major part of the JWE installation also includes mixing and effluent handling stations – both of which are linked directly to the processing facility. “This is designed to allow any mix of acids to be safely delivered to the process line – a blend of three in specific tanks is not uncommon,” Nick Weston continues, “with the acids themselves securely held in 1000 litre IBC’s positioned within a bund linked directly to the JWE mixing station. The particular blend of solution required, and the precise tank that is to be pumped into, is selected by the operator on a touch screen HMI. The entire measuring and mixing of the required solution and subsequent transfer to the selected tank is undertaken automatically.

“The effluent treatment plant ensures that the process only produces clear water and filter cake – the former safely removed to drain according to authorisation requirements, whilst the latter is taken off site for separate disposal,” he continues. He adds that the installation also gains from a ducting, extraction and scrubbing facility installed by JWE, designed and manufactured to the D1 and M1 requirements as specified by the E.A.

“This is a major facility in our worldwide network and one that we are delighted is now fully operational and fulfilling a key role in our production process,” adds Russell Robinson. “The work that Jacquet Weston Engineering has now completed follows on from a temporary line that they were able to install quickly for us following a fire at the factory, which helped to ensure that our production processes were interrupted as little as possible,” he continues.

“With the new line now fully operational, we are confident that the inherent versatility, safety and performance capability of the JWE installation will continue to enable us to deliver products of the highest quality to our customers across both surgical and aerospace sectors. Moreover, the facility will help us to maintain the excellent reputation that the name Symmetry has in these leading and technically challenging industries,” Russell Robinson concludes.