Coating machines built by specialist in hard coatings

Nanoscale coatings for a variety of materials offer significant advantages for designers in sectors ranging from aerospace to medical devices. Hard-coating specialist Tecvac serves global customers; for example, the company has coated gas turbine blades, landing gear components, orthopaedic implants and sophisticated invasive brain probes. Not only does Tecvac offer a coating service, but it also manufactures machines that customers can use for coating their own components.

Tecvac's advanced physical vapour deposition (PVD) machines are installed in universities, research centres and critical production operations worldwide. The coatings - including titanium nitride, chromium nitride, chromium aluminium nitride, titanium aluminium nitride and tungsten carbide-carbon, sometimes combined with copper, carbon or silver and rare-earth elements - offer extreme hardness, lubricity, biocompatibility and antimicrobial properties, sometimes through a series of graded layers. The machines are used to produce micron-scale nanocomposites, 'glassy metals', and metallic and ceramic coatings.

As well as building coating machines, Tecvac has also applied its expertise to the development of special-purpose machines for welding exotic aerospace alloys. Another recent project has seen radio-frequency surface modification technologies applied to achieve low-temperature transformations of polymer and aluminium surfaces.

Coating requirements

Jonathan Housden, Tecvac's research and development manager, comments: "Experience helps to meet our customers' demanding requirements. We build all our own process machines to support our own multi-million-pound business in PVD coatings services - often offering an overnight turnaround for key aerospace and medical customers - so we understand the difficulties of achieving operational process reliability required by a business, as well as the flexibility required for research. Depending on the specification, the machines include vacuum chambers operating at between 180 and 800 degrees centigrade at pressures of 5x10-5mbar, using a variety of metal vapourisation technologies including electron beams and high-power magnetrons, sometimes within the same machine."

Tecvac focuses on understanding the customer's needs, since the technical solutions to customers' problems can be very complex. Furthermore, Tecvac works with the customer to prepare a tight initial specification - which is very important when a machine may cost a six-figure sum. After all, a special-purpose machine is only as good as the specification.

Mark Frogley, the engineering manager who leads the machine build team, states: "We devote a lot of our resource to understanding our customers' initial requirements. Of course, that extends to all requirements of health and safety, CE marking, the current Machinery Directive... and all the related software requirements of automated machines producing to agreed recipes 24 hours a day, seven days a week, on rigorous cycles designed to conform to US FDA and cGMP and other medical or aerospace traceability standards. A successful implementation also depends on regular customer reviews as the project moves toward completion, with regular risk and compliance checks and adherence to regulatory protocols. By definition a custom-built machine is unique, so we also invest in customer training to ensure optimised productivity whilst maintaining safety levels and minimising running costs."

Versatile hardware and software

The critical design consideration for a research machine, for example, is how much flexibility can be built into the software and hardware starting from the initial concept models. In one recent machine built for the University of Sheffield, the specification called for multiple sequential coatings of metals, ceramics and metalloids... not to mention the ability to vaporise a wide range of source elements. This resulted in a decision to duplicate the electron beam configuration, and the addition of many software protocols. While this had an unavoidable impact on initial capital cost, it also enabled the research team to be far more productive and achieve reliable data quickly on a variety of closely controlled nanostructures to encourage both the rapid production of academic papers and rapid progress towards the commercial development of material surfaces with ceramic standards of hardness, and steel-like standards of elastic modulus.

Richard Burslem, the site director at Tecvac's Cambridge facility, states: "Naturally, successful outcomes depend on transparent project management, robust detail design, and very reliable mechanical assembly and testing. But flexible systems are a critical part of our investment here. Since customer flexibility and provable reliability are vital in the machine building world, we decided that all software would be managed in-house to ensure robust research and production processes were 'built-in'. This also allows Tecvac to quickly update processes as well as machine designs during project definition and completion of the final specification."

Frogley adds: "Yes, we do have robust processes, but certainly software is the key... it helps us give the maximum flexibility right at the start of the specification design process. We believe customer satisfaction and a good partnership between machine builder and the customer depends on specification, specification and specification. If this is right all the other elements will fall into place... including the production timetable and cost."

Contact Tecvac for more information about its coating services or special-purpose coating machines.