Doing business with major defence and aerospace companies can appear a daunting prospect for many SMEs. The volume of regulation and the potential cost of accreditation may seem like insurmountable barriers, but there remain ways in which smaller suppliers can prove their value and quality within this potentially lucrative market. Tom Rose, technical sales engineer at North Yorkshire-based investment casting specialist Micro Metalsmiths reports.

Micro Metalsmiths has been heavily involved in aerospace, whilst maintaining diverse appeal to numerous other market sectors throughout the life of the company. This helps provide an informed insight into the challenges which must be overcome to flourish in both high technology and general engineering simultaneously. It also helps to prove that many opportunities still exist for suppliers of all types and sizes.

A recent comment from longstanding customer BAE Systems highlighted the critical role played by foundries and precision engineers, who comprise a significant proportion of the 9,000 companies who supply the UK aerospace and defence industries: ‘SMEs play an important role across the complete aerospace supply chain, providing valuable contribution in terms of intellect, technologies and products’.

However, the Parliamentary report from which it was drawn focused heavily on the pressures and challenges facing SMEs in those sectors, stating: ‘During the course of this inquiry we heard a specific concern about the difficulties facing SMEs in entering the aerospace supply chain from other sectors. Witnesses highlighted the fact that the level of regulation in the aerospace industry, and costs involved in gaining accreditation were significant obstacles to entry. Whilst we accept that a high level of regulation is necessary in the aerospace industry to ensure the safety standards are maintained these should not be an insuperable barrier to entry.’

Better is best

It has become increasingly clear in recent times that however broad or narrow a company’s field of expertise may be, the most essential attribute required to survive and flourish within aerospace and defence manufacture is to be exceptionally skilled within your chosen capabilities. As competition from Asian suppliers has increased steadily over the years, the answer has remained a constant ‘to be better’.

The ambition to deliver parts with unparalleled complexity and detail has caused Micro Metalsmiths to develop many technological advances and amass a wealth of experience, meaning that there are exceptionally few engineering challenges that cannot be undertaken and successfully achieved. Creative designs find the greatest benefits; solutions are available to resolve many issues associated with manufacturing components which contain fine or internal details. The impossible has been disproven on many occasions.

Two examples of so-called ‘impossible’ aerospace casting work undertaken by Micro Metalsmiths include: an aircraft LED housing (fig.1) which requires exceptional toolmaking skills. The structure of the part calls for the wax tool to include multiple removable cores. No other process allows so many fine holes to be cast integrally with diameters of just 2mm. The quality of plaster investment material makes this possible.

The second component (fig.2) is testimony to soluble wax technology. The length, diameter and curvature of the bore running through these parts means that wax impressions must be formed around a soluble wax which is removed prior to casting. Solubility is the key to removing the mould material from within the casting. Plaster provides the advantage over ceramic shell investment, which could not be removed from inside this part.

Specialisation is by no means a prerequisite for success, but it is certainly advantageous to be able to offer something that your competitors cannot achieve. For Micro Metalsmiths, its individuality is characterised by the thinnest wall sections, tightest surface tolerances and greatest freedom of design in the foundry industry.

Pivotal but not essential

Removing unnecessary weight from cast parts without compromising on strength has become an obsession – little wonder when you consider that the estimated cost of putting anything into orbit is up to as $30 per gram (based on NASA statistics). This principle has brought advantages to a multitude of customers, across all sectors – with raw material costs continually rising, there are few more effective ways to save costs, than to use less to begin with.

Accreditation is a pivotal concern with AS9100 becoming the industry benchmark for aerospace compliance. Costs associated with becoming accredited are considerable, however smaller companies are entitled to enter the supply chain at a lower level without holding this standard. In such a case the purchasing company take the onus of responsibility, using their own quality control procedures to verify compliance of parts supplied to them. Micro Metalsmiths continued to make use of this approach for many years, although since February it has held AS9100 which has simplified the buying process for its aerospace customers.

An additional consequence of obtaining the standard is that Micro Metalsmiths is now able to supply parts and services from an extensive network of high quality, non-accredited subcontractors to its customers, fully scrutinised and approved under the AS9100 banner. This provides a unique way to offer vendor reduction opportunities to buyers, based on the desire among large companies to rationalise and minimise their supply chains, which shows no signs of abating.

However, this need not affect SMEs adversely if they can group together with a recognised leader who shares their desire to deliver excellence to aerospace customers across a broad range of capabilities. John Brockett, quality manager at Micro Metalsmiths comments: “Only a few of our suppliers and subcontractors have AS9100, but our rigorous supplier approval process ensures that they meet our exacting criteria and with our flow-down process, all our suppliers know exactly what we require from them”. In this way, the long traditions of independent specialists supplying the finest bespoke components may actually be enhanced by mutual cooperation, rather than condemned by stringent legislation.

Fully equipped

To become a solution provider, in the true sense, must depend on the ability to present a range of effective, attractive options for production. Micro Metalsmiths take that as a personal responsibility, being equipped from its two facilities to carry a design from conception, through development and trial, to mass production. Owing to the full spectrum of capabilities available onsite, nearly all combinations of requirements can be delivered more quickly and cost-effectively than the vast majority of multi-staged supply lines.

Involvement begins at the design stage, either with a 2D drawing or a 3D model. Whether a complete product assembly has been prepared with sub-components and tolerances applied, or no more than a conceptual sketch exists, skilled CAD/CAM designers ensure parts conform to chosen production methods, suggesting beneficial improvements where applicable.

When a design is finalised, there is usually a desire and often a requirement to have sample parts for testing and scrutiny. Until recently this has required outside involvement from rapid prototype specialists, but no longer as delivery has just been taken of a brand new Solidscape wax printing machine.

For any investment casting purposes from aesthetic, styled parts to mechanically critical components, Solidscape delivers stunning accuracy and complexity. The technology was originally designed to produce fine jewellery and dental implants and therefore mirrors the faithful attention to minute detail found throughout Micro Metalsmiths’ high volume production methods. Internal features can all be included by virtue of the easily removable soluble wax that is incorporated into the wax generating process.

Proven over decades

For a company to produce the most exceptional castings, it must first produce the finest waxes. A team of five dedicated toolmakers produce up to 200 wax injection moulds every year, equipped with a wealth of technology and gadgetry to deliver intricacy beyond the capabilities of most subcontract firms. Multiple 5-axis CNC machines, wire and CNC EDM comprise the major part of Micro Metalsmith’s armoury, allowing the production of everything from cost-effective simple impression tools to the most highly polished, intricate mould architecture with multiple moving cores.

Micro Metalsmiths made its name by using a rare form of investment casting, essentially a hybrid technique incorporating the enhanced detail of jewellery casting with high volume production methods. This process has been delivering parts of high complexity in aluminium, zinc and copper-based alloys for decades, albeit with constant improvements from on-going research and development. The recent AS9100 accreditation has meant that comparable castings in steel and titanium alloys can also now be offered from the most capable suppliers, providing a full spectrum of material options to designers and engineers.

Skill development

Precision engineering capabilities have grown and developed over many years, so much so that there is a dedicated machining facility a few miles from the main site. Originally its purpose was to deliver the best and quickest machining to the castings already produced – there are many subtleties that must be learnt as the machining of castings can be far more complex than cutting straight into a uniform billet.

As the portfolio of skills and equipment increased however, the demand for involvement in other areas prevailed. For those projects which do not justify casting, Micro Metalsmiths can offer extensive options to have parts machined from solid which is a suitable method for many low volume requirements. Turning and multi-axis milling are available, in addition to essentials such as tapping, threading and helicoil insertion. A number of other options can be included, brazing and manual assembly of components.

Finishing services provide innumerable options for customisation. Alochrom and Iridite are available as standard and a wealth of specialist painters, polishers and plating services provide every conceivable variation required to complete parts to the desired specification. To ensure compliance with a wide range of military and aviation standards, any combination of testing procedures can be facilitated, from chemical analysis and mechanical testing to destruction, to the most advanced NDT techniques.

Amongst Micro Metalsmiths’ current priorities is the development of enhanced waxes and plaster investment material; to deliver larger parts of equal quality; to cast in a wider range of metals; to deliver excellence in shorter timescales at reasonable costs and to offer as many services as possible that our customers require.

Micro Metalsmiths
www.micrometalsmiths.com