Home >> Case Studies >> Navtech Radar Ltd: Commercial Security System

Navtech Radar Ltd: Commercial Security System

The production of low volume, high value equipment is an important part of our manufacturing economy, and such products often also involve leading-edge knowledge in their design and manufacture. The problem that products like these face is that the high tooling and production costs can severely limit product viability in the marketplace.

Far from simply being another way to make a set of parts, the concept of Rapid Manufacturing allows companies to continuously improve their product without paying any tooling or set-up penalty, and the use of Selective Laser Sintering (SLS) technology makes low volume production viable and cost-effective.

As a result of using the SLS technology provided by 3T RPD Ltd, radical changes have taken place with the production methods used by Navtech Ltd for their Commercial Security System. Until recently, they were making about fifty systems a year using cast aluminium bases fitted with covers that were machined from high-density polyethylene. All their internal components were also machined from stock aluminium and stainless steel, with the result being that the products, though very durable, were heavy and expensive to manufacture. (Fig 1).

Fig 1	Fig 2

Crucible Industrial Design Ltd was asked to find new production methods to reduce the manufacturing costs of a new range of lightweight sensors, with a projected annual production of 200 units. The new base was designed as a GRP moulding, and the cover was vac formed in styrene. However, the internal components remained complex and expensive, and machining all the parts would have been too expensive and moulding the components as an assembly would have been uneconomic (Fig 2).

Based on their previous experience, Crucible suggested Selective Laser Sintering (SLS) as a possible production process. The main components to be replaced by SLS parts were the rotating sensor system, support and guidance for the lens, and the mounting and location of the emitter reel (Fig 3).

Fig 3

Crucible has a close working relationship with 3T RPD Ltd, the UK's leading SLS supplier, and has used their services extensively for model making and the production of functional prototypes, so were well aware of the durability of the process. The first experiments focused on the appropriate orientation of parts to achieve consistency of build and functionality of the parts. The design process took into account the build characteristics of the SLS process and the 'packing' efficiency of the geometry to maximise cost effectiveness. 3T's large P700 SLS machine enabled optimum packing of the build chamber and initial samples proved the basic technical effectiveness of the parts (Fig 4).

Fig 4

As the parts were internal components of the security system, the surface finish was not a major issue, so labour intensive finishing work was not necessary. Furthermore, the complexity of a machined or moulded alternative made sintering a more viable and economical option.

An extensive test programme placed the parts in extreme versions of a normal operating environment, simulated over 15 million cycles of the critical components during a two month period. This tested the reliability and wear on the SLS components, and the results were extremely positive. Very little wear was recorded to any of the parts, all of which functioned well at the end of the test. The image below shows the surface of the pivot arm following completion of the tests, which became highly polished within a few hours, improving efficiency and suggesting that the friction had created a form of 'work hardness' (Fig 5).

The durability of the SLS parts enabled Navtech to build additional new features into their design, and the flexibility of the material led to the creation of built-in springs as a return mechanism for the lens. This possibility had not been identified until the material properties were examined in detail, and created a new feature that would have been expensive to produce by more conventional means (Fig 6).

Fig 5	Fig 6

The use of Rapid Manufacturing techniques offers tremendous opportunities to designers, particularly when working on complex equipment that has to be made in small quantities. The ability to build multiple functions into one component, in ways that would be totally uneconomic or impossible using conventional methods, offers real competitive advantages. This is further enhanced by the properties of the sintered materials, which can add more functionality to a part.

Navtech's use of SLS as a production method for their new range of security sensors has offered them far more scope for innovation than was originally thought. The new design is dramatically less expensive to produce than the original product, and the technology has allowed them to introduce new features that were not thought possible at the outset. Rapid Manufacturing can deliver the kind of competitive advantage that small high technology companies need to stay at the forefront of innovation and design.

Credits: Full paper written by Mike Ayre of Crucible Industrial Design Ltd (www.crucibleid.com).

Home | Contact Us | Newsletter | Request A Quote | Case Studies | Latest News |About Us | Our Services | Seminars | Technical Data | Site Map

3T RPD LTD
Fulton Court, Wofford Way, New Greenham Park, Newbury, Berkshire, RG19 6HD, UK
Telephone: +44 (0)1635 580284 | Fax: +44 (0)1635 569857 | E-mail: post@3trpd.co.uk