Innovate 2 Make (i2M) is a leading proponent of the very latest additive-manufacturing (AM) technology, using direct metal laser sintering. However, the company relies on the tool-room skills and knowledge of Warwickshire-based James Camden Engineering to finish AM components using wire-cut EDM.

i2M was initially set up in 2011 in Warwick but moved to Birmingham a year later to establish an AM facility. This technology offers a new approach to the manufacture of complex structures in a wide range of materials, including aluminium, titanium, Inconel and stainless steel.

The company recognised that it needed to provide ready access to this new technology, and it has already helped a number of major manufacturing companies to adopt AM as part of their production processes.

The AM process works directly from a 3-D CAD model. It orientates the components and slices the model into layers that are then ‘drawn’ in the build chamber; in i2M’s case, this is achieved using an ytterbium fibre laser that is ‘fired’ on to a powder bed containing fine metallic powder particles. Layers are progressively fused together to produce the final metallic component.

i2M co-director Mike Kelly says that the company’s plan from the outset was to target customers in the technically challenging spheres of motor-sport and aerospace. “That said, the first part we produced was a titanium stiletto heel for a shoe designer. Since then, we’ve done just about everything — jewellery, teeth, car and bike components, as well as aerospace parts.”

“Elegant welding”

One of the advantages that many advocates of the AM process highlight is its ability to produce parts without tooling. While i2M calls it tool-less production, Mr Kelly is quick to point out that this is not strictly true.

“People see it as casting, but I like to think of it as elegant welding; and as the parts are grown, they will often require some form of support structure, which is grown at the same time as the component.

“While we can vary the density of the supporting element, so that it can be removed by hand — peeled away from the finished component — sometimes the support is more intricate, requiring specialist knowledge and equipment to remove it.”

This is where James Camden Engineering comes into the picture. Possessing both the precision engineering knowledge and the specialist equipment — in the form of three Excetek CNC wire-cut EDM machines from Warwick Machine Tools (www.warwickmachinetools.co.uk) — the company works with i2M to remove all of the supporting structures, protective shells and excess material such as base plates.

Dave Bloxham, managing director of James Camden Engineering, says: “The AM process allows design engineers to push the boundaries in industries looking for performance and also cost advantages. They can create components to fit exactly within very confined spaces, reducing weight without compromising performance. For example, we worked with i2M on components for an intricate motor-sport cooling system. There was no way the part as designed could have been achieved without using additive manufacturing.”

Post-AM work

Complex components such as these will always require an element of post-AM work, and the skilled tool makers at James Camden work with i2M to finish parts to the customer’s specification. Most of this is achieved using James Camden’s CNC wire-cut EDM machines. Housed in the company’s 4,000sq ft facility, the three wire machines are complemented by manual and CNC machine tools.

To meet the requirements of i2M, James Camden initially purchased a V350G Excetek machine. The company says that while this is an entry-level machine, it provides ample capacity and a level of performance that is comparable to Swiss and Japanese machines costing significantly more. It features a 600-litre tank and can accommodate workpieces up to 700 x 500 x 215mm and weighing up to 450kg.

It has U- and V-axis travels of 80mm, a ±30deg taper capability and an accuracy of 3µm over 100mm.

Mr Bloxham says: “With an ever increasing amount of work from i2M, we required more capacity. The ease of use and the faultless performance of the first Excetek machine resulted in us returning to WMT for a further two. We selected two mid-size V650G machines.”

As standard, the V650G has a work envelope of 650 x 400 x 350mm and accommodates parts up to 1,000 x 700 x 345mm and weighing up to 800kg. It has U- and V-axis travels of 160mm, a ±33deg taper capability and a resolution of 0.0001mm for its linear axes. However, the V650G machines specified by James Camden feature an extended Z axis to allow larger base plates to fit between the wire guides.

In conclusion, Mr Kelly says: “Between the AM process and the skills provided by James Camden, we can effectively offer the complexity of handcrafted parts, but with the production integrity of mass-produced items.”