Laser Prototypes Europe (LPE) is one of the UK and Ireland’s longest-standing specialists in rapid prototyping and rapid manufacturing for a range of industries.

Among its many services is DMLS (direct metal laser sintering) — the 3-D printing of metal parts.

The ability to print components with complex geometries in short cycle times offers a ‘huge competitive advantage’ for LPE and its customers.

The DMLS process requires a lot of heat and energy to sinter the powder, which creates stresses that can lead to distortion of the part.

To counter this effect, ‘heat-sinks and anchors’ must be added to the component.

After 3-D printing, wire-cut EDM is used as a finishing process to remove these and achieve final tolerance.

LPE recently added a second machine to its EDM portfolio — a VL600QH from Warwick-based Sodi-Tech EDM Ltd (www.sodi-techedm.co.uk) — and this is proving to be some 50% faster than the existing Sodick machine, which was installed in 2017.

LPE was established in 1991 by current managing director Tom Walls.

The first UK company to install an EOS rapid prototyping system, LPE has continued to invest in the latest technologies and materials; it provides a complete metal sintering service that includes in-house metallurgy, stress relieving, wire EDM, bead blasting and five-axis machining.

Central to LPE’s offer is DMLS, which sinters together layers of metal powder to form parts with a density as high as 99.99%.

However, this level of density creates a number of subsequent challenges, as Mr Walls explains: “AM presents a unique problem for EDM, as the density and shape of the support structures make DMLS parts very difficult to ‘wire’ without repeated wire breakages.

“In addition, there are lattice-type structures within the parts, and sometimes powder can be found in pockets, all of which adds to the challenge.

“The high frequency of wire breakage means we need wire EDM machines with quick re-threading and re-datuming capabilities, which is why we use Sodick.”

Rapid growth

LPE installed its first Sodick wire EDM — an AQ537L model — in 2017; and although the machine has performed well, the company’s growth has been such
(5-20% year-on-year) that wire EDM became a bottleneck.

Mr Walls said: “We also thought it was a risk to continue running with just one wire EDM; and while the machine hasn’t missed a beat, if anything unforeseen was to happen, it would have a major impact on lead times.

“To both increase capacity and mitigate risk, we decided to invest in a second Sodick.

“The reliability of our first machine has been such that there was never any chance we would look elsewhere.”

At LPE, which relocated to larger premises in 2013, both high-resolution (down to 0.015mm) and ‘production standard’ resolution (0.06mm) are offered to cater for differing customer requirements; and with LPE’s focus on quality, all DMLS parts are stress-relieved before making their way to the Sodick wire EDMs.

“With the new machine, we’ve certainly noticed that technology has moved on.

“The way the wire is driven has been improved, delivering better control if the machine ‘thinks’ the wire might break; and if the wire does break, the machine is much faster at re-threading and getting back to its cut position, which in turn contributes to higher productivity.

“Undertaking wire EDM on a row of 20 DMLS parts would previously have taken about 4hr, but this time can be halved with the VL600QH — plus the machine interface and software are better.”

Installed in late July 2019, the Sodick VL600QH features linear-motor technology; it can also accommodate tall workpieces, thanks to 500mm of Z-axis travel.

“We deliberately opted for a machine with axis travels that would allow us to grow the size of workpiece we can process,” added Mr Walls.

LPE currently offers metal sintering in four materials: stainless steel, hardening stainless steel, aluminium and titanium.

DMLS parts offer a direct replacement for traditional machined components, which is why they are proving increasingly popular for Formula One parts, medical devices, dental devices, aerospace components, tooling inserts and high-temperature applications, for example.

LPE, which is both ISO 9001 and ISO 13485 registered, estimates that it will grow by a further 10-15% this year, as demand for metal additive manufacturing continues to ramp up.

In conclusion, Mr Walls said: “There are many factors that set us apart from our competitors.

“For instance, all customers receive a rapid quote, a dedicated project team and on-going support and advice from a designated sales contact.

“Moreover, our knowledge is second to none, which is why we are continuing our research with universities and industry; indeed, we currently support four PhD students and four post-doctoral students with their research in advanced process control and powder development for metal laser sintering.”