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Metals at 3T RPD
The collective noun for EOS machines is a herd.
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What is Six Sigma
What is Six Sigma?3 of 3
Pa12 properties
Properties of PA12As the snow fell silently across the UK in January I looked pensively at my diary. In the middle of the month was a 3-hour trek down the motorways of England — not something to be relished in even the most helpful weather. The Gods were kind to me however, and the worst of the weather held off affording me safe passage to the heart of Berkshire.
I was heading to something of a historic destination; the site of the former Royal Air Force and US Air Force base, Greenham Common. Opened in 1942 the air base was active throughout World War II and during the Cold War — being closed in 1993. Greenham Common played an important part in the D-Day operations and were visited by Dwight D. Eisenhower who came to watch the preparations. In the event, some 81 overloaded aircraft left the runway at Greenham Common in just 15 minutes.
When the air base was no longer needed it was acquired by the Greenham Common Trust with the aim of ensuring that the land was not lost to the community through piecemeal regeneration schemes. The trust reopened much of the land to the public, while also undertaking to redevelop the hangars and Air Force buildings into Greenham Business Park. It was within this maze of buildings that the old and the new sit next to each not as uneasy companions, but as reminders of the ingenuity of man kind.
The company I was here to see, 3T RPD, occupy a large unit at the heart of the park in which around 40 staff work on plastics and metals additive manufacturing and the associated processes. Established in 1999, 3T has become the largest supplier of plastics AM (through selective laser sintering) in the UK, supplying a reported 50% of the UK market. Currently the split between plastics and metals capacity is 2:1, however it was the metals machines that I was most keen to see.
3T’s Metals Systems
- 2 x EOS M270 running Argon
- 1 x EOS M270 running Nitrogen
- 2 x EOS M280 400w running Argon and Nitrogen
3T runs EOS systems almost exclusively across both its plastics and metals machines. I asked Ian Halliday, CEO at 3T RPD, why this was: “We believe that currently EOS are at the top of the game when it comes to these systems. We are always looking at the competition in terms of other suppliers and other technologies, but at the moment we are happy with EOS.”
As we make our way into the metals section of the facility we’re greeted by the first two EOS machines, one of which is shrouded in secrecy sporting a ‘3T RPD: CONFIDENTIAL’ poster across the viewing window into the build chamber. This particular machine is an EOS M270 building in Maraging steel in a Nitrogen atmosphere. Ian explained: “This particular machine has been running the same part, for the same customer, for over 12 months. Unfortunately we can’t give any more information than that at this stage!”
While the inevitable non-disclosure issues that occur with technology at this level are irritating, it was interesting to see a company that is not just running one off parts or the occasional design iteration, but actually manufacturing. Ian explained: “The move from prototyping quality control to manufacturing quality control was a game change for us. Running the same part for 12 months is one of the ways we can fine tune our production abilities.”
When I asked Ian about how easy it is to use AM as a true manufacturing technology, he explained that although the machine technology played a large part — especially in the creation of otherwise impossible geometries — it was the part selection, preparation, build setup, process control and finishing that had a huge effect on whether the final part is fit for purpose.
In terms of the build setup, there are ‘tricks of the trade’ that each company and even each machine operator employs, most learned from hours of trial and error with both real and test parts. During my visit 3T were running the same test part on one M280 and two M270s so that the builds could be calibrated to get the same standard of part off any of the machines in a repeatable manner.
Ian elucidated on the process: “We have one six sigma black belt and two green belts within the company (see sidebar 2 for details) which means we have exceptionally strong statistical analysis of our manufacturing process. We believe this is the only reliable method for dealing with a process that has so many sources of potential variability.”
Later in the day I had chance to quiz some of the team about some of the specific industries they are involved in. I was particularly interested in their take on the medical industry. Speaking with Phil Kilburn, Sales Manager — Metals, I discovered that the company’s growth predictions for the industry had not been met in reality: “We saw medical applications as one of the major growth areas for additive manufacturing but a number of issues have stopped this developing at the rate we anticipated. We see companies becoming more sensitive to litigation following some high-profile issues in the US market. Likewise the major players are tending to take projects back in house — no doubt these projects are still going on but it is less common to have sight of them as a service provider. However, the aerospace sector has accelerated faster than we expected.”
In terms of materials I was able to speak with Mark Beard, formerly of The University of Exeter. As 3T are active in both metals and plastics they have a good understanding of the developments in both areas. In terms of metals Mark’s opinion was that current offerings covered the majority of current applications and those of the immediate future. In terms of plastics Mark explained: “There is certainly more room for more developments here. One of the main problems here has been the prevalence of a single polymer in the form of PA12. This polyamide has such a wide and useful range of properties (see sidebar 3 for details) that developing new materials for AM processes hasn’t been a priority.”
This inequality between the metals and polymers materials development is easy to see within the offerings of 3T itself, with seven metals and alloys available (Aluminium {AlSi10Mg}, Cobalt Chrome Alloy {Co28Cr6Mo}, Nickel Alloy {In718}, Maraging Steel {1.2709}, 316L Stainless Steel, 15-5PH Stainless Steel, Titanium Alloy {Ti6Al4V}) versus just two for plastics (PA12 and glass-filled PA12).
Future developments:
With new machines being added to the line up all the time, 3T are set for continued growth. Since my visit another EOS M280 has just been installed upstairs (I asked how one gets a behemoth AM machine installed upstairs — answer: don’t ask!) furthering the company’s metal portfolio. Equally importantly the company has been updating its plastics machinery to the latest versions as Ian explained: “In a dynamic industry like this, technology develops rapidly and we continually update our inventory to make sure we can make the most of the technological advances.”
