Sean Dillow
Vacuum vessel made of aluminium produced by a 3D printer for the VMXM beamline.
Harwell is one of the UK’s best kept secrets, just South of Oxford it is perhaps Europe’s leading science, innovation, and technology campus. The 710 acre site is host to over £1 billion of research infrastructure. Naturally, additive manufacturing and 3D printing plays a big part in developments there particularly in the fascinating Diamond Synchrotron, which opened in 2007.
Andy Stallwood is a Mechanical Designer at Diamond Light Source Ltd., he recently worked on a project that required the expertise of one of the bureaux on our service provider map. Here, Andy talks us through the 3D printing of a complex part enabling the study of objects at a cellular level.
Diamond Light Source is the UK’s synchrotron; a 562 m circumference particle accelerator used to produce extremely bright X-rays. From the accelerator the X-rays are fed into 28 operational beamlines where scientific studies are carried out. The whole machine acts like a giant microscope allowing users to see and identify atomic and molecular structures throughout a sample. Scientists are able to study anything from fossils to jet engines to viruses and vaccines.
Initial CAD drawings of the Vessel
VMXm is a new crystallography beamline being developed to study very small protein crystals measuring just 0.3 µm across with a 300 nm wide X-ray beam. At the sample position many pieces of equipment converge to carry out the analysis. Equipment such as a Scanning Electron Microscope to see the samples, six cameras for clash detection, a fluorescence detector, the sample changer, sample stages, cryogenic cooling, beam position monitor and beam clean up slits, beam stop and various sensors. To add an additional level of complexity the sample is also held in a high vacuum.
Due to all of these constraints it was clear from a very early stage that the vacuum vessel needed to hold the sample was going to be complex. Initial layouts and vessel designs using conventional manufacturing and fabrication techniques just didn’t work so we looked at designing the vessel to be 3D printed in aluminium using DMLS (Direct Metal Laser Sintering). 3D printing allowed us the design freedom to shape the vessel how we wanted and build in many features that would otherwise require a number of different components. The layout was improved and saved on space that was in very short supply.
After finalising a design (not optimised for the DMLS process) that achieved all of our goals, the vessel was sent out for quotation. Through this process we received a number of replies; some saying the job was too high risk and declining to quote, while others wanted to re-model the component quite considerably and quoted a very high price. Then we were lucky to come across CA Models based in Stirling.
On first contact they quickly supplied us with a competitive price with no re-design conditions attached. Being wary of such a good offer I spoke with the managing director Clark Campbell, a very enthusiastic man confident of his company’s abilities and up for the challenge. He showed me some of the work they had previously produced and that was enough to place the order.
Vessel as it comes off the SLM 500 plate at CA Models
Clark was excited about working on this particular project. Though extremely challenging, the vessel would be an ideal showcase opportunity for their new quad laser SLM 500HL metal additive manufacturing machine.
After interrogating the CAD file and associated machining PDF details, the optimal build orientation and support strategy were formed. Once set up, the aluminium build took two and a half days to complete. The build structure was then removed and the vessel was hand finished, polished, inspected, CNC machined and finally (at the request of the principal scientist) painted in Ironman colours!
The finished vessel was delivered in March this year and looks fantastic. It is now in vacuum testing and will be used to prototype other parts of the beamline design. If no changes are required it will be installed on the final beamline which is due to be operational early 2018.
Diamond has now been operational for 10 years and has been using DMLS technologies for a number of these. DMLS is often the only manufacturing choice for some our designs that work in extreme environments where space, mass and complexity are key requirements.
Functional finished 3D print
What is it?
The sample vessel for the national synchrotron’s new VMXm beamline endstation. Made from aluminium the vessel will hold a vacuum of 10-6 mbar.
Technical details:
- Manufactured by CA Models
- Material: Aluminium
- Mass: 4 kg
- Machine: SLM 500HL
- Build time: 60 hours
- Dimensions HWD: 262 mm x 300 mm x 200 mm
- Wall section: 3 – 12 mm
- 8x Equipment ports
- 5x Camera / Inspection ports
- 4x Laser sensor ports
- 3mm X-Ray input hole and large output window cone
- Internal and external features for mounting additional equipment
- 70 Tapped Holes
- Polished internal surfaces
- Painted external surfaces
