|Prof. Andrew Lewis MA, DIC, PhD, FInstP, CPhys
National Physical Laboratory
Phone: +44 (0)20 8943 6074
|University of Cambridge
|University of London
|Principal Research Scientist, Dimensional Metrology
1988 to present:
Employed at the National Physical Laboratory (NPL)
1988 – 1993
On joining NPL as a Research Scientist, I immediately started research into high accuracy length measurement of material length standards using a combination of phase-stepping and multiple-wavelength interferometry. This led to the construction of the Primary Length Bar Interferometer, which formed the subject of my PhD thesis. In the development of the interferometer, I learned a lot about optical and mechanical design – most of the engineering drawings were my own, I wrote all of the control software (in Pascal) and interfaced the various sensors to the PC. I had to balance the research budgets and also train staff in the use of the equipment when it was finished. In effect, I acted as Project Manager for the entire project, over its 5 year research lif, as well as being involved in liaison with the engineering and marketing departments. I researched equipment specifications and performed a thorough literature review, and wrote up the work both as my Thesis (for which I was registered as an external student at Imperial College, London, and as a couple of articles in the scientific journal Measurement Science and Technology. The research work was one of my contrbutions which were taken into account when I was promoted to Higher Research Scientist.
The Primary Length Bar Interferometer which I designed has been seen by visitors from around the world and its design has now been licensed to Brown & Sharpe who are able to supply commercial versions to interested parties. The capabilities are remarkable: the ability to measure the length of length standards up to 1000 mm in length to an uncertainty of less than 0.1 micrometres (about 2000 atomic spacings) with short-term repeatability approaching 0.01 micrometres (200 atoms), as well as the automatic measurement of surface geometry and thermal expansion coefficient! Every well-equipped metrology lab should have one!
Aside from managing the various measurement services for length bars and long gauge blocks, I used the algorithms from my earlier research into phase-stepping interferometry as my contribution to a major software project in our group to develop new, modular software for controlling length measuring interferometers. The software was written in Borland C++ and was adapted to control most of the group’s laser interferometers. The software has now been licensed to a company (Brown & Sharpe) which manufactures and markets our interferometer designs. So far, 23 of our previous design of interferometer have been sold worldwide where theyn are in use in many national metrology institutes and 3 instruments now contain the new C++ software. During this period I was promoted to Senior Research Scientist.
In 1996 I wrote a proposal in response to an invitation to tender for a £0.5M package of work to build the world’s most accurate, fully-3D coordinate measuring machine (Small CMM). The proposal was successful and I then managed the research project at NPL to design and build the instrument. The goal of the project was to produce a CMM with a working volume of 50 mm x 50 mm x 50 mm with an associated uncertainty of measurement of 50 nm. This is of considerably higher accuracy than conventional CMMs which typically only achieve 1000 – 2000 nm uncertainty. This project involved laser interferometry as well as some special probe designs to cope with such special requirements. As well as responsibility for project management, I was involved with the process of recruiting 3 new members of staff, including interviewing prospective recruits. Although many of the technical achievements of the project were due to the skills and knowledge other members of the excellent project team, I was responsible for keeping to budget and timetable, and for ensuring constant liaison between various groups at NPL.
Following the success of the Small CMM project I was appointed project manager for the followup project to further develop the capabilities of the Small CMM. In 2001 I was promoted to Principal Research Scientist and became GroupProject Manager for Co-ordinate Metrology. I had reporting responsibility for 5 members of staff, project management responsibility for two projects (£0.6M) and the development of the coordinate metrology and large scale metrology themes of the next Length Metrology research programme (2002 to 2005).
During the 2002-2005 Length Programme, I became Theme Manager for Large Scale Metrology and project manager for 3 projects. Much of my time was dealing with international issues and overseeing the work on large scale metrology. I co-organised an international 2 day workshop on Large Scale Metrology, atracting ove 50 attendees from companies such as Boeing, BaE, Leica, etc as well as academic representatatives from CERN and several major observatories.
Following restructuring of NPL , I volunteered and was accepted as temporary Group Leader for Length Metrology. I became responsible for the annual budget and for just under 20 staff. Following permanent appointment of a new Group Leader I no longer have these responsibilities, however I am now the science lead for the area. I continued to be involved with software writing (C++) and also with a recent major overhaul of the NPL web site. My R&D efforts are now concentrated in the area of Large Volume Metrology where I was the project coordinator in the LUMINAR project – Large volume Unified Metrology for Innovation, Novel Applications and Research and now coordinate the follow-on project LaVA – Large Volume Applications. The third project in the series, DynaMITE will start in autumn 2021.
Aside from the physics, computing and management I have been involved in promoting the work of our group and NPL as a whole, and have presented a lecture on the work of NPL at the Cambridge University Physics Society, as well as demonstrating the group’s work to visitors from around the world. I am also the author of a set of web pages which promote the work of the team.
I have represented the UK as the NPL Contact Person for Length Metrology at the meetings of the European Collaboration on Metrology (EURAMET) Technical Committee, at 8 annual meetings, and have just stood down from the position of Technical Committee Chairman, a job I undertook for the maximum 4 year term of office. I also serve as an NPL representative on the international CCL Working Group on Dimensional Metrology (WGDM) and have organised two international key comparisons in the field of long gauge block measurement. I serve as technical expert on a BSI committee and am the NPL Corporate Member of the distinguished body known as CIRP.
In 2009 I finally got round to applying for membership of the Institute of Physics and also gained my Chartered Physicist status.
2009 was also an interesting year because I got to take part in an episode of the BBC flagship science programme, Horizon, which was concerned with measuring a piece of string. If you can access BBC content, you can see part of the programme here. I also had the opportunity to show my work and some of the history of length measurements to Stephen Fry. Which was nice.
When not ‘hacking’ around with the innards of my PC (in the traditional sense of the word) you could as easily find me at the controls of a light aircraft, or driving a kart around a circuit. Or perhaps you would find me relaxing in the garden, or juggling flaming torches. I am unlikely to be doing more than one of these at the same time though! I also had a penchant for chatting with airline pilots on the flight deck of airliners, often taking the cockpit jumpseat for the landing, and adding a trained pair of eyes and ears (not to mention the odd map). However this particular activity has now been curtailed in light of recent events.
I’m hoping to continue my research into dimensional metrology problems and applications and at the same time broaden my experience of IT and hopefully find links with my hobbies. Eventually I plan to complete my PPL.