The most accurate ruler

 

As many of you know, we love manufacturing. Over the last 8 years (It's been that long, crazy!) we have learned a lot by focusing on making watches. However, 3 or 4 years ago, parallel precision sectors, like the medical, space, semiconductor and high-end scientific instrumentation sectors, started to become curious about our capabilities. Specifically in handling complex, highly precise and very small parts. This interest was big enough to spin-out a separate business called NH Micro. If you've been following along our newsletter and journey, you might have heard of NH Micro before - in short, watchmakers making parts for other sectors. ANSTO is the Australian Nuclear Science and Technology Organisation. It's the leading research body for nuclear science. Between a particle accelerator called a synchrotron located in Melbourne, and a nuclear research reactor in Lucas Heights, south of Sydney, ANSTO employs 1300 people. Over the last 2 years ANSTO has been one of NH Micro's key clients - They use NH Micro to help manufacture very precise parts and assemblies for their research applications, and often come to us when their internal workshops, and usual vendors tell them it cannot be done. Just last week we shipped off a very complex and highly demanding project to the synchrotron in Melbourne. Currently they are building, in layman's terms, a new sensor for their particle accelerator. One of the main features of this new upgrade is that the sensor has to be able to move incredibly accurately. https://www.ansto.gov.au/x-ray-fluorescence-nanoprobe-beamline

In fact so accurately that for us, dealing in microns every day, we cannot fathom how precise this device will be. Our machines in the workshop regularly work in the micron and sub micron range. This is hard to visualise, but you can try by taking a sheet of paper, dividing the thickness of it 100 times, and you will be left with something 1 micron thick. Now, ANSTO's new device will be positioning around 300 times more accurately than that divided piece of paper. 3 Nanometers. Some more perspective. Dust that you find around the house is usually in the order of 10-20 Microns, a red blood cell is around 8 microns in diameter, the wavelength of red light is around 0.7 microns (700 nanometers), the diameter of a SARS-CoV-2 virus is around 100 nanometers (coronavirus!) and ANSTO's new device is still operating at accuracies smaller than that scale, at 3 nanometers... Just amazing. Where NH Micro fits in, is in the manufacture of the motion and metrology components of this new device. Last year we built the motion platform that actually moves in these absolutely tiny increments (Photos will be coming of this, but they are still under an embargo), and just last week we manufactured the "ruler" that measures how far this motion stage has moved. In more detail, we really manufactured the holder, that holds 3 separate rulers to measure the devices displacement. The design of this "ruler holder" was completed by a team of incredibly talented engineers at ANSTO, and we were given the task to manufacture and assemble each component.

The challenge? Everything metallic was to be made from a very special material called invar. Invar is an Iron-nickel alloy that has an incredibly small coefficient of thermal expansion. In fact, it's used widely when you really don't want things to grow or move when they heat up and cool down. At ANSTO, they are keeping their environment incredibly well controlled, but even still, fractions of a kelvin can drastically alter the performance of your measurement. The tricky part about invar is that it is quite difficult to machine. It's sort of like machining bubble-gum mixed with sand. It wears out tools, and machining geometry to tight tolerances is not trivial. Not to mention, it's egregiously expensive! Mistakes are costly! Between our Kern Micro HD 5 axis milling machine, our Makino u32j wire EDM, as well as countless hand tools and measuring tools, we were able to manufacture this one-off "ruler holder". This frame holds 3 laser interferometers, which bounce light off a surface and measure the change in displacement of the object that they are pointing at. The whole project took over 1 month in the workshop, and around 4 months overall, between waiting for material, tools and the like.

What's vital in projects like these is that we are able to handle the entire scope of work, "soup to nuts". Many workshops globally are able to mill Invar, or wire cut it, or put together components, or measure them accurately, but very few places have the key competency to do all of the above - especially in Australia. In fact, without our watchmaking knowledge, heritage, and expertise, even if we had all the machines, we would not be able to complete a project like this one. Manufacturing these ultra-complex assemblies is an engineering miracle in itself. It's been a long road to get to this point, many failures, lots of learning and teaching opportunities, but in the end, we are happy to be able to offer our services to the Australian government, people and industry. Long live Manufactured in Australia! Josh