Invar is ideal for components that require near constant dimensions as it is able to maintain its shape between temperatures of -100°C & 260°C without experiencing warping or thermal expansion.
Its unique qualities make it a popular choice for a range of applications where accuracy is key, including clock pendulums, measuring devices, aerospace engineering and the transportation of liquid natural gas due to the significant insulation it provides.
It is also a highly durable material, so it is perfect for precision instruments such as microscopes and telescopes.
One of Invar’s original uses was in clock pendulums. When it was first invented, the pendulum clock was the world’s most precise way of telling the time, however accuracy was limited due to the possible thermal variations in pendulums. In 1839, Clemens Riefler invented the first clock to use an Invar pendulum and its unprecedented accuracy (10 milliseconds per day) meant it served as the primary time standard for national time services until the 1930s.
Specialist cutting equipment is essential to complete Invar machining without having a detrimental effect on the material, and our expert team’s experience and equipment means we are perfectly placed to cast Invar parts to the most precise specification.
Benefits of Invar Components
Low thermal expansion
The key reason Invar is so popular as a component for the likes of telescopes and microscopes is its low thermal expansion properties. This means that unlike other alloys, it is able to maintain between temperatures of -100°C & 260°C without changing shape. Even small changes can have a huge impact on the accuracy of results, so being able to use a material which isn’t impacted is a huge bonus.
Invar’s low thermal expansion also means it is an incredibly durable material. In fact, it’s a popular choice for transporting liquid natural gases due to the significant insulation it provides.
This combined makes Invar the primary industry choice for machining parts where a high level of accuracy is required. Its stability as an alloy mean it is unrivalled in applications such as clock pendulums (where it was originally used), optical engineering and precision instruments, as well as a variety of scientific instruments.
Our Invar Components projects
WHT Enhanced Area Velocity Explorer (WEAVE)
We created Invar components for the WEAVE, (WHT Enhanced Area Velocity Explorer), a new multi-object survey spectrograph being constructed for the William Herschel Telescope (WHT) in the Canary Islands. The spectrograph is an instrument that splits light into wavelengths to make it possible for astronomers to record and analyse and requires a high level of precision to ensure accuracy of results.
The new spectrograph will allow astronomers to take a spectra of up to 1000 stars and galaxies in a single exposure and marks a significant jump forward in the efficiency of the telescope (currently it is only possible to observe 100 objects simultaneously).
When completed, it’s hoped that the telescope will allow us to understand how the Milky Way was assembled by measuring the speeds of several millions of stars being mapped by the European Space Agency’s GAIA satellite.
Dark Energy Spectroscopic Instrument (DESI)
We were involved in machining the cast Invar components for a new spectroscopic instrument designed to measure the spectra of more than 30 million galaxies and quasars covering 14,000 square degrees over a five-year period.
The Dark Energy Spectroscopic Instrument (DESI), which is mounted on the Mayall telescope at Kitt Peak National Observatory in Arizona, USA, began its five year operating life last year.
Astronomers use the term ‘dark energy’ to describe the unknown form of energy hypothesised to be responsible for the constant expansion of the universe. Scientists such as DESI hope to be able to learn more about the nature of dark energy in an attempt to help us better understand the universe.
We were approached by the team involved to cast the ring to hold the lens due to our experience in precision and quality casting of large objects. The accuracy level of this project was highly demanding, as the impact of fractions of mms movement of the lens would impact hugely on the results of galaxies viewed at such distances.
We worked closely with the team to understand the requirements for the material composition, which was a specially blended alloy free from residual elements to give a cleaner alloy.
Our manufacturing processes took into account an oxygen-free annealing environment since the heat treatment is critical to ensuring the correct TEC and we consulted with the team throughout our full proof-machining, pattern and casting process.