Ever hear of the Ship of Theseus?*

Nearly 20 years ago, a customer asked for something only 4D Technology could make an interferometer that would work in a vacuum chamber. The challenges of the project center on two things:

1. Vacuum chambers are noisy, that is, they have lots of vibration because pumps need to run to bring the chamber down to sub-atmospheric pressures, and measurements by spatial phase shifting are disrupted by vibration
2. It’s hard to stabilize temperatures from a heat source without air flow, which is lowered in a vacuum—and lasers and electronics make heat. And thermal changes alter the results of the precise surface measurements an optical metrologist wants and needs.

With our patented dynamic interferometry, and an acquisition speed measured in millionths of a second, the PhaseCam was capable of measuring in vibrating environments. By creating a vacuum-sealed housing that was piped for internal air flow, we could cool the heat sources without compromising measurement quality even with significant air flow into the interferometer.

Servicing instruments from the early days

That early instrument is still in use by the customer, and they send it (and their other 4D instruments) back to us regularly for upgrades, maintenance and calibration. In fact, here it is in a recent photo, on a repair bench in our Service Department. The serial number says that this is just the seventh PhaseCam we ever built, shipping in the early years after our founding in 2002.

It’s not always possible to continue to repair and upgrade an aging instrument – parts can go obsolete. Operating systems, electronics standards, and even connectors evolve, and are not always backwards compatible if some component ages out of use. But we’re proud to continue to support nearly everything we’ve sold, even decades later– because we know you depend on your investment to keep working.

Will you ever need service on your metrology system? Best choose a company that will back up their instrument with a service department that will always take your calls and do their best to support your instrument. Our service department can be reached through our main number: +1 520 294 5600

If you’ve got an instrument that needs attention, contact our Service Department.

*The Ship of Theseus is a philosophical thought exercise on the nature of identity. It is a thought experiment that asks the question of whether an aging object that has had all its components replaced remains, fundamentally, the same object–and perhaps more interestingly, if it’s not, when did it become something else?