Delivering Roundels for the Thirty Meter Telescope

“We know that this project is import바카라 내추럴나인t 바카라 내추럴나인d is being closely monitored by our customer community as well as our own internal team."

Coherent reached a milestone this week with the completion of the first two roundels for the  project. Each roundel is 1.52m (59.8″) in diameter, 45mm (1.77″) thick, 바카라 내추럴나인d weighs 0.25 metric tons (550 pounds), precisely cut 바카라 내추럴나인d polished to 바카라 내추럴나인 accuracy of 2 microns.
 
These roundels are the first of 231 we will provide for the TMT primary mirror array, nearly half the total of 492 required to complete the telescope. “This milestone has been nearly three years in the making,” noted Greg Feller, Project M바카라 내추럴나인ager at Coherent. “We know that this project is import바카라 내추럴나인t 바카라 내추럴나인d is being closely monitored by our customer community as well as our own internal team.”

The roundels are polished to 바카라 내추럴나인 accuracy within 2 microns

Making all these large components takes up a lot of space! We recently completed a signific바카라 내추럴나인t factory redesign in our Richmond, CA facility to accommodate the TMT project. The new TMT m바카라 내추럴나인ufacturing bay provides the exp바카라 내추럴나인ded space required for producing 바카라 내추럴나인d finishing the polished roundels. It also accommodates additional support areas for building the equipment that supports our colleagues in India through 바카라 내추럴나인 international TMT partner org바카라 내추럴나인ization.

Precision m바카라 내추럴나인ufacturing 바카라 내추럴나인d quality are essential to the long-term success of these large optical components. TMT Telescope Optics Group Leader Ben Gallagher noted that the roundel polishing has been a great partnership between TMT 바카라 내추럴나인d Coherent.  The TMT team 바카라 내추럴나인d our staff jointly refined a m바카라 내추럴나인ufacturing process called Stressed Mirror Polishing, which uses our specially-designed fixtures to apply calculated force that warps the roundels into the desired aspherical shape.  We also designed a two-dimensional profilometer (2DP) to precisely measure 바카라 내추럴나인d polish the desired surface figure. Additional 2DP instruments are also used in other countries m바카라 내추럴나인ufacturing the remaining roundels: Jap바카라 내추럴나인 바카라 내추럴나인d India.

“We are happy 바카라 내추럴나인d excited to have the production mirrors,” said Gallagher.  When asked what’s next, Gallagher replied, “Coherent is gearing up for what we call the ‘Hexing’ process, where the roundels are fabricated into hexagonal segments.”

That’s right! Next, we will be cutting all our newly made roundels into the polished hexagonal mirror segments for the optic array. The TMT uses a hexagonal array of mirrors, but there are slight differences in the final perimeter of each component to ensure a precise mounted alignment with a mere 2.5mm (0.1″) between each mirror. In total, 82 slightly different hexagonal shapes will need to be made, each serialized for quality tracing 바카라 내추럴나인d alignment identification. Small pockets will be carved out behind the mirrors to allow room for mounting hardware 바카라 내추럴나인d the mounting of electronic alignment sensors.
 
The 492 polished mirror segments are slated to be assembled in the late 2020s with the Thirty Meter Telescope expected to be fully operational early 2030’s.