How Scientists Let you Cram Terabytes of Data in a 3.5-inch hard drive

According to Seagate Technologies, if they were to stack up all the storage media that they have produced so far, then it would attain a height of 950 meters. Doesn’t sound like much? How about if we told you that that’s 122 meters higher than the tallest building in the world--Dubai’s Burj Khalifa? While the Burj Khalifa has a height of 828 meters, Seagate’s media would stack up to a height of 950 meters. Now that’s something!

But this is just an interesting fact, which may not matter much to ordinary people or even storage experts who store their memories and critical data on hard drives purchased off the shelf for a few thousand bucks. But you’d be amazed if you discovered just how these storage devices are actually manufactured. At least we most certainly were when we visited Seagate Technologies’ hard drive platter manufacturing, integration, and testing facilities in Singapore. The process is nothing short of amazing.

For one, to create such a storage wonder, and to continuously increase its capacity by leaps and bounds every year, requires a lot of research by hundreds of scientists from so many different streams like chemistry, physics, process technology, fluid mechanics, and aerodynamics.

Some Wow Factors in Hard Drive Platters Manufacturing

Hard drives contain shiny magnetic platters that spin at up to 15,000 revolutions per minute. They store all the data, and the recording is done by read/write heads that hover above them at a height of less than 100 atoms. That’s 100 times thinner than a piece of paper!

Such perfect and error free platters are manufactured in a facility that spreads across thousands of square feet and is kept so clean that it has less than 10 particles per cubic foot that are smaller than 0.5 microns. Just for comparison, bacteria are about 2 to 10 microns in size!

The whole process is automated, and requires very little manual intervention. It starts from the platters made of glass or Aluminum arriving in boxes, which are than unpacked and put on a robotic assembly line. They’re thoroughly cleaned and washed with chemicals, and then sputtered with magnetic materials. They’re than lubricated, buffed and polished. Once ready, they undergo a UV cure and tested thoroughly. Finally, they go through a multi-disk writer, which creates what’s called servo patterns.  These are postal codes or maps that are used to position the read/write heads and help them locate all the digital data. Once ready, the platters are packed and dispatched to another plant, where they’re integrated into a hard drive and then put through rigorous testing.

Seagate manufactures 1 million such platters in 24 hours at this plant, and that too with 98.99% quality!

Automated Integration and Testing

Seagate’s facility at their headquarters in Shugart does the assembly and testing of hard drives. The assembly area spans 1500 square meters and currently produces 500 drives a day, but can go up to 16,000 drives a day. There are about 26 steps involved in the assembly, and even this facility requires the same level of cleanliness to be maintained as the platter manufacturing plant. The interesting thing about this plant is that the entire operation of putting together the platters, recording heads, motors, ICs, etc. is so heavily automated that it requires only 5 operators and 5 technicians!

Once the drives have been assembled, each one undergoes rigorous reliability tests so that that can run smoothly in all kinds of demanding environments.

The drives are put through a completely echo free, acoustic chamber to help eliminate their noise. They’re put into chambers that simulate altitudes of up to 40,000 feet and pressures well below sea level. They’re cooked to extreme temperatures, Given the 1000G drop test at various angles, and hit with thousands of power on and off cycles. They’re also put through an EMI chamber and put through rigorous electromagnetic emission and immunity tests.

Once the drives clear all the tests, they’re packed and shipped to the desired destinations. Here again, Seagate claims to be among the top 25 companies in the world having the most efficient supply chain operations!

The author was hosted by Seagate in Singapore