While you tend to think of diamonds as ornamental gemstones, diamonds also have many important industrial uses, and many of those diamonds are now synthetic polycrystalline diamonds. How are they made? [JerryRigEverything] takes us behind the scenes at a diamond manufacturing facility, something you don’t get to see every day. Check out the giant presses that exert about a million pounds of pressure in the video below.
The process starts with diamond powder, which is just what it sounds like. Although you can get real diamond powder, most uses today start with synthetic diamonds. The powder has many uses in cosmetics and as an abrasive. But the video will combine it with cobalt and table salt to form diamond shapes.
The salt is a high-temperature electrode. The process requires temperatures of nearly 1400C (2500F) and a lot of pressure. Common talc, some metal electrodes, and a heater tube are also used in the process.
The press can convert a little diamond dust into a diamond in about 10 minutes. However, because the machines are so dangerous, they are each set in their own blast room, which is sealed when the press is in operation.
While this press was — no pun intended — impressive, we’ve seen bigger. Nothing like this will show up in your garage anytime soon, although, as the video shows, you can buy 3D printer nozzles made from the material. As for a press, you might have to just settle for an arbor press.
Does anyone know why these machines are built in this way? Best I know, the sintering temperature is so hot that the salt melts and becomes a liquid. So why not just use a cylinder to apply force from one side? I already saw this video a few days ago, (the youtube algorithm), and although interesting enough to watch, it is light on detail.
You can also buy these things from Alibaba, (Search for “diamond press”) but they look a bit different. Instead of the “round bars” connecting the sections, there are heavy “chain links”. The sections are also from cast steel instead of (probably) turned.
its engineering right
so the “3d” press is going to be the pragmatic way to get a larger
“ingot”, and the Chinese are going after faster ,cheaper , high volume
in all senses, but will sacrifice tooling failure to keep costs down
and so syntetic diamond production is growing rapidly, as is the size of the finished diamonds.
while the chinese presses look rough, I am very curios about the metalurgy behind there castings.
the chains on the chinese presses might be for “saftey” and just catch the press head, when it fails, rather than having the expense of
running the press inside a bunker, but I bet that there is no one in the building, when while a press run is happening,