Perfectly flat

Plansee’s new cold-rolling mill represents a technological milestone in the cold forming of molybdenum sheet.

The first impressions alone are jawdropping: Visitors enter a clearly laid out and thoroughly clean production hall in the Plansee production plant in Reutte, Austria. To the west, 15-meter glass walls offer a panoramic view of the mountains, with several Alpine peaks. And the technology in the hall is the finest around. Without a sound, a robot takes a molybdenum sheet from the transport container. The sheet is weighted and positioned “in flight” before being laid down gently onto the roller table. Now two clamps approach from the front and back to firmly clamp the sheet. Once it has been clamped, the real work starts: An x-ray machine moves over the sheet, measuring its thickness and profile.

The control system calculates the optimum rolling program in an instant. The rolls of the mill start to turn. The sheet is rolled backwards and forwards, and the final thickness is reached after just a few passes. A laser monitors the speed and controls the rolling process. And all is done with the utmost care; after all, the material should not degrade during the process. The finished material has been rolled to an impressive size of up to eleven meters by 950 millimeters at a thickness of up to 0.15 millimeters. “And we can work at a tolerance of less than 3 micrometers,” says process engineer Dr. Andreas Hoffmann proudly. It is the impressive combination of width, thickness and tolerance which means that Plansee High Performance Materials’ new cold rolling mill represents a technological milestone in the cold forming of molybdenum sheet. Once it has been rolled, the strip is wound onto reels or cut to single sheets. With its new cold rolling plant, Plansee has laid the foundations for end-to-end industrial manufacture of flat products. Hoffmann: “We are supporting our customers from a huge range of industries with rapid throughput times, high capacity and completely dependable quality.”

Wide formats
The molybdenum sheets are subsequently processed to make shield packs for hightemperature furnaces. They are shaped to form tubes before being riveted and then joined to other tubes. Wider sheets mean that it is possible to save several rows of rivets. When punching, wider sheet formats offer more flexibility to allow optimal use of the material.

Thin and completely flat
The electronics industry requires extremely thin material with an outstanding surface quality and thickness tolerance for heat spreaders and semiconductor base plates. What is more, the precise adjustment of the rollers means that the rolled sheets are exceptionally flat. This makes it possible to avoid expensive follow-up operations and therefore to achieve both material and cost savings.

Reliable material properties
Creep resistance plays a crucial role in high-temperature applications such as annealing boats and sintering boats. This property can be influenced beneficially and, most importantly, in a reproducible way through the use of defined, high, adjustable levels of deformation.

You can read other interesting stories in our magazine livingmetals.