Late last year, a fully digitally controlled press, totally powered by hydraulics, was introduced.* The new system is about the size of a refrigerator, rather than the huge, up-ended tractor-trailer size of most traditional compaction presses. Initially developed specifically for the powder metallurgy industry, the system has recently been proven to successfully produce complex-geometry ceramic parts as well. The new system produces parts with much greater green strength, lower and more uniform shrinkage, and minimal ejection/deflection cracking.
Although the new system incorporates dozens of individual innovations, the real key to the success of the new technology is in replacing brute force with intelligence and art with digital technology. From the carefully calculated weighing of the powdered materials, to the “fluidization” of the materials that assures uniform distribution of materials in the die cavity, to the digitally controlled pressure system, each step applies a level of intelligence that requires far less size and weight than a traditional press—while producing a superior product. The digital control also makes possible highly accurate, constant quality control, as well as remote diagnostics and troubleshooting.
The new system, recently named one of three “Inventions of the Year” by TIME Magazine, offers ceramic manufacturers the potential to expand the design envelope, producing higher-quality parts and a larger range of parts with little or no post-press machining, while affording dramatically lower downtime for presses.
The new system, by contrast, measures the powder by weight, ensuring that measurements are consistent to within ±0.1 gram and as fine as ±0.04 gram, regardless of the part size, versus a typical weight variation reported at 5 to 8% per part. The result is reliable consistency in density—a key requirement for high performance from one part to another. Higher density can also be achieved compared to conventional pressing technologies—compaction pressures have reached 50 tons per square in. (TSI) in initial production runs with ceramic materials, and a potential of 65 TSI is possible.** This compares with the 5 to 10 TSI achieved with traditional ceramic compaction presses.
The new technology solves this problem by “fluidizing” the powder before pressing. Once in the die, a rapid flow of air is introduced to the die, turning the powder into a fluid. When the fluidized powder settles, it settles uniformly throughout the die, assuring uniform performance throughout the part.
By combining an accurate method of measuring inflow to the system—the weight system—and a method of assuring even distribution of the materials in the press—fluidization—the new technology reliably produces parts that require little or no after-press machining.
In the new system, the power is hydraulic and comes from a separate and remote power system that is digitally controlled. While tapping into a common hydraulic power system, each punch—the top and bottom faces of the manufactured part—is independently controlled. Each level of a punch (up to eight levels) has its own position transducer and its own pressure transducer. This allows each part of the press to monitor and manage its own piece of the manufacturing process, all within a total manufacturing system that manages the entire process.
The docking system also allows manufacturers to quickly remove a press from service—unplugging it from the hydraulic, electric and electronic connections in the docking station—and replace it with another. With traditional compaction presses, several days of downtime are often required for retooling when the manufacturing regime shifts from one part to another. With the new system, this type of changeover can be accomplished in a matter of hours, rather than days.
If any problems arise with the new system when no operator is present, the system’s computer can call or “beep” an operator who may be able to diagnose and solve the problem remotely. Otherwise, the operator can go in to the factory to make the fix or simply shut the system down until the next business day. If the problem is too difficult for the operator to address, off-site support staff can use the same remote diagnostics and troubleshooting tools from virtually any location.
The digital, computer-controlled system also allows manufacturers to draw on the much larger pool of potential employees with computer experience rather than the much smaller pool of experienced traditional press operators. And the small size means that a manufacturer can move a press from one location to another easily to respond to changing business opportunities—in North America or abroad.
“For Ferro, advances in pressing are extremely important, since our customers often ask us to investigate complex parts that, unfortunately, we just cannot manufacture using traditional technologies,” explained Jyoti Chakraverty, new product development manager for Ferro’s North American Ceramic Division.
“Our initial findings [with the new press] have been extremely positive. Although further research and collaboration are necessary, Ferro may soon be able to press even the most complex shapes requested by our customers, including some that currently would not be possible using existing technologies,” Chakraverty added.