Sodick has developed a high-speed machining center for making graphite and copper electrodes that is designed to meet the high-volume and precision needs of automated sinker electrical discharge machining (EDM).
The TT1-400A, designed and built in Japan, combines the speed and accuracy of Sodick’s HS Series machining centers at a price that is up to 50 percent less, says the company’s president, Dave Thomas. Sodick’s U.S. office is in Schaumburg, Ill.
In an interview with IMT Machining Journal, Thomas says that automated, 24/7 sinker EDM manufacturing has become key to competitiveness and profitability and creates more demand for graphite and copper electrodes. Robotic loading mandates that electrodes be machined with high precision, especially with micrometer (µm) tolerances.
The TT1-400A has features that meet these needs, Sodick says. One innovation is the use of carbon fiber in the worktable. Thomas says the 16.54 by 10.24 in worktable on the machine tool is 50 percent carbon fiber and 50 percent steel. Carbon fiber provides comparable strength to steel but at lower weight. The table thus weighs 50 percent less than one made entirely of steel, and, as a result, it moves faster than a conventional steel table — X-, Y-, and Z-axis acceleration can reach 1.2 g.
This, in turn, optimizes the use of the four linear motor drives on the machine. Sodick is a pioneer in the development and use of linear drives. They outperform and outlast ball screw drives, Thomas says, and maintain accuracy. He says Sodick has sold more than 32,000 machining systems over the years with an average of five linear motor drives on each and hasn’t yet needed to replace a drive.
Compared with HS Series machines, the TT1-400A is up to 10 percent faster, Thomas says. But when compared with competitive machining systems, especially most with ball screw drives, the machine could be 30 to 40 percent faster.
An important enabler of that speed is the new LN3X controller, developed by affiliate Sodick America of San Jose, Calif. Thomas says that the controller’s processing power is faster than that of the company’s previous controller and offers a “tremendous advantage” when operating the linear drives and other components.
Thomas believes that the linear motor drives Sodick offers are a major benefit in machining speed and precision, but adds there is a “lack of awareness” in the machining industry when it comes to their advantages over ball screw drives. Nevertheless, he says that in 10 years linear drives will be dominant.
Other features of the TT1-400A include a 40,000-rpm high-torque spindle (adjustable from 6,000 rpm) that is designed for precision milling of graphite and copper and long life. Positioning accuracy, full-stroke repeatability, and circular cutting are all within 3 µm. The feed rate is 1,440 ipm, while the X-axis travel is 15.75 in, Y-axis travel is 9.84 in, and Z-axis travel is 11.81 in.
Of importance, the machining system has many standard features that Thomas says are usually options on competitive machines. These include the high-speed spindle, Heidenhain glass scales, Blum laser tool measurement, integrated Torit graphite dust collector, air-purged dust protection system, oil mist system with mist collector, and an integrated part probe.
Sodick maintains an inventory of TT1-400A machines, and delivery times are two to four weeks. Thomas wants to sell 40 to 50 units per year in the U.S.