August 2012 / Volume 64 / Issue 8|
New grinder boosts production capacity
By CTE Staff
ZPS-Frézovací Nástroje a.s., a manufacturer of HSS milling tools, was looking to boost its market share and better equip a new training and education center at its headquarters in Zlín, Czech Republic. The center allows the company’s employees, as well as experts and students from technical-vocational schools and technical universities, to become acquainted with new manufacturing technology.
The company accomplished both goals with the installation of a new high-speed grinding machine, Lean Selection speed, from Erwin Junker Maschinenfabrik GmbH, Nordrach, Germany. Equipped with two grinding spindles and employing CBN or diamond grinding wheels, the machine combines fast grinding times and an automated loading system. ZPS uses the grinder for production runs and training demonstrations.
Courtesy of Junker
The new machine replaced several conventional cylindrical grinding machines at ZPS, providing a higher rate of machine availability, higher part quality and higher output, according to the company.
Founded in the 1930s, ZPS has been manufacturing HSS milling cutters since the 1950s. Today, the company is the largest milling cutter manufacturer in the Czech Republic and employs about 120 people. In 2011, the company exported approximately 70 percent of its tools, with half going to Germany.
Courtesy of Junker
In recent years, ZPS has increased its export volume but its capacity for rough and finish grinding of milling cutters was limited. The new Junker machine, which supplies all the machines that follow it in the production line, provides the company with the capacity it needs. In 2012, ZPS estimates it will produce more than 300,000 milling cutters on the Lean Selection speed grinder and additional capacity is available on the machine if needed.
The Lean Selection speed grinding machine is equipped with a high-resolution B-axis. Each of the two 12,000- rpm grinding spindles has 12kVA drive power. The machine also features a glass scale on the X-axis, a Fanuc 0i control, Junker’s Juwop programming system and a tailstock with microfine adjustment.
With peripheral speeds of up to 140 m/sec., rough and finish grinding can be performed efficiently at high metal-removal rates using the Junker Quickpoint grinding method, according to Junker. With the Quickpoint method, the grinding wheel creates the final dimension on the outer contour of the milling cutter and removes the entire grinding allowance in one longitudinal pass. Grinding between male or female centers results in high accuracy, Junker reports. In addition to tool grinding, the machine can grind parts such as gearbox components and camshafts.
At ZPS, an automation system for the Lean Selection speed machine includes Junker’s Jurogot automated loading cell. A robot loads the parts through an opening in the machine hood. The machine grinds cylindrical, stepped and tapered ODs, as well as the cutting edge, in one clamping. In addition, a diameter gage on the grinding table provides automatic dimension correction.
ZPS is particularly pleased with the machine’s uptime. With batch sizes of 50 to 2,000 tools, ZPS’ Lean Selection speed requires two changeovers per day, on average. A three-point mounting interface on the grinding spindle and workpiece spindle simplifies this task.
ZPS is reportedly pleased with the start-up process, grinding quality and on-site customer service. CTE
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