Mitsui Seiki J Series VMC's Thermal Sensors Maximize Accuracy
Mitsui Seiki J Series VMCs are designed to maximize accuracy in precision boring, milling, drilling and tapping.
Mitsui Seiki has launched a new series of CNC vertical machining centers named the “J” series for “jig,” suitable to machine medical, optical, mold and die, and aerospace parts.
The machines are said to provide positioning accuracy and repeatability of +/- 1 micrometer. A thermal compensation system employs sensors on the machine faceplate and inside the spindle to minimize the effects of temperature changes on part accuracy, and to cut temperature-generated displacement by as much as 60%. This system is also said to reduce Z-axis thermal growth and deflection by 30%. Cooling systems for slideway lubrication and ballscrew cores stabilize axis feed precision.
Mechanical design features that maximize machine rigidity and accuracy include hardened and ground tool steel box slideways as well as contact elements that enhance acceleration, reduce stick-slip and allow for feed accuracy of 0.1 micrometer, the company says. In addition, the design is said to improve the static rigidity of the Z-axis more than six times over conventional arrangements.
These heavy-duty machines are designed to allow for complete machining of precision components including boring, milling, drilling and tapping. They feature the technology of a machining center with the precision of a jig borer, according to the company.
The line includes four machines: The PJ812, with X/Y/Z travels of 1,200/800/500 mm, a maximum workpiece size of 1,200 × 800 mm, a table load of 1,500 kg, spindles between 10,000 to 30,000 RPM, and automatic toolchangers with 60, 90 or 100 tools; the J1220 with X/Y/Z travels of 2,000/1,250/500 mm, maximum workpiece size of 2,200 × 1,500 mm, table loads of 3,000 or 4,000 kg, spindles from 10,000 to 15,000 RPM, and ATCs with 60, 90 or 120 tools; the J1230 with X/Y/Z travels of 3,000/1,250/500 mm, a maximum workpiece size of 3,000 × 1,500 mm, tables loads of 3,000 or 4,000 kg, spindles from 10,000 to 15,000 RPM, and ATCs with 60, 90, or 120 tools; and the J162 with X/Y/Z travels of 2,500/1,600/500 mm, maximum workpiece size of 2,700 × 1,700 mm, a table load of 6,500 kg, spindles from 10,000 to 15,000 RPM and ATCs with 20, 60, 90, or 120 tools. All machines feature a full enclosure and various coolant system options.
Different machines offer different approaches to rotary travel, and each design has its own strengths. Here's how they compare.
While aluminum molds are commonly used to create prototypes or to serve as stopgap bridge tooling, they are starting to receive greater attention for production work. This shop’s approach to creating aluminum molds in one day to three weeks is the same for each of these situations.
Cryogenic machining achieves dramatic tool life gains not by flooding the cut, but by refrigerating the tool.