Mitsui Seiki
The Mitsui Seiki PJ812 vertical machining center.

VMC for Jig Milling/Boring Accuracy, Plus Productivity

June 15, 2022
A vertical machining center for precision processing of critical medical, optical, electric vehicle, mold and die, and aerospace parts.

MITSUI SEIKI’s PJ812 vertical machining center will be on display at IMTS 2022 – Booth 338700. The “J” represents “Jig”, which is ideal to machine critical medical, optical, electric vehicle, mold and die, and aerospace parts. The model to be shown at IMTS will be equipped with a Renishaw spindle probe and a Dynavision system.

The PJ812 offers travels X-1200mm, Y-800mm, Z-500mm. Its maximum work size is 1200 x 800 x 450 mm, and its table load accommodates 1500 kg. The VMC provides positioning accuracy and repeatability of +/- 1µm. 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 cut temperature-generated displacement by 60 percent.

This system also reduces Z-axis thermal growth and deflection by 30 percent. Cooling systems for slide way lubrication and ball screw 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 µm.

Another proprietary engineering detail drastically improves the static rigidity of the Z-axis to more than six times that of conventional Z-axis arrangements.

This machine allows for complete machining of precision components, including precision boring, milling, drilling, and tapping.

The PJ812 features a full enclosure and various coolant system options. The model displayed at IMTS 2022 will be outfitted with a 690-liter cooling tank, a 40-tool ATC, and the advanced Fanuc F31i-B5 control with the i-H Pro panel.

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