Mitsui Seiki's J350G Jig Grinder Enables Various Operations Without Wheel Change
The Mitsui Seiki J350G jig grinder is designed to provide a combination of application flexibility, accuracy and user-friendly operation. The machine has a long grinding infeed stroke, with a U-axis range of -3 to +50 mm relative to the spindle center. This is said to provide the flexibility to grind small- and large-diameter holes, as well as multiple features, using a single wheel in a continuous, automatic mode.
According to Tom Dolan, vice president of sales and marketing, “The J350G jig grinder gives users the ability to grind a wide variety of features automatically, without changing wheels. It thereby provides the flexibility required in today’s manufacturing environment.”
To maximize accuracy, the hand-scraped X and Y axes of the J350G incorporate needle roller bearings. The machine bed consists of a thick, rigid casting supported by three level points, providing consistent perpendicularity and parallelism. Built-in, custom-designed Heidenhain scales contribute to ±0.0007 mm accuracy on the X, Y and Z axes, the company says.
The machine’s X-, Y- and Z-axis travels measure 500 × 300 × 100 mm, respectively. The maximum distance from the table surface to the grinding spindle nose is 450 mm. The work surface measures 700 × 350 mm, with a permissible table load of 300 kg. Table and saddle maximum rapid feed rates range to 2,000 mm/min., while grinding feed rates are variable from 0.1 to 2,000 mm/min. The standard high-frequency spindle motor operates from 9,000 to 45,000 rpm. A variety of spindle motor options include an air-turbine motor with 75,000-rpm capability.
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Roughing and finishing on a single machine, using a single setup, has appeal for most shops. The advantages in time savings and accuracy are obvious. Eliminating the transport of workpieces between machines, as well as the setup for those secondary operations, is a boon for throughput. Critical features that need to maintain dimensional relationships can be much more reliably produced if machined complete in one clamping.
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