• Product Info.
  • Swiss Type Automatic Lathe SB-12R type G Newly Released

    A Model with G.B/N.G.B Switching Function Added to the Bestselling SB Series Aimed at Machining of Small-Diameter Workpieces

    Photo:SB-12R type G

    STAR MICRONICS has developed SB-12R type G as a new model of the Swiss type automatic lathe (Note 1) mainly targeted to the automobile, information & communication equipment and medical industries. The model being scheduled for release in April, 2015.

    Since the release of the SB-16 in 2003, the SB series has been a bestseller with sales totaling more than 7,000.

    The new SB-12R type G employs a guide bush/non-guide bush switching function (Note 2) like the SB-16R/20R type G released in June, 2014, and designed for machining of small-diameter workpieces (with max. machining diameter of ø13mm).

    The 7 controlled spindles include the main spindles (Z1, C1), gang-type tool posts (X1, Y1) and sub spindles (Z2, X2, C2).

    The guide bush type functions to work as a steady rest for maintaining long workpieces such as motor shafts in order to suppress workpiece deflection and achieve accurate machining. For short workpieces such as nuts, the non-guide bush type is effective to reduce the length of remaining materials to be discarded, thus reducing the cost of materials. With these two types, the optimal machining can be selected according to parts to machine.

    Like the conventional SB series, the gang-type tool post accommodates the STAR original slant-slide guideway structure (Note 3) to allow continuous machining with stable accuracy thanks to high rigidity inherent to the machine.

    The main spindle achieves a maximum rotation speed of 15,000 rpm. Both the main and sub spindles are equipped with C-axis control function as standard. The tool post specifically designed for back working equipped with a tool rotation drive unit to enhance complex machining performance on the rear end.

    The NC unit has a variety of help functions, such as an alarm help function for monitoring alarm contents on the NC screen. A swing type operation panel also ensures the optimum working position and contributes to the improved operability and workability.

    Features of SB-12R type G

    • The guide bush type/non-guide bush type can be switched over according to the workpiece overall length.
    • The gang-type tool post can accommodate four kinds of power tools such as 4-spindle cross drill unit, 5-spindle cross drill unit and cartridge type 5-spindle/5-spindle high-speed type for selecting optimum efficiency.
    • Mounting the cartridge type 5-spindle/5-spindle high speed type enables the combination of large variety of tool units at three cartridge positions.
    • The 4-spindle unit designed for rear-end working can be equipped with a tool rotation drive unit to improve eccentric drilling, slitting and other complex machining on the rear end.
    • The main spindle employs a built-in motor for enhanced indexing accuracy.

    Major Specifications

    SB-12R type G
    Max. machining diameter ø13mm
    Max. headstock stroke 205mm
    Max. main spindle speed 15000 min-1
    Main spindle motor 2.2kw / 3.7kw
    Max. sub spindle speed 12000 min-1
    Sub spindle motor 0.55kw / 1.1kw
    Max. power-driven att. spindle speed ER11 10000 min-1
    ER16 6000 min-1
    Power-driven att. drive motor 1.0kw / 1.2kw
    Max. drilling capability on the front-end Stationary tool ø10mm
    Power-driven tool ER11 ø6mm
    ER16 ø7mm
    Max. tapping capability on the front-end Stationary tool M10×P1.5
    Power-driven tool ER11 M5×P0.8
    ER16 M6×P1.0
    Max. drilling capability on the rear-end Stationary tool ø8mm
    Max. tapping capability on the rear-end Stationary tool M6×P1.0
    Dimensions (W x D x H) 2,070 x 1,177 x 1,760 mm
    Weight About 1,750kg

    NOTE 1: Swiss-type automatic lathe

    The Swiss-type automatic lathe was devised as watch component processing machinery in Switzerland in 1870s. Known as a “sliding head-type automatic lathe” as well, it has remarkable characteristics of high-precision cutting of components with longer length compared with the diameter.
    In general, if long and narrow parts are processed with a general-purpose lathe, flexure will occur on the workpiece, making finishing with the correct dimensions impossible. The Swiss-type automatic lathe utilizes a guide bush to function as a material steady rest. The tool, positioned at a certain distance from the guide bush, gives a cutting motion only the direction of outside diameter. This allows the workpiece to be cut accurately with no flexure. As for axial motion, the headstock, rather than the tailstock, moves while clamping a workpiece.

    NOTE 2: Non-Guide Bush Type

    This is a sliding head-type automatic lathe which is designed based on the Swiss-type automatic lathe with a guide bush dismounted. Without a guide bush, it is not best suited for machining narrow and long parts. If the workpiece is short and does not deflect without using a guide bush, however, such a material can be handled effectively.
    With the Swiss-type automatic lathe, the rear side of the bar material needs to be handled as waste as a portion equivalent to the size of the guide bush structure which functions as a material steady rest cannot be machined. The non-guide bush type reduces the wastes from materials to about 1/3 in length compared to the waste made by the guide bush type.

    NOTE 3: Slanted slide guideway structure

    The machine main body base and the tool post are slanted and each sliding surface is in a trapezoidal shape, called a dovetail structure. This structure allows each sliding surface to come into contact with its entire plane to improve the machine rigidity. The ball screw center and the cutting point are close to each other to reduce a load (moment load) applied in the direction of torsion caused by cutting resistance.