The present invention relates to a machining center, and more specifically to a horizontal multi-spindle machining center, in which 2-axis (Y- and Z-axis) or 3-axis (X-, Y- and Z-axis) transfer drive units are disposed in the machining center installed to machine workpieces, in which a ram equipped with spindles is moved in the up-down, front-back, and/or left-right directions of the workpieces, in which the spindles are configured to include a plurality of spindles, i.e., 2 to 8 spindles, so that a plurality of workpieces may be machined simultaneously, and in which tool change is simultaneously performed for tools fastened to the plurality of spindles and configured to machine workpieces by using an auto tool changer (ATC), so that tool change speed may be improved and thus manufacturing efficiency may be improved.

The present invention relates to a machining center, and more specifically to a horizontal multi-spindle machining center, in which 2-axis (Y- and Z-axis) or 3-axis (X-, Y- and Z-axis) transfer drive units are disposed in the machining center installed to machine workpieces, in which a ram equipped with spindles is moved in the up-down, front-back, and/or left-right directions of the workpieces, in which the spindles are configured to include a plurality of spindles, i.e., 2 to 8 spindles, so that a plurality of workpieces may be machined simultaneously, and in which tool change is simultaneously performed for tools fastened to the plurality of spindles and configured to machine workpieces by using an auto tool changer (ATC), so that tool change speed may be improved and thus manufacturing efficiency may be improved.

Provided are a method of manufacturing, and a working tool for, a member having a closed-bottom hole portion that can achieve a good yield of the material, can improve the durability of the cutting blade, and can reduce the force required for the work, by forming a hollowed-out bottom portion using a cutting wire having a two-point support. A method of manufacturing a member having a closed-bottom hole portion by inside-removing-working a raw material made of a carbonaceous material, the closed-bottom hole portion having a hollowed-out side portion and a hollowed-out bottom portion formed by hollowing out an inner portion of the raw material, including: a step of forming a cylindrical trench by digging the raw material frontward from a near-side end face of raw material while rotating the raw material, to form the hollowed-out side portion; and a step of forming the hollowed-out bottom portion by supporting a cutting wire inserted into a bottom portion of the cylindrical trench at two points while rotating the raw material, and pressing the cutting wire being supported at the two points in a direction approaching an axis line of the raw material.