drawing. As the program data, the coordinate values on this coordinate system are 2) Coordinate system specified by the CNC. The coordinate system is prepared on the actual machine tool table. This can be achieved by programming the distance from the current position of the tool to the zero point of the coordinate system to be set as The positional relation between these two coordinate systems is determined when a workpieces Fixed distance standard p Fixed distance Workpiece zero point Fig 4-4: methods of setting the two coordinate systems in the same position The tool moves on the coordinate system specified by the CNC in accordance with the command program generated with respect to the coordinate system on the part drawing, and cuts a workpiece into a shape on the dray Therefore, in order to correctly cut the workpiece as specified on the drawing, the two coordinate systems must be set at the same position To set the two coordinate systems at the same position, simple methods shall be used according to workpiece shape, the number of machinings 1) Using a stardard plane and point of the workpiece. Bring the tool center to workpiece standard point, and set the coordinate system specified by CNC at this position as shown in Fig 4-4a) 2) Mounting a workpiece directly against the jig. Meet the tool center to the reference position, and set the coordinate system specified by CNC at this position. Jig shall be mounted on the predetermined point from the reference position as shown in Fig 3) Mounting a workpiece on a pallet, then mounting the workpiece and pallet on the jig Jig and coordinate system shall be specified by the same as(2)as shown in Fig 100,30.0,20.0) Command specifying movement from G91 X40.0Y-300Z-100drawing. As the program data, the coordinate values on this coordinate system are used. 2) Coordinate system specified by the CNC. The coordinate system is prepared on the actual machine tool table. This can be achieved by programming the distance from the current position of the tool to the zero point of the coordinate system to be set as shown in Fig 4-3. The positional relation between these two coordinate systems is determined when a workpiece is set on the table. a) b) c) Fig 4-4: methods of setting the two coordinate systems in the same position The tool moves on the coordinate system specified by the CNC in accordance with the command program generated with respect to the coordinate system on the part drawing, and cuts a workpiece into a shape on the drawing. Therefore, in order to correctly cut the workpiece as specified on the drawing, the two coordinate systems must be set at the same position. To set the two coordinate systems at the same position, simple methods shall be used according to workpiece shape, the number of machinings. 1) Using a stardard plane and point of the workpiece. Bring the tool center to workpiece standard point, and set the coordinate system specified by CNC at this position as shown in Fig 4-4a). 2) Mounting a workpiece directly against the jig. Meet the tool center to the reference position, and set the coordinate system specified by CNC at this position. Jig shall be mounted on the predetermined point from the reference position as shown in Fig 4-4b). 3) Mounting a workpiece on a pallet, then mounting the workpiece and pallet on the jig. Jig and coordinate system shall be specified by the same as (2) as shown in Fig 4-4c)