Method of and an apparatus for machining a workpiece with plural tool heads

A method of simultaneously machining at least two machining portions of a workpiece with plural tool heads, comprising:

• executing a first machining process for said machining portions under measuring each diameter of said machining portions;
• backing off all of said tool heads predetermined distance, when one of diameter of said machining portions became a required value during said first machining process;
• resuming said first machining process for another machining portions whose diameter have not become each required value;
• and
• executing a second machining process for said machining portions after diameters of all of said machining portions became each required value.

An apparatus for simultaneously machining at least two machining portions of a workpiece, comprising:

• a base;
• a worktable unit arranged on said base, which rotatably support the workpiece around predetermined axis;
• at least two tool heads movably arranged on said base in a direction to cross said rotational axis of the workpiece, each of said tool heads supports a tool;
• feeding units corresponding to said tool heads, said feeding units move each of said tool heads;
• gauging units arranged corresponding to each of said machining portions, said gauging units measure each diameter of said machining portions at least during a first machining process;
• and
• a control unit controlling said feeding units according to signals of diameters provided from each of said gauging units;
• wherein
• controls all of said feeding units to execute a first machining process;
• controls one feeding unit to back off one tool head predetermined distance, said one tool head corresponds one machining portion whose diameter became a required value during said first machining process;
• and
• controls all of said feeding units to execute a second machine process for said machining portions after diameters of all of said machining portions became each required value.

An apparatus for simultaneously grinding two grinding portions of a workpiece, comprising:

• a base;
• a worktable unit arranged on said base, which rotatably support the workpiece around predetermined axis;
• two wheel heads movably arranged on said base in a direction to cross said rotational axis of the workpiece, each of said wheel heads supports a grinding wheel;
• two feeding units corresponding to said wheel heads, said feeding units move each of said wheel heads;
• two gauging units arranged corresponding to each of said grinding portions, said gauging units measure each diameter of said machining portions at least during a finish grinding process;
• and
• a numerical control unit controlling said feeding units according to signals of diameters provided from each of said gauging units;
• wherein
• controls both of said feeding units to execute a finish grinding process;
• controls one feeding unit to back off one wheel head predetermined distance, said one wheel head corresponds one grinding portion whose diameter became a required value during said finish grinding process, and to keep backed off position of said one wheel head until a diameter of the other grinding portion become a required value;
• and
• controls both of said feeding units to execute a spark-out process for said machining portions after diameters of both of said machining portions became each required value.