Automatic operating systems of machine tools and method

An automatic operating system of a machine tool having a spindle on which a tool is mounted for machining a workpiece mounted on a machining area of said machine tool in accordance with a numerically controlled machining program, said system comprising:

• tool storage means containing a plurality of tools for use on said machine tool;
• means for detecting a machining load while said tool is mounted on the machine tool for machining said workpiece;
• memory means including:
• a first memory having first, second and third memory areas corresponding to the tools contained in said tool storage means, said first memory area being adapted to store a first data which is referred to for judging a broken state of said tool mounted on said spindle, said second memory area being adapted to store a second data which represents that said tool has been judged to be broken in accordance with said first data, and said third memory area being adapted to store a fourth data which represents that said tool has been judged to be worn out in accordance with said first data,
• a second memory in which is stored a third data representing the machining load detected by said detecting means after the machining operation has been changed to a state of an actual normal machining state, said third data being compared with said first data for judging that said tool has been worn out or broken during said actual normal machining operation,
• means for reading out said first and third data from said first and second memories repsectively and then comparing said read out data with each other to judge that said tool has been worn out, and then storing said fourth data into said tool when it is judged to be worn out;
• means (76) responsive to the judgement of the worn out tool for decreasing a feed rate of said tool;
• means for reading out said first and third data from said first and second memory respectively and then comparing said read out data with each other to judge that said tool has been broken, and then storing said second data into said second memory area of said first memory corresponding to said tool when the judgement of the broken state of said tool has been made;
• means (75) responsive to the judgement of the broken state of said tool for interrupting the machining of said workpiece by said tool;
• means (77) for moving said spindle relative to said workpiece to separate said tool therefrom;
• means (79) for removing said workpiece out of said machining area;
• means (81) for mounting another workpiece on said machining area;
• means (83) for selecting a machining program corresponding to said another workpiece;
• means (82) for selecting a tool out of said tool storage means for exchanging the selected tool with said tool judged to be broken;
• and
• means (84) for starting the machining operation of said another workpiece with said another tool.

A method of automatic operation of a machine tool having a spindle on which a tool is mounted for machining a workpiece mounted on a machining area of said machine tool in accordance with a numerically controlled machining program, said machine tool being combined with tool storage means containing a plurality of tools for use on said machine tool, detecting means for detecting a machining load while said workpiece is being machined, and memory means including a first memory having first and second memory areas corresponding to the tools contained in said tool storage means;

• said method comprising the steps of:
• detecting said machining load after a machining operation has changed to a state of actual normal machining state;
• storing the detected machining load into said first area of said first memory as a first data which is referred to for judging the broken state of said tool on said spindle;
• detecting said machine load during said actual normal machining state;
• storing the detected machining load into said second memory as a third data which is compared with said first data during actual normal machining operation of said workpiece with said tool mounted on said spindle;
• reading out said first and third data from said first memory areas of said first memory and said second memory respectively;
• comparing said read out data with each other for judging a broken state of said tool;
• storing a second data which represents that said tool has been broken into said second memory area of said first memory when said tool is judged to be broken as a result of said comparison;
• interrupting the machining of said workpiece by said tool when it is judged to be broken;
• moving said spindle relative to said workpiece to separate said tool therefrom;
• removing said workpiece out of said machining area;
• mounting another workpiece on said machining area;
• selecting another machining program corresponding to said another workpiece;
• selecting a usable tool out of said tool storage means and exchanging said usable tool with said tool judged to be broken;
• and
• machining said another workpiece with said usable tool.

A method of automatic operation of a machine tool having a spindle on which a tool is mounted for machining a workpiece mounted on a machining area of said machine tool in accordance with a numerically controlled machining program, said machine tool being combined with tool storage means containing a plurality of tools for use on said machine tool, detecting means for detecting a machining load while said tool is machining said workpiece, and memory means including a first memory having first to third memory areas corresponding to the tools contained in said tool storage means and a second memory, said method comprising the steps of:

• detecting said machining load after a machining operation has changed to a state of actual normal machining operation;
• storing the detected machining load into said first memory area of said first memory as a first data which is referred to for judging a broken state of said tool on said spindle;
• detecting said machining load during actual normal cutting state;
• storing the detected machining load into said second memory as a third data which is compared with said first data during actual normal cutting operation of said workpiece with said tool mounted on said spindle;
• reading out said first and third data from said first memory area of said first memory and said second memory respectively;
• comparing said read out data with each other to judge that said tool has been worn out;
• storing a fourth data which represents that said tool has been worn out into said third memory area of said first memory when said tool is judged to be worn out as a result of said comparison;
• decreasing a feed rate of said tool when said tool is judged to be broken;
• comparing said read out data with each other to judge that said tool has been broken;
• storing a second data which represents that said tool has been broken into said second memory area of said first memory when said tool is judged to be broken as a result of immediately preceding comparison;
• interrupting the machining of said workpiece by said tool when it is judged to be broken;
• moving said spindle carrying said tool relative to said workpiece to separate the same away from said tool;
• exchanging said workpiece with another workpiece;
• selecting a machining program corresponding to said another workpiece;
• selecting a usable tool out of said tool storage magazine and exchanging the selected tool with said tool judged to be broken;
• and
• machining said another workpiece with said usable tool.