Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
1998-07-02
2001-07-24
Lee, Thomas (Department: 2182)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C700S096000, C700S159000, C700S173000
Reexamination Certificate
active
06266572
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a machining simulation device and method used in NC machining. More specifically, the present invention relates to a device and method for generating a numerical control command and actual tool performance information, based on machining simulation using data specifying material shape, tool shape, and machining shape.
BACKGROUND OF THE INVENTION
Referring to a block diagram in
FIG. 1
, an adjustment control command generating system used in a conventional numerical control system will be briefly explained hereinafter.
In an NC program memory
11
, an NC program which will be used for up-coming machining is stored.
An NC program interpreting unit
12
reads the NC program in the NC program memory
11
block by block, and interprets the blocks. The NC program interpreting unit
12
sends to an interpolation processing unit
13
an interpolation kind, a target position, and a feedrate specified in the current block or specified prior to the current block as modal commands.
The interpolation processing unit
13
sends to a servo control unit
14
movements per unit time (per interpolation period) &Dgr;x, &Dgr;y, and &Dgr;z of each shaft, based on the interpolation kind, the target position, and the feedrate.
The servo control unit
14
controls revolution of each motor based on the movements per unit time &Dgr;x, &Dgr;y, and &Dgr;z of each shaft provided by the interpolation processing unit
13
, and carries out an operation for each shaft.
A cut monitoring unit
15
receives a spindle load and a feeding shaft load actually detected by the servo control unit
14
, and supplies at least one of the loads to an adjustment control unit
16
.
The adjustment control unit
16
compares the spindle load and the feeding shaft load provided by the cut monitoring unit
15
with predetermined load values. If the spindle load or the feeding shaft load exceeds a predetermined overload judgment value, the adjustment control unit
16
raises an alarm or the like, and sends a command to the interpolation processing unit
13
to stop each shaft. If the spindle load or the feeding shaft load does not fall within a speed control detection range, the adjustment control unit
16
sends a speed changing command to the interpolation processing unit
13
to increase or decrease a feedrate. If the spindle load or the feeding shaft load is less than a predetermined air-cut judgment value, the adjustment control unit
16
sends to the interpolation processing unit
13
a feedrate command appropriate for air-cut.
Based on these commands, the interpolation processing unit
13
recalculates the movements per unit time (per interpolation period) &Dgr;x, &Dgr;y, and &Dgr;z of each shaft, and sends the movement values to the servo control unit
14
.
The above processing will then be repeated until the machining is finished.
A conventional NC program generating system will be explained hereinafter referring to a block diagram in FIG.
2
.
An operator inputs to a machining data input unit
21
information necessary for generation of an NC program such as a kind of tool, size of the tool, material composition, and a tool path. The input result is sent to an NC program generating unit
23
.
Using the information such as the tool kind, tool size, and material composition, a cut condition data table
22
has a data table structure which enables determination of a feedrate and spindle speeds or the like appropriate for the information. The NC program generating unit
23
refers to the cut condition table.
The NC program generating unit
23
generates an NC program based on the machining data such as the tool kind, the tool size, the material composition, and the tool path provided by the machining data input unit
21
, and the cut condition read from the cut condition data table
22
such as the feedrate and spindle speeds or the like which are based on the tool kind, the tool size, and the material composition.
A table data changing unit
24
instructs a change in a relation table between the tool kind, tool size, material composition or the like and the feedrate, spindle speeds or the like.
An NC program editing unit
25
is for the operator to directly edit the NC program.
In the NC program generating system having such a configuration, if the operator wants to change the feedrate or the like in the NC program, one of the following three methods is adopted.
That is, any one of directly commanding the feedrate by the machining data input unit
21
, commanding the change in the relationship table between the tool kind, tool size, material composition or the like and the feedrate, the number of spindle revolution or the like in advance, using the table data changing unit
24
, or changing an F command using the NC program editing unit
25
is adopted.
A conventional actual tool performance information generating system will be explained referring to a block diagram in FIG.
3
.
An NC program which will be used for up-coming machining is stored in an NC program storing unit
31
.
An NC program interpreting unit
32
reads the NC program in the NC program memory
31
block by block, and interprets the blocks. The NC program interpreting unit
32
sends to an interpolation processing unit
33
an interpolation kind, a target position, and a feedrate specified in the current block or specified prior to the current block as modal commands. At the same time, based on the NC program, the NC program interpreting unit
32
sends to an actual tool performance information generating unit
36
information for generating actual tool performance information (such as a T command, a G01/G02/G03 command and an F command accompanying it, an S command, and an M02 or M03 command or the like).
The interpolation processing unit
33
sends to a servo control unit
34
movements per unit time (per interpolation period) &Dgr;x, &Dgr;y, and &Dgr;z of each shaft, based on the interpolation kind, the target position, and the feedrate.
The servo control unit
34
controls revolution of each motor based on the movements per unit time &Dgr;x, &Dgr;y, and &Dgr;z of each shaft provided by the interpolation processing unit
33
, and carries out an operation for each shaft.
A cut monitoring unit
35
receives a spindle load and a feeding shaft load actually detected by the servo control unit
34
, and supplies at least one of the loads to an adjustment control unit
36
.
The actual tool performance information generating unit
36
performs accumulation of actual tool performance information or the like, based on the information obtained from the NC program interpreting unit
32
. More specifically, the actual tool performance information generating unit
36
confirms a tool number based on the T command, recognizes that machining is being carried out based on the G01/G02/G03 command, recognizes the number of workpieces to be machined, based on the M02 or M03 command, and calculates a feedrate or a cut speed upon the machining, based on the information such as a tool diameter or the like specified by the F command, the S command, and the T command. Furthermore, the actual tool performance information generating unit
36
judges whether or not the tool is in an air-cutting state, based on the spindle load or the feeding shaft load provided by the cut condition monitoring unit
35
.
The obtained actual tool performance information is then stored in an actual tool performance information storing unit
37
in the form of, for example, an actual cutting time of each tool, duration of a power-ON state, an air-cutting time during tool feeding, and the number of workpieces to be machined by each tool.
Problems to be Solved by the Invention
In an adjustment control command generating system in a conventional numerical control system, no matter how fast machining state information such as a spindle load or a feeding shaft load is fed back to the system, a delay in adjustment can essentially not be prevented from occurring, and control of “the present” can only be performed by information concerning “the past”
Matsumiya Sadayuki
Morita Naoki
Yamamoto Kyoichi
Yamazaki Kazuo
Cao Chun
Lee Thomas
Okuma Corporation
Oliff & Berridg,e PLC
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