Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
2000-04-21
2003-01-07
Picard, Leo (Department: 2125)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C700S179000, C700S183000
Reexamination Certificate
active
06505092
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a device for supporting preparatory work of machine operators who extract, generate, and download various information from numerical control (NC) programs prepared for NC machining in which all machining control carried out using numerical control information, and who operate actual numerically controlled machine tools using the NC programs.
BACKGROUND ART
The operation of numerically controlled machine tools can be automatically controlled by inputting NC programs, and such machine tools are now widely used in many industrial fields. Computerized numerically controlled machine tools (CNC machine tools) are used in combination with microprocessing, power electronics, and software technology.
Generally, numerical control information, such as an NC program, comprises a tool selection command, a spindle speed command, a cutting speed command, a feed rate command, a spindle movement/interpolation command, miscellaneous function command, or the like, and numerical control information suitable for the machine tool which is to be the object of machining control is prepared in the form of an NC program as occasion demands.
Generally, such an NC program is prepared by an NC programmer in a programming section, or else is automatically prepared by inputting data concerning classifications of machining, areas to be machined, data of materials, shapes of parts, or the like into a device such as a CAD-CAM system, automatic programming unit, or the like. In either case, an NC programmer determines the areas to be machined based on drawings for machining which illustrate shapes of materials and shapes of parts, and then further determines machining procedures, such as tools to be used for machining the respective areas, routes of the respective tools at the time of machining, cutting conditions, and machining order. The NC program is then individually prepared or prepared by inputting data required for the automatic programming unit mentioned above. A machining operator carries out adjustment (editing for correction) of the NC program made in the manner described above by the repetition of test cutting using an actual machine tool at a machining site, and completes the NC program for machining so as to use it for machining control of the machine tool.
Further, even when the machining operator operates a machine tool using an NC program which was previously adjusted, when machining circumstances, such as machine tools or tools, differ, the operator will perform similar test cutting so as to adapt the NC program to the present machining circumstance, and will adjust the NC program as occasion demands before using it for machining control of the machine target tool. Such procedures for adjusting NC programs to be carried out by machining operators will be described with reference to the flowchart of FIG.
1
and to
FIGS. 2 through 4
.
Generally, a machining operator is provided with a drawing for machining as shown in
FIG. 2
, an NC program as shown in
FIG. 3
, and a tool list as shown in
FIG. 4
as information for preparation of machining. In the drawing for machining of
FIG. 2
, only shapes and dimensions of materials, shapes and dimensions of parts, and a position of the NC program origin are illustrated. The NC program shown in
FIG. 3
comprises a tool selection command, a cutting speed command, a spindle speed command, a feed rate command, a spindle movement/interpolation command, miscellaneous function commands, or the like. These commands are primitive command codes which can be interpreted and executed by a numerically controlled unit, and the primitive command codes are merely arranged in order of execution. Further, the tool list shown in
FIG. 4
is made in a simple manner such that for each tool number, a shape of the tool is illustrated and a classification of the tool, the spindle speed, the cutting speed, the feed rate, and the cutting depth are specified. In a column for cutting conditions in the tool list, reference symbols N, V, F, and D represent spindle speed, cutting speed, feed rate, and cutting depth, respectively.
First, the machining operator prepares a tool illustrated in the tool list and furnishes a tool post with the tool at Step
1
shown in FIG.
1
. At this time, the tool post must be furnished with a tool of dimensions such that ejection of the tool post furnished with the tool or a tool holder does not interfere with work pieces during the machining operation. For the purposes, the machining operator recognizes a number and shape of the tool to be installed based on the tool list and finds on the NC program spots where the tool number is selected. Based on the spindle movement/interpolation command instructed and shapes of materials and shapes of parts illustrated in the drawing for machining, the machining operator then recognizes the position at which an area to be machined is situated within the overall shapes of materials and parts, and determines an approximate dimension of the ejection. The tool post is then furnished with the tool so that the actual dimension of the ejection meets or exceeds the determined value.
At Step
2
, a value of the NC program origin is set and stored in the numerically controlled unit so that the NC program origin is positioned as shown in the drawing for machining. Further, an offset value of the tool installed on the tool top is set and stored in the numerically controlled unit. Further, at Step
3
, the NC program is input and stored in the numerically controlled unit. Here, preparatory work for no-load running which will be described hereinafter is completed.
Next, at Step
4
, by executing the input NC program, the operator understands and confirms approximate machining operation to be controlled by the NC program during no-load running when no materials are installed. Further, the operator operates each block of the NC program, and precisely understands and confirms machining procedures, such as an area to be machined by each tool, a route of the tool at the time of machining the area, cutting conditions at the time of machining the area, and order of machining each area, referring to the drawing for machining. At the same time, the operator precisely understands and confirms at which locations on the NC program the tool selection command, the spindle speed command, the feed rate command, the spindle movement/interpolation command, the miscellaneous function command, and the like which execute the machining operation are issued. This comprehension and confirmation are preparation for the adjustment of the NC program to be performed while carrying out a test cutting with materials installed. The understanding and confirming work during no-load operation is repeated until the operator gains a clear understanding and confirmation as shown in Step
5
. At this point, the test cutting preparation is completed.
The test cutting will be carried out in the following procedures. First, materials are installed at Step
6
. At the next Step
7
, in order for rapid traverse positioning to be performed at a safety speed, a traverse speed override which usually operates at the fastest speed tolerated for machine tools is regulated to 100 percent or less. Under such a condition that the rapid traverse positioning can be performed at a safety speed, the NC program is operated at Step
8
in block units. By operating the NC program in block units, the operator confirms whether or not the tool, the tool holder, the tool top, or the like interfere with the work pieces. Also, the operator confirms whether or not abnormal oscillation or noise arises during machining. Further, the operator measures the dimensions of the work pieces so as to confirm that the dimensions of the work pieces are within a tolerance, and conducts a careful examination of the surfaces of the work pieces machined so as to confirm whether or not the surfaces have desired roughness (smoothness?).
At Step
9
, if the operator judges, after confirmation, that there is a problem which results from the NC program,
Fukaya Yasushi
Matsumiya Sadayuki
Uneme Masayoshi
Yamazaki Kazuo
Kosowski Alexander
Okuma Corporation
Oliff & Berridg,e PLC
Picard Leo
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