GB2168173A

GB2168173A - Automatic machine tool

Info

Publication number: GB2168173A
Application number: GB08525286A
Authority: GB
Inventors: Koichi Asakura
Original assignee: Brother Industries Ltd
Current assignee: Brother Industries Ltd
Priority date: 1984-10-15
Filing date: 1985-10-14
Publication date: 1986-06-11
Also published as: KR860004623U; JPS6195852A; GB2168173B; GB8525286D0; KR930000974Y1; DE3536712A1

Abstract

An automatic machine tool allows an operator to specify or change tools and tool mounting positions in a tool magazine for automatic control of a machining operation, the automatic machine tool displaying on a screen the tools required for a machining operation as well as their mounting positions in the tool magazine. <IMAGE>

Description

SPECIFICATION Automatic machine tool In using a conventional automatic machine tool, an operator first selects the tools he will need to use from the machining plans. He then mounts those tools in the tool magazine and determines their mounting positions. He must also input a program into the automatic machine tool, taking care that the program uses the proper tool mounting positions in the tool magazine for each operation of the machining program. Since the tool mounting positions must be considered and checked in inputting the machining program, it is troublesome to write the machining program.

In accordance with the present invention, however, a machine tool for automatically selecting and actuating tools in a tool magazine according to one or more machining programs comprises: a) first memory means for storing said machining programs and data relating to said tools in said magazine; b) second memory means for storing mounting positions of said tools in said magazine; c) means for selecting a tool from said magazine; d) means for actuating said tool selected from said magazine; e) means for displaying representations of said tools required for performing a machining operation according to said machining programs and representations of mounting positions of said tools in said magazine; f) means for designating tool in reference to said mounting position in said magazine to store mounting positions of said tool in magazine; and g) control means coupled to said first and second memory means, said tool selecting means, said display means, and said designating means for getting mounting position of using tools from second memory means according to said machining program, and for effecting automatic tool selection and actuation by controlling said selecting means and actuating means according to said machining program and said tool data.

The present invention thus alleviates the difficulties of programming a conventional automatic machine tool and does not require that the tool mounting positions be prechecked in setting up a new machining program.

In operating the machine tool of this invention, an operator inputs a machining program, presumably from the plans for a workpiece, and then views the tools to be used on a screen as well as tool magazine mounting positions. An operator may then use the machine tool to change tool positions already displayed or specifically new tool mounting positions. The changed or specified tool mounting positions are stored in a memory.

The machine tool then performs the operations indicated in the program using the stored tool mounting positions. Accordingly, it is unnecessary for the operator to check the tool mounting positions in forming the machining program.

A preferred embodiment of the invention will be described with reference to the accompanying drawings.

Figure 1 is a block diagram showing a machine tool according to this invention; Figure 2 is a tool list; Figures 3(a) to 3(e) are front views of a variety of tools and their features; Figure 4 is a tool pattern list for one example of a premachining operation; Figure 5 is a tapped hole's starting hole diameter list showing another example of a premachining operation; Figure 6 is a sectional view showing the structure of the machine tool; Figure 7 is a perspective view showing an external appearance of the machine tool in Fig.

6; Figure 8 is a front view of a computer in the machine tool; Figure 9 is a flow chart showing a method of machining a workpiece with the machine tool; Figures 10(a) and (b) are a plan view and a sectional view, respectively, of a workpiece used as an example of a final machining operation; Figure 11 is a machining program table showing a machining program; Figures 12 to 18 are front views of a CRT screen appearing during a machining program input; Figure 19 is a flow chart for a tool assignment procedure; Figure 20 is a front view of a CRT screen used to describe a method of changing or specifying tool mounting positions; Figure 21 is a flow chart for executing of a machine program; and Figure 22 is a flow chart of a program for carrying out a tapping operation.

Fig. 1 is a block diagram showing an embodiment of a machine tool 100 according to the present invention. Machine tool 100 shows random access memory (RAM) 1 which stores tool data 2, machining program 3, and premachining operations 4, all of which are used for the final machining operation. Machine tool 100 also includes central processing unit (CPU) 5 (or, more generally, calculating means), cathode ray tube (CRT) 7, and keyboard 6 (or, more generally, an instructing means). When an operator presses certain keys in keyboard 6, CPU 5 causes RAM 1 to store tool data 2, machining program 3, and premachining operation 4, and allows the operator specifications for a tool displayed on CRT 7 with respect to a tool mounting posi tion stored in a magazine mounting position memory 8 (or, more generally, a memory means).Read-only memory (ROM) 9 contains a computer program used to control CPU 5 according to the contents of RAM 1 and magazine mounting position memory 8. Specifically, CPU 5 carries out operations for selecting tools, exchanging tools, and performing machining operations. Feed motor 10 is used for feeding a selected tool and spindle motor 11 drives the selected tool at a predetermined speed.

As indicated in a tool list shown in Fig. 2, tool data 2 in RAM 1 includes tool names, necessary dimensions, tool lengths, and remaining times of use (minutes) of tools numbered 01 through 06. As many as sixty (60) tools can be stored in the preferred embodiment. The data for various tools, such as two drills, a centre drill, a chamfering tool, a tapping tool, and a spot facing drill (countersunk drill) are recorded as shown in the tool list of Fig. 2.

In that tool list, a drill's stored data include top angle a, outside diameter fD, and edge length 1. The data for a spot facing drill include, in addition to the data for a drill, a smaller outside diameter dd and a smaller diameter length I,. The same data are stored for a centre drill as for a drill, except that data for edge length I is unnecessary, but data for a centre angle 0 is stored together with the smaller diameter d and the smaller diameter length I. For a tapping tool, data for chamfer length L, nominal outside diameter, pitch number of threads, edge length I, and thread direction are stored. The data necessary for a chamfering tool are a smaller diameter fd, centre angle 0, and outside diameter fD.

These stored data for a centre drill, drill, tapping tool, chamfering tool, and spot facing drill are shown in Fig. 3 (a) to (e), respectively.

Premachining operations, 4 includes a tool pattern list such as the one shown in Fig. 4.

In that tool pattern list, tool patterns necessary for various machining operatios (i.e., final machining), such as centre hole machining operations, hole machining operations, tapping operations, spot-faced hole machining operations, upper surface machining operations, reaming operatios, and spot-faced reamed hole forming operations are stored separately when chamfering is required and when chamfering is not required. Another part of the stored contents of the premachining operation 5 is a tap starting-hole drill diameter list shown in Fig. 5.

In that list, starting hole drill diameters for nominal sizes and pitches in the final machining operations are stored for metric coarse threads.

In order to edit machining program 3, keyboard 6 in Fig. 1 is used for a variety of functions, such as inputting data for tool diameters (or hole diameters), determining the order of machining operations, changing tool patterns, assigning and changing tools, changing cutting conditions, displaying, eliminating and arranging a program, controlling the used and unused memory capacity, and exchanging data with an external program memory means.

Fig. 6 shows the construction of a machine tool 500 having an automatic tool exchanging device according to this invention. In Fig. 6, reference numeral 12 designates a feed screw driven by feed motor 10; reference numeral 13 designates a spindle head reciprocated by feed screw 12 and on which spindle motor 11 is mounted; reference numeral 14 designates a spindle rotated by spindle motor 11; reference numeral 15 denotes a machining tool, such as a drill, connected to the spindle 14; and reference numeral 16 denotes a tool magazine supported on supporting stand 18 so that it can be rotationally indexed. Supporting stand 18 is supported by frame 17 moved in the axial direction of the spindle 14.

Fig. 7 is a perspective view of machine tool 500. In Fig. 7, feed motor 10, the spindle motor 11, the tool magazine 16, (with cover), and frame 17 are connected as described in Fig. 6. Computer 19 and keyboard 6 are secured to frame 17 through supporting arm 20.

Computer 19 includes CPU 5, RAM 1 and ROM 9.

Fig. 8 shows a front view of computer 19.

Computer 19 includes keyboard 6 and cathode ray tube (CRT) 7. Computer controls the display on the CRT. Keyboard 6 has a program editing key 61, a ten-key unit 62, a setting key 63, up and down keys 64, and an eliminating key 65. There are also other keys but they are not necessary to an understanding of this invention and will not be described.

The flow chart shown in Fig. 9 is executed to machine a workpiece with a machine tool according to the invention. Step 101 consists of inputting a machining program, step 102 consists of assigning a tool, and step 103 consists of starting a machining operation.

The final machining operation can be explained with reference to the workpiece shown Fig. 10. To form this workpiece the first machining operation involves forming a tapped hole having a nominal size and M6 a pitch of 1, and the second machining operation involves forming a spot-faced hole 5 mm in diameter with an 8.5 mm spot facing diameter.

Fig. 11 shows a machining program, identified as a "Machining Program Table," for forming the workpiece in Fig. 10. In the first machining operation, "Machining Operation No. 01," a tapped hole is formed according to various data given by the drawing. In the second machining operation, "Machining Operation No. 02," a spot-faced hole is cut according to data indicated by the drawing. A method of inputting the machining program of Fig. 11 into computer 19 will be described with reference to CRT displays shown in Figs.

12 through 18.

By depressing program editing key 16 on keyboard 6 (Fig. 8), a program picture is selected, as shown in this embodiment, and seven menus are displayed in a program display area located in the upper portion of CRT 7's screen. Cursor 7a in the input request display area is used to input a menu number. To input the machining program of Fig. 11, an operator selects Menu No. 1, "Machining Data Mode" by depressing key "1" of ten-key unit 62 and then depressing setting key 63 to input the machining data mode. In response to these keys, the display on the CRT 7 changes as shown in Fig. 13. Cursor 7a is then used to input a program number while the bright point 7b flickers. For instance, to call "Program No. 1000", the number "1000" is inputted using ten-key unit 62, and then setting key 63 is depressed.This causes the program number to be shifted to the program display area in the upper portion of the screen of the CRT 7. The display on the CRT 7 is then as shown in Fig. 14. With the screen as shown in Fig. 14, the operator inputs the X value of the machining origin (100 in the program in Fig. 11) using cursor 7a. The X value (100) is inputted by first pressing the proper keys on ten-key unit 62 and then depressing setting key 63. The Y value of the machining origin is requested next, and a Y value (100 in the program in Fig. 11) is also inputted using tenkey unit 62 and setting key 63.

The CRT 7 display screen then becomes similar to the one shown in Fig. 15, which requests the number of workpieces. For the machining program of Fig. 11, only one workpiece is machined, so the number "1" is inputted using ten-key unit 62 and setting key 63.

Next, the the CRT 7 display becomes as shown in Fig. 16, and the operator is requested to input the workpiece material. For example, if that material is carbon steel S45C, the No. 1 is selected from a menu provided in the indicating data display area of the screen that area is in the lower portion of the screen.

The number "1" is inputted using ten-key unit 62 and setting key 63.

The display on the CRT 7 next becomes as shown in Fig. 17, and a machining pattern list is displayed in the indicating data display area in the lower portion of CRT 7's screen. The display on the screen requests the operator to input the kind of machining operation. For the machining program of Fig. 11, a tapped hole is formed in the first machining operation (Machining Operation No. 01), so the number "3" for the tapping operation is inputted using tenkey pad 62 and setting key 63.

The display on the CRT 7 then becomes as shown in Fig. 18, and the operator is requested to input the kind of thread desired.

Assuming the tapped hole should have a metric coarse thread, the number "1" for the metric coarse thread is inputted via ten-key pad 62 and setting key 63 is depressed.

Next, the operator is requested to input the nominal size. According to the machining program of Fig. 11, the number "6" for size M6 is inputted via ten-key pad 62 and setting key 62. As a result, "M6" is displayed after "TAP" in the program display area (not shown). Next, the pitch input is requested, so the number "1" is inputted.

In responses to subsequent requests displayed on CRT 7 for the machining program of Fig. 11, data for "Chamfering (Required)," "Z-axis end (through-hole)," "Starting hole depth (30) mm," "Machining depth (25) mm," "Workpiece height (40) mm," "Return height (45) mm," and X and Y positions (X=20) and (Y=20) are inputted. Thus, the machining program for the first machining operation, i.e., the tapped hole forming operation, are all inputted.

For the second machining program in the machining program of Fig. 11, all the data for that operation "Machining operation No. (02)," "Machining method (Spot-faced hole)," "Hole diameter (5) mm," "Spot facing diameter (8.5) mm," "Chamfering (Not required)," "Z-axis end (Through-hole)," "Machining depth (25) mm," "Work height (40) mm," "Return height (45) mm," "Spot facing depth (10) mm," and X and Y positions (X=60) mm and (Y=35) mm, are inputted.

The next of the flow chart in Fig. 9, step 102, is for "performing the assignment of tools." This step is carried out according to a flow chart as shown in Fig. 19. In step 201, tool assignment is started. In the next step 202, the number of tool assignments (N) is initially set to 0, and in step 203 the number of assignments is incremented (N=N+1). In step 204, the kind of machining operation for tool assignment number N in the machining program is initially read out. In step 205, (premachining) data are read out of the tool pattern list according to the kind of machining operation read (Fig. 4).

For the program in Fig. 11, the first machining operation is a chamfered-tapped, holeforming operation. The premachining data read from the tool pattern list in Fig. 4 shows that the tools required for the machining operation are (1) a center hole drill, (2) a drill, (3) a chamfering tool, and (4) a tap. In step 206, tools are selected from the tool list (Fig. 2) according to the kind of machining operation.

In conformance with the machining program, and these selected tools are written into a "using tool" area. In step 207, the program is tested. If the program has not ended (NO), steps 203 through 206 are reexecuted, so that those steps repeatedly executed until the program is ended.

For the second machining operation of this example, i.e., the spot-faced hole forming operation (chamfering not required), (1) a center hole drill and (2) a spot-faced hole drill are read from the tool pattern list in Fig. 4, as being the necessary tools selected from the tool list in Fig. 2. According to the kind of machining operatiion, the required tools are selected from those in the machining program area and written as tool data in the "using tool" area. If the result of the inquiry in step 207 is that the program is finished (YES), then instruction 208 is executed, and the data in the using tool area and the magazine mounting position are displayed on the CRT 7.

The tool assigning program is then ended.

When tool assignment step 102 is completed as described above, the machining tools are displayed as shown in Fig. 20 in the indicating data display area in the lower portion of the screen of the CRT in their order of use. For example, as Fig. 20 shows, the display includes for this example "1 03 Centre Hole Drill", "2 02 Drill", "3 04 Chamfering Tool", and "4 05 Tap." In addition, in the program display area in the upper portion of the screen of the CRT 7, tool mounting position in the tool magazine 16 are indicated by magazine numbers "1," "2," "3,"..., "10." The operator aligns cursor 7b with the magazine number "1" by operating the up and down keys 64 (Fig. 8). The tool mounting positions in tool magazine "1", "2", "3" and 4" are specified using ten-key unit 62 and setting key 63.To specify the positions in order, cursor 7b is moved downwardly and the tool mounting positions are stored in the magazine mounting position memory 8 in Fig.

1. In practice, machining operation starting step 103 (Fig. 9) can be carried out by mounting tools on the tool magazine 16 accoriding to the display in the upper portion of the screen of the CRT 7.

In many cases, the tools used for the previous machining program are left mounted on the tool magazine 16, and some of the tools can be used for the next machining program to be executed. In such a case, the tools used for the previous machining program are indicated in the upper portion of the screen of the CRT 7. By correcting that indication according to the new machining program, an operator can reduce the number of times tools must be mounted on or dismounted from the tool magazine.

To change the tool indications, new tool numbers are inputted to the magazine number using the ten-key unit 62 and setting key 63.

To remove a tool, the cursor 7b is aligned with the magazine number and the erasing key 65 is depressed. This causes the indication of the tool of the magazine number to be eliminated.

Execution (start) of the machining program is effected according to a flow chart shown in Fig. 21. In step 301, a program for executing the machining program is started. In step 302, the number of execution times (N) is initially set to 0. In step 303, the number of execution times is incremented, and in step 304, the kind of machining operation corresponding to execution times number N is read.

In step 305, data are obtained from the tool pattern list (Fig. 4) according to the kind of machining operation read and a premachining operation is read. In step 306, the tools to be used are selected from the tool list (Fig. 2) according to the kind of machining operation.

In step 307, the end of machining program is determined. If not, steps 303 through 307 are repeated in order. If so, then the machining operation is ended. The execution of the machining program is as described. One example of a tapping operation will be described with reference to the flowchart shown in Fig. 22.

The flowchart in Fig. 22 is for a program for carrying out a tapping operation. The program begins with step 401. In step 402, the machining pattern of the tapping operation is obtained from the tool pattern list shown- in Fig. 4. Specifically (1) a center hole drill, (2) a drill, (3) a chamfering tool and (4) a tap are read in that order. In step 403, the diameter of the starting hole for a tapped hole is obtained from the tapped hole's starting hole diameter list in Fig. 5. In this example, the tapped hole is of nominal size M6 and pitch 1.0 metric coarse thread, and so the diameter of the starting hole drill is determined to be 5.0 mm.

In step 404, from the tool list of Fig. 2, the tool number ("03") of a center hole drill whose end diameter is smaller than the starting hole diameter (5.0 mm), is confirmed. The mounting position (No. 1) of the center hole drill in the tool magazine 16 is obtained from the magazine mounting position memory 8, and the tools are exchanged. In response to step 405, the machining operation is carried out, and the center hole is formed at the position specified by the machining program.

In step 406, a drill (tool number "02") with a diameter equal to the starting hole drill diameter (5.0 mm) is obtained from the tapped hole's starting hole drill diameter (Fig. 5), and a length longer than the depth (30 mm) of the starting hole is determined in accordance with the tool list of Fig. 2. The drill's mounting position (No. 2) is obtained from the magazine mounting position memory 8, and the tools are exchanged.

In step 407, a machining operation is carried out. Specifically, the starting hole is formed at center hole. In step 408, the chamfering tool (tool number "04") which has an outside diameter larger than the diameter (5 mm) of the starting hole and an end diameter smaller than the diameter of the starting hole, and which has a chamfering angle of 90 degrees, is selected from the tool list in Fig. 2.

Its mounting position (No. 3) is obtained from the magazine mounting position memory 8, and the tools are exchanged.

In step 409, a chamfering operation is carried out for the starting hole (5 mm) formed in step 407. In instruction 410, a tap (tool number "05") which has an edge length longer than the machining depth (25 mm) and a nominal size M6 is selected according to the tool list (Fig. 2). The mounting position for the tools is obtained from the magazine mounting position memory 8, and the tools are exchanged.

In step 411, the starting hole (5 mm) is subjected to tapping. In step 412, spindle 14 is moved to the position which corresponds to the return height (45 mm) and held there.

The first machining operation, namely the tapping operation according to the machining operation, namely the tapping operation according to the machining program shown in Fig. 11, is thereby accomplished. The second machining operation, i.e., the spot-faced hole machining operation, can be carried out in the same manner.

In this embodiment of the invention, tools to be used are indicated in the lower portion of the screen of the CRT 7 and tool magazine mounting positions are displayed in the upper portion. Therefore, merely by operating the keyboard to specify or change using tools in association with the tool magazine mounting positions, an operator can continuously perform several kinds of machining operations while exchanging the tools. This requires minimum tool mounting and demounting work.

Furthermore, the operator can edit a machining program by successively inputting the final machining operation and its relevant data in response to the requests displayed on the CRT. Therefore, the difficulties accompanying conventional machine tools are eliminated with this invention in which tools are set in a tool magazine prior to programming a machining operation and an operator inputs the program while checking the mounting positions of these tools in the tool magazine. The order of use of tools for a machining operation and the selection of the tools can be inputted as the tool data of the machine tool and as data in the premachining operation for the final machining operation.

While the invention has been described with reference to the tapping operation and the spot-faced hole forming operation, the technical concept of the invention can be applied equally to a centre hole machining operation, a drilling operation, a spot-faced tapped hole forming operation, an upper surface machining operation, a reamed hole forming operation, and a spot-faced reamed hole forming operation. With the machine tool of this invention, a machining operation can be carried according to a machining program if the operator merely specifies or changes the tool mounting positions by selecting, via the keyboard, the tools to be used for the machining operation and their mounting positions in the tool magazine. Furthermore, the technical concept of the invention can be effectively applied to ordinary numerical control machine tools and other machine tools.

As is apparent from the above description, the machine tool of the invention is designed so that tools used for a machining operation and their mounting positions in the tool magazine are displayed on the screen of the CRT.

Therefore, several kinds of machining operations can be carried out with the tools in the tool magazine being exchanged merely by specifying or changing tools in association with their mounting positions in the tool magazine.

Accordingly, an operator need not check the tool mounting positions in the tool magazine in editing a machining program. This is another one of the advantages of the invention.

Claims

1. A machine tool, for automatically selecting and actuating tools in a tool magazine according to one or more machining programs, comprising: a) first memory means for storing said machining programe and data relating to said tools in said magazine; b) second memory means for storing mounting positions of said tools in said magazine; c) means for selecting a tool from said magazine; d) means for actuating said tool selected from said magazine; e) means for displaying representations of said tools required for performing a machining operation according to said machining programs and representations of mounting positions of said tools in said magazine; f) means for designating tool in reference to said mounting position in said magazine to store mounting positions of said tool in magazine; and g) control means coupled to said first and second memory means, said tool selecting means, said display means, and said designating means for getting mounting position of using tools from second memory means according to said machining program, and for effecting automatic tool selection and actuation by controlling said selecting means and actuating means according to said machining program and said tool data.

2. A machine tool according to claim 1, wherein said first and second memory means each comprises a random access memory.

3. A machining tool according to claim 1 or claim 2, wherein said tool selecting means includes a feed motor.

4. A machine tool according to any preceding claim, wherein said actuating means includes a spindle motor.

5. A machine tool according to any preceding claim, wherein said display means in cludes a cathode ray tube.

6. A machine tool according to any preceding claim, wherein said designating means include a keyboard.

7. A machine tool according to any preceding claim, wherein said control means includes a central processing unit and a read only memory containing programs for said central processing unit.

8. A machine tool substantially as hereinbefore described with reference to the accompanying drawings.