JPH02160402A - Cutting feed setting device for machine tool - Google Patents

Abstract

PURPOSE:To shorten the time required for machining by providing a detection device that detects the cutting starting position of rough machining and a control device that property corrects the feed starting position of cutting tool for finishing machining to a NC machine tool that performs the finishing machining after the rough machining is performed. CONSTITUTION:A detection device 30 that performs detection of the vibration generated on a bite 25 and detects the execution position of starting rough machining by a vibration sensor 29 when a work 20 to be wrought checked by a check device 21 is roughly machined is provided in this cutting feed setting device. Further, a control device 31 that stores the execution position of starting cutting at the time of rough machining detected by the detection device 30 and corrects the set position of starting cutting feed of the bite for finishing machining at the time of finishing machining to be nearer to the work 20 to be wrought than the time of rough machining is provided in the cutting feed setting device. Therefore, the time of air cut at the time of finishing machining can be shortened as much as possible against individual works to wrought whose deflection in centering is different each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a cutting feed setting device for a machine tool that is applied to an NC-controlled machine tool or the like having an automatic processing function.

(Prior art) In general, when a workpiece such as a cast metal part with varying shape and dimensions is chucked and rotated by a chuck or table of a machine tool such as an NC lathe, the shape and dimension of the workpiece is Due to variations in the workpiece and centering deviation allowed when chucked, the rotation locus of the outer shape of the workpiece increases considerably compared to the designed dimensions of the workpiece. The degree of increase in this dimension is not constant and varies depending on each workpiece. When performing cutting on such a workpiece, the cutting tool is moved in a rapid traverse state to the cutting feed start setting position, and from there it is moved at the cutting feed rate to cut the workpiece. However, the cutting feed start position has conventionally been set at a position that corresponds to the maximum dimension of the rotation locus of the external shape, which varies depending on the individual workpiece.

FIGS. 4 and 5 are diagrams showing the movement of a cutting tool during a conventional cutting process, which will be explained below. A cylindrical workpiece 1 with a non-circular outer shape has a center line a of an inner peripheral portion 2.
It is chucked by a chuck device (not shown) so as to rotate around . The tool 3 for rough machining is moved rapidly to the cutting feed start setting position A as shown in FIG. The end face of the workpiece 1 is rough-machined. Further, the rough machining tool 5 is moved in rapid traverse to the cutting feed start setting position C as shown in FIG. An annular convex strip 7 on the inner circumference of the workpiece 1
Roughly process the inner surface of. After this, the cutting tool 8 for finishing is moved from the cutting feed start setting position A, which is the same as in the case of rough machining, to the cutting feed end setting position B at the cutting feed rate along the path shown by the broken line 9, as shown in FIG. , finishing the end face of the workpiece 1. Then, the finishing tool 10 is moved along the broken line 1 from the cutting feed start setting position C as shown in FIG.
The machine is moved along the path indicated by 1 at the cutting feed rate to the set cutting feed end position, and the inner surface of the stepped portion 7 on the inner circumference of the workpiece 1 is finished. In this case, even if the cutting tools 3 and 8 are moved from the cutting feed start setting positions A and C at the cutting feed rate, the cutting start execution position A' where the cutting of the workpiece 1 is actually started.
Until reaching C', the cutting tool 3.8 is in a so-called air cut state in which it is not cutting the equivalent workpiece 1.

(Problem to be Solved by the Invention) By the way, in the movement of the conventional cutting tool described above, the cutting feed start setting positions A and C are set at the maximum rotation locus of the external shape that changes depending on the individual workpiece as described above. It is set at a position that matches the dimensions and is also set at the same position for both rough machining with the rough machining bit 3 and finish machining with the finishing machining bit 8. For this reason, depending on the individual workpiece, the cutting start execution position A', C'
In contrast, the cutting feed start set positions A and C may be located considerably earlier than the cutting feed start positions A and C. In such a case, during finishing machining, the cutting feed rate is low, so it takes a considerable amount of wasted time when the workpiece is not being cut in the air cutting state, and this results in a considerable amount of wasted time in the overall machining time. The proportion of wasted time is increasing, and this wasted time is causing processing costs to rise.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a cutting feed setting device for a machine tool that can shorten the time required for machining and reduce machining costs in a machine tool that performs finishing machining after rough machining. .

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a method for cutting a workpiece chucked in a chuck device and a cutting tool after one of them is moved in rapid traverse relative to the other to a cutting feed start setting position. In machine tools that cut by being moved at a feed rate and that performs finishing after rough machining, the cutting tool for rough machining of the workpiece is designed to reduce vibrations that occur in the cutting tool during rough machining. A detection device is provided to detect the cutting start execution position during rough machining, the cutting start execution position during rough machining detected by this detection device is stored, and finishing machining is performed based on the stored cutting start execution position. The present invention is characterized in that it is provided with a control device that corrects the cutting feed start position of the cutting tool for finishing machining so that it is closer to the workpiece than during rough machining.

(Function) According to the above-described means, the cutting feed start position of the finishing cutting tool is corrected during finishing machining so that it is closer to the workpiece than during rough machining. The time required for air cutting during finishing machining can be reduced as much as possible for individual workpieces with variations in centering and centering runout, which reduces the time required for machining and reduces machining costs. can.

(Embodiment) An embodiment in which the present invention is applied to a vertical NC automatic lathe will be described below with reference to FIGS. 1 to 3.

Reference numeral 20 denotes a cylindrical workpiece with a non-circular outer diameter, which is chucked by a chuck device 21 fixed to a main shaft (not shown) so as to rotate around the center line of the inner peripheral portion 22. , an annular protruding portion 23 is formed on the inner peripheral portion 22 . Reference numeral 24 denotes a tool rest, to which a cutting tool 25 as a cutting tool for rough machining is attached. Although not shown in detail in this tool post 24, there are a cutting tool 26 as a cutting tool for rough machining shown in FIG. 2 and a cutting tool 27, 28 as a cutting tool for finishing machining shown in FIG. They are provided in a replaceable manner. A vibration sensor 29 is attached to the tool rest 24, and its output is given to the detection device 30. Reference numeral 31 denotes a control device, which is provided with an NC control device, etc. for controlling the rotation of the main shaft and the movement of the tool rest 24, etc., and signals are exchanged between this and the detection device 30. There is.

Next, the operation of the above configuration will be explained. First, the workpiece 2 is chucked by the chuck device 21 by the rotation of the main shaft.
0 is rotated, and then the rough machining tool 25 is rapidly moved from the standby position to the cutting feed start setting position A.
From here, the path indicated by the broken line 32 is indicated by the arrow 33 at the cutting feed rate.
direction. Then, when the cutting tool 25 is moved in the direction of the arrow 33 and passes the cutting start execution position A' where the workpiece 20 is actually cut, the workpiece 20 will be cut. Vibration is caused by the turret 24
The vibration sensor 29 detects this vibration and provides its output to the detection device 30. Then, the detection device 30 gives an output signal to the control device 31 at the position where the cutting tool 25 starts to vibrate, that is, the cutting start execution position A', and when this signal is given, the control device 31 calculates the coordinates of the current position of the cutting tool 25. Remember. When the cutting tool 25 is moved in the direction of the arrow 33 and approaches the cutting end execution position B', the cutting tool 25 is intermittently separated from the workpiece 20 and reaches the cutting end execution position B'.
After passing through, the cutting tool 25 becomes completely separated from the workpiece 20, but the vibration generated in the cutting tool 25 changes from continuous to intermittent, and finally the vibration disappears. The detection device 30 determines that the cutting tool 25 has passed the cutting end execution position B' when there is no output from the vibration sensor 29 even if the main shaft rotates a predetermined amount, and sends a signal to the control device 31. When the signal is given, the control device 31 further rotates the main shaft by a predetermined amount, and at a position where the cutting tool 25 is at a predetermined gap from the workpiece 20, changes the tool rest 24 from the cutting feed rate to a rapid traverse state, and moves the cutting tool 25 to the standby position. return.

Next, the rough machining tool 26 is rapidly moved from the standby position to the cutting feed start setting position C, and from there is moved in the direction of the arrow 35 along the path shown by the broken line 34 at the cutting feed rate. Then, when the cutting tool 26 is moved in the direction of the arrow 34 and passes the cutting start execution position C' where the convex strip 23 of the workpiece 20 is actually cut, the vibrations generated in the cutting tool 26 during cutting, as in the case described above, occur. is detected by the vibration sensor 29 provided on the tool rest 24 and provided to the detection device 30, so the position where the cutting tool 26 starts to vibrate, that is, the cutting start execution position C
An output signal is given to the control device 31 at ', and when this signal is given, the control device 31 stores the coordinates of the position of the cutting tool 26 at that time. When the cutting tool 26 is moved in the direction of the arrow 35 and passes the cutting end execution position D' and the vibration of the cutting tool 26 disappears, the control device 31 causes the main shaft to further rotate by a predetermined amount and the cutting tool 26 moves to the workpiece 20 in the same way as described above. At a position with a predetermined gap from the convex strip 23, the tool rest 24 is changed from the cutting feed speed to a rapid feed state, and the cutting tool 26 is returned to the standby position.

Subsequently, the cutting tool 27 for finishing is moved from the standby position to the cutting feed start setting position A' in rapid traverse, and from there it is moved at the cutting feed rate in the direction of arrow 33 along the path shown by the broken line 32 to cut the workpiece. 20 is started, and this cutting feed start setting position A' is determined based on the cutting feed start execution position A' stored in the control device 31, taking into consideration only the following speed of the operation, and determining the external shape of the workpiece 20. is set as close as possible to . In this way, finishing machining is performed while the cutting tool 27 is moved in the direction of the arrow 33, and the cutting end position B'
When the vibration of the cutting tool 27 disappears after this point, the control device 31 causes the main shaft to further rotate by a predetermined amount and move the cutting tool 27 to the tool rest 24 at a position where there is a predetermined gap from the workpiece 20, as in the case of rough machining described above. is changed from the cutting feed rate to a rapid feed state and the cutting tool 27 is returned to the standby position.

Next, the cutting tool 28 for finishing is moved from the standby position to the cutting feed start setting position C' in rapid traverse, and from there it is moved at the cutting feed rate in the direction of arrow 35 along the path shown by the broken line 34 to cut the workpiece 20. Cutting is started, and this cutting feed start setting position C' is set based on the cutting feed start execution position C' stored in the control device 31 in the same way as described above, and the workpiece 20 is set by considering only the follow-up speed of the operation. It is set at a position as close as possible to the outer shape of the protruding portion 23. In this way, byte 28
is moved in the direction of the arrow 35, finishing machining is performed, and when the cutting end execution position D' is passed and the vibration of the cutting tool 28 disappears, the control device 31 causes the main shaft to further rotate by a predetermined amount, as in the case of rough machining described above. Then, at a position where the cutting tool 28 has a predetermined gap from the convex strip 23 of the workpiece 20, the tool rest 24 is changed from the cutting feed speed to a rapid feed state, and the cutting tool 28 is returned to the standby position.

In this way, in this embodiment, the cutting feed start set positions A', C'' during finishing machining are changed to the cutting feed start set positions A' and C'' during rough machining.
, C, the position is corrected to be closer to the workpiece 20 than in the case of C, so that the time required for air cutting at the start of finishing can be reduced as much as possible compared to the conventional method.

In addition, in the above-described embodiment, by detecting the vibrations of the cutting tools 25 to 28, both during rough machining and finishing machining, the cutting tools 25 to 28 are slightly past the cutting end execution position B'D'. Since the cutting tools 25 to 28 are returned to the standby position in a rapid traverse state from the position where they were cut, the cutting feed is performed to the cutting feed end setting positions B and D in both rough machining and finishing machining. Compared to the conventional method, the time required for air cutting after passing the cutting end execution position B'D' can be reduced as much as possible in both the rough machining time and the finishing machining time.

In the above-mentioned embodiment, the case where it is applied to an NC lathe was explained, but it can also be applied to other machine tools such as an NC milling machine in which a table that chucks a workpiece is moved and displaced relative to a cutting tool. Can be implemented.

[Effects of the Invention] As is clear from the above description, the present invention minimizes the time required for air cutting during finishing processing for individual workpieces that have variations in shape and size and differ in centering runout. This has the excellent effect of shortening the time required for processing and reducing processing costs.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention. FIG. 1 is a perspective view of the main part, FIGS. 2 and 3 are action explanatory views, and FIGS. 4 and 5 are conventional FIG. In the drawing, 20 is a workpiece, 21 is a chuck device, 25 to 28 are bits (cutting tools), and 29 is a vibration sensor 3
0 is a detection device, and 31 is a control device. Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure and Figure

Claims (1)

[Claims] 1. One of the workpiece and the cutting tool chucked by the chuck device is moved relative to the other by rapid traverse to a cutting feed start setting position, and then moved at a cutting feed rate to perform cutting. In a machine tool that performs finishing machining after rough machining, a cutting tool for rough machining detects the vibration generated in the cutting tool during rough machining of the workpiece, and determines the cutting start position of the rough machining. A detection device is provided to detect the cutting start position during rough machining detected by the detection device, and the cutting feed of the cutting tool for finishing machining is controlled during finishing machining based on the memorized cutting start execution position detected by the detection device. A cutting feed setting device for a machine tool, comprising a control device that corrects a starting setting position so that it is closer to the workpiece than during rough machining.