JP4605875B2 - Processing tool defect detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a defect inspection DeSo location of the processing tool, even more specifically, loss of a predetermined size to the processing tool is rapidly detect the defects when generated, thereby it is possible to improve the product yield about the loss detection DeSo location of Do processing tool.
[0002]
[Prior art]
Machine components such as gears and screws are manufactured by subjecting a workpiece to various processes such as turning and cutting. An example of a processing apparatus for performing such processing is a hobbing machine 1 shown in FIG.
[0003]
The hobbing machine 1 is supported by a hob head 2 so as to be rotatable along the direction of the arrow X and through a hob shaft 4 having a hob cutter 3 attached to the outer periphery thereof, and a through hole 5a formed in the work 5. Rod 6. The hob head 2 is attached to a base 7 and supported by a support board 8 that can be displaced in the vertical direction (arrow Y direction) and the horizontal direction (arrow Z direction). The movable platen 9 can be moved closer to or away from the support plate 8 along the direction of arrow A under the action of a movable platen moving mechanism (not shown).
[0004]
The support rod 6 has a diameter-reduced portion 6a that is tapered upward in FIG. 7 , a large-diameter portion 6b that has a larger diameter than the diameter of the through-hole 5a of the workpiece 5, and a diameter of the support rod 6 A small diameter portion 6c substantially equal to the diameter of the through hole 5a is provided in this order from the bottom. Among these, the reduced diameter portion 6a is supported by a table 10 that is rotatably mounted on the movable plate 9 via a portion having a substantially cylindrical shape , while the small diameter portion 6c is rotatable on a bearing (not shown). It is supported.
[0005]
The workpiece 5 in which the small-diameter portion 6c of the support rod 6 is passed through the through hole 5a abuts on the upper end surface of the large-diameter portion 6b and stays there. Of course, the position of the workpiece 5 at this time is a position where machining can be performed by the hob cutter 3.
[0006]
The support rod 6 and the workpiece 5 supported by the support rod 6 rotate as the table 10 is urged to rotate in the arrow B direction. On the other hand, when the hob shaft 4 is urged to rotate, the hob cutter 3 is also rotated, and in this state, the movable platen 9 is moved toward the support platen 8 under the action of the movable platen moving mechanism. As a result, the workpiece 5 is cut by the hob cutter 3, and teeth 11 are formed on the outer peripheral wall portion of the workpiece 5. Finally, the workpiece 5 is cut until it becomes a gear as a finished product.
[0007]
[Problems to be solved by the invention]
In recent years, it has become a mainstream to use a WC-Co based cemented carbide as the constituent material of the hob cutter 3. This is because the hob cutter 3 made of cemented carbide has a remarkably high processing speed and is excellent in wear resistance.
[0008]
However, the hob cutter 3 made of a cemented carbide has a low toughness, and thus has a disadvantage of being easily lost. When cutting of the workpiece 5 is continued using the hob cutter 3 in which the chipping has occurred, the load on the other blade portion of the hob cutter 3 increases. If cutting of the workpiece 5 is further continued in such a state, the other blade portion will be lost. In this case, since it becomes impossible to manufacture the teeth 11 having a predetermined shape, the manufacturing yield of the gears is lowered.
[0009]
The present invention has been made in order to solve the above-described problems, and when a predetermined-scale defect occurs in a processing tool such as a hob cutter, the processing can be stopped quickly, thereby improving the product yield. and to provide a defect detection DeSo location of the processing tool.
[0010]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a first spark state generated at a machining position of the workpiece when the workpiece is machined using the missing first machining tool, and a second It is determined whether or not a defect has occurred in the second processing tool by comparing the state of the second spark generated at the processing position of the workpiece when processing the workpiece with the processing tool. And
[0011]
That is, in this processing tool defect detection method, when the states of the first and second sparks are equal to each other, it is determined that the second processing tool is missing.
[0012]
In addition, by stopping the processing when it is determined that the second processing tool is missing in this way, it is possible to avoid manufacturing a product that is difficult to repair in the post-processing. Inducing defects in other machining parts of the tool can be avoided. For this reason, the manufacturing yield of a product can be improved.
[0013]
Further, the present invention is a processing tool defect detection apparatus attached to the processing apparatus for detecting a defect of the processing tool,
To light the dots constituting the screen by displaying an first spark generated on the screen of the display device in working position of the workpiece using a first processing tool that defect occurs when processing the workpiece First storage means for storing in advance the ratio of the first number of lit dots with respect to the total number of dots as a first occupation rate ;
When the workpiece is machined using the second machining tool , the second dot that is lit with respect to the total number of dots when the dot is lit by projecting the second spark generated at the machining location of the workpiece onto the screen. Second storage means for sequentially storing a ratio of the number as a second occupation ratio ;
An arithmetic circuit for comparing the pre-stored first occupancy in the first storage means and said second sequential stored Ru said second occupancy in the storage means,
With
The arithmetic circuit compares the before and Symbol first occupancy said second occupancy, when said second occupancy becomes equal to the first occupancy said second pressure A determination signal that the same amount of chipping as the first processing tool has occurred in the tool is issued,
The control unit that has received the determination signal issues a control signal for stopping machining.
[0014]
The processing tool defect detection apparatus automatically performs the observation of the states of the first and second sparks and the stop of the processing when it is determined that the shapes and generation amounts of both sparks are substantially equal to each other. That is, the defect of the processing tool is detected quickly and easily, and when the defect reaches a predetermined scale, the processing is quickly stopped. For this reason, it is avoided to manufacture a product that is difficult to repair in post-processing, and it is reliably avoided to induce defects in other blade portions, so that the manufacturing yield of the product can be reliably improved. .
[0015]
Comparison with the state of the second spark and state of the first spark, reflects the first or second spark display device, it is done by comparing the ratio of the screen area of the display device Can do. That is, when the ratios of the screen area of the display device in the first and second sparks are substantially equal to each other, it can be determined that a defect has occurred in the second processing tool.
[0016]
In addition, as a suitable example of a processing tool, cutting tools, such as a hob cutter and a milling cutter, can be mentioned.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a processing tool defect detection method according to the present invention will be described in detail with reference to the accompanying drawings in connection with an apparatus for carrying out the same. Components corresponding to those shown in FIG. 7 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0018]
A processing tool defect detection apparatus according to the present embodiment is shown in FIG. The processing tool defect detection device 20 includes a CCD camera 22, a monitor 24 that displays an image captured by the CCD camera 22, first and second ROMs 26 a and 26 b, first to third RAMs 28 a to 28 c and a CPU 30. And a comparison unit 32. In the present embodiment, the processing tool defect detection device 20 detects a defect of the hob cutter 3 of the hobbing machine 1 that cuts the workpiece 5, and the CPU 30 of the comparison unit 32 receives the hob shaft via the cable 34. 4 is electrically connected to a hobbing machine control unit 36 that controls rotation energization or stoppage of 4.
[0019]
The CCD camera 22 is supported in a state in which it is directed to the cutting portion of the workpiece 5. For this reason, the spark F generated at the cutting position of the workpiece 5 is photographed by the CCD camera 22 and displayed on the monitor 24. At this time, on the screen 38 of the monitor 24, the dots (not shown) constituting the screen 38 are lit so as to correspond to the shape and amount of the spark F. Information on the ratio of lit dots with respect to the total number of dots (hereinafter referred to as occupancy ratio) is sent as a signal to the comparison unit 32 and input to the first to third RAMs 28a to 28c.
[0020]
The first ROM 26a of the comparison unit 32 has a spark occupancy ratio (hereinafter referred to as a hob cutter) having a blade portion having a defect of about 0.2 mm or less that is relatively easy to repair the damage although it is damaged. , Referred to as a lower limit occupancy). On the other hand, the second ROM 26b stores in advance the occupancy rate of sparks (hereinafter referred to as the upper limit occupancy rate) generated by a hob cutter having a blade portion that is difficult to repair damage, that is, a blade portion that is missing larger than 0.2 mm. Has been. The lower limit occupancy and the upper limit occupancy are obtained by cutting the workpiece 5 using a deficient hob cutter, as will be described later.
[0021]
The CPU 30 of the comparison unit 32 compares the lower limit occupancy ratio and the upper limit occupancy ratio stored in advance in the first and second ROMs 26a and 26b with the occupancy ratio of the spark F input to the first to third RAMs 28a to 28c. As will be described later, when the occupancy rate input to any of the first to third RAMs 28a to 28c becomes equal to the lower limit occupancy rate or the upper limit occupancy rate, the CPU 30 passes a cable (not shown) to a movable board moving mechanism (not shown). Then, a control signal “stop one cycle” or “stop cutting” is issued to the hobbing machine controller 36 electrically connected.
[0022]
Next, a method for detecting a defect of the hob cutter 3 by the processing tool defect detection device 20 configured as described above will be described.
[0023]
First, the workpiece 5 is cut with a hob cutter that does not have a defect, and the occupancy ratio of the spark F generated at the machining location of the workpiece 5 is measured.
[0024]
Then, the workpiece 5 is cut by a hob cutter with a relatively small defect size, and the occupancy ratio of the spark F generated at the machining location of the workpiece 5 is measured in the same manner as described above.
[0025]
Hereinafter, the size of the defect of the hob cutter is sequentially increased, and the size of the defect when the defective product is manufactured and the occupation ratio of the spark F generated at the processing location of the workpiece 5 are examined.
[0026]
FIG. 2 shows an example of a graph representing the relationship between the size of the hob cutter defect and the occupancy rate of the spark F. FIG. In FIG. 2, curves a, b, and c indicate that a hob cutter that does not have a defect, a hob cutter that has a relatively small defect size, and that can be repaired by re-polishing, and a large defect size can be repaired. It was obtained by a hob cutter that was not easy. The horizontal axis of the graph is the elapsed time since the start of cutting.
[0027]
From FIG. 2, when the work 5 is cut using the hob cutter 3, the hob cutter is obtained when the occupation rate of the generated spark F is equal to or greater than the occupation rate (7.5%) indicated by the flat area of the curve b. 3 is determined to have a defect on a relatively small scale, and the cutting process can be stopped in one cycle, so that the induction of the defect can be avoided, and the occupancy ratio indicated by the flat area of the curve c ( 15%) or more, by determining that the hob cutter 3 is defective and stopping the cutting process, it is possible to avoid the production of a gear that is difficult to repair the damage to the teeth 11 It is understood that can be done.
[0028]
Therefore, the first and second ROMs 26a and 26b of the comparison unit 32 store 7.5% as the lower limit occupancy rate and 15% as the upper limit occupancy rate, and the CPU 30 controls the hobbing machine control unit 36. When the occupancy ratio of the spark F generated during cutting of the workpiece 5 is 7.5% or more and less than 15%, a control signal “stop 1 cycle” is issued, and when the control signal reaches 15%. Set to issue a control signal for “stop machining”.
[0029]
After completing this setting, the hob shaft 4 and the table 10 are urged to rotate, and the hob cutter 3 and the work 5 are rotated. In this state, the movable platen moving mechanism (not shown) is energized to bring the movable platen 9 closer to the support platen 8, and cutting of the workpiece 5 by the hob cutter 3 is started. Thereby, the teeth 11 are formed on the outer peripheral wall portion of the workpiece 5.
[0030]
In this cutting process, as shown in FIG. 3, a spark F is generated at the cutting position of the workpiece 5. The shape and amount of the spark F change depending on the size of the defect of the hob cutter 3. Note that reference numeral 40 in FIG. 3 is chips generated when the workpiece 5 is cut.
[0031]
The spark F is captured by the CCD camera 22 and displayed on the screen 38 of the monitor 24 (see FIG. 1).
[0032]
Information relating to the occupancy rate of the spark F within 10 seconds immediately after the start of cutting is sent to the first RAM 28a of the comparison unit 32 as a signal and input to the first RAM 28a. The CPU 30 compares the occupation rate input to the first RAM 28a with the lower limit occupation rate (7.5%) or the upper limit occupation rate (15%) stored in advance in the first and second ROMs 26a and 26b.
[0033]
Similarly, the second and third RAMs 28b and 28c are input with information on the occupancy rate of the spark F in the period from 10 seconds to 20 seconds and from 20 seconds to 30 seconds after the start of cutting. These occupation ratios input to the second and third RAMs 28b and 28c are also compared with the lower limit occupation ratio or the upper limit occupation ratio stored in advance in the first and second ROMs 26a and 26b by the CPU 30.
[0034]
Specifically, it is as follows.
[0035]
When no defect occurs in the hob cutter 3 during the cutting process, the occupation ratio of the spark F changes according to the curve a in FIG. That is, since the occupation ratio does not reach 7.5%, the CPU 30 does not issue a control signal for “stop machining”, and the machining for the workpiece 5 is continued.
[0036]
As shown in FIG. 4, when a defect 42 occurs in the hob cutter 3 during the cutting process, the occupation ratio of the spark F increases according to the scale of the defect 42. Then, as indicated by a curve d in FIG. 5, for example, when the occupancy rate of the spark F reaches the lower limit occupancy rate (7.5%) in 15 seconds after starting the cutting process, the first ROM 26a is controlled by the hobbing machine control unit. A control signal of “stop 1 cycle” is issued to 36, thereby stopping one cycle of cutting.
[0037]
In this case, the operator visually confirms the state of the hob cutter 3, displaces the support plate 8 as necessary, and changes the position of the hob cutter 3 so that the blade portion without a defect contacts the workpiece 5. Thereafter, the hobbing machine 1 is re-biased to restart the cutting of the workpiece 5, and finally the teeth 11 are formed to obtain a finished gear.
[0038]
When cutting of the workpiece 5 is resumed without changing the position of the hob cutter 3, the subsequent occupation rate of the spark F is compared with the upper limit occupation rate stored in the second ROM 26b. And even if the occupation ratio of the spark F is 7.5% or more, if the upper limit occupation ratio stored in the second ROM 26b does not reach 15%, the cutting process is continued, and a gear as a finished product is manufactured. Is done.
[0039]
On the other hand, when the scale of the defect 42 becomes large and the occupancy rate of the spark F increases and finally reaches 15% as shown by the curve e in FIG. Then, a control signal “stop cutting” is issued to the hobbing machine control unit 36.
[0040]
Upon receiving this control signal, the hobbing machine control unit 36 sends a control signal to the movable board moving mechanism (not shown) via the cable (not shown). As a result, the hob cutter 3 and the workpiece 5 are separated from each other as the movable plate 9 is separated from the support plate 8 under the action of the movable plate moving mechanism, whereby the cutting process on the workpiece 5 is stopped.
[0041]
That is, the cutting process by the hob cutter 3 in which the defect 42 is generated is continued. Eventually, the cutting process is automatically stopped even when the scale of the defect 42 is increased, so that a defective product is manufactured. There is no.
[0042]
As described above, in the processing tool defect detection method according to the present embodiment, the cutting process of the workpiece 5 is stopped when a predetermined size of the defect 42 is generated in the hob cutter 3, so that post-processing is performed. It is possible to avoid the production of a gear that is difficult to repair the wound of the tooth 11 even if it is performed.
[0043]
Moreover, since cutting is stopped before the load of the other blade part in the hob cutter 3 increases, the defect | deletion of another blade part is not induced. For this reason, it is possible to reliably manufacture a gear having a predetermined shape.
[0044]
From the above, the product yield of gears can be improved.
[0045]
In the above-described embodiment, the case where the hob cutter 3 is used as a processing tool and the gear is manufactured by cutting the workpiece 5 with the hob cutter 3 has been described as an example, but the present invention is particularly limited thereto. It is not a thing. For example, a milling cutter may be used as a processing tool, and the workpiece may be chamfered with the milling cutter. In this case, chamfering is performed in advance using a milling cutter having a deficiency that reduces the manufacturing yield, and the spark occupancy at that time is measured, and this is used as the first and second ROMs 26a and 26b of the comparison unit 32. You can make it memorize.
[0046]
【The invention's effect】
As described above, according to the defect detection method for a processing tool according to the present invention, the state of a spark generated in a processing part of a workpiece when processing with the defective processing tool is observed, and the state of the spark and use By comparing the state of sparks generated at the machining position of the workpiece with the inside machining tool, it is determined whether or not the working tool in use is defective. And when it determines with the processing tool in use missing, a process is stopped. For this reason, the effect that the defect | deletion of the other site | part of a processing tool can be avoided is achieved.
[0047]
Moreover, according to the processing tool defect | deletion detection apparatus which concerns on this invention, the stop of a process when the above-mentioned observation of the state of both sparks and the determination that the defect exceeding the allowable limit has arisen in the processing tool was made from this observation. Done automatically. That is, when the defect generated in the processing tool reaches a predetermined scale, the processing is promptly stopped, so that the above effect can always be achieved with certainty.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a schematic overall configuration of a processing tool defect detection device according to an embodiment.
FIG. 2 is a graph showing a correlation between the size of a hob cutter defect and the state of a spark generated when the hob cutter is used.
FIG. 3 is a plan view showing a state in which a spark has occurred at a machining part of a workpiece.
FIG. 4 is a plan view showing a state in which a spark is generated at a machining location when a workpiece is cut by a missing hob cutter.
FIG. 5 is a graph showing a state in which the hob cutter is defective during cutting.
FIG. 6 is a graph showing a state in which the cutting of a workpiece is continued using a hob cutter in which a defect has occurred, and the size of the defect has increased.
FIG. 7 is a schematic configuration explanatory diagram of a main part of a hobbing machine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Hobbing machine 3 ... Hob cutter 5 ... Work 6 ... Support rod 8 ... Supporting board 9 ... Movable board 10 ... Table 11 ... Teeth 20 ... Processing tool defect | deletion detection apparatus 22 ... CCD camera (imaging means)
24 ... Monitor 26a, 26b ... ROM
28a-28c ... RAM 30 ... CPU
32 ... Comparison part 36 ... Hobbing board control part 38 ... Screen 42 ... Deficit F ... Spark

Claims (2)

A processing tool defect detection device attached to the processing apparatus to detect a processing tool defect,
To light the dots constituting the screen by displaying an first spark generated on the screen of the display device in working position of the workpiece using a first processing tool that defect occurs when processing the workpiece First storage means for storing in advance the ratio of the first number of lit dots with respect to the total number of dots as a first occupation rate ;
When the workpiece is machined using the second machining tool , the second dot that is lit with respect to the total number of dots when the dot is lit by projecting the second spark generated at the machining location of the workpiece onto the screen. Second storage means for sequentially storing a ratio of the number as a second occupation ratio ;
An arithmetic circuit for comparing the pre-stored first occupancy in the first storage means and said second sequential stored Ru said second occupancy in the storage means,
With
The arithmetic circuit compares the before and Symbol first occupancy said second occupancy, when said second occupancy becomes equal to the first occupancy said second pressure A determination signal that the same amount of chipping as the first processing tool has occurred in the tool is issued,
The control part receiving device which received the said determination signal emits the control signal which stops a process, The processing tool defect | deletion detection apparatus characterized by the above-mentioned.   The processing tool defect detection apparatus according to claim 1, wherein the processing tool is a cutting tool.

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