JP4061636B2 - Deburring method and deburring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus used to remove burrs generated at the end of a through hole in drilling a workpiece, and more particularly, to a burr at the end of a through hole that has been drilled so as to open in a hollow portion of the workpiece. The present invention relates to a burr removal method and a burr removal apparatus suitable for removing the burr.
[0002]
[Prior art]
The workpiece W shown in FIG. 4 is subjected to drilling from the outside toward the hollow portion C, and a burr B is generated at the end of the through-hole H formed thereby. is doing. Conventionally, in order to remove such burrs B, a bar-off tool T provided with cutting teeth A has been used.
[0003]
The bar-off tool T includes a trapezoidal cutting tooth A on one side of the tip, and a radial length L from the axis to the outer periphery of the cutting tooth A corresponds to the radius R of the through hole H. It is mounted on a main shaft (not shown) that is driven to rotate. Then, after the cutting teeth A are inserted into the through holes H to a position where they pass through the terminal end, the cutting teeth A are removed so as to scrape off the burrs B by being pulled out while rotating around the axis.
[0004]
As for this type of burr removal, there are techniques disclosed in JP-A-9-290308 and JP-A-200-254846.
[0005]
[Problems to be solved by the invention]
However, in the conventional burr removal as described above, the bar-off tool T having the cutting teeth A on one side is used, and the burr B is forcibly removed by pulling out while rotating the bar-off tool T. Therefore, when the burr B is strong, there is a problem that it may be difficult to remove the burr B well or the tool T may be damaged. To solve such a problem Was an issue.
[0006]
OBJECT OF THE INVENTION
The present invention has been made by paying attention to the above-described conventional problems, and when removing burrs generated at the end of a through hole in drilling a workpiece, even if the burrs are strong, It is an object of the present invention to provide a burr removing method and a burr removing device that can remove the burrs well and can eliminate the risk of breakage of the tool.
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a method for removing burrs, wherein, when removing burrs generated at the end of a through hole in drilling a workpiece, the workpiece and the tool are relatively moved in three orthogonal directions and the tool is moved. As a tool to be mounted on the motion control means, the tip side is a tapered part having a large diameter portion corresponding to the lower limit of the diameter tolerance of the through hole and a small diameter toward the base end side. Using an end mill, after inserting the end mill to a position where the large diameter portion passes the end of the through hole, move at least one of the workpiece and the end mill so that the rotating end mill moves along the opening edge of the end of the through hole. removing burrs Te was to measure the load current for driving forward the end mill in the axial direction when inserting an end mill into the through hole, measured load current reaches a predetermined upper limit threshold When the value exceeds the value, it is judged that the hole diameter is defective, and when removing the burr, the load current for rotationally driving the end mill is measured, and when the measured load current is less than the predetermined lower threshold, the hole diameter is defective. It is characterized by judging that there is.
[0008]
Further, the burr removal apparatus according to the present invention, as claimed in claim 2, an apparatus for removing burrs generated in the through hole terminating in drilling the workpiece relative to the workpiece and the tool in the three axial directions perpendicular to each other The movement control means for rotating the tool and rotating the tool, and the tool attached to the movement control means has a distal end with a large diameter portion corresponding to the lower limit of the diameter tolerance of the through hole and a small diameter toward the proximal end. includes a tapered end mill was Rutotomoni, a load current to be driven forward towards the end mill to work, to measure the load current for rotating the end mill in removing burrs, the hole diameter on the basis of these measurement results It is characterized by having an inspection means for performing pass / fail judgment .
[0009]
In the above configuration, the operation control means for relatively moving the workpiece and the tool in the three axis directions orthogonal to each other and rotationally driving the tool includes various numerically controlled machine tools and a multi-axis on which the tool is mounted. A combination of a control type robot and a movable jig for holding a workpiece can be used.
[0010]
[Effects of the Invention]
In the burr removal method according to claim 1 of the present invention, a tapered end mill having a large-diameter portion at the tip side is inserted in a coaxial state into a through-hole after drilling in a workpiece. Insert it to the position where it passes through the end of the through hole, which is the burr generation site. At this time, since the end mill has a tapered shape with a small diameter toward the base end side, a gap is formed between the cutting edge on the outer periphery and the opening edge at the end of the through hole. Then, while rotating the end mill around the axis and moving the end mill in the direction perpendicular to the axis by the gap described above, the end mill is moved around along the opening edge of the end of the through-hole, so that the end of the through-hole is reached. The generated burrs are removed by cutting.
[0011]
Thus, in the burr removal method, the end mill inserted into the through hole is rotated and moved in a direction perpendicular to the axis to bring the blade edge into contact with the burr. The end mill is not damaged and the end mill is tapered, so that the large diameter part on the tip side is located outside the opening edge of the end of the through hole. Thus, it can be removed without leaving burrs.
[0012]
In the above description, the end mill is moved in each of the insertion of the end mill into the through hole of the workpiece, the movement of the end mill in the direction orthogonal to the axis, and the end mill rotating along the opening edge of the through hole. However, the movement control means for holding the workpiece can move the workpiece and the end mill relative to each other in the three axial directions orthogonal to each other.
[0013]
Further, in Bali removal method of the present invention, the large diameter portion of the end mill, the diameter corresponding to the lower limit of the diameter tolerances of the through hole, the end mill forward drive in the axial direction when inserting an end mill into the through hole Measure the load current. At this time, an upper threshold value larger than this is set in advance for the normal load current for advancing the end mill, and the measured load current is compared with the upper threshold value when the end mill is driven forward. To do. When the measured load current exceeds the upper limit threshold value, it is determined that the hole diameter is defective.
[0014]
That is, since the large diameter portion of the end mill has a diameter corresponding to the lower limit of the allowable error diameter of the through hole, when the diameter of the through hole is less than the lower limit of the allowable error, that is, when the diameter of the through hole is too small. The large diameter portion of the advancing end mill interferes with the inner surface of the through hole, and the load current increases due to the resistance. Therefore, when the measured load current exceeds the upper limit threshold, it can be considered that the diameter of the through hole is less than the lower limit of the allowable error, and it is determined that the through hole has a poor hole diameter.
[0015]
Furthermore, in Bali removal method of the present invention, to measure the load current for rotating the end mill in removing burrs. At this time, a lower limit threshold value smaller than this is set in advance for the normal load current for completely removing burrs, and the measured load current and lower limit threshold value are measured when the end mill is driven to rotate. Compare If the measured load current is less than the lower limit threshold value, it is determined that the hole diameter is defective.
[0016]
That is, for example, when the diameter of the through hole exceeds the upper limit of the allowable error, that is, when the diameter of the through hole is too large, the contact between the end mill and the burr becomes insufficient, and the load current is usually reduced due to the reduction of the cutting resistance. Smaller than the value. Therefore, when the measured load current is less than the lower limit threshold, it can be considered that the diameter of the through hole exceeds the upper limit of the allowable error, and it is determined that the through hole has a poor hole diameter.
[0017]
In the deburring device according to claim 2 of the present invention, a taper-shaped end mill having a tip end side having a large diameter corresponding to the lower limit of the diameter tolerance of the through hole is formed in the through hole after drilling the workpiece. It is inserted in a coaxial state, and at this time, the large diameter portion is inserted to a position where it passes through the end of the through-hole that is a burr generation site. At this time, since the end mill has a tapered shape with a small diameter toward the base end side, a gap is formed between the cutting edge on the outer periphery and the opening edge at the end of the through hole. Then, while rotating the end mill around the axis and moving the end mill in the direction perpendicular to the axis by the gap described above, the end mill is moved around along the opening edge of the end of the through-hole, so that the end of the through-hole is reached. The generated burrs are removed by cutting.
[0018]
In this way, in the burr removing device, the end mill inserted into the through hole is rotated and moved in a direction perpendicular to the axis to bring the cutting edge into contact with the burr. The end mill is not damaged and the end mill is tapered, so that the large diameter part on the tip side is located outside the opening edge of the end of the through hole. Thus, it can be removed without leaving burrs. Further, the load current for driving the end mill forward toward the workpiece and the load current for rotating the end mill when removing the burrs are measured by the inspection means, and the quality of the hole diameter is determined based on these measurement results.
[0019]
In the above description, the end mill is moved in each of the insertion of the end mill into the through hole of the workpiece, the movement of the end mill in the direction orthogonal to the axis, and the end mill rotating along the opening edge of the through hole. However, the movement control means for holding the workpiece can move the workpiece and the end mill relative to each other in the three axial directions orthogonal to each other.
[0020]
【The invention's effect】
According to the burr removal method of the present invention, the operation control means and the end mill having a taper shape are used. After the end mill is inserted into the through hole, the end mill is moved along the opening edge at the end of the through hole. Since the burrs are cut and removed in the same way, even if the burrs are strong, they can be removed completely without leaving burrs, and the end mill can be broken to extend the life of the end mill. In addition, the insertion and withdrawal of the end mill into the through hole can be fast-forwarded, and the operation time for removing burrs can be greatly shortened.
[0021]
Further, according to the Bali removal method of the present invention, a diameter corresponding to the large diameter portion of the e Ndomiru the lower limit of the diameter tolerances of the through hole, the load current is predetermined upper limit threshold for driving forward the end mill in the axial direction By determining that the hole diameter is poor when the value is exceeded, it is possible to make a pass / fail judgment on the lower limit of the diameter of the through hole formed with a predetermined tolerance, and pass / fail for all workpieces. Since the determination is made, it is possible to contribute to the quality improvement of the workpiece.
[0022]
Furthermore, according to Bali removal method of the present invention, by the load current for rotating the end mill in removing the burrs it is determined to be a pore diameter defective when less than the predetermined lower threshold value, a predetermined It is possible to make a pass / fail judgment on the upper limit of the diameter for a through-hole formed with an allowable error, and to make a pass / fail judgment for all the workpieces, contributing to the improvement of the work quality. Can do.
[0023]
According to the deburring device according to claim 2 of the present invention, by adopting the operation control means and the tapered end mill, after inserting the end mill into the through hole, the end mill is attached to the opening edge at the end of the through hole. The burrs can be cut and removed in the manner that they are moved, so even if the burrs are strong, they can be removed completely without leaving burrs, and the possibility of breakage of the end mill is eliminated. The life of the end mill can be increased, and the insertion and withdrawal of the end mill through the through-hole can be fast-forwarded, so that the operation time for removing burrs can be greatly shortened.
Furthermore, according to the deburring device of the present invention, it is possible to perform pass / fail judgment of the lower limit of the diameter and pass / fail judgment of the upper limit for the through-hole formed with a predetermined tolerance, and for all workpieces. The pass / fail judgment is performed, which can contribute to the improvement of the work quality.
[0024]
【Example】
Hereinafter, an embodiment of a deburring method and a deburring device according to the present invention will be described with reference to the drawings.
[0025]
A workpiece W partially shown in FIG. 1 has a hollow portion C having a circular cross section and a through hole H that intersects the hollow portion C by drilling with a drill. The through hole H has a diameter slightly smaller than the diameter of the hollow portion C. Examples of the workpiece W subjected to such drilling include a crankshaft of a vehicle engine. The crankshaft is formed with a hollow portion (hole) or a through-hole as described above as a cooling oil passage.
[0026]
Here, when the through-hole H intersecting the hollow portion C is formed in the workpiece W, a burr B is generated at the end of the through-hole H opened in the hollow portion, and the burr B in the hollow portion C is directly connected from the outside. It is impossible to remove them automatically. Therefore, in order to remove the burr B well, the burr removing apparatus shown in FIGS. 1 and 3 is used.
[0027]
The deburring device includes a motion control unit 1 that relatively moves the workpiece W and the tool in three axial directions orthogonal to each other and rotationally drives the tool, and a tip portion on the large-diameter portion D as a tool mounted on the motion control unit 1. And a tapered necked end mill E having a small diameter toward the base end side.
[0028]
As the operation control means 1, as shown in FIG. 3, a numerically controlled machine tool can be used. The illustrated operation control means 1 is provided with a table 3 for holding a workpiece W on a base 2 so as to be reciprocable in the X direction (horizontal direction) perpendicular to the paper surface. Columns 4 and 4 are erected, and a cross rail 5 is provided between the columns 4 and 4 so as to be movable up and down in the Z direction (vertical direction) which is the vertical direction in the figure.
[0029]
A slide body 6 is provided on the cross rail 5 so as to be able to reciprocate in the Y direction (horizontal direction) which is the left-right direction in the figure. The slide body 6 has a spindle head 8 provided with a spindle 7 in a suspended state at the lower end. Is provided so as to be movable up and down in the Z direction (vertical direction) which is the vertical direction of the figure. An end mill E can be attached to the lower end of the main shaft 7 and is driven to rotate about the Z axis.
[0030]
The table 3 is reciprocally driven by an X-axis servo motor 9 and a ball screw (not shown). The cross rail 5 is driven up and down by a lift servo motor 10 and a ball screw 11 provided in each column 4. The slide body 6 is driven to reciprocate by a Y-axis servo motor 12 and a ball screw 13 provided on the cross rail 5. The spindle head 8 is driven up and down by a Z-axis servo motor 14 and a ball screw 15 provided on the slide body 6. The spindle 7 is rotationally driven by a spindle motor 16 provided on the spindle head 8.
[0031]
The spindle 7 can be moved up and down by either the cross rail 5 or the spindle head 8, but in this embodiment, both the cross rail 5 and the spindle head 8 are used when changing the tool or setting the tool as the origin. The main shaft 7 is greatly moved up and down by means of, and when removing the burr, the main shaft 7 is moved up and down only by the main shaft head 8.
[0032]
Further, the operation control means 1 includes a control unit 17 that controls the servo motors 9, 10, 12, 14 and the spindle motor 16. In addition to driving each motor based on various preset data, the controller 17 drives the load current of the Z-axis servomotor 14 when the end mill E is driven forward or down toward the workpiece W, and the burr B An inspection unit is provided that measures the load current of the spindle motor 16 during removal and determines the quality of the hole diameter based on the measurement results. This inspection will be described later.
[0033]
As shown in FIG. 1, the end mill E has a tapered shape in which the distal end side (lower end side) has a large diameter portion D and the diameter decreases toward the proximal end side (upper end side). The diameter d corresponds to the lower limit of the diameter tolerance of the through hole H. In this embodiment, since the hollow portion C and the through hole H intersecting each other are circular in cross section, the surface surrounded by the opening edge of the through hole H is a curved surface corresponding to the arc of the hollow portion C. Become. For this reason, the end mill E has a height dimension sufficiently larger than the vertical dimension difference h of the opening edge shown in FIG.
[0034]
Next, the burr removal method according to the present invention will be described together with the operation of the above burr removal apparatus.
[0035]
The deburring device holds the workpiece W on the table 3 so that the through hole H is vertical, and the operation control means 1 operates so that the through hole H and the end mill E coincide on the coaxial line in the Z direction. Position.
[0036]
Further, the control unit 17 of the operation control unit 1 sets an upper limit threshold value for the load current of the Z-axis servomotor 14 when the end mill E is driven forward toward the workpiece W. In this embodiment, the upper threshold value is 1.3 times the normal load current when the end mill E is moving forward without any problem. Further, in the control unit 17, a lower limit threshold is set for the load current of the spindle motor 16 when the burr B is removed. The lower threshold value of this embodiment is 0.7 times the normal load current when the burrs are well removed.
[0037]
Note that the upper and lower thresholds can be appropriately changed according to the dimensional relationship between the through hole H and the end mill E, the material of the workpiece W, and the like.
[0038]
Next, as shown in the flowchart of FIG. 2, when the burr removing process is started, the end mill E is lowered together with the spindle head 8 in step S <b> 1, and the end mill E is inserted into the through hole H. At this time, the end mill E descends to a position where the large diameter portion D passes through the end of the through hole H as shown in FIG.
[0039]
Here, in the burr removal method, while the end mill E is descending, the load current of the Z-axis servomotor 14 is measured, and the load current measured in step S2 is compared with the preset upper threshold value to measure. If the load current does not exceed the upper threshold (NO), the process proceeds to step S3. On the other hand, if the measured load current exceeds the upper limit threshold value (YES), the process proceeds to step S9, where the hole diameter of the through hole H is defective (NG), and alarm means is provided as necessary. And the display means are operated, and the process proceeds to step S8 to raise the end mill E.
[0040]
That is, since the large diameter portion D of the end mill E has a diameter corresponding to the lower limit of the allowable error diameter of the through hole H, the diameter of the through hole H is less than the lower limit of the allowable error. If it is too small, the large-diameter portion D of the descending end mill E interferes with the inner surface of the through hole H, and the load current of the Z-axis servomotor 14 increases due to the resistance. Therefore, when the measured load current exceeds the upper limit threshold, it can be considered that the diameter of the through-hole H is less than the lower limit of the allowable error, and it is determined that the through-hole H has a poor hole diameter.
[0041]
When the end mill E is lowered to a predetermined position without any trouble, the end mill E has a taper shape with a small diameter toward the base end side, and therefore, between the edge of the outer periphery and the opening edge at the end of the through hole H. A gap is formed as shown in FIG.
[0042]
Next, in step S3, after the end mill E is rotated by the main shaft 7, the end mill E is moved in the X direction (or Y direction) as shown by the arrow A1 in FIG. 1, the end mill E is moved around along the opening edge of the end of the through hole H as shown by the arrow A2 in FIG. The removed burr B is removed by cutting.
[0043]
In this embodiment, the end mill E is moved in the X direction by the operation of the table 3, and the end mill E is moved by the combined operation of the table 3 and the cross rail 5. Further, as described above, the opening edge of the through hole H has a vertical dimension difference h as shown in FIG. 1, and the end mill E has a tapered shape. The cutting position changes continuously up and down and the radius of the cutting position changes continuously. For this reason, the circular locus of the end mill E that follows the opening edge of the through hole H becomes an ellipse as shown by an arrow A2 in FIG.
[0044]
Furthermore, since the end mill E has a tapered shape, when the end mill E moves in the X direction from the state shown in FIG. 1A, the large-diameter portion D on the distal end side is outside the opening edge of the through hole H. It will be in a position. As a result, the burrs B can be completely removed without leaving them.
[0045]
In the above burr removal process, the load current of the spindle motor 16 is measured, the load current measured in step S5 is compared with a preset lower threshold, and the measured load current exceeds the lower threshold. If yes (NO), the process proceeds to step S6. In step S6, it is determined whether or not the end mill E has made one round along the opening edge. If the circular movement has not been completed (NO), the process returns to step S4.
[0046]
On the other hand, in step S5, when the measured load current is less than the lower limit threshold value (YES), the process proceeds to step S10, where the hole diameter of the through hole H is defective (NG). In response to this, the alarm means and the display means are activated, the process proceeds to step S7, the end mill E is returned to the axis of the through hole H, and the rotation of the end mill E is stopped.
[0047]
That is, for example, when the diameter of the through hole H exceeds the upper limit of the allowable error, that is, when the diameter of the through hole H is too large, the contact between the end mill E and the burr B becomes insufficient, and the cutting resistance decreases. The load current of the spindle motor 16 becomes smaller than the normal value. Therefore, when the measured load current is less than the lower limit threshold, it can be considered that the diameter of the through hole H exceeds the upper limit of the allowable error, and it is determined that the through hole H has a poor hole diameter.
[0048]
Then, when it is determined in step S6 that the end mill E has completed the revolving movement, the end mill E is returned to the axis of the through hole H in step S7, the rotation of the end mill E is stopped, and the end mill E is raised in step 8. To finish the burr removal step.
[0049]
As described above, according to the deburring method using the deburring device, the end mill E having a tapered shape with the operation control means 1 is inserted into the through hole H, and then the rotating end mill E is passed through. Since the burr B is cut and removed in the manner of moving along the opening edge of the hole H, even if the burr B is strong, it can be completely removed without leaving the burr B. Even if the crossing angle of the through hole H with respect to the hollow portion C is different, the burr B can be removed well.
[0050]
Further, when the end mill E is inserted into the through hole H, the end mill E and the burr B do not collide, so that the end mill E can be prevented from being damaged and the tool life can be extended. In addition, the insertion and withdrawal of the end mill E into the through-hole H can be fast-forwarded, thereby greatly reducing the work time for removing burrs.
[0051]
Further, in addition to the work for removing burrs, the pass / fail determination of the lower limit and the upper limit of the diameter is performed for the through-hole H formed with a predetermined tolerance, and such pass / fail determination is performed for all workpieces W. As a result, the quality of the workpiece W can be improved.
[0052]
Further, the operation control means 1 described in the above embodiment can be used in a process dedicated to burr removal in the production line of the workpiece W. However, the operation control means 1 includes a known tool changer, and performs drilling and burr removal. It is also possible to adopt a configuration in which work is performed continuously. Moreover, it is naturally possible to adopt a configuration in which a plurality of end mills corresponding to different hole diameters of the through holes H are selectively used.
[0053]
Further, in the operation control means 1 of the above embodiment, it is possible to determine the quality of the upper limit of the diameter of the through hole H by measuring the load currents of the X-axis servo motor 9 and the Y-axis servo motor 12 at the time of burr removal. Although it is possible, if the load current of the spindle motor 16 is measured as in the above embodiment, the configuration of the inspection means can be simplified.
[0054]
Furthermore, as a configuration other than the above embodiment, even if an end mill having a diameter that is clearly smaller than the diameter of the through hole is used, the burrs can be satisfactorily removed. In this case, for example, it is possible to inspect the diameter of the through hole by measuring the load currents of the X-axis servo motor 9 and the Y-axis servo motor 12 shown in FIG.
[Brief description of the drawings]
FIG. 1 is a vertical sectional view (a) and a horizontal sectional view (b) for explaining a main part of a deburring apparatus according to the present invention.
FIG. 2 is a flowchart illustrating a process of a burr removal method according to the present invention.
FIG. 3 is a schematic diagram illustrating the entire burr removing device.
FIG. 4 is a cross-sectional view illustrating conventional burr removal.
[Explanation of symbols]
1 Operation control means B Burr D Large diameter E End mill H Through hole W Workpiece

Claims (2)

When removing burrs generated at the end of the through hole in drilling a workpiece,
A motion control means for relatively moving the workpiece and the tool in three axial directions orthogonal to each other and rotationally driving the tool, and a diameter corresponding to the lower limit of the diameter tolerance of the through-hole as a tool to be mounted on the motion control means Using a tapered end mill with a large diameter portion and a small diameter toward the base end side,
After inserting the end mill to the position where the large diameter part passes the end of the through hole, remove the burr by moving at least one of the workpiece and the end mill so that the rotating end mill moves along the opening edge of the end of the through hole. And
When the end mill is inserted into the through hole, the load current that drives the end mill forward in the axial direction is measured, and if the measured load current exceeds the specified upper threshold, it is determined that the hole diameter is defective, and burrs are removed. A method for removing burrs, wherein a load current for rotationally driving the end mill is measured, and the hole diameter is judged to be defective when the measured load current is less than a predetermined lower threshold . A device for removing burrs generated at the end of a through hole in drilling a workpiece, an operation control means for moving the workpiece and the tool relatively in three axial directions orthogonal to each other, and rotating the tool, and an operation control towards Rutotomoni includes a tapered end mill which is smaller in diameter toward the large-diameter portion and to and proximal of the diameter corresponding to the lower limit of the diameter tolerances of the through hole of the tip end side as a tool attached to the means, the end mill to the work Measures the load current to drive forward and the load current to rotationally drive the end mill when removing burrs, and has an inspection means to determine the quality of the hole diameter based on these measurement results apparatus.

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