JP2017124408A - Stylus, method for detecting cast defect hole in mold, and mold manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform detection of a cast detect hole in a mold in a shorter time.SOLUTION: A stylus 1 includes a shaft 10, a contact piece 20, and a holding mechanism 30. The shaft 10 of the stylus 1 is formed by a hollow carbon fiber. The contact piece 20 is arranged on one side of the shaft 10 of the stylus 1. The contact piece 20 is made of a resin such as PEEK and has a disc shape having a diameter which is slightly smaller than a cushion pin hole of a mold. The holding mechanism 30 holds the contact piece 20 so that the contact piece 20 may move relative to the shaft 10 in an axial direction while applying an axial elastic force to an area between the shaft 10 and the contact piece 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stylus, a method for detecting a casting defect hole in a mold, and a method for manufacturing a mold.

  The press die used in the drawing process has, for example, an upper die in which many cushion pins are arranged and a lower die in which many cushion pin holes are arranged. Such a press die is formed by, for example, a full mold casting method.

Of the press dies, cushion pin holes are formed at the casting stage, but there is a casting defect in which extra objects adhere to the hole walls during casting, or the cushion pin holes themselves are blocked by extra objects. There are things to do.
Non-Patent Document 1 discloses a technique for detecting these casting defects using an NC processing machine and drilling a cushion pin hole having a casting defect.

  The detection of a casting defect hole in Non-Patent Document 1 uses a mechanism in which a probe and a stylus are attached to a rotation main shaft of an NC processing machine via a tool holder. The stylus includes, for example, a ceramic type shaft to increase shaft rigidity, and a disk-shaped contact attached to the tip of the shaft and having a slightly smaller diameter than the cushion pin hole. In the casting defect detection step, a stylus contact is sequentially inserted in the Z direction with respect to all cushion pin holes, and when the stylus receives a buffer, it is regarded as a cushion pin hole having a casting defect.

“Die Technology December 2015” pages 50-51 “(B-2) Press Cushion Pin Hole Confirmation and Processing System” (published by Nikkan Kogyo Shimbun)

  In the technique described in Non-Patent Document 1, when a stylus contact is inserted into a cushion pin hole having a casting defect and cannot be lowered any more, the stylus shaft bends. If this deflection exceeds a certain level, the shaft of the stylus bends or breaks, so when the stylus is inserted into the cushion pin hole, it is detected that it cannot be further lowered, and when it cannot be lowered, the descent drive is stopped. ing.

  However, there is a time lag between such detection and the stop operation, and the descending distance of the stylus due to the time lag depends on the descending speed of the stylus. That is, in the casting defect hole detection process, it is necessary to regulate the stylus lowering speed in consideration of bending and bending of the stylus shaft caused by the stylus lowering due to the time lag. One press die is provided with a large number of cushion pin holes, typically about 400 cushion pin holes. In the casting defect hole detection process, the casting defect holes are detected for all the holes. There is a need. Therefore, in the technique described in Non-Patent Document 1, it takes a long time to detect a casting defect hole.

  In view of the circumstances as described above, an object of the present invention is to provide a stylus capable of detecting a casting defect hole in a mold in a shorter time, a method for detecting a casting defect hole in a mold, and a method for manufacturing a mold. is there.

  In order to achieve the above object, a stylus according to an aspect of the present invention provides a shaft, a contact disposed on the tip end side of the shaft, and an axial elastic force between the shaft and the contact. A holding mechanism for holding the contactor movably in the axial direction with respect to the shaft.

In the stylus according to one aspect of the present invention, the contactor is held so as to be movable in the axial direction with respect to the shaft while being given an elastic force in the axial direction between the shafts. Even if the stylus is inserted, the shaft of the stylus does not bend and it is not necessary to regulate the descending speed of the stylus. That is, the descending speed of the stylus can be set to the maximum speed of the NC processing machine, and the casting defect hole of the mold can be detected in a shorter time.
A stylus according to an aspect of the present invention is a carbon fiber having a hollow shaft.

  If the lifting speed of the stylus increases, the probe may erroneously detect that the stylus is buffered by the inertial force due to its own weight, but the weight of the stylus shaft is reduced by using a hollow carbon fiber. Such false detection is eliminated. In addition, by using a hollow carbon fiber, bending is reduced, and false detection due to bending is eliminated. For example, the contact cannot be accurately inserted into the hole of the mold due to the bending of the shaft, and erroneous detection occurs, but this can be prevented.

According to one aspect of the present invention, there is provided a method for detecting a casting defect hole in a mold, wherein a mold having a large number of holes is placed on a table of an NC processing machine, a rotation main shaft of the NC processing machine, a shaft, A contact disposed at the tip, and a holding mechanism that holds the contact movably in the axial direction with respect to the shaft while applying an elastic force in the axial direction between the shaft and the contact. A stylus having a stylus is attached through a probe, a stylus contact is sequentially inserted into all the holes of the mold, and when it is detected that the stylus has been buffered by the probe, a hole of a casting defect is detected. I reckon.
Thereby, the detection of the casting defect hole of the mold can be performed in a shorter time.

  A mold manufacturing method according to one aspect of the present invention is such that a mold having a large number of holes is placed on a table of an NC processing machine, and is disposed on a rotation main shaft of the NC processing machine, at a shaft, and at the tip of the shaft. A stylus having a contactor, and a holding mechanism that holds the contactor movably in the axial direction with respect to the shaft while applying an elastic force in the axial direction between the shaft and the contactor. The stylus contacts are inserted sequentially through all the holes of the mold, and when the stylus is buffered by the probe, it is regarded as a hole having a casting defect, A drill is attached to the rotary spindle of the NC processing machine, and the holes regarded as the casting defects among the holes of the mold placed on the table of the NC processing machine are sequentially processed by the drill.

  As a result, it is possible to detect the casting defect hole of the mold in a shorter time, and further, by successively drilling the holes regarded as the casting defect by the NC processing machine, the mold without the casting defect hole can be obtained. It becomes possible to manufacture in a shorter time.

  According to the present invention, it is possible to detect a casting defect hole in a mold in a shorter time.

It is sectional drawing of the stylus which concerns on one Embodiment of this invention. It is a figure which shows the state in which the stylus of FIG. 1 was attached to NC processing machine. It is a flowchart which shows the manufacturing method of the casting_mold | template which concerns on one Embodiment of this invention. It is a figure which shows an example of a casting defect hole. It is a figure which shows the other example of a casting defect hole. It is a flowchart which shows the detection method of the casting defect hole of the casting_mold | template which concerns on one Embodiment of this invention. It is the schematic seen from the upper surface of the casting_mold | template which concerns on one Embodiment of this invention. It is the schematic seen from the upper surface of the casting_mold | template with the cushion pin hole considered as the casting defect hole. It is a flowchart which shows the determination method of the order (path | route) of the cushion pin hole considered as the casting defect hole.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a stylus according to an embodiment of the present invention.
As shown in FIG. 1, the stylus 1 includes a shaft 10, a contact 20, and a holding mechanism 30.

  The shaft 10 of the stylus 1 is typically made of a hollow carbon fiber. One end of the shaft 10 has a screw portion 11 for attaching the stylus 1 to a probe to be described later.

  A contact 20 is disposed on the other end side of the shaft 10 of the stylus 1. The contact 20 is made of a resin such as PEEK for weight reduction, and has a disk shape whose diameter is slightly smaller than the cushion pin hole of the mold.

  The holding mechanism 30 holds the contact 20 movably in the axial direction with respect to the shaft 10 while applying an elastic force in the axial direction between the shaft 10 and the contact 20. The holding mechanism 30 includes a slide pin 31, a stylus sliding bush 32, a coil spring 33, and a movable slice arm 34.

  The slide pin 31 has a contact 20 attached to one end, a coil spring 33 disposed on the outer periphery of the intermediate portion, and the other end accommodated in the shaft 10. The stylus sliding bush 32 is attached to the inner periphery near the other end of the shaft 10, and the other end of the slide pin 31 is slidably held in the stylus sliding bush 32. The coil spring 33 is disposed between the contact 20 and the other end of the shaft 10, and an intermediate portion of the slide pin 31 is coaxially disposed on the inner peripheral side thereof. The movable slice arm 34 surrounds the slide pin 31 and the coil spring 33, one end is attached to the contact 20, and the other end surrounds the outer periphery in the vicinity of the other end of the shaft 10 so as to be movable (not fixed). .

When the contact 20 is pressed against the shaft 10 (assuming that the contact 20 has moved to the right in FIG. 1), the slide pin 31 and the movable slice arm 34 are moved to the right with respect to the shaft 10 in the holding mechanism 30. The elastic force is applied to the contact 20 from the coil spring 33. When this pressing is released, the contact 20 returns to the original position by the elastic force from the coil spring 33 to the contact 20.
FIG. 2 is a view showing a state in which the stylus 1 is attached to the NC processing machine 40.
As shown in FIG. 2, the NC processing machine 40 includes a table 41, a rotation main shaft 42, and a control unit 43.
On the table 41, a mold 50 provided with a large number of cushion pin holes 51 vertically and horizontally is placed.

A probe 62 is attached to the rotation main shaft 42 via a tool holder 61, and the stylus 1 is attached to the probe 62 by screwing the screw portion 11 of the stylus 1 to the probe 62. The probe 62 detects the force applied to the stylus 1 and sends the detection result to the control unit 43.
The control unit 43 controls a mechanism for moving the rotary spindle 42 based on the setting, detection result, and the like to move up and down in the Z direction, a mechanism for moving the table 41, and the like.
FIG. 3 is a flowchart showing a method for manufacturing the mold 50 according to this embodiment.
First, the mold 50 is cast by a full mold casting method (step 301). Cushion pin holes 51 are formed at the casting stage.

  Next, in the state shown in FIG. 2, an extra object 52 adheres to the hole wall of the cushion pin hole 51 during casting (FIG. 4), or the cushion pin hole 51 itself is blocked by the extra object 52 (FIG. 2). The casting defect of the cushion pin hole 51 of 5) is detected (step 302).

After that, a drill (not shown) is attached to the rotary spindle 42 of the NC processing machine 40 via a tool holder 61, and the cushion pin hole 51 of the mold 50 that is still mounted on the table 41 of the NC processing machine 40. Cushion pin holes 51 regarded as casting defect holes are sequentially processed by a drill (step 303).
FIG. 6 is a flowchart showing the casting defect hole detection method in step 302 described above.

  First, the mold 50 is placed on the table 41 of the NC processing machine 40 (step 601), and the probe 62 and the stylus 1 are attached to the rotary spindle 42 of the NC processing machine 40 via the tool holder 61 (step 602, FIG. 2). reference).

  Next, the rotating spindle 42 is sequentially lowered with respect to all the cushion pin holes 51 of the mold 50 so that the contact 20 of the stylus 1 is inserted in the Z direction (step 603). As shown in FIG. 7, the mold 50 is provided with a large number of cushion pin holes 51 in the X direction and the Y direction. For example, as indicated by a dotted line, the contact 20 of the stylus 1 is inserted into each cushion pin hole 51 while moving the rotary spindle 42 or the table 41.

And as shown in FIG.4 and FIG.5, when the extra object 52 adheres to the hole wall of the cushion pin hole 51, or the cushion pin hole 51 itself is obstruct | occluded by the extra object 52, The contact 20 of the stylus 1 contacts the object 52. In that case, since it is detected that the stylus 1 has been buffered by the probe 62, in that case, it is regarded as a casting defect hole, and the position information of the cushion pin hole 51 is recorded in the control unit 43 (step 604). .
As described above, the position information of the cushion pin hole 51 having a casting defect among all the cushion pin holes 51 of the mold 50 is recorded in the control unit 43.

Thereafter, with the mold 50 placed on the table 41 of the NC machine 40, a drill is attached to the rotary spindle 42 of the NC machine 40 via the tool holder 61 and placed on the table 41 of the NC machine 40. Of the cushion pin hole 51 of the mold 50 thus formed, a casting defect hole is sequentially processed by a drill based on the positional information recorded in the control unit 43 (see step 303, FIG. 8, black is a casting defect hole).
The control unit 43 determines the order (path) for processing such a casting defect hole as follows, for example.

  Here, if the total of the path length (total path length) is minimum as the processing order (path) of the casting defect hole, it is preferable because the processing time can be shortened, but it takes a lot of time for computer processing to determine such a path. Is not practical. Therefore, in the present embodiment, the route is determined by the following method using the local search method. There are various methods as the local search method. In this embodiment, a plurality of methods of the local search method are used, and a predetermined number of change paths and distances of the change portions are obtained for each method. The route with the shortest distance of the changed portion is selected from among the routes.

  For example, as shown in FIG. 9, the control unit 43 first sets an appropriate initial path as a processing path for a casting defect hole (step 901). The initial route may be set as appropriate for each method.

The control unit 43 changes 30 routes by the 1.5-opt method for the set initial route (step 902), and obtains the distance of the changed portion (step 903). Similarly, the control unit 43. Thirty routes are changed by the 2-opt method (step 904), and the distance of the changed portion is obtained (step 905). Further, the control unit 43 changes 30 routes by the 3-opt method (step 906), and obtains the distance of the changed portion (step 907).
The control unit 43 selects the path with the shortest distance of the changed portion from the 90 pieces of data obtained as described above as the machining path for the casting defect hole (step 908).

  In this embodiment, since the machining path is determined by reducing the number to some extent, it can be performed by computer processing within a practical time. In addition, since various processing methods are mixed and the processing path is determined by utilizing the characteristics of these methods, the processing time can be shortened more effectively.

In addition, this invention is not limited to said embodiment, Various deformation | transformation is possible within the range of the technical thought, and the range of the deformation | transformation belongs to the technical scope of this invention.
For example, a hollow carbon fiber has been described as a typical example as the stylus shaft, but other materials such as a ceramic may be used.
Further, the elastic force is applied to the holding mechanism by the coil spring, but other elastic members may be used as a matter of course.
Furthermore, the present invention can be applied even if the mold is formed by a method other than the full mold casting method.

1 Stylus 10 Shaft 20 Contact 30 Holding Mechanism 40 NC Machine 41 Table 42 Rotating Spindle 50 Mold 51 Cushion Pin Hole 62 Probe

Claims (4)

The axis,
A contact disposed at the tip of the shaft;
A stylus comprising: a holding mechanism that holds the contactor movably in the axial direction with respect to the shaft while applying an elastic force in the axial direction between the shaft and the contactor. The stylus according to claim 1,
The shaft is a stylus made of hollow carbon fiber. Place the mold with many holes on the table of NC machine,
While applying an elastic force in the axial direction between the shaft, the contact disposed on the tip end side of the shaft, and the shaft and the contact to the rotation main shaft of the NC processing machine, A stylus having a holding mechanism for holding the contactor so as to be movable in the axial direction through a probe;
A method for detecting a casting defect hole in a mold, wherein a stylus contact is sequentially inserted into all the holes in the mold, and a hole having a casting defect is detected when the probe detects that the stylus has received a buffer. Place the mold with many holes on the table of NC machine,
While applying an elastic force in the axial direction between the shaft, the contact disposed at the tip of the shaft, and the shaft and the contact to the rotation main shaft of the NC processing machine, A stylus having a holding mechanism for holding the contactor so as to be movable in the axial direction is attached via a probe;
A stylus contact is sequentially inserted into all the holes of the mold, and when it is detected by the probe that the stylus is buffered, it is regarded as a hole having a casting defect,
A drill is attached to the rotary spindle of the NC machine,
A method for manufacturing a mold, wherein holes which are considered to have the casting defect among holes of the mold placed on the table of the NC processing machine are sequentially processed by the drill.

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