JP6719908B2 - Stylus, mold casting defect hole detection method and mold manufacturing method - Google Patents

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

Cushion pin holes are formed in the lower die of the press die at the casting stage, but extraneous substances adhere to the hole wall during casting, or casting defects occur when the cushion pin holes themselves are blocked by extraneous substances. There is something to do.
Non-Patent Document 1 discloses a technique of detecting these casting defects using an NC processing machine and drilling a cushion pin hole having a casting defect.

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

"Mold technology December 2015 issue" pp. 50-51 "(B-2) Press type cushion pin hole confirmation and processing system" (Published by Nikkan Kogyo Shimbun)

In the technique described in Non-Patent Document 1, when the stylus contactor is inserted into a cushion pin hole having a casting defect and cannot move further down, the stylus shaft bends. If this deflection exceeds a certain level, the stylus shaft will bend or break, so insert the stylus into the cushion pin hole to detect that the stylus cannot be lowered any more, and when it is detected that the stylus 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 step of detecting the casting defect hole, it is necessary to regulate the descending speed of the stylus in consideration of the bending and breaking of the stylus shaft due to the descending of the stylus due to the time lag. Such one press die is provided with a large number of cushion pin holes, typically about 400 cushion pin holes, and in the step of detecting casting defect holes, casting defect holes are detected for all of these holes. There is a need. Therefore, in the technique described in Non-Patent Document 1, it takes a lot of time to detect a casting defect hole.

In view of the above circumstances, 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 contactor disposed on the tip side of the shaft, and an elastic force in the axial direction between the shaft and the contactor. And a holding mechanism for holding the contactor so as to be movable in the axial direction with respect to the shaft.

In the stylus according to one aspect of the present invention, the contact is held so as to be movable in the axial direction with respect to the shaft while being provided with the elastic force in the axial direction between the contact and the shaft. 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, it is possible to set the descending speed of the stylus to the maximum speed of the NC processing machine, and it is possible to detect the casting defect hole of the mold in a shorter time.
A stylus according to an aspect of the present invention has a hollow shaft made of carbon fiber.

If the stylus rises and falls faster, the probe may erroneously detect that the stylus has been buffered by the inertial force of the shaft, but the stylus shaft is made of hollow carbon fiber to reduce weight. Such false detection is eliminated. In addition, by using a hollow carbon fiber, the bending is reduced, and erroneous detection due to the bending is eliminated. For example, due to the bending of the shaft, the contact cannot be accurately inserted into the hole of the mold, and erroneous detection occurs.

A method for detecting a casting defect hole of a mold according to an aspect of the present invention is to place a mold having a large number of holes on a table of an NC processing machine, and to a rotating main shaft of the NC processing machine, a shaft and a shaft of the shaft. A contactor disposed at the tip, and a holding mechanism that applies an elastic force in the axial direction between the shaft and the contactor while holding the contactor axially movable with respect to the shaft. The stylus having a, attached through the probe, through the contact of the stylus sequentially through all the holes of the mold, if the probe detects that the stylus has been buffered and a hole of a casting defect. I reckon.
This makes it possible to detect the casting defect hole in the mold in a shorter time.

According to one embodiment of the present invention, there is provided a method for manufacturing a mold, in which a mold having a large number of holes is placed on a table of an NC processing machine, the rotary main shaft of the NC processing machine is provided with a shaft and a tip of the shaft. A stylus having a contactor and a holding mechanism that holds the contactor axially movable with respect to the shaft while applying an elastic force in the axial direction between the shaft and the contactor. , Attached via a probe, sequentially insert a stylus contactor through all the holes of the mold, if the stylus is detected to be buffered by the probe, it is regarded as a hole with a casting defect, A drill is attached to the rotary spindle of the NC processing machine, and among the holes of the mold placed on the table of the NC processing machine, the holes regarded as the casting defects are sequentially processed by the drill.

This makes it possible to detect casting defect holes in the mold in a shorter time, and by successively drilling holes that are considered casting defects by the NC processing machine, a mold without casting defect holes 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 with which the stylus of FIG. 1 was attached to the NC processing machine. It is a flow figure showing the manufacturing method of the mold concerning one embodiment of the present invention. It is a figure showing an example of a casting defect hole. It is a figure which shows the other example of a casting defect hole. It is a flow figure showing a detecting method of a casting defective hole of a mold concerning one embodiment of the present invention. It is the schematic seen from the upper surface of the mold concerning one embodiment of the present invention. It is the schematic seen from the upper surface of the mold with the cushion pin hole considered as a casting defect hole. It is a flowchart which shows the determination method of the processing order (path|route) of the cushion pin hole considered as a casting defect hole.

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

The shaft 10 of the stylus 1 is typically made of hollow carbon fiber. A screw portion 11 for attaching the stylus 1 to a probe described later is provided at one end of the shaft 10.

A contact 20 is arranged on the other end of the shaft 10 of the stylus 1. The contactor 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 contactor 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 contactor 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 contactor 20 is attached to one end of the slide pin 31, the coil spring 33 is arranged on the outer periphery of the intermediate portion, and the other end is accommodated in the shaft 10. The stylus sliding bush 32 is attached to the inner circumference 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 arranged between the contact 20 and the other end of the shaft 10, and an intermediate portion of the slide pin 31 is coaxially arranged on the inner peripheral side thereof. The movable slice arm 34 surrounds the slide pin 31 and the coil spring 33, and has one end attached to the contactor 20 and the other end movably (without being fixed) around the outer periphery near the other end of the shaft 10. ..

When the contact 20 is pressed against the shaft 10 (when the contact 20 moves to the right in FIG. 1), the slide pin 31 and the movable slice arm 34 in the holding mechanism 30 move to the right with respect to the shaft 10. The coil spring 33 applies elastic force to the contactor 20. When this pressing force is released, the contactor 20 returns to its original position due to the elastic force from the coil spring 33 to the contactor 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 rotary spindle 42, and a control unit 43.
On the table 41, a mold 50 having a large number of vertical and horizontal cushion pin holes 51 is placed.

A probe 62 is attached to the rotary spindle 42 via a tool holder 61, and the stylus 1 is attached to the probe 62 by screwing the threaded portion 11 of the stylus 1 onto 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 that moves the rotating spindle 42 based on the settings and detection results and moves up and down in the Z direction, a mechanism that moves the table 41, and the like.
FIG. 3 is a flow chart showing the method of manufacturing the mold 50 according to this embodiment.
First, the mold 50 is cast by the full mold casting method (step 301). Cushion pin holes 51 are formed during this casting stage.

Next, in the state shown in FIG. 2, an extra substance 52 is attached to the hole wall of the cushion pin hole 51 during casting (FIG. 4), or the cushion pin hole 51 itself is closed by the extra substance 52 (FIG. The casting defect of the cushion pin hole 51 referred to as 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 the tool holder 61, and among the cushion pin holes 51 of the mold 50 still mounted on the table 41 of the NC processing machine 40. The cushion pin holes 51 regarded as casting defect holes are sequentially drilled (step 303).
FIG. 6 is a flowchart showing the method for detecting a casting defect hole 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 contactor 20 of the stylus 1 is inserted in the Z direction by successively lowering the rotary spindle 42 with respect to all the cushion pin holes 51 of the mold 50 (step 603). As shown in FIG. 7, the mold 50 is provided with a large number of cushion pin holes 51 in the X and Y directions. For example, as shown by the 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.

Then, as shown in FIGS. 4 and 5, when the extra material 52 is attached to the hole wall of the cushion pin hole 51 or the cushion pin hole 51 itself is blocked by the extra material 52, The contact 20 of the stylus 1 contacts the object 52. In that case, since the probe 62 detects that the stylus 1 has been buffered, in this 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 holes 51 having a casting defect among all the cushion pin holes 51 of the mold 50 is recorded in the control unit 43.

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

Here, if the total of the path lengths (total path length) is the minimum as the processing order (paths) of the casting defect holes, the processing time can be shortened, which is preferable, but a huge amount of time is required for computer processing for determining such a path. May be required and is not practical. Therefore, in this embodiment, the route is determined by the following method using the local search method. Although there are various methods as the local search method, in the present embodiment, a plurality of methods among the local search methods are used to obtain a predetermined number of changed paths and distances of the changed portions for each method, and The route with the shortest changed distance is selected from the above.

For example, as shown in FIG. 9, the control unit 43 first sets an appropriate initial route as a route for processing a casting defect hole (step 901). The initial route may be set appropriately 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 controls the. 30 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 route having the shortest distance of the changed portion among the 90 pieces of data obtained as described above as the route for processing the casting defect hole (step 908).

In this embodiment, since the processing paths are determined by narrowing down the number to some extent, the processing can be performed by computer processing within a practical time. Moreover, since various methods are mixed and the processing route is determined by utilizing the characteristics of these methods, the processing time can be shortened more effectively.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the technical idea thereof, and the scope of the modifications also belongs to the technical scope of the present invention.
For example, a hollow carbon fiber has been described as a typical example of the stylus shaft, but other materials such as ceric may be used as a matter of course.
Further, although the elastic force is applied to the holding mechanism by the coil spring, other elastic members may be used as a matter of course.
Furthermore, the present invention can be applied even if the mold is molded by a method other than the full mold casting method.

1 Stylus 10 Shaft 20 Contact 30 Holding mechanism 40 NC processing machine 41 Table 42 Spindle 50 Mold 51 Cushion pin hole 62 Probe

Claims (4)

A stylus used to detect casting defect holes in a mold,
Axis and
A contact arranged on the tip side of the shaft,
The contactor is attached to one end, the other end is housed in the shaft, and a slide pin having a coil spring is arranged on the outer periphery of an intermediate portion, and the coil is provided between the tip of the shaft and the contactor. A holding mechanism that applies an elastic force in the axial direction between the shaft and the contact by disposing a spring, and holds the contact with respect to the shaft so as to be movable in the axial direction. stylus. The stylus according to claim 1,
The shaft is a stylus made of hollow carbon fiber. Place a mold with many holes on the table of NC processing machine,
While applying an elastic force in the axial direction between the shaft, a contactor disposed on the tip side of the shaft, and the shaft and the contactor to the rotating 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 via a probe,
A method for detecting a casting defect hole in a mold, in which a stylus contactor is sequentially inserted through all the holes of the mold, and when the stylus is detected to be buffered by the probe, it is regarded as a hole having a casting defect. Place a mold with many holes on the table of NC processing machine,
With respect to the rotating main shaft of the NC processing machine, while applying an axial elastic force between the shaft, a contactor arranged at the tip of the shaft, and the shaft and the contactor, A stylus having a holding mechanism that holds the contactor movably in the axial direction, is attached via a probe,
Stylus contacts are sequentially inserted through all the holes of the mold, and if it is detected that the stylus is buffered by the probe, it is regarded as a hole having a casting defect,
Attach a drill to the rotating spindle of the NC processing machine,
A method for manufacturing a mold, in which holes that are considered to have the casting defect among the holes of the mold placed on the table of the NC processing machine are sequentially processed by the drill.

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