JP3233897B2 - Safety equipment for metal injection molding machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a metal opening / closing part in a metal injection molding machine for injection molding a pure metal such as aluminum, magnesium, zinc, tin and the like and an alloy material thereof.

[0002]

2. Description of the Related Art The construction and operation of a general injection molding machine for molding metal materials will be described with reference to FIG. First, at room temperature or preheated pure metal or metal alloy
10 mm grains, cut pieces or crushed pieces (hereinafter referred to as metal raw material 5
Three. ) Is fed into a material hopper 3 installed above the material supply hole 2 at the rear of the heating cylinder 1. Metal raw material 5
The screw 3 falls into a spiral groove on the surface of the screw 4 inserted into the heating cylinder 1 so as to rotate and move forward and backward, and is conveyed to the distal end side of the heating cylinder 1 while being kneaded by the rotation of the screw 4. Heated by a heater 5 mounted on the outer surface of the heating cylinder, the molten or semi-melted state is stored in the distal end portion 6 of the heating cylinder 1. (Hereinafter, this molten or semi-molten high-temperature metal raw material 53 is referred to as a molten metal material.) As the molten metal material is stored in the distal end portion 6 of the heating cylinder 1, the pressure or the hydraulic cylinder of the molten metal material is increased. By the forcible retreat operation 9, the screw 4 retreats. The above is the measuring step. The rotation of the screw 4 and the forced retreat operation described above are performed by the rotation motor 8 in the screw driving device 50.
And a hydraulic cylinder 9. Next, screw 4
Is moved forward, and the molten metal material 53 stored in the distal end portion 6 of the heating cylinder 1 is attached between the fixed platen 11 and the movable platen 12 of the mold opening / closing portion 51 from the distal end nozzle 10 of the heating cylinder 1, Is injected into the space inside the mold 52 to which the tightening force is applied.
This is the injection process. (Hereinafter, the fixed-side mold 16 attached to the fixed board 11 and the movable-side mold 17 attached to the movable board 12 are collectively referred to as a mold 52.) The above-described forward movement of the screw 4 is performed by the screw. It is driven by the hydraulic cylinder 9 in the driving device 50. When the molten metal material injected into the space in the mold 52, that is, the sprue hole 14 or the runner groove 15 that connects the cavity 13 and the nozzle 10 with the cavity 13 having a predetermined molded product shape, is cooled and solidified, it is not shown. The movable mold 17 is retracted by the mold opening / closing mechanism, the mold 52 is opened, and a molded product, a runner, and a sprue (hereinafter, referred to as a molded product) adhered to the movable mold 17 protrude (not shown). It is projected from the mold surface by the mechanism. After the protruding molded article or the like falls under its own weight or is taken out manually or by an unloader, the movable mold 17 is advanced by the mold opening / closing mechanism to close the mold 52, and the next injection step starts. .

In injection molding of a metal material, a mold 52 is used.
In order to facilitate removal of the molded article from the mold, the mold release agent is sprayed onto the mold surface that comes into contact with the molded article or the like by a manual operation or a sprayer every molding cycle. In addition, so-called insert molding, in which small parts made of different materials made in advance are mounted on a metal surface and the periphery thereof is formed of a molten metal material, is also often performed. The flow of the injection molding process including these will be described with reference to FIG. 7. A release agent is sprayed on the surface of the opened mold 52 (first step 100), and insert parts are mounted (second step 101). The mold 52 is closed (third step 102), an injection step is performed (fourth step 103), a weighing step is performed in parallel with cooling (fifth step 104), and the mold 52 is opened (fifth step 104). 6 steps 10
5) The molded product or the like is projected (seventh step 106), and after the molded product or the like is taken out (eighth step 107), the next release agent spraying is performed (first step 100). A major feature of the injection molding method is that a series of molding cycles are repeated in a short period of time to efficiently produce a molded product of a metal material.

[0004]

The safety device of a conventional metal injection molding machine has the following problems because it is configured as described above. That is, usually, when the injection molding of the metal material enters the mass production stage, spraying of the release agent,
Automated equipment such as a release agent sprayer and molded product removal machine is used for operations such as removal of molded products and insertion of parts, and a series of operations including injection molding machines are automatically repeated as a molding cycle. It is. Therefore, since there is no need for human intervention in the injection molding process, the operation and trouble of machines and devices do not threaten the physical safety of workers.
However, in the preparatory stage of injection molding, that is, molding of a prototype, molding test of a new mold, molding test for determining molding conditions, etc., it is difficult to completely automate the molding operation, and partially manual operation is required. Is required. And
In the course of these molding operations, it is necessary for the operator to put all or part of the body between the opened molds 52. Therefore, as shown in FIGS. 8 and 9, the safety doors 18 must be installed on both sides of the mold opening / closing section 51, that is, on the operation side and the non-operation side, and the safety doors 18 on both sides must be closed. An electrical, hydraulic or mechanical safety device is provided so that the mold 52 cannot be closed, so that an operator can be injured when the whole or a part of the body is sandwiched between the molds 52. I try not to be. The limit switch 39 in FIG. 1 is an example of an electrical safety device that detects that the safety door 18 is closed. However, in the injection molding of the metal material, if the molten metal material is stored for a long time in the state of being stored in the distal end portion 6 of the heating cylinder 1, the molten metal material is moved to the distal end of the nozzle 10 by the residual internal pressure or the expansion pressure of the contained gas component. May erupt from Further, at this time, the ejected molten metal material may pass through the sprue hole 14 of the mold 52 and scatter to the surface of the movable mold 17 in an opened state. For this reason, there is a risk that a worker who works while putting all or a part of his body between the opened molds may suffer damage such as burns. As a method of preventing this danger, as shown in FIG. 8, it is conceivable to place a shielding plate 19 in front of a sprue hole 14 which is an outflow hole of the fixed mold 16. For example, as shown in FIGS. 8 and 9, every time work is performed between the molds, a method of suspending the shielding plate 19 on the member 19 </ b> A passed between the upper tie rods 20 and 20 ′,
Have been done at the molding site. However, the shielding plate 19
Since the mold 52 cannot be closed unless it is removed, suspending and removing the shielding plate 19 itself is a complicated operation. In addition, if the molding time is prolonged by this operation or the mold 52 is closed by forgetting to remove the shielding plate 19, the mold 52
There is also a risk of damage. On the other hand, the molten metal material ejected from the tip of the nozzle 10
4 and rarely scatters to the surface of the movable mold 17. Therefore, the shielding plate 19 that has been prepared is
It was hardly used in practice, and could not prevent disasters caused by the ejection of molten metal material.

SUMMARY OF THE INVENTION An object of the present invention is to provide a safety device for a metal injection molding machine which solves the above-mentioned conventional problems, and in particular, automatically and quickly mounts and removes a shielding plate between dies. The present invention aims to provide a safety device for a metal injection molding machine capable of preventing a disaster caused by ejection of a molten metal material and preventing a risk of damaging a mold due to forgetting to remove a shielding plate.

[0006]

A safety device for a metal injection molding machine according to the present invention is provided with a shield plate which is rotatably provided on a fixed plate on which a fixed side die of a die is mounted, and in a state where the die is opened. The shielding plate is configured to be positioned corresponding to an outflow hole through which the molten metal material is exposed when exposed to the surface of the fixed mold,
Further, in a state where the shielding plate is located between the fixed mold and the movable mold of the mold, the closing operation of the mold is prevented,
And, when the mold closing operation is forcibly performed, an alarm is issued.Furthermore, when the shielding plate does not correspond to the outflow hole, it is provided on the side of the mold so as to be openable and closable. The automatic opening of the safety door is prevented, and an alarm is issued when the safety door is manually opened.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a safety device for a metal injection molding machine according to the present invention will be described below with reference to the drawings. The same or equivalent parts as those in the conventional example will be described with the same reference numerals. The safety device 200 shown in FIG. 1 includes a base plate 24 mounted on the die mounting surface of the fixed platen 11 at a position which does not interfere with the fixed die 16, and the base plate 24.
The lever 26 pivots around a pin 25 fixed to the center and rotates in parallel with the mold mounting surface, the shielding plate 21 attached to one end of the lever 26, and the head side via another pin 27. A pneumatic cylinder 30 attached to the base plate 24 and having a distal end of a piston rod 28 connected to the other end of the lever 26 via a pin 29, a limit switch 31 which comes into contact with the lever 26 when the safety device is operated, and a safety switch A limit switch 32 which comes into contact with the lever 26 when the device 200 is released.

The lever 26 comprises an upper lever 36, a lower lever 37, and a connecting bolt 38. By adjusting the connecting length between the upper lever 36 and the lower lever 37, the shielding plate 21 and the fixed mold 16 are fixed. It is configured such that the gap with the surface can be adjusted. The shielding plate 21 has a bottom plate 22 having a plane perpendicular to the sprue hole 14 as shown in FIG.
And a side plate 34 which borders the periphery of the bottom plate 22. The side plate 34 is removed from a part of the side plate 34, that is, a part of the drop port 35 located at the lowest position in the operation state of the safety device.
When the safety device 200 is released, that is, when the shield plate 21 is at the lowest position as shown in FIG. 3 and the piston rod 28 of the cylinder 30 is retracted, the fixed mold 16 and the movable mold 17 are Can be closed without interfering with the lever 26 and the shielding plate 21. Safety device 2
00, that is, when the shielding plate 21 is at the uppermost position as shown in FIG. 2 and the piston rod 28 of the cylinder 30 is projected, the shielding plate 21 is
Since it corresponds to the front of the sprue hole 14, which is the outflow hole of No. 6, it is possible to shield the molten metal material ejected. However, in this state, the movable mold 17 is
The mold 52 cannot be closed because it interferes with the shielding plate 21, and a warning device (not shown) issues a warning when the closing operation is forcibly performed. As shown in FIG. 3, when the shielding plate 21 does not correspond to the sprue hole 14, the automatic opening of the safety door 18 provided on the side of the mold 52 so as to be openable and closable is prevented. When the door 18 is manually opened, the sensor is detected by a sensor such as the limit switch 39 in FIG. 1 and an alarm is issued.

Next, the operation of using the safety device 200 will be described. For example, in a molding operation of a prototype or the like, when taking out a molded product or the like and spraying a release agent by an automatic machine, and performing an operation of attaching an insert part of another material to the movable side mold 17 manually, FIG. The operation of the injection molding machine is programmed in advance so that the safety device is activated after the release agent is sprayed in the process diagram of FIG. 7 and the safety device is released after the safety door 18 is closed. The mold 21 is opened by opening the mold, the molded product and the like are protruded, the molded product and the like are taken out by the take-out machine, the release agent is sprayed on the mold surface by the sprayer, and the safety device is operated to activate the safety device shown in FIG. After the shielding plate 21 is positioned in front of the sprue hole 14 of the fixed mold 16 as shown in FIG.
Is manually opened, and the insert part is mounted on the movable mold 17.

[0010] At that time, the work takes time, or the mold surface is noticed to be abnormal, and cleaning is performed, etc., so that an unexpectedly long time elapses, during which the molten metal material ejected from the tip of the nozzle 10 is fixed. When a situation occurs in which the fuel flows through the sprue hole 14 of the side mold 16 and is ejected in the direction of the movable mold 17,
The ejected molten metal material collides with the bottom plate 22 of the shielding plate 21 and is prevented from being scattered to the side by the side plate 34, falls down from the drop port 35, and is collected in a receiving box (not shown) installed below. . Therefore, the safety of the worker working between the dies is ensured.

When the worker closes the safety door 18 after mounting the insert part on the movable mold 17, the sensor is detected by a sensor such as the limit switch 39 in FIG. 1 and transmitted to the control device of the injection molding machine. Then, the cylinder 30 is operated to move the shielding plate 21 to the release position (a position not corresponding to the sprue hole 14 as shown in FIG. 3), the safety device is released, and the steps after the mold closing are continued. As described above, the safety device 20 is used as part of the molding cycle by the control program.
If the safety device 200 can be activated and released by switching a manual switch in addition to the operation of the mold 0, even if work between the molds 52 becomes necessary in an unexpected process. By operating the safety device 200, the safety of the worker can be ensured.

Next, another embodiment of the present invention will be described with reference to FIG. This corresponds to the upper lever 3 of the lever 26 for mounting the shielding plate 21 in the embodiment shown in FIGS.
Instead of 6, a bellows tube 33 having rigidity such that it is not deformed by a known normal operation and capable of being deformed by human power is provided. With the bellows tube 33, the position of the shielding plate 21 can be adjusted to exactly correspond to the sprue hole 14 even when the mold is replaced with a mold having a different size from the last time. However, in this case, after adjusting the position of the shielding plate 21, it is necessary to sufficiently confirm that it does not interfere with the movable mold 17 in the mold closing step.

In the above embodiment, the fixed mold 16
Although only the sprue hole 14 is considered as the outflow hole of the molten metal material exposed on the surface of the above, even if there are a plurality of outflow holes of the molten metal material such as a hot runner mold, it is possible to cope by increasing the size of the shielding plate 21. can do. In the above-described embodiment, the pneumatic cylinder 30 is used for driving the safety device.
However, it is also possible to use a hydraulic cylinder such as a hydraulic pressure, or use an electric driving means. Further, in the above-described embodiment, the limit switches 31 and 32 are used to detect the position of the shielding plate 21, but a non-contact type sensor such as a photoelectric tube may be used instead. Further, the bottom plate 22 of the shielding plate 21 may be formed in a shape in which the central portion is depressed with respect to the sprue hole 14, and the side plate 34 may be omitted. Further, in the above-described embodiment, the base plate 24,
The safety device main body such as the pneumatic cylinder 30 is installed on the mold mounting surface on the side opposite to the operation side of the fixed platen 11. However, the die mounting surface of the fixed platen 11 may be used depending on circumstances such as a die, an unloader, and a sprayer. It may be installed in a place such as the upper surface other than the above. One more or two
It may be attached to a tie rod 20.

As another embodiment different from the above, a shielding plate is attached to a molded product take-out machine used in an injection molding machine.
It is possible to add functions to insert and remove,
Since the structure and operation of the unloader are complicated, the reliability of the unloader and the safety device is reduced. Further, since the molding operation is often performed in a state where the unloader is not used or in a state where the operation of the unloader is insufficiently adjusted, the above-described embodiment is the most preferable form.

[0015]

The safety device for a metal injection molding machine according to the present invention is constructed as described above, so that the following effects can be obtained. In other words, the molten metal material ejected from the fixed mold is shielded by a shield plate to prevent disasters, and the shield plate is moved automatically and quickly to reduce the burden on the operator. Damage to the mold due to forgetting can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a safety device for a metal injection molding machine according to the present invention, showing a state in which a safety device for a mold opening / closing section of the injection molding machine is operated.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a configuration diagram showing a state in which the safety device of FIG. 2 is released.

FIG. 4 is a configuration diagram showing details of a shielding plate in a cross-sectional view taken along line CC of FIG. 1;

FIG. 5 is a cross-sectional view showing another embodiment of the present invention.

FIG. 6 is a front view showing a main part of a conventional general metal injection molding machine.

FIG. 7 is a process diagram of a conventional general metal injection molding.

FIG. 8 is a configuration diagram of a mold opening / closing unit showing a conventional metal injection method as viewed from an operation side.

FIG. 9 is a sectional view taken along line DD of FIG. 8;

[Explanation of symbols]

 Reference Signs List 50 screw driving device 51 mold opening / closing section 52 mold 53 metal raw material 1 heating cylinder 2 material supply hole 3 material hopper 4 screw 5 heater 6 heating cylinder tip 8 rotation motor 9 hydraulic cylinder 10 nozzle 11 fixed plate 12 movable plate 13 Cavity 14 Sprue hole (outflow hole) 15 Runner groove 16 Fixed mold 17 Movable mold 18 Safety door 19 Shielding plate 20, 20 ′ Tie rod 21 Shielding plate 22 Bottom plate 23 Drive unit 24 Base plate 25, 27, 29 Pin 26 Lever 28 Piston rod 30 Cylinder 31, 32, 39 Limit switch 33 Bellows tube 34 Side plate 35 Drop port 36 Upper lever 37 Lower lever 38 Connecting bolt

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-112011 (JP, A) JP-A-5-18821 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22D 17/26 B29C 45/84

Claims (3)

(57) [Claims] A shield plate (21) is rotatably provided on a fixed platen (11) on which a fixed mold (16) of a mold (52) is mounted, and said mold (52) is provided.
In the open state, the shielding plate (21) is fixed to the fixed mold (16).
A safety device for a metal injection molding machine, wherein the safety device is located corresponding to an outflow hole (14) that is exposed to the surface of a metal material and through which a molten metal material flows out. 2. The mold for fixing the shielding plate (21) on a fixed side of a mold (52).
(16) and the movable mold (17)
The safety device for a metal injection molding machine according to claim 1, wherein the closing operation of the mold (52) is prevented, and an alarm is issued when the closing operation of the mold (52) is forcibly performed. 3. When the shielding plate (21) does not correspond to the outflow hole (14), the safety door (18) provided on the side of the mold (52) can be automatically opened and closed. 3. The safety device for a metal injection molding machine according to claim 1, wherein an alarm is issued when the safety door (18) is manually opened.