JPH0363455B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an injection molding machine such as a die casting machine for casting metal, and particularly to an injection molding machine with an improved riser device.

[Conventional technology] In injection molding machines such as die casting machines,
The molten metal is filled into the cavity from the casting device through the biscuit portion and runner portion of the mold device, where it solidifies into a molded product.

By the way, if this molded product is a pressure-resistant product that does not like blowholes inside, in order to crush and eliminate the blowholes, press the cavity directly with a push rod after filling with molten metal. Either a hot water effect is given, or the injection plastic tip is made of a double structure of an outer tip and an inner tip to give a hot water effect.

[Problems to be Solved by the Invention] When pushing the cavity directly with a push rod, if the push rod is pressed early after the filling of the molten metal is completed, the molten metal in the cavity is not solidified yet. , the injection plunger is pushed back by the volume pushed in by the push rod, making it impossible to provide the feeder effect. On the other hand, if you push the cavity directly and push it too late, the molten metal has solidified and you will not be able to push the push rod in even if you apply considerable force, or even if you can push it in, it will not form. This causes cracks in the product and produces defective products.

In addition, when directly pressing the cavity part, there are two conditions: when the mold is relatively cold at the start of casting, and when the mold is at a relatively high temperature after continuous casting a certain number of times. In this case, the timing at which the push rod starts moving forward must be changed. For this reason, in an injection molding machine in which the cavity is directly pressed with a push rod, the operation is extremely complicated, and it is not easy to stably produce a good molded product.

Furthermore, in the case of an injection molding machine in which the cavity part is directly pressed by a push rod, the product part is pushed by the push rod, so that the resulting product has to be subjected to more machining than necessary.

For injection molding machines in which the plunger tip has a dual structure of an inner tip and an outer tip to give a feeder effect, it is recommended that the inner tip be pushed out early after filling the molten metal to ensure that the molten metal solidifies properly. As a result, the outer tip retreats by the amount that the inner tip moves forward, making it impossible to provide a feeder effect. Furthermore, since the inner chip slides on the inner periphery of the outer chip, the plastic chip must be sufficiently cooled to prevent seizure. Therefore, in order to secure a cooling section, the diameter of the plunger tip becomes larger than necessary, and the diameter of the injection cylinder also has to be made correspondingly larger, resulting in an unnecessarily high cost for the device configuration.

[Means for Solving the Problems] The injection molding machine of the present invention includes a fixed mold attached to a fixed plate, and a mold attached to a movable plate, which is movable in directions toward and away from the fixed mold. A movable mold is provided, and a cavity and a molten metal receiving biscuit part communicating with the cavity via a runner part are formed on the mating surfaces of the fixed mold and the movable mold. a mold device, and a casting device for supplying molten metal that is detachable from the biscuit portion;
In the injection molding machine, the injection molding machine includes a valve device for cutting off communication between the runner portion and the biscuit portion, a feeder rod that can project into the runner portion, and a cylinder device for advancing and retracting the feeder rod, respectively. It is characterized by being provided in a mold device.

[Function] In the injection molding machine of the present invention, after filling the cavity with molten metal, the communication between the runner part and the biscuit part is cut off by the valve device, and then the feeder rod is pushed into the runner part. Can give riser effect. In this case, since the communication between the runner part and the biscuit part is cut off, the molten metal in the runner part does not escape to the biscuit side, and a sufficient pouring effect can be imparted to the cavity.

[Examples] Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an injection molding machine according to an embodiment of the present invention. This injection molding machine mainly consists of a mold device 10 and a casting device 12.
The mold device 10 includes a fixed mold 16 held on a fixed platen 14 and a movable mold 20 held on a movable platen 18.
It is equipped with A column 24 is connected to the fixed platen 14 via a nut 22, and the movable platen 18 is movable in directions toward and away from the fixed platen 14 along the column 24 by a toggle mechanism (not shown). has been done.

A cavity 26, a runner part 28, and a biscuit part 30 are provided on the mating surfaces of the fixed mold 16 and the movable mold 20.
is provided.

The fixed mold 16 is provided with cylinder holes 32 and 34, in which pistons 36 and 38 are installed, respectively. The pistons 36 and 38 have feeder rods 4.
0 and the rear ends of the closing rod 42 are connected to each other, and the riser rod 40 and the closing rod 42 can each protrude into the runner section 28. Closure rod 42
is capable of blocking the communication port of the runner portion 28 to the biscuit portion 30 when it protrudes. The closing rod 42, the cylinder hole 34, and the piston 38 constitute a valve device.

The mold device 10 is installed on a machine base 44, and the machine base 44 is connected to a ground base 46.
It is installed so as to straddle a pit 48 recessed in the area.

The casting device 12 is installed within the pit 48. The casting device 12 has an injection cylinder 50, a block 52, and a sleeve 54 installed in this order from the lower stage. injection cylinder 50
is supported via a pin 58 on a seat 56 fixed to the bottom surface of the pit 48, and its upper end is tiltable about the pin 58. A piston 60 is installed within the injection cylinder 50, and a rod 62 that extends upward is connected to the piston 60.

The block 52 is provided with a cylinder hole 64 extending in the vertical direction, and a docking ram 66 is inserted into the cylinder hole 64, and the lower end of the docking ram 66 is fixed to a flange 68 formed on the upper surface of the injection cylinder 50. ing.

The sleeve 54 is connected to the upper side of the block 52 via a connecting member 68, and its upper end can be inserted into the lower end of the biscuit portion 30 of the mold device 10. A plunger tip 70 is slidably installed inside the sleeve 54, and a plunger 72 that holds the plunger tip 70 is provided.
The lower end of the rod 62 is connected to the upper end of the rod 62 via a coupling 73.

A tilting cylinder 74 is pivotably supported on the side wall of the pit 48 via a seat 76 and a pin 78, and a rod 82 connected to a piston 80 of the tilting cylinder 74 has its tip end. Joint 84
It is pivotally connected to the side surface of the flange 68 of the injection cylinder 50 via a pin 86.

The operation of the injection molding machine constructed in this manner will now be described with reference to FIGS. 2 to 4.

By releasing the hydraulic pressure supplied to the cylinder hole 64, the block 52 is lowered and the cylinder 50
You will be seated on top. In addition, the injection cylinder 5
By releasing the hydraulic pressure supplied to the head end of the piston 60, the piston 60 descends to its lower limit, and the plunger tip 70 also descends to its lower limit. In this state, the rod 82 of the tilting cylinder 74
When the casting device 12 is projected, the entire casting device 12 is tilted. Therefore, molten metal is poured into the sleeve 54.

Thereafter, the rod 82 of the tilting cylinder 74 is moved back, and the casting device 12 is placed in a vertical position. Next, hydraulic pressure is introduced into the cylinder hole 64 of the block 52 to cause the docking ram 66 to protrude. This causes the block 52 to rise and the sleeve 54 to be inserted into the biscuit portion 30 of the mold device 10.

Therefore, hydraulic pressure is introduced into the chamber on the head end side of the injection cylinder 50 to push up the piston 60.
As a result, the plunger tip 70 is raised, and the molten metal stored in the sleeve 54 is introduced into the cavity 26 via the biscuit portion 30 and the runner portion 28.

After the cavity 26 is completely filled with the molten metal as shown in FIG. 2, hydraulic pressure is introduced into the chamber on the head end side of the cylinder hole 34 to close the piston 38 and the piston 38 connected thereto. Bar 42
By moving forward, the connection port between the runner section 28 and the biscuit section 30 is closed. After that,
As shown in FIG. 4, hydraulic pressure is introduced into the chamber on the head end side of the cylinder hole 32 to advance the piston 36 and push the riser rod 40 connected thereto into the runner section 28. Since the exit path of the molten metal in the runner section 28 is blocked by the closing rod 42,
All the pressure received from the riser rod 40 is transferred to the cavity 26.
It is possible to provide a reliable feeder effect.

After the molten metal in the cavity has finished solidifying, the movable platen 18 is moved back to open the mold, and the movable mold 2
The product is extruded by a product extrusion device (not shown) provided at 0.

In addition, prior to this mold opening, the piston 60,
The block 52 and the like have been lowered to the lower limit and are in a standby state for the next casting operation.

In the above embodiment, the closing rod 42 constitutes a valve means for cutting off communication between the runner section 28 and the biscuit section 30, but in the present invention, various valve mechanisms other than the closing rod may be employed. I can do it. Further, although the above embodiments show a horizontal clamping type mold and a vertical casting type casting device, the present invention also applies to injection molding machines having various other types of molds and casting devices. The applicability is clear.

[Effects] As described above, the injection molding machine of the present invention applies the feeder after blocking the molten metal exit path of the runner to prevent the molten metal from escaping, so it is possible to reliably press the molten metal regardless of the state of the molten metal in the mold. It can give a hot water effect.

Further, in the present invention, since the non-product part is pushed by a push rod, the product part is not damaged. Furthermore, since the casting equipment such as the injection cylinder does not need to provide a riser effect and is used exclusively for filling the cavity, a small casting pressure is required and the equipment configuration cost is low. Become.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an injection molding machine according to an embodiment of the present invention, and FIGS. 2, 3, and 4 are explanatory views of the operation of the injection molding machine. 10... Mold device, 12... Casting device, 14
...Fixed plate, 16...Fixed mold, 18...Movable plate, 20...Movable mold, 26...Cavity, 2
8...Runner section, 30...Biscuit section, 40...
...Riser rod, 42...Closing rod, 50...Injection cylinder, 70...Plunger tip.

Claims (1)

[Claims] 1. A fixed mold attached to a fixed plate, and a movable mold attached to a movable plate and movable in directions toward and away from the fixed mold, A mold device in which a cavity and a biscuit part for receiving molten metal are formed in a mating surface of a mold and a movable mold, and the biscuit part is connected to the cavity through a runner part, and the biscuit part is attached to and detached from the biscuit part. An injection molding machine having a casting device for freely supplying molten metal, comprising: a valve device for cutting off communication between the runner section and the biscuit section; a feeder rod that can protrude into the runner section; An injection molding machine characterized in that the mold device is provided with a cylinder device for advancing and retracting, and a cylinder device for advancing and retracting.