JPH0513750B2 - - Google Patents

Description

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

[Prior Art] In an injection molding device such as a die casting machine, molten metal is filled into a cavity from a casting device through a biscuit portion and a runner portion of a mold device, where it is solidified to form 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 swings around the inner circumference 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] In the injection molding apparatus of the present invention, a biscuit portion serving as a molten metal receiving inlet is provided on the outer surface of the mold, and the biscuit portion communicates with a cavity inside the mold via a runner portion. In an injection molding apparatus having a mold device, a casting device for supplying molten metal provided in the biscuit part, and a feeder rod that gives a feeder effect to the molten metal in the cavity, the biscuit in the runner part is A communication port is formed between a part of the side surface of the biscuit part and the biscuit part, and the feeder rod protrudes into the runner part so as to cover the opening of the communication port, and Provided so that a distance of 0.5 to 5 mm is formed between the opening on the runner side of the communication port and the surface of the runner where the communication port is open, and the feeder rod. It is characterized by:

[Function] In the injection molding apparatus of the present invention, the cavity is filled with molten metal from the biscuit portion and the runner portion. At this time, the feeder rod is arranged so as to cover the communication port of the runner section to the biscuit section with a required gap therebetween. Therefore, at this communication port, the molten metal is rapidly solidified as heat is removed by the feeder rod.
Even immediately after the filling of the molten metal is completed, the communication port remains blocked with solidified metal.

Therefore, when the feeder rod is moved forward after filling of the molten metal is completed, the molten metal in the runner section does not escape to the biscuit side, and a sufficient feeder effect can be provided 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 apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged view of the main parts thereof.

This injection molding apparatus mainly consists of a mold apparatus 10 and a casting apparatus 12. Mold device 1
0 is a fixed mold 16 held on a fixed platen 14,
It includes a movable mold 20 held on a movable platen 18. The column 2 is connected to the fixed platen 14 via a nut 22.
4 are connected to each other, and the movable platen 18 is connected to the fixed platen 1 along the column 24 by a toggle mechanism (not shown).
It is said that it can move freely in the direction toward and away from 4.

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.

A cylinder hole 34 is provided in the fixed mold 16, and a piston 38 is installed inside the cylinder hole 34. The piston 38 is connected to the feeder rod 4 via a piston rod 40.
2 are connected, and the feeder rod 42 is connected to the runner section 2.
It is possible to protrude within 8. The feeder rod 42 is arranged so as to cover the communication port 43 of the runner portion 28 to the biscuit portion 30 and to be connected to the communication port 43 and the feeder rod 42 whether it is in the protruding state or in the retracted state. They are installed so that a gap d of 0.5 to 5 mm is formed between them.

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

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 swingably installed inside the sleeve 54, and a plunger 72 that holds the plunger tip 70 is attached to the sleeve 54.
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 has its tip connected to a joint. 84 and pin 86 to the flange 6 of the injection cylinder 50
It is pivoted on the side of 8.

The operation of the injection molding apparatus configured as described above will be described next.

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 molten metal, hydraulic pressure is introduced into the chamber on the head end side of the cylinder hole 34 to advance the piston 38 and the riser rod 42 connected thereto. Thus, the feeder rod 42 is placed over the communication port 43 of the runner section 28 to the biscuit section 30 with a required gap d therebetween. Therefore, the molten metal at the communication port 43 is rapidly solidified by heat removal by the riser rod 42, and the communication port 43 remains blocked with solidified metal even immediately after filling of the molten metal is completed.

Therefore, when the feeder rod is advanced after filling the molten metal, the exit path of the molten metal in the runner section 28 is blocked by the feeder rod 42, so the pressure received from the feeder rod 42 is reduced. All of this is transmitted into the cavity 26, providing a reliable feeder effect.

After solidification of the molten metal in the cavity 26 is completed, the movable platen 18 is moved back to open the mold, and the product is extruded by, for example, a product extrusion device (not shown) provided in the movable mold 20.

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 present invention, if the gap d is larger than 5 mm, the feeder rod 42 will separate too much from the communication port 43, and the molten metal near the communication port 43 will not solidify as quickly. Therefore, even if the feeder rod 42 is pushed into the runner part 28, the runner part 2
The molten metal in 8 escapes from the communication port 43 to the biscuit part 30 side, reducing the feeder effect.

On the other hand, if the gap d is smaller than 0.5 mm, the flow resistance of the molten metal flowing from the biscuit part 30 to the runner part 28 will be excessive, which may impede smooth filling of the molten metal, and also make it difficult to push out the solidified product. This will cause inconvenience. That is, after the mold is opened, the product solidified in the mold is pushed out of the mold by the product extrusion device (not shown) provided in the movable mold 20, for example, by pushing the solidified material in the cavity 26. It is pushed out, but at this time the above-mentioned gap d
If it is smaller than 0.5 mm, the solidified material in the cavity part 26 and the runner part 28 and the solidified material in the biscuit part 30 will separate, and the biscuit part 30 will be separated.
The coagulated material inside can no longer be pushed out. Therefore, if the gap d is smaller than 0.5 mm, a separate extrusion device must be provided to extrude the coagulated material from the biscuit portion 30, which increases the cost of the device configuration. In addition, it becomes a double effort to take out the coagulated bodies separately.

Although the above embodiments show a horizontal clamping type mold and a vertical casting type casting device, the present invention can also be applied to injection molding devices having various other types of molds and casting devices. is clear.

[Effects] As described above, since the injection molding apparatus of the present invention applies the feeder while blocking the molten metal exit path of the runner to prevent the molten metal from escaping, the injection molding apparatus of the present invention reliably feeds the feeder regardless of the state of the molten metal in the mold. can give an 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.

In the present invention, since the coagulated material in the cavity and runner part and the coagulated material in the biscuit part are not separated but are integrated, it is easy to take out the coagulated material, and one set of coagulated material removal device is sufficient. .

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an injection molding apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged view of the main parts thereof. 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, 42...
...Riser rod, 43...Communication port, 50...Injection cylinder, 70...Plunger tip.

Claims (1)

[Scope of Claims] 1. A mold device in which a biscuit portion serving as a molten metal receiving port is provided on the outer surface of the mold, and the biscuit portion is communicated with a cavity inside the mold via a runner portion, and the biscuit portion In an injection molding apparatus having a casting device for supplying molten metal provided in the cavity, and a feeder rod providing a feeding effect to the molten metal in the cavity, a part of the surface of the runner portion on the biscuit portion side and the biscuit portion. a communication port is formed between the runner portion, and the feeder rod protrudes into the runner portion so as to cover the opening of the communication port;
Provided so that a distance of 0.5 to 5 mm is formed between the opening on the runner side of the communication port and the surface of the runner where the communication port is open, and the feeder rod. An injection molding device featuring: