JPS60127063A - Injection molding method using venting device for die - Google Patents

Abstract

PURPOSE:To prevent formation of a defective product owing to misrun and formation of cavities by blowing hot air into the cavity to evaporate the water drops on the surface after clamping of the stationary die and movable die of a die casting machine then charging a molten metal under pressure into the dies. CONSTITUTION:A valve 14 movable in the direction where the molten metal from a cavity 7 for casting acts is provided to the end of a vent groove 10 communicating with a vent way 9 from the cavity 7 on the parting plane of a stationary die 3 and a movable die 4 of an injection molding machine such as a die casting machine. Cooling water or parting material is sprayed on the surface of the cavity 7 and if the cavity 7 has an intricate shape, a part of the cooling water and parting material remains in the form of water drops on the surface. The water drops on the surface of the cavity 7 are evaporated by the temp. of the molten metal in the stage of injecting the molten metal such as Al alloy into the cavity 7 after clamping of the dies 3, 4. The steam passes through the vent way and groove 9, 10 and lifts the valve 14 by overcoming the force of a spring 17. The steam is thus released to the outside. The rate of formation of defective products occurring in misrun and cavities owing to the presence of the steam in the cavity is considerably decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a mold gas venting device for handling gas from a person ff1 from the mold cavity during injection of an injection molding device such as a die casting machine or an injection molding machine, and This relates to the injection molding method described above, in which hot pressure is blown into the cavity after tightening to sufficiently remove water droplets in the cavity before injection is performed.

Traditionally, in index molding machines such as die casting machines, cold fill water or a water-soluble mold release agent was sprayed onto the mold after the mold was separated, but when the mold was clamped, If water droplets remain, there is no place for them to escape, and if they are injected as is, the surface of the injected product will become black, the flow will be poor, and nests will form, making it impossible to obtain a high-quality injected product. .

Therefore, in the past, it was necessary to clamp the mold after the water droplets on the mold surface had sufficiently dried and disappeared.

On the other hand, during injection, the molten metal is not discharged outside the mold.
Ensure that the gas and water vapor inside the cavity are sufficiently removed from the mold, and
There was no satisfactory device for reliably and easily discharging.

This invention is intended to solve these problems.

To this end, in this invention, the separation surface of the mold includes
A valve slidable in the axial direction is provided at the end of the gas vent groove led from the cavity, and a first gas exhaust path is provided from the middle of the if gas vent groove to the side surface of the movement path of the valve. P,
A second gas exhaust path is provided that communicates with the outside of the mold from a side surface of the movement path of the valve, which is an end of the first gas exhaust path, and the second gas exhaust path is connected to the first gas exhaust path. Using a gas venting device for a mold, in which the valve is directly moved by the action of the inertia of the injected melt advancing from the cavity to directly block the first gas exhaust path, the valve is opened after the mold is clamped. Hot air was sent into the cavity through a valve device, followed by injection.

Next, the present invention will be explained in more detail with reference to an embodiment shown in the drawings.

In one embodiment of the mold gas handling device shown in FIGS. 1 to 3, 3 is a fixed mold and 4 is a movable mold.

On the movable mold 4 side, there is provided an extrusion plate that is moved forward and backward by a cylinder (not shown), and a plurality of extrusion pins 6 are provided on this extrusion plate.

A cavity 7 is formed in the abutting surfaces of the fixed and movable molds 3.4, and below the cavity 7, illustration is omitted! , : A casting hole is formed for molten metal, which is the molten material to be injected, to be injected by the injection cylinder.

On the other hand, on the fixed mold 3 side or the 7iJ movable mold 4 side, a gas handling path 9 with a sufficient area is provided around the cavity 7 in the part facing the other mold 3. The waste removal groove 10 is in communication with the upper end of the path 9. This gas handling groove 10 may be formed so as to be shared between the dividing surfaces of the two molds 3.4.

Then, the valve head is guided from the cavity 7 of the C1 mold 3.4 and faces the lζ sludge groove 10, and is moved directly in the direction of action of the molten metal by the action of the molten metal advancing from the cavity 7. A disc-type valve 1/I was provided.

18 is attached to the fixed mold 3 via the bracket 40.
The cylinder 19 is a piston rod of the cylinder 18, and a spool 22 consisting of several parts that can be assembled and disassembled is fixed to the lower #i1 part of the piston rod 19.
2 is movable within a vertical half-hole 23 provided in a fixed mold 3 and a vertical half-hole provided in a movable mold 4 that matches this half-hole.

A chamber 271 is installed at the top of the spool 22.
A gas discharge hole 13 opening downward and a tapered valve seat 12 are provided at the bottom of the valve 2. A rod 25 with a vertical valve stem ℃ is provided at the center of one end of the valve 14, and a rod 25 with a vertical valve stem ℃ is provided.
is. Of course, the rod 25 is provided slidably relative to the spool 22. A compression spring 17 was installed between the upper surface of the head 26a of the valve 14 located inside the chamber 24 and the ceiling surface of the spool 22. However, around the rod 25, the valve 1
A compression spring 17 may be provided between the upper end surface of the valve head 141) of No. 4 and the bottom surface of the waste discharge hole 13 of the spool 22. Furthermore, a cylinder stroke may be provided instead of the compression spring 17.

The gas exhaust hole 13 has a gas exhaust path 20 leading to the outside of the mold.
communicated. The outlet of this gas exhaust path 20 is
The IC is released to the outside air and connected to a hot air supply device (not shown).

Following the waste handling groove 10, a valve chamber 11 that can be split in half is provided on both dividing surfaces of the two molds 3.4.

As can be seen from FIG. 1.2, the valve cap 11 has an upper large diameter portion 11a into which the spool 22 is inserted, and a valve head 14 of the valve 14.
1) is the small diameter part at the lower end where the valve head 1fff hole 11 is inserted.
It consists of 1).

Boo? The valve head 141) of No. 14 has a tapered surface on the outer periphery of the back surface that seats on the valve seat 12, and when the valve head 14b is at the lower limit, the valve head 141) is located in the valve chamber where the valve head is installed. Valve 11ri 14l]
The outer circumferential surface of the valve chamber 11 is fitted into the inner circumferential surface of the lower end of the valve chamber 11 in an active manner. 14a is a dish-shaped recess provided on the lower surface of the 51-head 14b.

From the middle of the gas vent groove 10 just before the valve chamber 11, the valve head 14
A bypass 15 is provided between the side surface of the valve chamber 11 immediately in front of the valve seat 12, which is the side surface of the movement path b, and is a gas exhaust passage that bypasses the valve 14, and when the valve 14 is operated, Communication and interruption of the gas exhaust path between the bypass 15 and the outside of the mold are directly regulated. The intersecting angle θ between the gas vent groove 10 and the 8th part of the bypass 15 is an acute angle or a right angle, and the 11th part 16 of the gas vent groove 10 facing the valve chamber 12 is narrowed into a nozzle shape.

The spool 22 was slidably held by a guide 41 attached to a part of the bracket 40. Also, bracket 4
A sensor 42.43 such as a limit switch or a non-contact switch is installed on the side of the spool 22, and a bar 44 is attached to a part of the spool 22 to activate the sensor 42.43. Check the lower and higher limits of . From the head 26a of the valve 14, a bar 45
, the spool 22 through the glue portion 22a of the spool 22.
A sensor 46 such as a limit switch or a non-contact switch is attached to a part of the spool 22, and by confirming that the bar 45 is separated from the sensor 46, the valve 14 is Valve seat 12
Make sure you are listening from a distance. and,
After confirming that the valve 14 is properly listening, the molten metal can be poured.

Injection using the gas venting device constructed as described above is carried out as follows.

In the mold open state, avoid operating the cylinder 18,
The spool 22 is moved to one arm via the piston rod 19, and the force of the compression spring 17 keeps the valve 14 open.

In this state, cooling water or a water-soluble mold release agent is sprayed onto the surface of the cavity 7 of the mold. In this case, water droplets are formed on the surface of the cavity 7. The water droplets generated on the surface of the cavity 7 evaporate to some extent and become water vapor due to the heat of the mold, but if the injection product is complex and the surface of the cavity 7 is considerably penetrated, the surface of the cavity 7 Water droplets
Instead of turning into water vapor, it remains as water droplets.

Therefore, in the present invention, as will be described later, hot air is blown into the carrier after mold clamping to forcibly evaporate water droplets on the surface of the cavity 7.

When the above-mentioned spun operation is completed, the mold is clamped with the valve device raised and the valve 14 floating above the lower end of the valve chamber 11, and the valve chamber 11 is brought together. , actuate the cylinder 18 and insert the lower end of the spool 22 into the valve chamber 11.
Insert the valve head 141) to the lower limit position of the valve head 14b, and insert the valve head 141) to the valve head installation hole 11b just above the valve chamber 16, while keeping the valve head 141) at the normal installation position of the valve head 14b. 1
1. Make sure it is tightly attached to the bottom end of 1.

In addition, if the wall surface of the valve head installation hole 11b and the gas vent groove 1
If there is a foreign object around the mouth 16 of the valve 14 that prevents the valve 14 from descending, the bar 45 and the sensor 46 will not operate, and the valve head 14b will not go all the way and the valve 14 will close. It is in a raised position relative to the spool 22. As a result, valve 1
4 is set in the normal position, no signal is generated, the injection cylinder is inoperative, and no casting operation is performed. Therefore, disadvantages such as poor gas handling do not occur.

Once the valve head 14b is securely set in the valve head installation hole 11b, hot air is sent from the gas exhaust path 2.0 to the open valve 14 section of the gas venting device, the bypass 15, and the gas venting groove 10.
A sufficient amount of hot air is sent into the cavity 7 of the mold through the above. As a result, the water droplets remaining on the surface of the cavity 7 completely evaporate into water vapor, which is evaporated due to the heat of the mold (1) and escapes to the outside through the injection sleeve due to the action of hot air. Of course, not all of the water vapor escapes to the outside through the injection sleeve, and some of it may remain in the cavity 7 together with the gas.

This feeding of hot air can also be performed after mold clamping or during hot water supply.

Therefore, if hot air is sent into the cavity through the degassing device during mold clamping, the mold can be clamped quickly after spraying, and the cycle will be completed and zero.

After the hot air has been fed for a predetermined period of time, the hot air is stopped, the molten metal is injected into the injection sleeve, and the injection is performed.

If so, during the filling of the molten metal into the cavity 7, the gas and remaining water vapor in the cavity 7 will be removed through the gas vent path 9.
Gas handling groove 10. The gas passes through the bypass 15 and the gas exhaust hole 13 in the spool 22, and is discharged from the gas exhaust path 20.

During this time, the valve 14 is located inside the valve head installation hole 111 (the lower end of the valve chamber 11), with the valve head 14b located in the gas vent groove 10.
The mouth 16 of the pump remains closed, and a large amount of gas and water vapor are drawn out through the bypass 15.

Of course, at this time, the tf gas and steam pass through the mouth 16 and act on the lower surface of the valve head 141), but since the quality m of the gas and steam is extremely small, the valve 14 does not rise.

When the filling of the molten metal into the cavity 7 is almost completed, the molten metal with a large mass rises in the gas vent groove 10 and collides with the lower surface of the valve head 14b, and as a result, the valve 171 resists the compression spring 17. It is pushed up and hits the valve seat 12, closing it. The molten metal pushes up the valve 14 and a part of it enters the bypass 15, but since the valve 14 is closed, the molten metal is blocked.

At this time, most of the gas and water vapor that escaped through the bypass 15 have been removed, and a small amount remains near the valve seat 12. It does not have any negative effect on the cast product.

With this mold gas handling equipment,
・With the gas exhaust path leading from + to the outside of the mold open by the action of the valve, perform indexing and
When the gas and water vapor with a small quality m in the interior of the cavity are almost completely discharged through the gas exhaust passage, the inertial force of the injected molten material with a large quality m that has advanced from inside the cavity and has been made is applied directly to the valve. By doing so, the valves are reliably and quickly moved and tightened, and 1) the valve 11 directly blocks the gas discharge path and prevents the melt to be injected from flowing out from the gas rII exit path. Therefore, gas inside the mold can be reliably and easily vented during injection.

When the casting work is completed, the cylinder 18 is operated to raise the screw rod 19 and the spool 22 and valve 14 are raised to a certain degree, and then the mold is opened.Subsequently, by operating the extrusion bottle 6, At the same time when the cast product is taken out from the movable mold 4, the gas vent groove 10, the valve chamber 11, and the bypass 1 are removed.
5. Remove the solidified metal.

In this way, in this invention, since the structure as described in the claims is adopted, water droplets generated on the surface of the mold cavity by spraying can be sufficiently removed by hot air, and the water droplets generated in the cavity can be removed by hot air. The gas and steam are sufficiently discharged through the degassing device as the molten metal advances at the time of tsurugisan, and the valve of the degassing device can be automatically, instantaneously, reliably and easily closed by the action of the inertia of the molten metal.

Therefore, it is possible to easily obtain a high-quality indexed product with no cavities and a clean surface. Of course, inconveniences such as spouting of molten metal do not occur.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of a device for carrying out the method of the present invention, and FIG. ■It is a line sectional view. 3... Fixed mold, 4... Movable mold, 7... Kirebidi, 10... Gas handling groove, 11... Valve chamber, 111
)...Valve head installation hole, 14...Valve, 14b...Valve head, 15...Bypass, 18...Cylinder, 20...
・Gas exhaust path, 22...spool, 46...sensor

Claims (1)

[Claims] A valve slidable in the axial direction is provided at the end of a gas vent groove led from the cavity on the separation surface of the mold, and a side surface of the movement path of the valve is provided in the middle of the gas vent groove. A first gas exhaust path leading to the step (2) is provided, and a second gas exhaust path is provided which communicates with the outside of the mold from the side surface of the valve travel path, which is the end of the first gas exhaust path. (b) The valve connecting the first gas exhaust path is directly moved by the inertial force of the molten material to be injected advancing from the cavity to directly block the first gas exhaust path. An injection molding method using a degassing device for a mold, in which after the mold is clamped, hot pressure is sent into the cavity through an open valve device, and then injection is performed. .