JPS6030551A - Method and device for spray molding - Google Patents

Abstract

PURPOSE:To prevent the adverse influence of pulsation in the initial period of spray packing and to perform spray-packing respectively according to the facing sand layer and the backing sand layer by controlling respectively the spray-packing pressures according to the respective stages for forming the facing sand layer of a self-curing molding material and forming the backing sand layer thereof. CONSTITUTION:The refractory particulate material of fine grains stored in one of two- tank type storage tanks 15 is supplied into a mixing trough 21 and further a binder and hardener are respectively fed 25, 26 into the trough 21 and are mixed 23. The resulting self-curing molding material (material A) is supplied from the top end side of the trough 21 into a compressed air injector 27 where the material is accelerated by the compressed air injected from said device and is thus spray-packed into the prescribed molding flask contg. a casting pattern from a spray hose 31. The material A is spray-packed to the surface of the casting pattern by controlling 32 the initial speed of the spray packing to 80-100m/sec, by which the facing sand layer having a prescribed thickness is formed. The refractory particulate material of coarse grains stored in the other of the tanks 15 is spray-packed on the facing sand layer at a spray packing speed of 30-50m/sec at the same operation as mentioned above to form the backing sand layer. The spray molding is thus completed.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a refractory particulate material and an I+iJ particulate 4Ai
A self-hardening mold-forming material produced by mixing +1 with a binder for curing and bonding is sprayed into a mold containing a model of a cast product (= I)
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PRIOR ART In general, when manufacturing a mold using the above-mentioned blow molding apparatus,
It is preferable to form a skin sand layer with high packing density on the surface of the casting model, and to form a back sand layer on the skin sand layer. The formation of this skin sand layer with high packing density is twinned due to the need to precisely form the casting surface of the mold, and the back sand layer that supports the skin sand layer is required to have a high packing density. Not done.

However, in the conventional spray molding method, since the spray filling pressure of the self-hardening mold forming material "A'31" is constant, there is a problem that the spray filling pressure cannot be obtained depending on each of the skin sand layer and the back sand layer. For example, in order to manufacture high-precision and high-quality molds, it is necessary to
Although it is necessary to increase the light filling force, maintaining the spraying filling pressure at a high pressure will blow the self-hardening mold forming material.
In addition, the dense packing of the backing sand layer impedes the crushing of used molds in order to reuse the refractory particulate material.

In addition, in the past, pulsation occurred at the initial stage of spray filling, and there was a defect that good formation of the surface of the casting surface of the mold was not possible overseas, which greatly affected the accuracy and quality of the casting.

Purpose The present invention has been made in consideration of the above-mentioned problems, and its purpose is to prevent the adverse effects associated with the pulsation at the initial stage of blowing (=J filling), and to prevent It is an object of the present invention to provide a spray molding method and an apparatus thereof, which can perform spray filling and form a mold with high precision.

Structure In order to achieve the above-mentioned object, the present invention prevents the formation of the textured surface due to the pulsation at the initial stage of spraying, and also prevents the vibration at each stage during the formation of the skin sand layer and the backing sand layer. Measures have been taken to control the spray filling pressure accordingly.

EXAMPLE Hereinafter, an example embodying the present invention will be described based on the drawings. At the upper end of the support frame 1, a first separating device 2 of a cyclone sideway is installed to separate coarse particles of a predetermined size. (
The separator 2 contains refractory particulate material obtained by crushing used molds, and the refractory particulate material obtained by peeling off the binder and hardening agent attached to the surface of the refractory particulate material to produce PJ. is supplied from the pipe 3 by pneumatic transport. A tank 4 for storing the coarse particles separated by the 1st minute 14ff device 2 is provided below the 1st minute 14ff device 2, and shoes 1 to 5 are provided at the bottom of the tank 4. The chute 5 is connected to a supply chute 7 of a packet elevator 6 erected on the side of the support frame 1.

An outlet pipe 8 is provided in the upper part of the first separation device 2,
It is communicated with a second separation device 10 via a duct 9.

The second separator 10 also has a one-neutron pattern similar to the first separator 2, and is designed to separate fine particles of a predetermined particle size.

The fine particles separated by the batch 1i111 device 10 are
It is stored in a hopper 11 provided below 1i10. A cutting belt conveyor 12 is disposed below the potter 11 to prevent the fine grains stored in the potter 11 from flowing into the supply shoe 1 7. Further, an outlet pipe 13 is provided at the upper part of the second separation device 10.
is provided and communicated with a collection device (not shown). The fine powder not separated by the separation device 10 is collected by the collection device.

A grinding device (not shown) is installed at the top of bucket 1 to elevator 6.
A shoe i~14 with a
The coarse particles and fine particles carried up are supplied to a two-cypress type storage tank 15 supported by a support frame 40, respectively. 2 (The upper part of the n-type storage tank 15 is equipped with a bell gate device 15A consisting of a fluid pressure cylinder and a valve, respectively.
and 15B are provided to control the supply of coarse particles or fine particles into the 241J type storage tank 15 and its stoppage. Further, at the bottom of the two-tank storage tank 15, there are provided a landscape control mechanism 16 that adjusts the outflow amount of coarse particles and fine particles, respectively, and a shutter gate 17 that controls the supply and stop of coarse particles and fine particles. ing. Coarse particles or fine particles supplied via the gate 17 are sent to a mixing device 19 via a supply chute 18.

One mixing device is mounted and fixed on a pedestal 20 in a horizontally extending state, and as shown in FIG.
A mixing shaft 22 is rotatably supported inside the mixing trough 21 . A large number of mixing blades 23 are provided on the outer periphery of the mixing shaft 22.
is removably fixed, and the base end of the mixing shaft 22 is operatively connected to a rotation drive device 24 such as a motor placed on the pedestal 20. In addition, a first feeding mechanism 25 is provided at the upper part of the mixing rough 21 to feed the binder supplied into the trough 21 through an electromagnetic valve (not shown), and A second feeding mechanism 26 is provided which feeds the curing agent into the rough 21 through an electromagnetic valve (not shown).

The mounting positions of the two feeding mechanisms 25 and 26 are not necessarily limited to the illustrated example, and may be mounted at other appropriate positions. the discharge side of the mixing device 19;
That is, a compressed air injection mechanism 27 is provided at the lower part of the tip side, and the J5 is equipped with a compressed air injection mechanism 27. l! A supply pipe 28 connected to a compressed air supply source (not shown) is connected to the structure 27. As shown in FIG. 4, the compressed air 16 injection mechanism 27
It has an annular air chamber 29 formed from an inner wall 27a1 and an outer wall 27b, and a supply pipe 28 is communicated with the air chamber 29.

Then, the compressed air that has entered the air chamber 29 is passed through the nfj iJJ nozzle hole 27C bored at the bottom of the air chamber 29.
It is designed to be injected into a dowel-shaped acceleration space 30 through the air. A flexible spray hose 31 is connected to the lower end of the acceleration bar 30.

Further, an automatic flow rate control valve 32 and a pressure reducing valve 33 are interposed in the supply pipe 28.The automatic flow rate control valve 32 is set in advance and is set in the LC program at the initial stage of spraying.
At each stage of forming the skin sand layer and forming the back sand layer I), the spraying charge is controlled respectively J6J. In this example, the spray filling speed was reduced to 80 per second at the beginning of spraying.
00m, I]! t second 'r'Ji when forming 1 sand layer 60 ~
80 m, and the speed is set to be 30 to 50 n1 per second when forming the backing sand layer.

Next, the operation of the embodiment configured as described above will be explained.

Now, refractory particulate materials such as silica sand, zircon sand, or chromite sand, which are recycled by crushing used molds, are pneumatically transported through a pipe 3 into the first separator 2, where the coarse particles are of refractory particulate material is separated and stored in tank 4.

The coarse refractory particulate material stored in the tank 4 passes through the chute 5, the supply shoes 1 to 7, the bucket elevator 6, and the chute 14 to the two-cypress type storage 1! 15. The fine refractory particulate material and fine powder that are not separated by the separator 2 pass through the outlet pipe 8 and duct 9 to the second
The fine refractory particulate material is separated by the separator 10 and collected in the hopper 11, while the fine powder passes through the outlet pipe 13 and is collected by the collection device (not shown). The 111 grains of refractory particulate material stored in the hopper 11 are cut out by the belt conveyor 12 at the stage when the transfer of the coarse refractory particulate material is completed, and transferred to the supply system v- t~7. Bakuttle Beta 6
and is stored in the other type 211 storage tank 15 via the chute 14.

In this way, fine-grained refractory granular material for forming the skin layer and coarse-grained refractory granular material for forming the backing layer i! '+1 is stored in the two-tank storage tank 15, and after the preparation for the spray molding work is completed, the rotary drive device 24 is driven and the mixing shaft 22 is
while rotating the seat gate 17,
The ill & refractory particulate material stored in one of the two-tank storage tanks 15 is mixed 1 to rough 2 through the supply sheet 18.
Supply within 1.

Additionally, a binder and a hardener are fed into the mixing 1-rough 21 from the first and second feed mechanisms 25, 26, respectively. J
Then, the refractory particulate material, the binder, and the hardening agent of 1 grain are mixed by the rotating mixing blade 23, and this mixing action forms a self-hardening stone-shaped particle. Forming a self-hardening mold (Δ material is sequentially sent to the tip side of the mixing trough 21.Then, the self-hardening mold forming material supplied from the tip side of the trough 21 into the compressed air injection machine 27 flows through the injection nozzle hole. Due to the pressure stripe air injected from 27c, 'h
The spraying material is sprayed from the spraying hose 31 into a predetermined mold 34 that accommodates the casting model. Note that the hose 31 is operated manually or by an arm of the robot 1.

At the beginning of this spray filling, the spray filling speed is controlled to 80 to 100,111 seconds per second by the automatic flow rate control valve 32.
Spray filling is performed at this spray filling speed for a predetermined period of time (several seconds in this embodiment). During this time, the spraying hose 31 is connected to the above 4! Make sure that the self-hardening mold forming material is not sprayed into the mold anywhere other than the mold.As a result, the pulsation that occurs at the initial stage of spraying has no effect on the formation of the casting surface of the mold. It does not hinder the formation of a good casting surface.

In addition, in this example, blowing (80 to 100111/
Although the pulsation is eliminated in a short time by setting a fast blowing speed of 1/1i S, it goes without saying that the spraying filling speed at the initial stage of spraying may be set to a lower speed than the above. do not have.

Following the initial stage of spraying, the automatic control valve 32 is operated to control the spraying filling speed to 60 to 80 m/s. The self-hardening mold forming material is sprayed and filled onto the surface of the casting model at this blow-filling speed, and a skin sand layer of a predetermined thickness is formed. The thickness of this sand layer varies depending on the weight of the cast product, etc., but is usually 10 to 50 m, preferably 10 to 30 m.

When the sand layer is formed at the above-mentioned spray filling speed of 60 to 80 m/s, the casting surface, which greatly influences the precision and quality of the casting, is formed well.

The surface sand layer is formed to have a uniform density, and a mold capable of manufacturing high-precision and high-quality castings is obtained.

When the spraying and filling of the spinning mold forming material made of fine refractory particulate material is completed and a sand layer is formed, the two-tank storage tank 15
The fine refractory particulate material stored in the other side is supplied to the mixing device 19, and a backing sand layer is formed on the facing sand layer by the same process as in the formation of the facing sand layer. During the formation of this backing sand layer, the spray filling speed is controlled to 30 to 50 [Il] per second by operating the automatic flow rate control valve 32. Therefore,
Although the packing density of the surface sand layer is not as high as that of the surface sand layer, it is sufficient to support the surface sand layer.

In addition, the spray speed switching control that occurs at the time of transition from the initial spraying stage to the surface sand layer formation stage is automatically performed, and the [puru blow f] filling speed is adjusted to the transition from the skin sand layer formation stage to the back sand layer formation stage. The switching control is carried out, for example, by the person operating the water hose 31 operating the W/I7 switch.

In this way, in this embodiment, the influence of pulsation that occurs at the initial stage of spraying on the easy surface is eliminated, and the initial stage of spraying and filling is controlled at each stage of forming the 11ll sand layer and forming the backing sand layer 11-pipe. As a result, a good casting surface can be formed, and appropriate blow-filling is performed according to each stage of formation of the skin sand layer and back sand layer, resulting in high-precision &
It is possible to form an h-shape. As a result, the quality and Vi degree of cast products are improved.

However, the present invention is not limited to the above-mentioned embodiments. For example, the spray charge J1i may be
By changing the i speed as appropriate, or by controlling the blowing filling speed in two stages when forming a sand layer, first spraying at a high speed and then spraying at a slightly slower speed. Or, when the man sand layer was formed, b 1ij1
It may also be possible to perform a similar blowing d&a+lI control. Further, in the above embodiment, the spray filling speed control at the transition from the surface sand layer forming stage to the back sand layer forming stage +17 was carried out in the nest, but the two-tank type storage tank 15
The switching of the refractory particulate material supply from the refractory particulate material may be automated, and the operation of the automatic flow rate control valve 32 may be automatically switched accordingly. Roughly speaking, at the initial stage of spraying, the blowing speed of 80 to 10011/S set in the above embodiment is a condition that allows the generation of pulsation to be controlled to a certain extent, and the fi'I required in mold formation is The family is secured 1
If you go to town, it is also possible to spray fill the living model with the above-mentioned high-speed spray filling method.

Effects As detailed above, the present invention prevents the influence of initial pulsation on the formation of the casting surface, and also controls the speed of spray filling at each stage of forming the skin sand layer and the back sand layer. Since it is covered, it is possible to form a good casting surface, and it is also possible to perform appropriate spray filling according to the skin sand layer and back sand layer, which has the excellent effect of forming a mold with high precision. It splits.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a spray molding device embodying the present invention, Fig. 2 is a partially cut-away side view of the same, and Fig. 3 is a partially cut-away side view of essential parts showing the vicinity of the mixing device. , FIG. 4 is a vertical cross-sectional view of a main part showing the compressed air injection mechanism. Two-tank storage tank 15, mixing device 19, compressed air injection mechanism 2
7. Flow rate automatic control valve 32° patent applicant Mitsubishi Heavy Industries Tokyu Co., Ltd. Representative Patent attorney Shi III Fushin

Claims (1)

[Claims] 1. A self-hardening mold-forming material produced by mixing a refractory particulate material and a binder for hardening and bonding the particulate material into a formwork containing a model of a cast product. In the blowing (= I modeling method, the blowing filling speed when forming the surface sand layer is made faster than when forming the backing sand layer. 2.1R The blowing filling speed when forming the sand layer is 60~80ts/
s, and the spray filling speed when forming the backing sand layer is 30 to 50!
The spray molding method according to claim 1, which is l/S. 3. A self-hardening mold forming material produced by mixing a refractory particulate material and a binder for curing and bonding the particulate material is sprayed into a mold containing a model of a cast product. In the spray molding method, at the initial stage of spraying, the self-hardening mold forming material is sprayed and filled into the model (= formation of a surface sand layer following the initial stage + 16 blows), and the filling speed is faster than when forming the backing sand layer. 4. A self-hardening mold forming material produced by mixing a refractory particulate material and a binder for curing and bonding the particulate material is used to form a cast product. In a spray molding device that sprays and fills a formwork containing a model, a storage cypress that stores the refractory particulate material, and the refractory particulate material supplied from the storage tank and the bonding material are mixed. a mixing device for producing the self-hardening mold forming material described in iyI; a blowing f size injection means connected to the II outlet side of the device; a compressed air supply source communicated with the injection means; and the injection means. and a fluid flow rate control stage installed between the spray molding device and the fluid flow rate control stage.