Casting mold forming apparatus and metal mold unit for use therein

Technical field [0001] The present invention relates to a device for making a mold by high pressure on a foam mixture which includes aggregate particles, water-soluble binders and water, as well as by injecting it into a cavity in a heated metal mold. The present invention also relates to the metal mold used in the device.

BACKGROUND OF THE INVENTION [0002] Recently, a mold making process is often used that uses water-soluble binders as the binder of aggregate particles, which are cured by heating and evaporating water from them, the method often being used with due to the favorable brittle properties of the mold after casting.

[0003] A device for producing this kind of mold is used, which includes: a cylinder running up and down, a plunger placed in the cylinder and sliding up and down inside the cylinder, and a gate for opening and closing the hole located at the bottom of the cylinder, these elements are means for injecting liquid foundry sand into a metal mold. The device can move up and down. The device is also connected to a mixer to prepare liquid foundry sand at the height of the hole in the center of the cylinder.

[0004] In this typical device, an additional gate is located in the center of the cylinder, where the positions of the gate located at the bottom and in the center of the cylinder change, as well as the position of the plunger changes to control the amount of liquid foundry sand to be injected into the metal mold . (See Patent Document 1.) [0005] However, in this typical device it is difficult to control the amount of liquid foundry sand to be injected into the metal mold so that it corresponds to the cavity in the metal mold. In addition, since more liquid foundry sand has to be loaded into the cylinder, which can be filled into the mold cavity, part of the liquid foundry sand remains

Cylinder after its injection into the mold cavity. Because this residue of liquid foundry sand is left behind, it is wasted.

[0006] Furthermore, it sometimes happens that there is not enough liquid foundry sand in the cylinder to fill the cavity of the metal mold.

[0007] Furthermore, since the foam mixture, which is the material for making the mold, contains water-soluble binders as the binder of the aggregate particles and contains a significant amount of water, it takes a long time to cure the foam mixture in metal form.

Patent Document 1: Japanese Patent Publication Open to Public, No. S55-54241.

Patent Document 2: Japanese Patent Publication Open to Public, No. H11-129054.

Disclosure of the Invention [0008] The object of the present invention is to solve the above problems of using a typical device. The invention is set out in the claims.

[0009] In addition, to solve the abovementioned problems that occur in the process of making a mold using a foam mixture made by mixing aggregate particles, more than one type of water-soluble binders and water, the metal mold for making the mold being filled with a foam mix, means are used to transfer gases from the metal mold cavity to the outside of the mold in such a way that aggregate particles cannot pass through.

[0010] Using this mold making machine, the mold is made based on the following steps:

closing step to close the injection opening by means of closing and opening the injection opening, mixing stage to mix a specific amount of aggregate particles, water soluble binders and water contained in the foam mixing means, the specified amount being more than the quantity, which can fit in a metal mold cavity,

And a joining step to connect the means for receiving the foam blend with the heated metal mold after mixing, and an injection step to inject the foam blend into the metal mold cavity by applying high pressure to the blend.

[0011] Next, the aggregate particles, water-soluble binders and water are introduced into the foam blending means and mixed for the next mold making process.

[0012] As mentioned above, since the device is equipped with at least any means or combination of means for measuring the temperature of the aggregate or foam mix particles or the viscosity of the foam mix or the humidity of the foam mix, when the temperature of the aggregate or foam mix particles is too high, the temperature of the radiator can be adjusted . In addition, when the viscosity of the foam mixture is too low, water from the water-supplying agents can be added to it, after which the foam mixture is stirred further, and when the humidity of the foam mixture is too low, water from the water-supplying agents can also be added to the foam mixture. the foam mixture is further mixed. As a result, the cavity of the metal mold can be filled with a foam mixture with appropriate properties.

[0013] Using the metal mold mentioned above, the vapor obtained from the foam mixture when the metal mold is heated can be released by passing it through means for transferring gases from the metal mold cavity outside the mold.

[0014] As explained above, the device of the present invention has the following structure: a device for producing a mold by high pressure on a foam mix which includes aggregate particles, water-soluble binders and water, as well as for injecting it into a cavity of a heated mold metal, whereby the device includes:

a hollow rectangular body having a bottom plate, the bottom plate having an injection hole for injecting the foam mixture, means for receiving the foam mixture, acting as a mixing bath to mix water-soluble aggregate particles

And binders and water, and a pressure vessel to inject the foam mixture into the metal mold, and means for closing and opening the injection opening.

[0015] Because the mold can be made using this device based on the following steps:

the step of adding to add the aggregate particles, water-soluble binders and water to the foam receiving means after filling the metal mold cavity with the foam mixture contained in the foam receiving means, followed by the mixing step to mix the water-soluble aggregate particles and water to force them to foam, a foam mixture that remains in the means for receiving it after the mixture is injected into the metal mold cavity, it can be effectively used at subsequent stages to make the mold.

[0016] As a result, while in a typical device the foam mixture remaining in the foam blending means is not recovered, the device according to the invention allows to obtain an excellent effect because the residue can be used effectively.

[0017] Furthermore, since the apparatus is equipped with any means or any combination of means for measuring the temperature of the aggregate or foam mix particles, the viscosity of the foam mix or the foam mix humidity, when the temperature of the aggregate or foam mix particles is too high, the radiator temperature can be adjusted by which, when the viscosity of the foam mixture is too low, you can add water to the foam mixture from the water supply means, whereupon the foam mixture is mixed further, and when the humidity of the foam mixture is too low, water can also be added to the foam mixture, after which the foam mixture is further mixed. As a result, the cavity of the metal mold can be filled with a foam mixture with appropriate properties.

[0018] In addition, in a mold making machine using a foam mixture obtained by mixing aggregate particles, more than one type of water-soluble binders and water, and using

EP 1 749 598 B1 of the metal mold, because the metal mold for making the mold by filling it with a foam mixture is provided with means for transferring gases from the metal mold cavity to the outside of the mold in such a way that aggregate particles cannot pass through them, steam obtained from the mixture Foam can be released by transferring it through gas transfer means. As a result, the metal form according to the invention gives an excellent effect, since the curing time of the foam mixture can be significantly reduced.

Brief description of the drawings [0019]

Fig. 1 is a front view and a partial view of a mold making apparatus in accordance with a preferred embodiment of the invention;

Fig. 2 is a drawing to explain the operation of the mold making apparatus, indicating the state in which the blend in the foam receiving means is injected into the horizontally separated metal mold;

Figure 3 is a front view and partial view of a mold making apparatus in accordance with one embodiment of the present invention;

Fig. 4 is a view of a fragment of the lower part of the metal mold;

Figure 5 is a perspective view of a metal mold in accordance with one embodiment of the invention;

Fig. 6 is an enlarged detailed view of the part "A" shown in Fig. 5.

Preferred Embodiments of the Invention [0020] Selected embodiments of the present invention regarding the mold making apparatus will be explained in detail below based on the drawings.

[0021] According to Figs. 1 and 2, the device is equipped with a base 1 having two cylinders 2, 2 arranged vertically and four guide rods 3, 3 located in four corners of the base 1. A lifting frame is placed on the top of the piston rods of the two cylinders 2, 2 and lowered 4 and is slidably connected to four guide rods 3, 3, thanks to which the frame

Lifted and lowered 4 can be raised and lowered. The lower part 6 of the horizontally separated metal mold 5 is placed on the lifting and lowering frame 4. The upper part 7 of the horizontally separated metal mold 5 is placed above the lower part 6 by connecting it to a support mechanism in a slip-connected manner with guide rods 3, 3.

[0022] The upper frame 9 is placed on top of the four guide rods 3, 3 and runs in the right and left directions. The means 10 for receiving the foam mixture, which act as a mixing bath and pressure vessel, are placed on the right side of the lower surface of the upper frame 9 via the first trolley 11, whereby the means 10 can move to the right and left.

[0023] The means 10 for receiving the foam mixture have a hollow rectangular body 12 having a bottom plate 14 that closes the holes in the bottom part of the body 12 having a number of injection holes 13, 13 for injecting the foam mixture. The bottom plate 14 has a water-cooled structure on its upper surface and has a thermal insulator on its lower surface.

[0024] Furthermore, a mixing fan mechanism 15 is arranged on the right side of the upper surface of the upper frame 9 for mixing aggregate particles, water-soluble binders and water in the foam receiving means 10, as a result of which the mixture foams. The mixing fan 16 of the mixing fan mechanism 15 is connected to the drive shaft of the motor 17 via the transmission 18. The motor 17 is mounted on support elements 20, which can be raised and lowered by driving a cylinder 19 vertically and positioned on the upper frame 9. The cover 21 is placed on the support elements 20 to close the opening of the top surface of the means 10 for receiving foam mixture. Mixing fan 16 and cover 21 can be raised and lowered by driving cylinder 19.

[0025] Furthermore, the means 22 for closing and opening the injection holes 13, 13 are located under the mechanism of the mixing fan 15,

EP 1 749 598 B1 located on the upper frame 9. A number of plugs 23, 23, which can be inserted into the injection holes 13, 13 of the means for closing and opening the injection holes, are arranged in the upper part of the piston rod of the cylinder, vertically routed through the support plate. 24. Plugs 23, 23 can be moved up and down to drive the cylinder 25. Cylinder 25 is arranged on the upper frame 9 using support elements 26, 26. The injection holes 13, 13 can be cleaned by inserting a number of plugs 23, 23 inside.

[0026] The high pressure-acting mechanism 27 is placed above the horizontally separated metal mold 5 and on the upper frame 9 to inject the foam mixture contained in the means 10 for receiving the foam mixture from the injection holes 13, 13 of the means 10. The high pressure mechanism 27 has a piston 29 having a number of exhaust ports 28, 28 extending from the bottom surface to the top surface of the piston 29. The piston 29 can be moved up and down by driving the upright cylinder 30.

[0027] The mechanism 31 for pushing the mold outwards is arranged on the left side of the lower surface of the upper frame 9 via a second carriage 32 to push the mold out of the upper part 7 in such a way that the mechanism 31 can be moved left and right. A number of mandrels 33, 33 for pushing the mold outwards are arranged vertically through the bottom of the piston rod 35 passing through the pressure plate 34. A number of mandrels 33, 33 for pushing the mold outwards can be moved up and down by driving the cylinder 35.

[0028] It is also possible to measure the temperature of the aggregate or foam mix particles by means of a contact or contactless thermal sensor (not shown) located in the means 10 for receiving the foam mix or outside the means 10.

[0029] A sensor (not shown) for measuring the viscosity of the foam mixture in the means 10 for receiving the foam mixture or outside the means 10 can also be placed.

EP 1 749 598 B1 [0030] Several types of sensors are used to measure the viscosity of the foam mixture, such as:

(1) Type of sensor that presses and introduces the probe: a method of measuring the relative viscosity of a foam mixture by measuring the load (reaction force) when the upper part of the probe, which has a spherical or cylindrical shape, is pressed into the foam mixture.

(2) The type of sensor that presses, inserts and rotates the probe: a method of measuring the relative viscosity of a foam mixture by measuring the load (torque) when the upper part of the probe, which has a fan part or fan integrated with it, is introduced into the foam mixture, after what is rotated.

(3) The type of sensor that rotates the probe: a method of measuring the relative viscosity of a foam mixture by measuring the load (reaction force and torque) when the upper part of the probe, which has a spherical or cylindrical shape, is rotated in the foam mixture, while the probe is pressed into the foam mix.

(4) A type of sensor that measures apparent viscosity: a method of measuring the relative viscosity of a foam mixture by measuring the flow rate of a foam mixture flowing from a hole in a cylindrical structure that contains a foam mixture and includes a hole of a certain diameter when high pressure is applied to the foam mixture.

[0031] The viscosity of the foam blend can be measured continuously or for each batch.

[0032] In addition, a sensor (invisible in the drawing) for measuring the humidity of the foam mixture in the means 10 for receiving the foam mixture or outside the means 10 can be arranged. Several types of humidity sensor are used, such as a sensor for measuring the electrical resistance of the foam mixture and a sensor for measuring the weight loss of the foam mixture when the moisture contained in the mixture is evaporated by heating the foam mixture.

[0033] Next, the process for making the mold using the device according to the invention will be explained.

[0034] As shown in Fig. 1, after closing the injection holes 13, 13 through plugs 23, 23 of the means 22 for closing and opening the injection holes, the means 10 for receiving the foam mixture is charged, for example silicon sand as aggregate particles, polyvinyl alcohol as water-soluble binders and water, and then the hole in the top surface of the means 10 is closed with the cover 21.

[0035] Next, silicon sand, polyvinyl alcohol and water are mixed by rotating the mixing fan 16 by driving the motor 17 of the mixing fan mechanism 15, as a result of which the mixture foams. Then, the mixing fan 16 and the lid 21 are lifted by driving the cylinder 19 of the mixing fan mechanism 15, after which the injection holes 13, 13 are opened by pulling out the plugs 23, 23 of the means 22 for closing and opening the injection holes by driving the cylinder 25 of the means 22 to closing and opening injection holes.

[0036] Next, the mechanism 31 for pushing the mold out and the means 10 for receiving the foam mixture are moved to the left side of the upper frame 9 by means of the second trolley 32 and the first trolley 11, respectively, and the means 10 are moved over the horizontally separated heated metal mold 5 through the heater. The lower part 6 of the horizontally separated metal mold 5 is lifted by means of a lifting and lowering frame 4 by driving the cylinders 2, 2, and the upper part 7 is placed on the lower part 6. The means 10 are also placed on the upper part 7, followed by the lower surface means 10 contacts the upper surface of the upper part 7.

[0037] Then, as shown in Fig. 2, the piston 29 is lowered by driving the cylinder 30 of the high pressure mechanism 27. After the air between the piston 29 and the foam mixture is blown out through the exhaust holes 28, 28, while the piston 29 is lowered, the upper hole of the exhaust holes 28, 28 is closed by means of closing the exhaust holes (not shown), followed by the foam mixture in the means for receiving the foam mixture, it is injected into a horizontally separated cavity

Metal mold 5 by high pressure on the foam mixture. The foam mixture injected into the cavity is cured because the moisture in the mixture is evaporated by heating the mixture using heat in a metal form 5.

[0038] After the foam mixture is injected into the horizontally separated metal mold 5, the piston 29 is raised by driving the cylinder 30, and the mechanism 31 for pushing the mold out and the foam receiving means 10 are moved to the right side of the upper frame 9 by means of a second trolley 32 and first trolley 11. The mechanism 31 is placed above the horizontally separated metal mold 5, and then the means 10 for receiving the foam mixture are placed under the mechanism of the mixing fan 15.

[0039] Then the mandrels 33, 33 for pushing the mold outwards are introduced into the upper part 7 horizontally separated by the metal mold 5 by driving the cylinder 35 of the mechanism 31 to push the mold outwards, and the bottom part 6 is lowered by driving the cylinders 2, 2. The mold is separated from the upper part 7, and then the mold is pushed outwards from the lower part 6 by means of a mechanism for pushing the mold outwards (not shown).

[0040] The means 10 for receiving the foam mixture, which have been displaced below the mixing fan mechanism 15, are filled with additional silicon sand, polyvinyl alcohol and water to carry out the next stage of mold making.

[0041] In these preferred embodiments, the foam mix is ​​injected into the horizontally separated metal mold 5 by applying high pressure to the mix by means of a piston 29 of the high pressure mechanism 27. However, the method of filling the metal mold 5 with the foam mix is ​​not limited to the system discussed above . As shown in Fig. 3, it is also possible to fill the metal mold with a foam mixture using compressed air. Namely, the cover 42, which closes the opening in the upper surface of the means 10 for receiving the foam mixture, provides airtightness

The closure and is connected to a source of compressed air, is located in the lower part of the piston rod of the cylinder 43 of the high pressure mechanism 27 instead of the piston 29 according to the preferred embodiments mentioned above, and then the foam mixture in the foam mixture receiving means 10 can be subjected to high pressure by providing compressed air to fill the horizontally separated metal mold 5 with the foam mixture.

[0042] Quality control of the foam mix is ​​very important to obtain a mold with excellent properties using the mold making apparatus of the invention. The form quality control method will be described in detail below.

[0043] When a mold is produced by injecting a foam mixture - which is obtained by mixing aggregate particles, water-soluble binders and water, as a result of which the mixture foams - into the cavity heated by a metal mold heater using a compression method, the following method can be used quality control of the foam mixture to produce a mold with excellent properties:

the first process to determine the basic values ​​of the foam mixture viscosity and humidity based on measurements of the foam mixture temperature, the second process to compare the basic values ​​of the foam mixture viscosity and humidity with the measured foam mixture viscosity, the third process to compare the basic values ​​of the foam mixture viscosity and humidity with the measured humidity a foam mix, if there is no problem in relation to the results of the second process, a fourth process for determining that the foam mixture has the appropriate properties if there is no problem with respect to the results of the third process.

[0044] When checking the quality of the foam mix, if the viscosity of the foam mix differs from the base viscosity value in the second process, the viscosity of the foam mix can be adjusted by mixing the mix again.

[0045] During quality control, if the foam mix moisture differs from the base humidity value in the third process, the mix moisture

The foam can be controlled by adding water and mixing the mix again.

[0046] During this quality control, the temperature of the foam mixture can be measured using a non-contact type thermal sensor.

[0047] Furthermore, during quality control, the viscosity of the foam mixture can be measured using the type of sensor that presses and inserts the probe, or the type of sensor that presses, inserts and rotates the probe, or the type of sensor that rotates the probe.

[0048] During this quality control, the foam mix moisture can be measured by measuring its electrical resistance.

[0049] Furthermore, during this quality control, temperature, viscosity and humidity can be measured by taking samples for each batch of foam mix.

[0050] Furthermore, during this quality control, temperature, viscosity and humidity can be continuously measured by installing sensors in the mixer.

[0051] Selected embodiments of the present invention regarding the metal form will be explained in detail below based on Fig. 4.

[0052] The bottom part 111 of the horizontally separated metal mold is provided with means 103 for communicating with the space outside the metal mold from the metal mold cavity 102 at the height of the surface of the upper inner part in the cavity of the bottom part 111. The means 103 for communicating with the space outside is constituted by a number of radial grooves 104, 104 located on the upper surface of the inner part in the cavity 102, the first communication opening 105 passing through the bottom part 111 from the top surface to the surface of the bottom bottom part 111 and connecting to a certain the number of grooves 104, 104 at the height of the upper surface of the lower part 111, as well as a second communication opening 106 connecting to the first communication opening 105 at the left end and extending to the right of the outer bottom part 111.

[0053] Since the metal mold has the structure given above, when the foam mix in the cavity 102 is heated, the steam obtained from the foam mix is ​​released by means 103 for communication with the space outside the metal mold.

[0054] According to the preferred embodiment of the invention mentioned above, although the means 103 for communicating with the space outside the metal mold is a number of radial grooves 104, 104 located on the upper surface of the inner part in the cavity 102, the first communication opening 105 passing through the bottom part 111 from the top surface to the bottom surface of the bottom part 111 and connecting to a number of grooves 104, 104 at the height of the top surface of the lower part 111, as well as the second communication opening 106 connecting to the first communication opening 105 at the left end and extending to the right of the outer bottom part 111, the design of the means 103 is not limited to this arrangement.

[0055] For example, as shown in Fig. 5, a gap between the upper part 121 of the horizontally separated metal mold and the part 107 which is introduced into the upper part 121 can be used as means for communicating with the space outside the metal mold. to inject the foam mixture into cavity 102. In addition, a gap between the holes (not shown in the drawing) into which the mandrels are inserted can be used and penetrate through the upper part 121 of the horizontally separated metal mold, as well as the mandrels (not shown in the figure) of the mechanism 31 to push the mold outwards as communication means with space outside the metal mold.

[0056] As shown in Figure 6, the portion 107 for injecting the foam mixture into the cavity 102 may be provided with flanges 109, 109 protruding from the cylindrical body 108 at the top and in the center of the body 108 to form a relatively wide space between the cylindrical body 108 of the part 107 and the upper part 121 when the part 107 is inserted into the upper part 121.

[0057] Since the structure of the part 107 can limit thermal conduction from the upper part 121 heated by the heater to the cylindrical body 108 of the part 107 for injecting the foam mixture into the cavity 102, the temperature of the cylindrical body 108 of the part 107 can be kept lower than that of the upper part 121.

[0058] On the other hand, the amount of foam compound in the cylindrical body 108 of the part 107 is less than in the upper part 121. As a result, the foam mixture in the cylindrical body 108 and in the upper part 121 can be cured at the same speed by controlling the temperature cylindrical body 108 in such a way that it is lower than that of the upper part 121.

[0059] Accordingly, the problem of overheating the foam mixture in the cylindrical body 108 can be solved.