Control Method for Die Casting Apparatus and Die Casting Method

Abstract

To provide a die casting apparatus and a die casting method in which, when a runner is pressurized before the completion of the filling of molten metal into a cavity, a feeding effect is improved to improve the quality of a die cast product.SOLUTION: A die casting apparatus 1 comprises: a die casting die 10 for defining a cavity 53 and a runner 50 communicating with the cavity 53; first pressurization means 24, 25 for filling molten metal toward the inside of the cavity 53; and second pressurization means 40, 41, 43 for pressurizing the molten metal of the runner 50. Each second pressurization means comprises a pressurization rod 43 which advances and retreats toward a direction almost orthogonal to a die opening direction of the die casting die 10. Then, a pressurization speed of the molten metal of the runner 50 with the pressurization rod 43 includes: a first step (ii) in which high speed pressurization is executed from the start of the pressurization of the pressurization rod 43 to the generation of high pressure on the cavity 53 with a flow passage blocked; and a second step (iv) in which low speed pressurization is executed after the generation of the high pressure on the cavity 53 with the flow passage clogged by the pressurization rod 43.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a die-casting apparatus Control method and a die-casting method, and particularly to a die-casting apparatus provided with a pressing means for pressing a runner of a die-casting mold Control method and the Capable of executing a control method for a die-casting device die-casting method performed using the die-casting apparatus.

Background Art

[0002] A die-casting apparatus provided with a first plunger for filling the molten metal in the sleeve into a cavity defined inside a die-casting mold and a second plunger for pressing the molten metal in the runner is known from the following Patent Document 1. The following Patent Document 1 suggests that the pressure of the molten metal in the runner by the second plunger is applied before, preferably immediately before, the completion of the filling of the molten metal into the cavity by the first plunger.

[0003] However, since the fluidity of the molten metal in the runner is good at a timing before the completion of the filling of the molten metal into the cavity, even if the molten metal in the runner is pressurized at this timing using the die-casting apparatus disclosed in the following Patent Document 1, there is a problem that the molten metal flows backward from the gap between the second plunger and the surface defining the runner, and the pressure cannot be maintained.

[0004] Therefore, in order to provide a die-casting device with an excellent pressing effect of molten metal when the runner is pressurized before the completion of filling the cavity with the molten metal, the applicant of the present application invented a die-casting device shown in Patent Document 2 below. This die-casting device includes a die-casting mold that defines a cavity and a runner communicating with the cavity, a first pressurizing means for filling the cavity with the molten metal, and a second pressurizing means for pressurizing the molten metal in the runner, and the second pressurizing means is a device provided with a pressurizing rod that advances and retreats in a direction substantially orthogonal to the mold opening direction of the die-casting mold. According to such a die-casting device, even when the runner is pressurized before the completion of filling the cavity with the molten metal, a sufficient pressing effect of molten metal can be obtained, so that it is possible to improve the quality of die-cast products formed in the cavity.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the industry, improvement of product quality is always required, and for the improvement of the quality of die-cast products, it is also required to provide a die-casting device that has a more significant effect and a die-casting method using the die-casting device. The inventors of the present invention focused on the runner pressurization by the second pressurizing means for the die-casting device disclosed in the above-mentioned Patent Document 2 and invented an improved technology for further improving the pressing effect of molten metal. That is, the present invention was made to provide an improved technology for the die-casting device disclosed in Patent Document 2, and when the runner is pressurized before the completion of filling the cavity with the molten metal, a further pressing effect of molten metal can be obtained compared with the prior art, and a die-casting device capable of improving the quality of die-cast products formed in the cavity Control methodand the Capable of executing a control method for a die-casting device An object of the present invention is to provide a die-casting method using a die-casting apparatus.

Means for Solving the Problems

[0007] Hereinafter, the present invention will be described. In order to facilitate understanding of the present invention, reference numerals of the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated forms thereby.

[0008] A die-casting apparatus (1) according to the present invention Control method includes a die-casting mold (10) that defines a cavity (53) and a runner (50) communicating with the cavity (53), a first pressurizing means (24, 25) for filling the cavity (53) with molten metal, and a second pressurizing means (40, 41, 43) for pressurizing the molten metal in the runner (50), and the die-casting apparatus (1) includes a pressurizing rod (43) that advances and retreats in a direction substantially orthogonal to the mold-opening direction of the die-casting mold (10). Control method The pressurizing speed of the molten metal in the runner (50) by the pressurizing rod (43) includes a first stage (ii) in which high-speed pressurization is performed from when the pressurizing rod (43) starts pressurization until a high-pressure is generated in the cavity (53) by blocking the flow path, and a second stage (iv) in which low-speed pressurization is performed after the pressurizing rod (43) blocks the flow path and a high-pressure is generated in the cavity (53). Operate the pressure rod (43) so as not to It is characterized by the above.

[0009] Further, in the die-casting apparatus (1) according to the present invention Control method it is preferable that the pressurizing speed consisting of the low-speed pressurization in the second stage (iv) is determined based on the solidification shrinkage amount of the molten metal based on solidification analysis.

[0010] The above-described die-casting apparatus (1) according to the present invention Control methodThen, when the time from the end of the injection of the molten metal into the cavity (53) by the first pressurizing means (24, 25) to the end of the first stage (ii) of the pressurization of the molten metal in the runner (50) by the second pressurizing means (40, 41, 43) is defined as T, the inequality 0 s < T ≦ 0.2 s is satisfied for the second pressurizing means (40, 41, 43). To Operation Cause this can be achieved.

[0012] The die-casting method according to the present invention is characterized in that die-casting is performed by any of the above-described die-casting apparatuses (1). Capable of executing a control method for a die-casting device (1)

Effect of the Invention

[0013] According to the present invention, when the runner is pressurized before the completion of the filling of the molten metal into the cavity, a further effect of pushing the molten metal can be obtained as compared with the prior art, and it is possible to improve the quality of the die-cast product formed in the cavity. A die-casting apparatus Control method and, the Capable of executing a control method for a die-casting device A die-casting method using the die-casting apparatus can be provided.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0015] Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. Note that the following embodiments do not limit the invention according to each claim, and not all combinations of features described in the embodiments are essential for the solution means of the invention.

[0016] The die-casting apparatus 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is a cross-sectional view showing a state in which the pressure rod is in the retracted position in the die-casting apparatus according to the present embodiment. FIG. 2 is a cross-sectional view showing a state in which the pressure rod is in the advanced position in the die-casting apparatus according to the present embodiment.

[0017] As shown in FIG. 1, the die-casting mold 10 includes a fixed mold 20 and a movable mold 30. The fixed mold 20 consists of a fixed holder 21 and a fixed die 22, and an injection sleeve 23 (sleeve) is disposed in the fixed holder 21. A plunger tip 25 connected to the tip of a plunger rod 24 is disposed in the injection sleeve 23. By operating an injection cylinder (not shown) to slide the plunger tip 25 within the injection sleeve 23, the molten metal such as aluminum alloy supplied from a non-illustrated hot water supply hole of the injection sleeve 23 can be filled into a cavity 53 described later. The plunger tip 25, the plunger rod 24, and the injection cylinder (not shown) constitute a first pressurizing means according to the present invention.

[0018] The movable mold 30 consists of a movable holder 31, a movable die 32, and a runner bar 33, and is movable in the moving direction of the movable mold 30 (the mold opening direction of the die-casting mold 10) indicated by the arrows A ←→ A'. In the mold-closed state shown in FIGS. 1 and 2, a runner 50, a gate 52, and a cavity 53 are defined inside the die-casting mold 10, and the space inside the sleeve 23 communicates with the cavity 53 via the runner 50 and the gate 52. The runner 50 includes a first runner 50A extending in a direction substantially coinciding with the axial direction of the injection sleeve 23 (the mold opening direction of the die-casting mold 10), and a second runner 50B extending in a direction substantially orthogonal to the axial direction of the injection sleeve 23. The first runner 50A is defined by the injection sleeve 23 disposed in the fixed mold 20 and the runner bar 33 of the movable mold 30. The second runner 50B has a portion defined by the injection sleeve 23 and the runner bar 33, and a portion defined by the fixed die 22 and the movable die 32. The gate 52 and the cavity 53 are defined by the fixed die 22 and the movable die 32.

[0019] A hydraulic cylinder 40 is fixed to the runner bar 33 via a bracket (not shown). A pressure rod 43 is connected to the piston rod 41 of the hydraulic cylinder 40 via a coupling 42. The pressure rod 43 is inserted into a through hole 34 formed in the runner bar 33, and the tip 43A of the pressure rod 43 closes the upper opening 34A of the through hole 34. The pressure rod 43 is configured to be able to advance and retreat in a direction substantially orthogonal to the mold opening direction of the die-casting mold 10 by the operation of the hydraulic cylinder 40. When the hydraulic cylinder 40 is operated, it enters the second runner 50B from the retracted position shown in FIG. 1 and can advance to the forward position shown in FIG. 2. Therefore, in the die-casting apparatus 1 according to the present embodiment, by advancing the pressure rod 43 into the second runner 50B, it is possible to pressurize the molten metal in the cavity 53 via the molten metal in the second runner 50B. The hydraulic cylinder 40, the piston rod 41, and the pressure rod 43 constitute the second pressurizing means according to the present invention.

[0020] Note that the tip 43A of the pressing rod 43 has a cylindrical shape. The second runner 50B is provided with a corresponding shaped portion 51 formed in a circular shape so as to correspond to the cross-sectional shape of the tip 43A of the pressing rod 43. The circumferential gap between the surface 51A defining the corresponding shaped portion 51 and the tip 43A of the pressing rod 43 is set in the range of, for example, 0.5 to 3.0 mm. When the gap is less than 0.5 mm, the thin-walled portion solidified in the gap will be cut off when the die-cast product is taken out. Also, when the gap exceeds 3.0 mm, when the molten metal in the second runner 50B is pressurized by the pressing rod 43, the molten metal cannot be sufficiently prevented from flowing back through the gap, and a sufficient pressing effect cannot be imparted to the molten metal in the cavity 53. When the fluidity of the molten metal in the second runner 50B is good, backflow is likely to occur from the gap. Therefore, when the molten metal in the second runner 50B is pressurized by the pressing rod 43 before the filling of the molten metal into the cavity 53 is completed, it is preferable that the gap between the surface 51A defining the corresponding shaped portion 51 of the second runner 50B and the tip 43A of the pressing rod 43 be 3.0 mm or less.

[0021] The basic configuration of the die-casting apparatus 1 according to the present embodiment has been described above. Next, with reference to FIGS. 3 to 7, a die-casting method executable by the die-casting apparatus 1 according to the present embodiment will be described. Here, FIG. 3 is a graph for explaining the die-casting method executable by the die-casting apparatus according to the present embodiment, showing the injection speed and the pressing rod stroke. FIG. 4 is a diagram showing the state of the die-casting apparatus at the location marked with the reference sign (i) in FIG. 3, FIG. 5 is a diagram showing the state of the die-casting apparatus at the location marked with the reference sign (ii) in FIG. 3, FIG. 6 is a diagram showing the state of the die-casting apparatus at the location marked with the reference sign (iii) in FIG. 3, and FIG. 7 is a diagram showing the state of the die-casting apparatus at the location marked with the reference sign (iv) in FIG. 3.

[0022] In FIG. 3, the horizontal axis represents time [s], the left vertical axis represents the injection speed [m / s] indicating the numerical value of the injection speed shown by the solid line, and the right vertical axis represents the pressing rod stroke [mm] indicating the numerical value of the pressing rod stroke shown by the dashed line.

[0023] In the die-casting method according to this embodiment, first, the movable mold 30 is moved in the moving direction of the movable mold 30 shown as A←→A' in FIG. 4 and the like to clamp the die-casting mold 10, and a runner 50, a gate 52, and a cavity 53 are defined inside the die-casting mold 10 (the state of FIG. 4).

[0024] Next, molten metal is supplied into the injection sleeve 23, and the plunger tip 25 is slid in the injection sleeve 23, so that the molten metal in the injection sleeve 23 is filled into the cavity 53 via the runner 50 and the gate 52. Further, as shown by the reference sign (ii) in FIG. 3, after the injection of the molten metal into the cavity 53 by the first pressurizing means (the plunger tip 25, the plunger rod 24, and an injection cylinder not shown) is started, before the injection speed of the molten metal drops, the die-casting apparatus 1 is operated so as to start pressurizing the molten metal in the runner 50 by the second pressurizing means (the hydraulic cylinder 40, the piston rod 41, and the pressurizing rod 43) (the state of FIG. 5). That is, in this embodiment, as shown in the graph diagram shown in FIG. 3, the first pressurizing means and the second pressurizing means are operated so that a line having a negative slope when the injection speed decreases and a line having a positive slope when the pressurizing rod stroke increases cross each other. In the execution of such an operation, it is important that the two pressurizing means operate in a short time without solidification occurring in the cavity 53, and by preventing the backflow of the molten metal from the cavity 53 side to the injection sleeve 23 side as shown by the arrow from the second runner 50B to the first runner 50A in FIG. 4, it is possible to suitably prevent problems such as no high-pressure being generated in the cavity 53.

[0025] Furthermore, as indicated by reference signs (ii) to (iv) in FIG. 3, regarding the pressurization speed of the molten metal in the runner 50 by the pressure rod 43, there is a first stage (from the position indicated by reference sign (ii) to the position indicated by reference sign (iii) in FIG. 3) in which high-speed pressurization is performed from when the pressure rod 43 starts pressurization until a high-pressure is generated in the cavity 53 by blocking the flow path, and a second stage (from the position indicated by reference sign (iii) to the position indicated by reference sign (iv) in FIG. 3) in which low-speed pressurization is performed after the pressure rod 43 blocks the flow path and a high-pressure is generated in the cavity 53. That is, in the present embodiment, as shown in the graph diagram shown in FIG. 3, the second pressurizing means is operated so as to be composed of a first stage in which the slope of the line where the pressure rod stroke is high-speed pressurization is large and a second stage in which the slope of the line where the pressure rod stroke is low-speed pressurization is gentle.

[0026] Note that the state of the position indicated by reference sign (iii) in FIG. 3 is shown in FIG. 6. The position of the tip 43A of the pressure rod 43 at the time of switching between the first stage where the pressure rod stroke is high-speed pressurization and the second stage where the pressure rod stroke is low-speed pressurization is the boundary position indicated by reference sign 50C which is the boundary portion between the first runner 50A and the second runner 50B. When the tip 43A of the pressure rod 43 moves to the boundary position 50C, a high-pressure state is generated in the cavity 53 (the state of FIG. 6). In this state, since the flow path is blocked by the pressure rod 43, the operation of the injection cylinder of the plunger rod 24 may be turned off.

[0027] Furthermore, regarding the pressurization speed consisting of the low-speed pressurization in the second stage, which is the position indicated by reference sign (iv) in FIG. 3, it is determined based on the solidification shrinkage amount of the molten metal in the cavity 53 based on the solidification analysis. By advancing the pressure rod 43 slowly toward the cavity 53 side according to the solidification shrinkage amount of the molten metal based on the pressurization speed consisting of the low-speed pressurization in the second stage, it becomes possible to execute the die-casting method under optimal conditions (the state of FIG. 7).

[0028] Furthermore, in the present embodiment, as shown in FIG. 3, when the time from the end of the injection of the molten metal into the cavity 53 by the first pressurizing means to the end of the first stage of pressurizing the molten metal in the runner 50 by the second pressurizing means is defined as T, 0 s < T ≤ 0.2 s the second pressurizing means is configured to operate so that the inequality holds. In the die-casting apparatus 1 according to the present embodiment, the rise time of the pressurizing pressure from the completion of the filling of the molten metal by the plunger tip 25 to the generation of pressurization by the pressurizing rod 43 is set to 0.1 s, and the second pressurizing means is configured to operate with the time T = 0.1 s as the target value. Regarding the operation of such a second pressurizing means, the operation may be controlled according to the performance of the hydraulic cylinder 40 or the like. Incidentally, in the present embodiment, considering that the hydraulic cylinder 40 having a pressure performance of 80 MPa is used and the operation delay time from the input of the operation start signal to the hydraulic cylinder 40 until the pressurizing rod 43 actually operates is 0.15 s, the operation start signal to the hydraulic cylinder 40 is input about 0.15 s before the start target of the first stage where the pressurizing rod stroke indicated by the reference symbol (ii) in FIG. 3 becomes high-speed pressurization.

[0029] Then, when the molten metal in the cavity 53 solidifies, the movable mold 30 is moved to open the mold. After the pressure rod 43 is retracted, the die-cast product is taken out from the movable mold 30. By executing the series of operations described above, a suitable pressing effect is obtained, so that it is possible to provide a die-casting apparatus 1 capable of improving the quality of the die-cast product formed in the cavity 53, and a die-casting method using the die-casting apparatus 1. In particular, by executing the die-casting method shown in FIG. 3, a large clamping force for preventing the mold opening phenomenon due to the molten metal pressure in the conventional die-casting method becomes unnecessary. Therefore, a large product (cavity) can be cast with a casting machine having a small clamping force. Further, unlike the prior art, since it is not necessary to further pressurize the molten metal by the first pressurizing means such as the plunger tip 25 after filling the molten metal into the cavity 53, it is possible to make the unnecessary portion called the biscuit that inevitably remains in the die-cast product as thin as possible. Therefore, according to the die-casting apparatus 1 according to the present embodiment, it is possible to obtain an effect of improving the yield compared to the prior art, and to gain an advantage in terms of cost.

[0030] As described above, the preferred embodiments of the present invention have been described, but the technical scope of the present invention is not limited to the scope described in the above embodiments. Various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that forms with such changes or improvements can also be included in the technical scope of the present invention.

Explanation of Reference Numerals

[0031] 1 Die casting device, 10 Die casting mold, 20 Fixed mold, 21 Fixed holder, 22 Fixed die, 23 Injection sleeve (sleeve), 24 Plunger rod (first pressurizing means), 25 Plunger tip (first pressurizing means), 30 Movable mold, 31 Movable holder, 32 Movable die, 33 Sub-runner, 34 Through-hole, 34A Upper opening, 40 Hydraulic cylinder (second pressurizing means), 41 Piston rod (second pressurizing means), 42 Coupling, 43 Pressurizing rod (second pressurizing means), 43A Tip portion, 50 Runner, 50A First runner, 50B Second runner, 50C Boundary position, 51 Corresponding shaped portion, 51A Surface, 52 Gate, 53 Cavity, T Time, (ii) First stage, (iv) Second stage.

Claims

1. A die-casting mold that defines a cavity and a runner communicating with the cavity, a first pressurizing means for filling the cavity with molten metal, a second pressurizing means for pressurizing the molten metal in the runner, A control method for a die-casting device comprising a pressurizing rod that advances and retracts in a direction substantially orthogonal to the mold opening direction of the die-casting mold, wherein the pressurizing speed of the molten metal in the runner by the pressurizing rod is a first stage in which high-speed pressurization is performed from when the pressurizing rod starts pressurization until a high-pressure is generated in the cavity by blocking the flow path, a second stage in which low-speed pressurization is performed after the pressurizing rod blocks the flow path and a high-pressure is generated in the cavity, A control method for a die-casting device, characterized in that the pressurizing rod is operated to include the above.

2. In the control method for a die-casting device according to Claim 1, the pressurizing speed consisting of the low-speed pressurization in the second stage is determined based on the solidification shrinkage amount of the molten metal based on solidification analysis. A control method for a die-casting device, characterized in that.

3. In the control method for a die-casting device according to Claim 1, When the time from when the injection of the molten metal into the cavity by the first pressurizing means ends until the first stage of pressurizing the molten metal in the runner by the second pressurizing means ends is T, 0 s < T ≦ 0.2 s A control method for a die-casting device, characterized in that the second pressurizing means is operated so that the inequality is satisfied.

4. A die-casting method, characterized in that die-casting is performed by a die-casting device capable of executing the control method for a die-casting device according to any one of Claims 1 to 3.

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