Die casting machine and die casting method based on die casting machine

Abstract

The invention provides a die casting machine and a die casting method based on the die casting machine. A die casting machine (10) is configured from: an injection plunger (44) that injects and fills a cavity (34) with a melt; a mold clamping device (12) that clamps the movable mold (32); and a gate closure detection parameter measurement device (27) for measuring gate closure detection parameters for detecting closure of the gate (G). Furthermore, by setting the clamping force X of the fixed mold (30) with respect to the movable mold (32) by the injection plunger (44), the casting pressure P is set such that the opening force Y of the movable mold (32) with respect to the molten metal injected into the cavity (34) is equal to or less than the clamping force X, and the molten metal is injected and filled in an amount equal to the volume of the cavity (34), and then the casting pressure P is set such that the opening force Y of the movable mold (32) with respect to the molten metal injected into the cavity (34) is equal to or less than the clamping force X. The mold opening force Y is greater than the mold closing force X and the molten metal exceeding the volume of the mold cavity 34 is injected, and the casting pressure P is reduced to a lower value or to zero after a predetermined time has elapsed by detecting the closing of the gate G.

Description

Technical Field

[0001] This invention relates to a die casting machine for casting castings by injecting molten liquid into a mold, and a die casting method based on the die casting machine. Background Technology

[0002] In conventional die-casting machines, molten aluminum alloy or other materials melted in a melting furnace are measured and scooped out using a ladle each time an injection is performed. The scooped-out molten material is poured into the gating port of the injection sleeve. The molten material is injected into the mold cavity by the forward movement of the injection plunger, which is configured to move in and out of the injection sleeve, thereby casting the product.

[0003] In die casting, which is typically based on a die casting machine, if the molten metal filling the mold cavity is pressurized using an injection plunger, a force (opening force) will be generated along the mold opening direction according to Pascal's principle. When mold opening occurs, burrs and flash will be generated on the casting, so the force for securing the mold (closing force) is usually set to be greater than the opening force.

[0004] Defects in castings produced using die casting machines are known to include shrinkage cavities (solidification shrinkage cavities) caused by the volume shrinkage of the molten metal as it cools and solidifies within the mold cavity. Castings exhibiting these defects have poor mechanical properties. Therefore, a common practice is to replenish the volume of the molten metal that has shrunk after filling by pressurizing the injection plunger (a shrinkage compensation effect), thereby reducing these defects (e.g., Japanese Patent Application Publication No. 2014-065062). Summary of the Invention

[0005] However, in existing die casting methods based on die casting machines, the molten metal needs to be injected and filled into the mold cavity at high speed. The inlet, i.e., the gate, leading to the mold cavity is generally extremely narrow and thin, and it solidifies immediately after filling. Therefore, the supply of molten metal to the volume shrinkage portion by pressurizing the injection plunger is blocked, resulting in the problem of not being able to obtain a sufficient shrinkage compensation effect.

[0006] The present invention was made in view of this problem, and its object is to provide a die casting machine and a die casting method based on the die casting machine, which can obtain a feeding effect even after solidification and gate closure, and furthermore, can improve the internal quality of the casting by maximizing the feeding effect.

[0007] According to one aspect of the present invention, a die-casting machine is provided, comprising: A mold consists of a fixed mold and a movable mold. A mold cavity, which is formed inside the mold; An injection plunger is used to inject molten liquid into the mold cavity; A mold-closing device, relative to the fixed mold, performs mold opening, closing, and mold closing on the movable mold; and A gate closure detection parameter measuring device is used to measure gate closure detection parameters that can detect the start of gate closure. The injection plunger sets the casting pressure relative to the clamping force of the movable mold on the fixed mold via the clamping device, so that the mold-opening force of the molten metal injected into the mold cavity on the movable mold is equal to or less than the clamping force, and the molten metal injected fills the mold cavity with an amount equal to the volume of the mold cavity. Then, the casting pressure is set such that the mold opening force is greater than the mold closing force, and the molten metal is injected to fill the mold cavity exceeding its volume. After the gate closure detection parameter measuring device detects the start of gate closure and a specified time has elapsed, the casting pressure is reduced to a lower level or to zero.

[0008] Preferably, The gate sealing detection parameter is the mold closing force. After the clamping force begins to decrease and a specified time has elapsed, the casting pressure is reduced to a lower level or to zero.

[0009] According to another aspect of the present invention, a die-casting method based on a die-casting machine is provided, the die-casting machine comprising: A mold consists of a fixed mold and a movable mold. A mold cavity, which is formed inside the mold; An injection plunger is used to inject molten liquid into the mold cavity; A mold-closing device, relative to the fixed mold, performs mold opening, closing, and mold closing on the movable mold; and A gate closure detection parameter measuring device is used to measure gate closure detection parameters that can detect the start of gate closure. The casting pressure is set by means of the injection plunger, relative to the setting of the clamping force of the movable mold on the fixed mold via the clamping device, so that the mold opening force of the molten liquid injected into the mold cavity on the movable mold is equal to or less than the clamping force, and the molten liquid injected fills the mold cavity with an amount equal to the volume of the mold cavity. Then, the casting pressure is set such that the mold opening force is greater than the mold closing force, and the molten metal is injected to fill the mold cavity exceeding its volume. After the gate closure detection parameter measuring device detects the start of gate closure and a specified time has elapsed, the casting pressure is reduced to a lower level or to zero.

[0010] Preferably, The gate sealing detection parameter is the mold closing force. After the clamping force begins to decrease and a specified time has elapsed, the casting pressure is reduced to a lower level or to zero.

[0011] According to the die casting machine and die casting method based on the die casting machine of the present invention, a feeding effect can be obtained even after solidification and gate closure. Furthermore, the feeding effect can be maximized by reducing the casting pressure based on the injection plunger to a lower level or to zero, thereby improving the internal quality of the casting. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating an example of a die-casting machine 10 according to an embodiment.

[0013] Figure 2 It is a graph showing the changes in casting pressure P (P'), mold pressure Q, clamping force X (X'), mold opening force Y, and compression force Z during the casting process using die casting machine 10.

[0014] Figure 3 This is a schematic diagram showing the mold 28 and the state of the molten liquid in the casting process using the die-casting machine 10, showing the state of the molten liquid being injected into the mold cavity.

[0015] Figure 4 This is a schematic diagram showing the mold 28 and the state of the molten liquid in the casting process using the die-casting machine 10, showing the state in which the movable mold 32 is separated from the fixed mold 30.

[0016] Figure 5 This is a schematic diagram showing the mold 28 and the state of the molten metal in the casting process using the die-casting machine 10, showing the state where the movable mold 32 is separated from the fixed mold 30 and the gate is closed.

[0017] Figure 6 This is a schematic diagram showing the mold 28 and the state of the molten liquid in the casting process using the die-casting machine 10, showing the state where the casting pressure P based on the injection plunger 44 is reduced to a lower level or to zero.

[0018] Figure 7 This is a schematic diagram showing the mold 28 and the state of the molten liquid in the casting process using the die-casting machine 10, showing the changing state of the gap between the movable mold 32 and the fixed mold 30 and the state after the molten liquid has solidified.

[0019] [Symbol Explanation] 10…Die casting machine 12… Mold Closing Device 14…Injection device 15…Control Device 16… machines 18…fixed plate 20… movable disc 22…tail seat 24…Pull rod 26…Toggle Mechanism 27…Clamping Force Measuring Device 28… mold 30… Fixed mold 31… Mold Closing Drive Mechanism 32…Modible mold 34…mold cavity 36…Pull rod through hole 38…Injection facilities 40…Hydraulic actuation mechanism 42…Injection sleeve 44…Injection plunger 46…Injection Piston 48…Injection cylinder 50…Gating gate O…work oil P…casting pressure Q… Mold internal pressure X…Closing force Y… Mold opening force Z…compression force G…Gate W…gap Detailed Implementation (Composition of die-casting machine 10) like Figure 1 As shown, the die-casting machine 10 involved in this embodiment generally includes a mold clamping device 12, an injection device 14, and a control device 15.

[0020] The mold clamping device 12 includes a machine base 16, a fixed plate 18, a movable plate 20, a tailstock 22, a tie rod 24, an elbow mechanism 26, and a mold clamping force measuring device 27.

[0021] The machine base 16 is a component that constitutes the mold clamping device 12 and serves as the base for the injection device 14.

[0022] The fixed plate 18 is fixed on the machine base 16 and a fixed mold 30 constituting the mold 28 is installed.

[0023] The movable plate 20 is a component that slides on the machine base 16 in a manner that is nearly separated from the fixed plate 18, and a movable mold 32 constituting the mold 28 is mounted on it. The movable mold 32 contacts the fixed mold 30 to form a mold cavity 34 filled with molten liquid.

[0024] Viewed from the movable plate 20, the tailstock 22 is a component mounted on the machine base 16 on the opposite side of the fixed plate 18.

[0025] The pull rod 24 is a rod-shaped component with one end fixed to the fixed plate 18 and the other end fixed to the tailstock 22. Furthermore, the pull rod 24 is inserted through a pull rod insertion hole 36 formed in the movable plate 20, which is positioned between the fixed plate 18 and the tailstock 22. Thus, the movable plate 20 can slide along the pull rod 24 on the machine base 16 in the left-right direction shown in the figure. It should be noted that multiple pull rods 24 are used (e.g., four).

[0026] The toggle mechanism 26 is a mechanism for bringing the movable disk 20 close to and holding it relative to the fixed disk 18. The mold closing drive mechanism 31 is mounted on the tailstock 22.

[0027] The clamping force measuring device 27 is used to measure the clamping force X of the movable mold 32 relative to the fixed mold 30. For example, it can be considered as a device mounted on the tie rod 24 and measuring the clamping force X based on the amount of deformation (elongation) when the tie rod 24 is extended. Of course, the measurement method is not limited as long as the clamping force X of the movable mold 32 relative to the fixed mold 30 can be measured.

[0028] The movable plate 20 moves along the tie rod 24 (moving left-right in the figure) by transmitting the driving force of the mold closing drive mechanism 31 via the toggle mechanism 26. If the movable plate 20 moves to the left, the fixed mold 30 separates from the movable mold 32. On the other hand, if the movable plate 20 moves to the right, the fixed mold 30 abuts against the movable mold 32, forming a mold cavity 34 (internal space) inside the mold 28. Moreover, if further pressure is applied to move the movable plate 20 to the right, the fixed mold 30 and the movable mold 32 close.

[0029] At this point, the toggle mechanism 26 gradually extends from its bent state. When the movable mold 32 contacts the fixed mold 30, the tie rod 24 begins to extend, undergoing deformation proportional to the tensile stress. The tension in the tie rod 24 is applied as a clamping force to both the fixed mold 30 and the movable mold 32. When the toggle mechanism 26 extends to its maximum, the tie rod 24 also extends to its maximum. When the movable mold 32 reaches the position where the mold is fully closed, the prescribed clamping force is applied to both the fixed mold 30 and the movable mold 32.

[0030] The injection device 14 generally includes an injection mechanism 38 and a hydraulic actuation mechanism 40.

[0031] The injection mechanism 38 includes an injection sleeve 42, an injection plunger 44, an injection piston 46, and an injection cylinder 48.

[0032] The injection sleeve 42 is a cylindrical component integrally formed with the fixed plate 18, and a pouring port 50 for supplying molten liquid is formed on its upper part.

[0033] The injection plunger 44 is a generally rod-shaped component that is retractably disposed within the injection sleeve 42.

[0034] The injection piston 46 is formed on the rear end side of the injection plunger 44 (the end opposite to the end in contact with the molten liquid) and is the part that is pushed by the working oil O.

[0035] The injection cylinder 48 is a cylindrical component that allows the injection piston 46 to move forward and backward, and it is filled with working oil O.

[0036] The hydraulic actuation mechanism 40 is used to supply the working oil O used in the injection process of the injection plunger 44 to the injection cylinder 48 and to make the working oil O act on the injection piston 46. In addition, by supplying pressurized oil to the injection cylinder 48, a force (casting pressure P) in the leftward direction shown in the figure is applied to the injection plunger 44.

[0037] When performing the injection process and the retraction process of the injection plunger 44, the control device 15, in addition to detecting the position information of the injection piston 46 and driving the hydraulic action mechanism 40, also performs all the control required for the die casting machine 10 to perform casting.

[0038] (The casting process of the die-casting machine 10 involved in this embodiment) The following uses Figures 2-7 The steps for casting a molded article (molded body) using the die-casting machine 10 according to this embodiment will be described. It should be noted that, due to... Figure 2 It is a graph showing the changes in casting pressure P, mold pressure Q, mold closing force X, mold opening force Y, and compression force Z throughout the entire casting process of the die casting machine 10, and can be used as a reference throughout the entire casting process.

[0039] It should be noted that the casting pressure P refers to the pressure exerted on the molten metal within the injection sleeve 42 by the injection plunger 44. As described below, before the gate G begins to close, according to Pascal's principle, the same casting pressure P is applied to the molten metal within the mold cavity 34. However, after the gate G begins to close, the casting pressure P becomes the pressure applied to the molten metal within the injection sleeve 42.

[0040] The pressure Q inside the mold refers to the pressure of the molten liquid (=cast product) acting inside the mold cavity 34.

[0041] The clamping force X refers to the force that pushes the movable disk 20 towards the fixed disk 18 through the movable mold 32, and can be calculated based on the elongation (deformation) of the pull rod 24 that extends from the movable disk 20.

[0042] The mold opening force Y refers to the thrust of the molten liquid and the fixed mold 30 in the direction that separates the movable mold 32 from the fixed mold 30.

[0043] The compressive force Z refers to the force obtained by subtracting the mold opening force Y from the mold closing force X during the compression process, which is the force applied by the movable mold 32 to the molten liquid (= casting) in the mold cavity 34.

[0044] Control device 15 drives mold closing drive mechanism 31 and causes movable mold 32 to close relative to fixed mold 30, thereby closing the mold with a specified mold closing force X. Figure 2 (1)).

[0045] Then, the control device 15 injects the molten liquid into the mold cavity 34 of the mold 28 by advancing the injection plunger 44. Figure 3 At this time, the control device 15 sets the casting pressure P by relative to the clamping force X of the movable mold 32 on the fixed mold 30, so that the mold opening force Y of the molten liquid injected into the mold cavity 34 on the movable mold 32 is equal to or less than the clamping force X, thereby injecting and filling molten liquid with a volume substantially equal to that of the mold cavity 34. Figure 2 (2)).

[0046] Next, after the control device 15 injects and fills the mold cavity 34 with a volume of molten liquid that is substantially equal to the volume of the mold cavity 34, it holds the mixture for a certain period of time to form a chilled layer on the surface of the mold cavity 34. Figure 2 (2) to (3)), causing the injection plunger 44 to advance further to increase the casting pressure P, thereby initiating the injection of molten liquid that fills a volume exceeding that of the mold cavity 34. Figure 2 (3)).

[0047] It should be noted that the chilled layer (cooled solidification film layer) refers to the metal structure formed after the molten liquid comes into contact with the surface of the mold cavity 34 and is rapidly cooled. Because the metal structure of the chilled layer formed on the surface of the casting is fine and dense, it is considered a beneficial structure that can improve the strength of die-cast castings.

[0048] When the mold opening force Y is less than or equal to the mold closing force X (Y≤X), the injection plunger 44 cannot move toward the mold cavity 34. However, if the casting pressure P is increased (the casting pressure after the pressure increase is denoted as "casting pressure P'"), and the mold opening force Y is greater than the mold closing force X (Y>X), the injection plunger 44 can move forward and inject molten liquid that fills a volume exceeding that of the mold cavity 34.

[0049] In addition, since the mold opening force Y is greater than the mold closing force X, such as Figure 4 As shown, through the mold opening force Y, the movable mold 32 and the movable disk 20 begin to separate from the fixed mold 30. Figure 2(3)). This separation is not caused by the bending of the toggle mechanism 26, but by the elongation caused by the elastic deformation of the tie rod 24. It should be noted that if the tie rod 24 elongates, the clamping force X will increase with the elongation (the increased clamping force is denoted as "clamping force X'"). The tie rod 24 is elongated only by a specified length by the mold opening force Y based on the casting pressure P' transmitted by the melt, so that the clamping force X' rises to be equal to the mold opening force Y. Thus, if the clamping force X' is equal to the mold opening force Y (Y=X'), the separation of the movable mold 32 and the movable disk 20 stops ( Figure 2 (4)).

[0050] If the movable mold 32 separates from the fixed mold 30, a gap W is formed between them at the mold parting surface. Molten metal will flow into this gap, potentially causing burrs and flash. However, in the die-casting machine 10 of this embodiment, as described above, after a chilling layer is formed on the surface of the mold cavity 34, the injection plunger 44 is advanced by the casting pressure P'. Therefore, the chilling layer on the surface of the mold cavity 34 acts to seal the gap W, preventing residual unsolidified molten metal from leaking out from the gap W. In other words, when the injection plunger 44 is advanced by the casting pressure P', although the molten metal on the surface of the mold cavity 34 solidifies, most of the molten metal inside the mold cavity 34 has not yet solidified.

[0051] After the movable mold 32 and the movable disk 20 stop separating from the fixed mold 30, the injection plunger 44 also stops. Figure 2 (4) to (5)). And during this period, such as Figure 5 As shown, the molten metal at gate G solidifies first, and gate G is closed. Figure 2 (5) to (6)). As a result, the pressurization of the mold cavity 34 by the injection plunger 44 and the supply of melt are blocked, and the feeding effect based on the injection plunger 44 is then interrupted.

[0052] Because the gate G is closed, even with pressure applied through the injection plunger 44, the molten metal filling the mold cavity 34 will not generate a mold-opening force Y based on Pascal's principle, and the molten metal begins to cool and solidify and shrink. Therefore, at this point, the mold pressure Q, which is almost equal to the casting pressure P or P', decreases compared to the casting pressure P', and the previously stable mold-opening force Y also begins to decrease sharply. Figure 2 (5)).

[0053] On the other hand, since the tie rod 24 is pre-extended, it will contract as the mold opening force Y decreases, causing the movable mold 32 and the movable disk 20 to move closer to the fixed mold 30. However, since the molten liquid in the mold cavity 34 (although a portion of it is not molten liquid but has solidified, but including this solidified portion, it will continue to be referred to as "molten liquid") is sandwiched between the movable mold 32 and the fixed mold 30, the movable mold 32 and the fixed mold 30 will gradually move closer together due to the volume reduction caused by the solidification and contraction of the molten liquid. Therefore, the molten liquid is always subjected to the closing force X' or X from the movable mold 32 and the fixed mold 30, generating a compressive force Z on the molten liquid.

[0054] Additionally, the volume reduction due to solidification shrinkage is replenished by molten metal pre-filled with a volume greater than that of the mold cavity 34. During the molten metal replenishment phase, the tie rod 24 gradually contracts, and the clamping force X' or X gradually decreases. Figure 2 (5) to (7)). During this period, the pressure Q and the compression force Z inside the mold also gradually decrease.

[0055] Thus, as the clamping force X' or X begins to decrease ( Figure 2 When (5) is reached, the start of gate G closing can be detected. Therefore, after the clamping force X' or X begins to decrease and a specified time (a margin of time reserved to ensure that gate G is completely closed) has elapsed, gate G closing is complete. Figure 2 (6) will reduce the casting pressure P based on injection plunger 44 to a lower level or to zero. Figure 2 (7) It should be noted that since the gate G is completely closed, even if the casting pressure P is reduced to a lower level or to zero, it will not have an effect on the molten liquid in the mold cavity 34 based on Pascal's principle.

[0056] Therefore, as Figure 6 As shown, the molten metal filled between the injection sleeve 42 and the gate G, under casting pressure P, loses the force (= residual mold opening force Y) pressing in the direction that opens the movable mold 32. Only the mold closing force X' or X acts on the molten metal in the mold cavity 34. As a result, the mold pressure Q and compressive force Z borne by the molten metal in the mold cavity 34 (i.e., the part that becomes the casting) increase, thus further improving the internal quality of the casting.

[0057] After the gate G is closed, if the casting pressure P generated by the injection plunger 44 is not reduced, the force exerted by the molten metal filling the space between the injection sleeve 42 and the gate G under the applied casting pressure P in the direction the movable mold 32 opens (= residual mold opening force Y) still exists. Therefore, as Figure 2 As shown, the mold opening force Y does not decrease but remains constant, and the mold pressure Q and compressive force Z borne by the molten liquid in the mold cavity 34 (that is, the part that becomes the casting) do not increase due to the mold opening force Y.

[0058] Then, as Figure 7 As shown, during the stage when the molten metal in the mold cavity 34 has solidified, there is a gap between the fixed mold 30 and the movable mold 32. Figure 2 The gap W' is narrower than the gap W' in (4) to (5). In this way, before the molten metal in the mold cavity 34 has solidified, it can always be subjected to the clamping force X' or X from the movable mold 32 and the fixed mold 30, and continuously generate pressure in the molten metal. Therefore, even after the gate G is closed, the shrinkage compensation effect can be obtained. This effect can be achieved by Figure 2 It can be seen that the clamping force at (8) to (9) is greater than the clamping force X at (1) when the clamping is completed.

[0059] Furthermore, after the molten metal has solidified, the mold closing drive mechanism 31 of the mold closing device 12 causes the movable mold 32 to separate from the fixed mold 30 (mold opening). Figure 2 (9) The casting is removed from the mold cavity 34 by an ejector pin (not shown). Thus, the casting of the casting based on the die casting machine 10 is completed.

[0060] Furthermore, in the die-casting machine 10 of this embodiment, as described above, by controlling the injection plunger 44 and adjusting only the casting pressure P (P') of the molten liquid in the mold cavity 34 (related to the mold opening force), the separation distance (gap W) of the mold 28 in the casting process and the time when the molten liquid solidifies can be freely adjusted without controlling the mold closing drive mechanism 31 in the casting process. Figure 2 The clamping force X of (7)).

[0061] (Variation Example 1) In the above embodiment, the clamping force measuring device 27 is used to detect the start of gate G closure by measuring the clamping force X, but if Figure 2 As shown, the decrease in mold pressure Q or compression force Z is used instead of mold clamping force X to confirm the start of gate G closure. When the mold pressure Q or compression force Z begins to decrease and a specified time has elapsed, it can be determined that gate G closure is complete.

[0062] In this specification, the clamping force X, the internal mold pressure Q, or the compression force Z that can detect the "start of gate G closure" are collectively referred to as "gate closure detection parameters". In addition, the device for measuring these "gate closure detection parameters" is collectively referred to as "gate closure detection parameter measuring device".

[0063] (Variation Example 2) The fixed mold 30 and movable mold 32 described in the above embodiments are shown as examples where the periphery of the mold parting surface is flat. However, the present invention is not limited to this, and a shearing edge structure can also be used. A shearing edge structure refers to a mating structure formed between the fixed mold 30 and the movable mold 32, which allows for insertion and removal while sliding against each other. By employing a shearing edge structure, leakage of the molten material injected into the mold cavity 34 to the outside of the mold can be effectively prevented. In particular, in the present invention, due to the effect of preventing molten material leakage produced by employing the shearing edge structure, the gap W can be further increased (allowing the tie rod 24 to extend further). Therefore, by increasing the clamping force X applied to the molten material and increasing the amount of molten material supplied, the shrinkage compensation effect can be made more significant. The shearing edge structure is also called a shearing clamp structure or an insert structure.

[0064] (Variation Example 3) The molten liquid described in the above embodiments is based on the premise that it consists only of a liquid phase exceeding the melting point of the metal, but the present invention is not limited to this. For example, it can be a metal in which a molten liquid consisting only of a liquid phase is cooled to a semi-solid state, or it can be a metal in a semi-molten state where a solid phase of metal is heated to generate a liquid phase, resulting in a solid-liquid coexistence. In the present invention, both molten liquid consisting only of a liquid phase and metal in a semi-solid state are collectively referred to as molten liquid.

[0065] (Variation Example 4) The injection device 14 in the above embodiment is based on hydraulic drive, but the present invention is not limited thereto. For example, the injection device 14 may also be configured as an electric cylinder driven by a motor. Since the plunger's movement accuracy can be improved compared to a hydraulic cylinder, the present invention is preferably applied in a die-casting machine 10 that allows for more stable variation of the casting pressure P.

[0066] (Variation Example 5) Although an example of a horizontal configuration of the die-casting machine 10 has been shown, the invention is not limited thereto. In the present invention, the die-casting machine 10 may also be configured as a vertical configuration.

[0067] (Variation Example 6) In this embodiment, although Figure 2 The process of varying the mold opening force Y shown in (2) to (6) illustrates an example of two stages, but the Figure 2 The mold opening force Y of (3) to (5) is the smallest number of mold opening force segments in this invention. That is to say, the casting pressure P (P') can also be adjusted by dividing it into 3 or more segments, thereby changing the mold opening force Y.

[0068] (Variation Example 7) Furthermore, the present invention can also be applied to multi-cavity molds with multiple cavities in one mold. In the case of a multi-cavity mold, the closing time of each gate G is different. If pressure is applied only by the injection plunger as in the past, the difference in the shrinkage compensation effect will lead to the difference in internal quality. However, as mentioned above, in the present invention, the clamping force X' or X from the movable mold 32 and the fixed mold 30 is always applied, and the shrinkage compensation effect can be obtained even after the gate G is closed. Therefore, the present invention is also suitable for multi-cavity molds.

[0069] The embodiments disclosed herein should be considered illustrative rather than limiting in all respects. The scope of the invention is indicated by the scope of the claims rather than the foregoing description, and is intended to include all modifications within the scope of the claims and of the same meaning.

Claims

1. A die-casting machine, comprising: A mold consists of a fixed mold and a movable mold. A mold cavity, which is formed inside the mold; An injection plunger is used to inject molten liquid into the mold cavity; A mold-closing device, relative to the fixed mold, performs mold opening and closing and mold closing on the movable mold; as well as A gate sealing detection parameter measuring device, used to measure gate sealing detection parameters that can detect the start of gate sealing, characterized in that... The injection plunger sets the casting pressure relative to the clamping force of the movable mold relative to the fixed mold via the clamping device, so that the mold-opening force of the molten metal injected into the mold cavity on the movable mold is equal to or less than the clamping force, and the molten metal injected fills the mold cavity with an amount equal to the volume of the mold cavity. Then, the casting pressure is set such that the mold opening force is greater than the mold closing force, and the molten metal is injected to fill the mold cavity exceeding its volume. After the gate closure detection parameter measuring device detects the start of gate closure and a specified time has elapsed, the casting pressure is reduced to a lower level or to zero.

2. The die-casting machine according to claim 1, wherein, The gate sealing detection parameter is the mold closing force. After the clamping force begins to decrease and a specified time has elapsed, the casting pressure is reduced to a lower level or to zero.

3. A die-casting method based on a die-casting machine, wherein the die-casting machine comprises: A mold consists of a fixed mold and a movable mold. A mold cavity, which is formed inside the mold; An injection plunger is used to inject molten liquid into the mold cavity; A mold-closing device, relative to the fixed mold, performs mold opening and closing and mold closing on the movable mold; as well as A gate sealing detection parameter measuring device, used to measure gate sealing detection parameters that can detect the start of gate sealing, characterized in that... The casting pressure is set by means of the injection plunger, relative to the setting of the clamping force of the movable mold on the fixed mold via the clamping device, so that the mold opening force of the molten liquid injected into the mold cavity on the movable mold is equal to or less than the clamping force, and the molten liquid injected fills the mold cavity with an amount equal to the volume of the mold cavity. Then, the casting pressure is set such that the mold opening force is greater than the mold closing force, and the molten metal is injected to fill the mold cavity exceeding its volume. After the gate closure detection parameter measuring device detects the start of gate closure and a specified time has elapsed, the casting pressure is reduced to a lower level or to zero.

4. The die-casting method according to claim 3, wherein, The gate sealing detection parameter is the mold closing force. After the clamping force begins to decrease and a specified time has elapsed, the casting pressure is reduced to a lower level or to zero.

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