Screw maintenance jig for metal injection molding machine, and screw maintenance method.

Abstract

To provide a jig for screw maintenance of a metal injection molding machine that prevents a screw from coming into contact with the atmosphere during screw removal and cooling, and facilitates exposure of the screw after cooling.SOLUTION: A jig (30) for screw maintenance is composed of: a screw storage part (43) into which a screw (16) is inserted and stored; and a plurality of hanging parts (40). The screw storage part (43) is composed of a plurality of pipe dividing members (34, 38). When the plurality of pipe dividing members (34, 38) are joined together, they are formed into a pipe shape, and when the pipe dividing members (34, 38) are separated from each other, the interior of the pipe is opened.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] The present invention relates to a screw maintenance tool for maintaining a screw of a metal injection molding machine that melts and injects a metal as an injection material, and a screw maintenance method.

Background Art

[0002] A so-called metal injection molding machine that handles a metal such as a magnesium alloy as an injection material includes, for example, a mold clamping device provided on a bed and an injection device also provided on the bed as described in Patent Document 1. The injection device includes a heating cylinder and a screw that can be driven in a rotational direction and an axial direction within the heating cylinder. When a metal injection material is supplied from a hopper and the screw is rotated while heating the heating cylinder with a heater, the metal is melted and sent downstream by the screw, and is metered at the downstream portion of the heating cylinder. When the molten metal is injected into a mold clamped by the mold clamping device, a molded product made of metal can be obtained.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Metal injection molding machines require heating cylinders to reach relatively high temperatures, such as 500°C, to melt the metal injection material. Driving the screw within such a high-temperature heating cylinder has a relatively large impact on the heating cylinder and screw, necessitating periodic maintenance such as screw cleaning. To maintain the screw, it is necessary to remove it from the heating cylinder. However, magnesium alloys, which are widely used as metal materials, have the problem of burning violently when exposed to the atmosphere at high temperatures. Magnesium alloy adheres to the screw after it is removed from the heating cylinder, so it is necessary to remove the screw while minimizing exposure to the atmosphere and then cool it. After cooling, the screw needs to be exposed. However, there is a problem in that there are no suitable jigs for performing this type of maintenance.

[0005] This disclosure provides a screw maintenance jig for a metal injection molding machine that minimizes contact with the atmosphere during screw removal and cooling, and allows for easy exposure of the screw after cooling.

[0006] Other challenges and novel features will become apparent from the description and accompanying drawings in this specification. [Means for solving the problem]

[0007] This disclosure provides a screw maintenance jig comprising a pipe-shaped screw housing section into which a screw is inserted and housed, and a plurality of suspension sections. The screw housing section is composed of a plurality of pipe division members divided by a cut surface parallel to the axis of the pipe. When the plurality of pipe division members are brought close together or joined together, a pipe shape is formed, and when at least some of the pipe division members are separated or moved apart, the inside of the pipe is opened. [Effects of the Invention]

[0008] This disclosure prevents contact with the atmosphere during screw removal and cooling, and allows for easy exposure of the screw after cooling. [Brief explanation of the drawing]

[0009] [Figure 1] This is a front view of a metal injection molding machine according to this embodiment. [Figure 2A] This is a perspective view of a screw maintenance jig according to the first embodiment. [Figure 2B] This is a perspective view of a screw maintenance jig according to the first embodiment. [Figure 3] This is a flowchart illustrating the screw maintenance method according to the first embodiment. [Figure 4A] This is a top view showing a part of the metal injection molding machine according to this embodiment. [Figure 4B] This is a front view of a screw maintenance jig according to the first embodiment. [Figure 4C] This is a top view of a part of a metal injection molding machine according to this embodiment and a screw maintenance jig according to the first embodiment. [Figure 4D] This is a top view of a part of a metal injection molding machine according to this embodiment and a screw maintenance jig according to the first embodiment. [Figure 4E] This is a front view of a screw maintenance jig according to the first embodiment, with the screw inserted. [Figure 4F] This is a front view of a screw maintenance jig according to the first embodiment, with the screw inserted. [Figure 4G] This is a front view of a screw and a screw maintenance jig according to the first embodiment. [Figure 5A] This is a front view of a screw maintenance jig related to a comparative example in which the screw is inserted. [Figure 5B] This is a front view of a screw and a screw maintenance jig related to a comparative example. [Figure 6A] This is a perspective view of a screw maintenance jig according to the second embodiment. [Figure 6B] This is a perspective view of a screw maintenance jig according to a third embodiment. [Figure 7A] This is a side cross-sectional view of a screw and a screw maintenance jig according to the fourth embodiment. [Figure 7B] It is a side cross-sectional view of a screw and a jig for screw maintenance according to the fourth embodiment. [Figure 8] It is a front view of a jig for screw maintenance according to a modified example of the first embodiment.

Mode for Carrying Out the Invention

[0010] Hereinafter, specific embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. For clarity of explanation, the following description and drawings are appropriately simplified. In each drawing, the same elements are denoted by the same reference numerals, and redundant explanations are omitted as necessary. Also, there are parts where hatching is omitted so that the drawings do not become complicated.

[0011] <Metal injection molding machine> The metal injection molding machine 1 according to the present embodiment, which is the object of the screw maintenance method to be described later, will be described. As shown in FIG. 1, the metal injection molding machine 1 according to the present embodiment includes a mold clamping device 2 provided on a bed B and an injection device 3 slidably provided on the bed B.

[0012] <Mold clamping device> The mold clamping device 2 includes a fixed platen 5 fixed to the bed B, a movable platen 6 slidably provided on the bed B, and a mold clamping housing 7 also slidably provided on the bed B. The fixed platen 5 and the mold clamping housing 7 are connected by tie bars 9, 9,... The movable platen 6 is penetrated by the tie bars 9, 9,... A mold clamping mechanism, in this embodiment, a toggle mechanism 10, is provided between the movable platen 6 and the mold clamping housing 7. A fixed-side mold 12 is provided on the fixed platen 5, and a movable-side mold 13 is provided on the movable platen 6, respectively. When the toggle mechanism 10 is driven in the mold clamping device 2, the fixed-side mold 12 and the movable-side mold 13 are opened and closed.

[0013] <Injection device> The injection device 3 is designed to melt and inject metal material and is configured as follows: The injection device 3 comprises a heating cylinder 15, a screw 16 that is movably mounted inside the heating cylinder 15 in both the rotational and axial directions, and a screw drive device 17 that drives the screw 16. A slidable base 18 is provided on the bed B, and the screw drive device 17 is mounted on this base 18. Therefore, the injection device 3 as a whole can move closer to and further away from the clamping device 2. The screw drive device 17 is connected to the base 18 via a pivot shaft 19. Therefore, the injection device 3 can be rotated horizontally around the pivot shaft 19. The heating cylinder 15 is equipped with a hopper 21 and an injection nozzle 22.

[0014] [First Embodiment] <Screw maintenance jig> A screw maintenance jig 30 according to the first embodiment is shown in Figure 2A. The screw maintenance jig 30 according to the first embodiment consists of a lower member 31 and an upper member 32. The lower member 31 consists of a lower pipe division member 34, which is a pipe division member obtained by cutting a metal cylindrical pipe in half at a cut surface parallel to the axis of the pipe, and lower connecting brackets 35, 35 fixed to the lower pipe division member 34. Bolt holes 36, 36, ... are formed in the lower connecting brackets 35, 35, respectively.

[0015] The upper member 32 also includes an upper pipe division member 38, which is a pipe division member obtained by cutting a metal cylindrical pipe in half at a cross-section parallel to the pipe axis. The upper member 32 is composed of this upper pipe division member 38, upper connecting brackets 39, 39 fixed to the upper pipe division member 38, and eye bolts, or suspension parts 40, 40, provided on the upper connecting brackets 39, 39. Bolts 42, 42, ... are provided on the upper connecting brackets 39, 39.

[0016] The lower member 31 and the upper member 32 are joined together as shown in Figure 2B. That is, the upper connecting brackets 39, 39 are joined to the lower connecting brackets 35, 35 and tightened with bolts 42, 42, ... This forms a single metal cylindrical pipe from the lower pipe dividing member 34 and the upper pipe dividing member 38. This pipe has a screw housing section 43 into which the screw 16 (see Figure 1) is inserted and housed, as will be explained later. Therefore, the inner diameter of the metal cylindrical pipe is slightly larger than the diameter of the screw 16 so that the screw 16 can be inserted.

[0017] <Screw maintenance method> The screw maintenance method performed using the screw maintenance jig 30 according to the first embodiment will be explained with reference to the flowchart shown in Figure 3. First, the injection device rotation process S01 is performed. That is, as shown in Figure 4A, the injection device 3 is rotated so that the tip of the heating cylinder 15, i.e., the downstream side, is separated from the clamping device 2. Before rotation, if necessary, the injection device 3 is retracted in the direction away from the clamping device 2. After rotation, the injection nozzle 22 (see Figure 1) is removed from the heating cylinder 15.

[0018] Next, preparation step S02 is carried out as shown in Figure 3. That is, as shown in Figure 4B, the lower member 31 and the upper member 32 are joined in the screw maintenance jig 30, and bolts 42, 42 are tightened to form a pipe-shaped screw storage section 43 from the lower pipe division member 34 and the upper pipe division member 38. In this screw maintenance jig 30, hooks 45, 45 are attached to the suspension parts 40, 40, i.e., eye bolts, and the jig is suspended by a crane not shown in the figure. The screw maintenance jig 30 is then transported by the crane and positioned so that the screw storage section 43 is downstream of the heating cylinder 15, as shown in Figure 4C.

[0019] As shown in Figure 3, the screw removal process S03 is performed. That is, as shown in Figure 4D, the extrusion rods 47, 47, ... are inserted into the heating cylinder 15 from the upstream side of the heating cylinder 15, and the screw 16 is pushed out. As a result, the screw 16 is inserted into the screw storage section 43 of the screw maintenance jig 30. The screw 16 is very hot and has flammable magnesium alloy and other materials attached to it, but the screw 16 pushed out from the heating cylinder 15 is quickly placed into the screw storage section 43 to prevent contact with the atmosphere. This prevents combustion.

[0020] Once the screw 16 is fully inserted and housed in the screw housing 43, the transport process S04 is carried out as shown in Figure 3. That is, as shown in Figure 4E, the screw maintenance jig 30 containing the screw 16 is transported by crane to a designated maintenance work area. The screw maintenance jig 30 in the transported state and placed in the maintenance work area is shown in Figure 4F. In this state, the cooling process S05 shown in Figure 3 is carried out. That is, with the screw 16 housed in the screw housing 43, the screw 16 is allowed to cool while preventing contact with the atmosphere.

[0021] Once the screw 16 has completely cooled, the screw removal process S06 shown in Figure 3 is performed. Specifically, as shown in Figure 4G, the bolts 42, 42 are loosened in the screw maintenance jig 30. This allows the upper member 32 to be separated from the lower member 31. The lower pipe splitting member 34 and the upper pipe splitting member 38 separate, exposing the screw 16. The screw 16 is removed using a transport means such as a crane. Necessary maintenance, such as cleaning the screw 16, is performed. Maintenance of the screw 16 is completed.

[0022] [Comparative Example] Figures 5A and 5B illustrate the screw maintenance jig 100 according to the comparative example. The screw maintenance jig 100 according to the comparative example consists of a screw housing section 101 made of metal pipe and eye bolts 102, 102 attached to the screw housing section 101. Even with such a screw maintenance jig 100 according to the comparative example, it is possible to position it downstream of the heating cylinder 15, as shown in Figures 4C and 4D, to house the screw 16 in a way that minimizes its contact with the atmosphere. Figure 5A shows the screw maintenance jig 100 according to the comparative example with the screw 16 housed inside, suspended by a crane (not shown) equipped with hooks 104, 104.

[0023] However, a problem arises when removing the screw 16 after it has cooled. The screw maintenance jig 100 in the comparative example does not have an opening for the screw storage section 101. Therefore, it is necessary to remove the screw 16 from either of the open ends of the screw storage section 101. For example, as shown in Figure 5B, the jig is suspended by a crane equipped with a hook 104 on only one eyebolt 102. In this way, the screw 16 slides out diagonally from the screw storage section 101 due to its own weight. In this manner, the screw 16 can be removed.

[0024] However, this removal method is dangerous as the screw 16 may fall or slide across the floor. This danger is especially high for heavy screws 16. Also, when the screw storage section 101 is tilted at an angle, some of the magnesium alloy and other materials attached to the screw 16 turn into powder and scatter in large quantities into the surrounding area. In contrast, by using the screw maintenance jig 30 according to the first embodiment (see Figure 3A), such dangers are eliminated and the screw 16 can be removed safely. Furthermore, by using the screw maintenance jig 30, some of the magnesium alloy and other materials attached to the screw 16 do not turn into powder and scatter in large quantities into the surrounding area.

[0025] [Second Embodiment] Figure 6A illustrates the screw maintenance jig 30A according to the second embodiment. The screw maintenance jig 30A according to the second embodiment comprises a pair of pipe division members 51, 51 obtained by cutting a metal cylindrical pipe in half on a plane parallel to the axis. The pair of pipe division members 51, 51 are connected to each other by a plurality of hinge structures 52, 52, ... and each is provided with two suspension parts 54, 54, ...

[0026] In the screw maintenance jig 30A according to the second embodiment, when each of the suspension parts 54, 54, ... is suspended by a crane (not shown), the pair of pipe dividing members 51, 51 rotate around the hinge structure 52, 52, ... and close together. This forms a single circular metal pipe, which is the screw storage section 43A. On the other hand, when the suspension parts 54, 54, ... are removed from the crane, the pair of pipe dividing members 51, 51 open up as shown in Figure 6A, and the inside of the pipe is opened.

[0027] When maintaining the screw 16 (see Figure 1) using the screw maintenance jig 30A according to the second embodiment, the procedure can be carried out in substantially the same manner as the screw maintenance method performed using the screw maintenance jig 30 (see Figures 2A and 2B) according to the first embodiment. That is, as shown in Figure 3, the injection device rotation process S01, the preparation process S02, ..., and the screw removal process S06 are performed.

[0028] However, when using the screw maintenance jig 30A (see Figure 6A) according to the second embodiment, in the preparation step S02, each of the suspension parts 54, 54, ... is suspended by a crane to form the screw storage section 43A. The cooling step S05 is performed without removing the crane from the suspension parts 54, 54, ... so that the pair of pipe dividing members 51, 51 are maintained in a pipe shape. Alternatively, the suspension parts 54, 54, ... may be fixed using a predetermined fastener or the like so that the pair of pipe dividing members 51, 51 are maintained in a pipe shape. In the screw removal step S06, the crane is removed from the suspension parts 54, 54, ... or the fastener or the like is removed. This exposes the screw 16 (see Figure 1) that is placed in the screw storage section 43A. The screw 16 can then be removed.

[0029] [Third Embodiment] Figure 6B shows a screw maintenance jig 30B according to a third embodiment. The screw maintenance jig 30B according to the third embodiment comprises one bifurcated pipe splitting member 56, which is shaped like a metal cylindrical pipe cut in half on a plane parallel to the axis, and two quarter-pipe splitting members 57, 57, which are shaped like a pipe divided into four sections. The quarter-pipe splitting members 57, 57 are connected to both ends of the bifurcated pipe splitting member 56 via hinge structures 52, 52, ... Suspension parts 54, 54, ... are provided on these two quarter-pipe splitting members 57, 57, respectively.

[0030] In this third embodiment of the screw maintenance jig 30B, similar to the screw maintenance jig 30A (see Figure 6A) of the second embodiment, the screw storage section 43B is formed when each of the suspension sections 54, 54, ... is suspended by a crane. Since the screw 16 (see Figure 1) can be maintained using the screw maintenance jig 30B of the third embodiment in the same manner as the screw maintenance method using the screw maintenance jig 30 of the first embodiment, a description of the screw maintenance method will be omitted.

[0031] [Fourth Embodiment] Figures 7A and 7B show a screw maintenance jig 30C according to a fourth embodiment. The screw maintenance jig 30C according to the fourth embodiment comprises a pair of pipe division members 60, 60, which are shaped like a metal cylindrical pipe cut in half on a plane parallel to the axis. The pair of pipe division members 60, 60 are connected to each other by hinge structures 52, 52, ... and rotate around the hinge structures 52, 52, .... In the screw maintenance jig 30C according to the fourth embodiment, operating levers 61, 61, ... are fixed to each of the pair of pipe division members 60, 60. These operating levers 61, 61, ... intersect with each other, and suspension parts 54, 54, ... are formed at the ends of the operating levers 61, 61, ...

[0032] As shown in Figure 7A, the screw maintenance jig 30C according to the fourth embodiment is lifted upward by a crane (not shown) by hooking hooks 45, 45 onto the suspension parts 54, 54, .... This narrows the distance between the operating levers 61, 61, ... shown on the left and right sides of the figure, i.e., the distance between the suspension parts 54, 54, .... This brings the pair of pipe dividing members 60, 60 closer together, forming the pipe storage section 43C. Figure 7A shows the screw 16 inserted and stored in the pipe storage section 43C. On the other hand, if the distance between the left and right operating levers 61, 61, ... i.e., the distance between the suspension parts 54, 54, ... is widened, the pair of pipe dividing members 60, 60 are separated, as shown in Figure 7B. This opens up the inside of the pipe, allowing the screw 16 to be removed.

[0033] The screw maintenance jig 30C according to the fourth embodiment is also provided with a locking mechanism. Specifically, a lock bar 63 is rotatably supported by operating levers 61, ... fixed to one of the pipe dividing members 60. The lock bar 63 has first and second projections 65, 66 formed thereon. As shown in Figure 7A, when the lock bar 63 is lowered with the pair of pipe dividing members 60, 60 closed, the first projection 65 contacts the operating lever 61. As a result, the left and right operating levers 61, 61, ... are prevented from opening. In other words, the pair of pipe dividing members 60, 60 are maintained in a closed state. On the other hand, as shown in Figure 7B, when the lock bar 63 is lowered with the pair of pipe dividing members 60, 60 separated, the second projection 66 contacts the operating lever 61. As a result, the left and right operating levers 61, 61, ... are prevented from closing. In other words, the pair of pipe dividing members 60, 60 are maintained in an open state.

[0034] <Other variations> The screw maintenance jigs 30, 30A, ... according to the first to fourth embodiments can be modified in various ways. Figure 8 shows screw maintenance jigs 30', 30' according to a modified version of the first embodiment. The screw maintenance jigs 30', 30' according to the modified version of the first embodiment have a shorter axial length, but their configuration is the same as that of the screw maintenance jig 30 according to the first embodiment (see Figures 2A and 2B), so a description of the configuration is omitted. The screw maintenance jigs 30', 30' according to the modified version of the first embodiment are designed to insert and house one screw 16 using two jigs.

[0035] Other modifications are also possible. In the screw maintenance jigs 30, 30A, ... according to the first to fourth embodiments, the suspension parts 54, 54, ... are all arranged at two different locations in the axial direction within the screw storage parts 43, 43A, ... However, they may be arranged at three or four or more locations.

[0036] The present invention has been described in detail above based on embodiments, but it goes without saying that the present invention is not limited to the embodiments already described, and various modifications are possible without departing from the spirit of the invention. The multiple examples described above can also be implemented in appropriate combinations. [Explanation of symbols]

[0037] 1 Metal injection molding machine 2 Mold clamping device 3 Injection device 5 Fixed plate 6. Movable plate 7. Clamping housing 9 Tie bar 10 Toggle mechanism 12 Fixed mold 13 Movable mold 15 Heating cylinder 16 Screw 17 Screw drive mechanism 18 Base 19. Swivel axis 21. Hopper 22 Injection nozzles 30 Screw maintenance jig 31 Lower member 32 Upper member 34 Lower pipe splitting member 35 Lower connecting bracket 36 Bolt holes 38 Upper pipe splitting member 39 Upper connecting bracket 40 Hanging part 42 Bolt 43 Screw storage compartment 45 Hook 51 Pipe division member 52 Hinge structure 54 Hanging section 56 Dividing member of two-part pipe 57 Quarter pipe dividing member 60 Pipe dividing member 61 Operating lever 63 Lock bar 65 First projection 66 Second projection

Claims

1. A pipe-shaped screw storage section into which a screw is inserted and stored, It comprises a plurality of suspension parts provided for the screw storage section, The screw storage section is composed of a plurality of pipe dividing members divided by a cut surface parallel to the axis of the pipe, and the plurality of pipe dividing members are arranged in close proximity to each other or joined together to form a pipe shape, or at least some of the pipe dividing members are spaced apart or separated from each other, opening up the inside of the pipe, in a screw maintenance jig for a metal injection molding machine.

2. The screw maintenance jig for a metal injection molding machine according to claim 1, wherein the pipe division member is provided with a plurality of connecting brackets, and when the connecting brackets are joined together, a sealed pipe shape is formed from the plurality of pipe division members, and the suspension portion is fixed to the connecting brackets provided on at least some of the pipe division members.

3. The screw maintenance jig for a metal injection molding machine according to claim 1, wherein the multiple pipe division members are connected to each other by a hinge structure.

4. The screw maintenance jig for a metal injection molding machine according to claim 3, wherein one pipe division member and another pipe division member are each provided with the suspension portion, and when the suspension portions of the one pipe division member and the other pipe division member are suspended, a sealed pipe shape is formed from the multiple pipe division members.

5. The screw maintenance jig for a metal injection molding machine according to claim 4, wherein the screw maintenance jig is equipped with a locking mechanism, and when the suspension portion provided on one pipe division member and the suspension portion provided on another pipe division member are locked together, a sealed pipe shape formed from the plurality of pipe division members is maintained.

6. The screw storage section comprises a pair of pipe division members formed by splitting a pipe in half, the pair of pipe division members are connected by a hinge structure and each has a suspension portion fixed to it, and when the gap between the suspension portion of one pipe division member and the suspension portion of the other pipe division member is widened, the pair of pipe division members open up and the inside of the pipe is opened, and when the gap is narrowed, the pair of pipe division members close up and form a sealed pipe shape, the screw maintenance jig for a metal injection molding machine according to claim 1.

7. The screw maintenance jig for a metal injection molding machine according to claim 1 or 2, wherein the screw maintenance jig is composed of a plurality of units, and when the plurality of screw maintenance jigs are arranged so that their respective screw storage sections are continuous in the axial direction, the entire screw is stored by each of the screw storage sections.

8. A screw maintenance method for maintaining the screws of a metal injection molding machine using a screw maintenance jig, The screw maintenance jig includes a pipe-shaped screw storage section into which the screw is inserted and stored, It comprises a plurality of suspension parts provided for the screw storage section, The screw housing is composed of a plurality of pipe division members divided by a cut surface parallel to the axis of the pipe, and the plurality of pipe division members are arranged in close proximity to each other or joined together to form a pipe shape, or at least some of the pipe division members are spaced apart or separated from each other, leaving the inside of the pipe open. The screw maintenance method includes a preparation step of forming the screw storage section into a sealed pipe shape from a plurality of pipe division members, hanging the screw maintenance jig by attaching the crane hook to the suspension part, and positioning the pipe-shaped screw storage section downstream of the heating cylinder, A screw removal process involves inserting an extrusion rod from the upstream side of the heating cylinder to push the screw downstream, and then inserting and storing the screw in the screw housing section. A transport process for transporting the screw maintenance jig, in which the screw is stored in the screw storage section, to the maintenance work area, A cooling step in which the screw is stored in the screw housing and the screw is allowed to cool down, A screw maintenance method for a metal injection molding machine, comprising: a screw removal step of separating at least some of the pipe dividing members from each other to open the inside of the pipe and remove the screw.

9. The screw maintenance method includes an injection device rotation step performed prior to the preparation step, The screw maintenance method for a metal injection molding machine according to claim 8, wherein the injection device rotation step is a step of rotating an injection device, which is rotatably mounted on the bed in the metal injection molding machine, to separate the downstream end of the heating cylinder from the clamping device of the metal injection molding machine.

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