Injection molding machine

Abstract

To provide an injection molding machine capable of molding both of a resin molded product having a through-hole formed thereto and a resin molded product having no through-hole formed thereto without damaging the appearance of the resin molded product.SOLUTION: In the injection molding machine 1 equipped with a fixed mold 2 and a movable mold 3 arranged so as to be opposed to each other, the fixed mold 2 for forming the design surface of the resin molded product has a molding surface following the design surface of the resin molded product and the shaft 9 for the prepared hole for forming the prepared hole 5 in the resin material M by being inserted toward the resin material M charged in a cavity C from the molding surface. The end face of the shaft 9 for the prepared hole is formed into a shape copying the design surface of the resin molded product and the movable mold 3 has a cylindrical part 19 protruding toward the fixed mold 2 so as to surround the leading end part of the shaft 9 for the prepared hole so as to leave a predetermined interval when the shaft 9 for the prepared hole is inserted in the resin material M.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an injection molding machine that supplies a resin material to a cavity formed in a mold to mold a resin molded product of a desired shape. [Background technology]

[0002] Patent Document 1 describes an injection molding method for molding a resin molded product with a through-hole penetrating through the plate thickness. The injection molding method described in Patent Document 1 is configured to mold the resin molded product through an injection molding process in which a resin material is supplied to a specified mold to obtain a molded product having a plate-shaped portion, and a drilling process in which a CO₂ laser is irradiated onto the plate-shaped portion of the molded product to form a through-hole. To easily and beautifully form the through-hole, the injection molding method described in Patent Document 1 is configured to form a recess in the area where the through-hole will be formed during the injection molding process. Patent Document 1 also describes that it is preferable to form a recess with a conical or pyramidal bottom, a bottom with an arc-shaped cross section, or a polygonal bottom to ensure smooth flow of the resin material around and behind the recess during injection molding. Furthermore, the minimum remaining thickness of the recessed area is set within a predetermined range to shorten the CO₂ laser irradiation time during the drilling process and to prevent deterioration of the flow of the resin material around the recess during the injection molding process. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-234081 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the injection molding method described in Patent Document 1, the recess serving as a pilot hole is formed so that its remaining thickness is thinnest at its center. That is, the tip surface of the pin used to form the recess has a shape in which its central portion protrudes toward the cavity more than the surrounding portion. Therefore, when resin material is supplied to the cavity with the pin retracted, a position corresponding to the center of the pin is recessed toward the cavity, or the portion of the tip surface of the pin surrounding the central portion protrudes from the cavity. That is, unevenness corresponding to the shape of the pin tip is inevitably molded on the surface of the resin molded product. Therefore, when the same injection molding machine is repurposed to mold a resin molded product without a hole, the mold is configured so that the pin is inserted into the cavity from the back side of the resin molded product.

[0005] On the other hand, when a through hole is formed by pressing the bottom surface of a recess with a punch or the like as a secondary process, the peripheral portion of the recess is cut while crushing the resin, so stress cannot be concentrated and burrs occur on the peripheral portion of the through hole formed by the cutting. Therefore, when punching is performed from the back side of the resin molded product, burrs are generated on the front (design surface) side of the resin molded product, which may mar the appearance of the resin molded product.

[0006] This invention was devised with an eye on the above-mentioned technical problems, and aims to provide an injection molding machine that can mold both resin molded products with through holes and resin molded products without damaging the appearance of the resin molded products. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides an injection molding machine which comprises a fixed mold and a movable mold arranged opposite each other and which molds a resin molded product by filling a cavity formed by the fixed mold and the movable mold with a resin material, wherein one of the fixed mold and the movable mold, which forms the design surface of the resin molded product, has a molding surface that conforms to the design surface of the resin molded product, and has a pilot hole shaft that forms a pilot hole in the resin material by being inserted from the molding surface toward the resin material filled in the cavity, the end face of the pilot hole shaft is formed in a shape that conforms to the design surface of the resin molded product, and the other of the fixed mold and the movable mold has a tubular portion that protrudes toward the one of the molds so as to surround the tip of the pilot hole shaft at a predetermined interval when the pilot hole shaft is inserted into the resin material.

[0008] The pilot hole shaft in the present invention may be formed in a cylindrical shape.

[0009] The injection molding machine according to the present invention may have a retaining shaft into which the prepared hole shaft is fitted, and an end face of the retaining shaft may be formed in a shape that matches the design surface of the resin molded product.

[0010] The injection molding machine of the present invention may be configured so that when the pilot hole shaft is retracted from the resin material, the molding surface, the end face of the pilot hole shaft, and the end face of the retaining shaft form a continuous surface.

[0011] The predetermined interval in the present invention may be determined based on the breaking strength of the thin-walled portion to be filled and molded in the predetermined interval. [Effects of the Invention]

[0012] In the injection molding machine of the present invention, one of the molds that forms the design surface of the resin molded product has a molding surface conforming to the design surface of the resin molded product and a pilot hole shaft that forms a pilot hole in the resin material by being inserted from the molding surface toward the resin material filled in the cavity. Therefore, by inserting the pilot hole shaft into the resin material, a pilot hole can be formed in the resin material. Furthermore, the end face of the pilot hole shaft is formed in a shape conforming to the design surface of the resin molded product. Therefore, by not inserting the pilot hole shaft into the resin material, a design surface of the resin molded product without a through hole can be formed. That is, depending on whether or not the pilot hole shaft is inserted into the resin material, it is possible to select whether to form a resin molded product with a through hole or without a through hole. Furthermore, even when the pilot hole shaft is not inserted into the resin material, the end face of the pilot hole shaft is shaped to conform to the design surface of the resin molded product, thereby preventing unintended irregularities from forming on the design surface of the resin molded product, thereby preventing the appearance of the resin molded product from being impaired.

[0013] Furthermore, when the pilot hole shaft is inserted into the resin material, the other mold surrounds the tip of the pilot hole shaft at a predetermined distance and has a tubular portion that protrudes toward the one mold, so the thickness of the resin material filled in that gap can be made thin. Therefore, by applying a pressing force to the pilot hole using a secondary process such as punching, the thin portion can be easily broken to form a through hole. [Brief explanation of the drawings]

[0014] [Figure 1] 1A and 1B are cross-sectional views for explaining an example of an injection molding machine according to an embodiment of the present invention, in which FIG. 1A shows a state in which the pilot hole shaft is retracted, and FIG. 1B shows a state in which the pilot hole shaft is inserted into the filled resin material. [Figure 2] FIG. 2 is an enlarged view of part A in FIG. [Figure 3]1A and 1B are enlarged cross-sectional views for explaining the process of molding a resin molded product using an injection molding machine, in which (a) shows the process of supplying resin material to a cavity, (b) shows the state in which a pilot hole shaft has been inserted into the resin material, and (c) shows the state in which the pilot hole shaft has been pulled out of the resin material. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are merely examples of specific embodiments of the present invention and are not intended to limit the scope of the present invention.

[0016] FIG. 1 is a schematic cross-sectional view of an example of an injection molding machine according to an embodiment of the present invention, in which (a) shows the state in which the pilot hole shaft in the embodiment of the present invention is retracted, and (b) shows the state in which the pilot hole shaft is inserted into the filled resin material.

[0017] The injection molding machine 1 shown in FIG. 1 is provided with a fixed mold 2 and a movable mold 3 facing each other, similar to conventional injection molding machines. In the example shown in FIG. 1, the fixed mold 2 is provided on the upper side, and the movable mold 3 is provided on the lower side. This fixed mold 2 is made of high carbon steel equivalent to S55C. The surface 2a of the fixed mold facing the movable mold 3 (the lower surface in FIG. 1) is formed in a shape imitating the design surface that will become the exterior of the resin molded product. This lower surface 2a corresponds to the "molding surface" in this embodiment of the present invention.

[0018] Like the fixed mold 2, the movable mold 3 is also made of high-carbon steel equivalent to S55C. The movable mold 3 is configured to move toward and away from the fixed mold 2, and by moving the movable mold 3 toward the fixed mold 2, a resin material M is filled into a cavity C formed between the fixed mold 2 and the movable mold 3, thereby molding a resin molded product. Therefore, when the movable mold 3 is moved toward the fixed mold 2, the gaps between the fixed mold 2 and the movable mold 3 at each location are formed to correspond to the shape (plate thickness of each location) of the resin molded product. In other words, the shape of the surface 3a of the movable mold 3 facing the fixed mold 2 (the upper surface in FIG. 1) is determined according to the plate thickness of the resin molded product. Note that FIG. 1 shows only a portion of the fixed mold 2 and the movable mold 3.

[0019] Therefore, after the cavity C is filled with a fluid resin material M (e.g., polypropylene) that has been heated to a predetermined temperature and softened, the filled resin material M is hardened (solidified) by cooling, and then the movable mold 3 is separated from the fixed mold 2, thereby molding a resin molded product of the desired shape.

[0020] This injection molding machine 1 is configured to be able to form an annular pilot hole 5 in a resin molded product by inserting a pilot hole shaft into the softened resin material M that has been filled in the cavity C. This pilot hole 5 is intended to facilitate the formation of a through hole by punching as a secondary process.

[0021] Here, the configuration for forming the pilot hole 5 will be described. In the example shown in Fig. 1, a housing H that houses various members and mechanisms for forming the pilot hole 5 is fixed to the upper surface of the fixed mold 2. This housing H is provided with a holding plate 6 that divides its internal space in the vertical direction. In the following description, the space below the holding plate 6 (on the fixed mold 2 side) will be referred to as a first housing section E1, and the space above the holding plate 6 will be referred to as a second housing section E2.

[0022] A through hole 6a is formed in the holding plate 6 at a position corresponding to the pilot hole 5, and a cylindrical guide shaft (holding shaft) 7 having an outer diameter smaller than the inner diameter of the pilot hole 5 is provided to pass through the through hole 6a. A through hole 2b is also formed in the fixed mold 2 at a position corresponding to the pilot hole 5, and the guide shaft 7 is provided from the holding plate 6 to the lower surface of the fixed mold 2. That is, the axial length of the guide shaft 7 is determined so that the lower end surface of the guide shaft 7 and the lower surface of the fixed mold 2 are flush with each other. In other words, if no through hole is formed in the resin molded product, the lower surface of the guide shaft 7 is formed in a shape that imitates the design surface of the resin molded product so as to function as a surface for forming the design surface of the resin molded product. In the example shown in FIG. 1, the lower end surface of the guide shaft 7 is formed in a flat surface that is continuous with the lower surface of the fixed mold 2.

[0023] A snap ring 8 having a diameter larger than that of the through hole 6a is fitted onto the upper end of the guide shaft 7 that protrudes above the holding plate 6. Therefore, the guide shaft 7 is held in the housing H by the contact between the snap ring 8 and the holding plate 6.

[0024] A cylindrical pilot hole shaft 9 is fitted onto the guide shaft 7 so as to be movable in the axial direction of the guide shaft 7. The pilot hole shaft 9 is made of alloy steel equivalent to SCM440, and its outer diameter is formed to be approximately the same as the inner diameter of the pilot hole 5. The pilot hole shaft 9 is configured to be inserted into the filled resin material M. Therefore, a resistance force corresponding to the filling pressure of the resin material M and its pressure-receiving area acts on the pilot hole shaft 9, so the area of ​​the lower end face of the pilot hole shaft 9 is determined so as to minimize the resistance force acting on the pilot hole shaft 9. In other words, the outer diameter of the guide shaft 7 and the inner diameter of the pilot hole shaft 9 are determined so as to achieve the determined area. The thickness of the pilot hole shaft 9 can be, for example, 1 to 2 mm.

[0025] Furthermore, the axial length of the pilot hole shaft 9 is determined so that when the pilot hole shaft 9 is retracted as shown in Figure 1(a), the lower end surface of the pilot hole shaft 9 is flush with the lower surface of the fixed mold 2. In other words, when no through hole is formed in the resin molded product, the lower end surface of the pilot hole shaft 9 is formed in a shape that imitates the design surface of the resin molded product so that it functions as a surface for forming the design surface of the resin molded product. In the example shown in Figure 1, the lower end surface of the pilot hole shaft 9 is formed in a flat surface that is continuous with the lower surface of the fixed mold 2.

[0026] A flange portion 9a is formed at the upper end of the pilot hole shaft 9, and the flange portion 9a is sandwiched between two clamping plates 10, 11. Specifically, an upper clamping plate 10 having a through hole 10a formed therein through which the guide shaft 7 passes, and a lower clamping plate 11 having a through hole 11a formed therein through which the guide shaft 7 and the pilot hole shaft 9 pass, are provided one on top of the other, and the flange portion 9a is sandwiched between these clamping plates 10, 11. The clamping plates 10, 11 are integrated with bolts or the like, and are provided so as to move up and down within the first housing portion E1.

[0027] An elevating mechanism 12 is provided that moves the clamping plates 10, 11 and the pilot hole shaft 9 up and down by applying a load in the vertical direction to the upper clamping plate 10. The elevating mechanism 12 is composed of a rod 13 connected to the upper clamping plate 10 and an actuator 14 for moving the rod 13 up and down, and is provided in the second storage section E2.

[0028] In the example shown in FIG. 1 , the rod 13 is disposed vertically, its lower portion passing through a through-hole 6b formed in the holding plate 6, and its end fixed to the upper clamping plate 10. An actuator 14 is provided at the upper end of the rod 13. The actuator 14 may be a hydraulic actuator that generates a load that presses the rod 13 downward in response to supplied hydraulic pressure, or an electromagnetic actuator that generates a load that presses the rod 13 downward in response to the supplied electric power. The actuator 14 may be an actuator that can selectively change the direction of the load acting on the rod 13. Alternatively, the actuator may be an actuator that applies a load to the rod 13 in a fixed direction. In this case, for example, a return spring may be provided to press the rod 13 toward the standby position.

[0029] 1, a holding member 15 that holds the actuator 14 is provided above the second housing portion E2. The holding member 15 is provided so as to be movable up and down within the second housing portion E2, and an actuator 16 for driving the holding member 15 is provided and placed on the upper surface of the housing H. The actuator 16 and the holding member 15 are connected by a rod 17, and the holding member 15 is configured to move up and down by controlling the actuator 16.

[0030] 1(b), the clamping plates 10, 11 and the holding member 15 are lowered, and the pilot hole shaft 9 held by the clamping plates 10, 11 is lowered as a unit. As a result, the pilot hole shaft 9 is inserted into the resin material M, and a pilot hole 5 is formed in the resin material M.

[0031] The above-described pilot hole shaft 9 is configured to be inserted into the resin material M after the cavity C is filled with the resin material M. This is to prevent the resin material M branched by the pilot hole shaft 9 from joining together downstream of the pilot hole shaft 9 in the flow direction of the resin material M, thereby preventing the occurrence of wade. Here, "filling with resin material M" does not necessarily mean that the filling pressure has increased to a predetermined threshold value, but rather means that the resin material M has flowed at a position corresponding to the pilot hole shaft 9 to an extent that wade can be prevented, and the cavity C does not necessarily need to be entirely filled with resin material M.

[0032] As described above, the end face of the pilot hole shaft 9 is formed in a shape that matches the design surface of the resin molded product when no through-hole is formed in the resin molded product. In other words, the end face of the pilot hole shaft 9 is not formed in a sharp shape. Therefore, when the pilot hole shaft 9 is inserted into the filled resin material M, no component force is generated that causes the resin material M to flow toward the inner or outer periphery of the pilot hole shaft 9, resulting in a relatively increased resistance force acting on the pilot hole shaft 9. As a result, the plate thickness (remaining thickness) between the pilot hole 5 and the back surface of the resin molded product may vary depending on factors such as the filling pressure. If the remaining thickness varies in this way, the punching load required in the punching process, which is a secondary process, will vary, which may result in punching defects.

[0033] Therefore, the injection molding machine 1 shown in Fig. 1 is configured to mold, together with the pilot hole 5, a thin-walled portion 18 that can be easily broken when a pressing force is applied to the bottom surface of the pilot hole 5. Fig. 2 shows an enlarged view of portion A in Fig. 1 to explain this configuration. As shown in Fig. 2, a cylindrical protrusion 19 that protrudes toward the fixed mold 2 side (i.e., cavity C) is formed on the upper surface of the movable mold 3. This protrusion 19 corresponds to the "tubular portion" in the embodiment of the present invention.

[0034] The height of the protrusion 19 is configured so that when the pilot hole shaft 9 is inserted into the resin material M, it surrounds the periphery of the tip of the pilot hole shaft 9 at a predetermined distance. In other words, the height of the protrusion 19 is determined so that the upper end of the protrusion 19 is higher than the lower end of the pilot hole shaft 9 in the vertical direction. In addition, draft angles are formed on the inner and outer surfaces of the protrusion 19. The height of the protrusion 19 is, for example, 0.3 mm.

[0035] The inner diameter of the protruding portion 19 is determined so that the distance between it and the outer diameter of the pilot hole shaft 9 is a predetermined distance (for example, 0.05 to 0.1 mm). Therefore, when the resin material M is cured, a thin-walled portion 18 is formed with a thickness corresponding to the distance between the inner surface of the protruding portion 19 and the outer surface of the pilot hole shaft 9. The thickness of this thin-walled portion 18 (i.e., the gap within the above-mentioned predetermined range) is determined to be a thickness that provides a breaking strength that allows the thin-walled portion 18 to break when the pilot hole shaft 9 is pressed with a pressing force corresponding to the characteristics of the actuators 14, 16.

[0036] Figure 3 shows an enlarged cross-sectional view to explain the process of molding a resin molded product using the above-mentioned injection molding machine 1, where (a) shows the process of supplying resin material M to cavity C, (b) shows the state where the pilot hole shaft 9 has been inserted into resin material M, and (c) shows the state where the pilot hole shaft has been pulled out of resin material M.

[0037] As shown in Figure 3(a), from the time when the resin material M starts to be supplied to the cavity C until the resin material M passes the point where the pilot hole shaft 9 is inserted in the flow direction of the resin material M, the pilot hole shaft 9 is retracted. Therefore, the resin material M does not branch and flow, and the branched resin material M does not merge. As a result, no wade is generated downstream of the pilot hole shaft 9 in the flow direction of the resin material M.

[0038] After the resin material M has flowed downstream of the position where the pilot hole shaft 9 is inserted in the flow direction of the resin material M, the pilot hole shaft 9 is lowered, thereby inserting the pilot hole shaft 9 into the resin material M as shown in Figure 3(b), and filling the cavity C with the resin material M. Whether the resin material M has flowed downstream of the position where the pilot hole shaft 9 is inserted in the flow direction of the resin material M can be determined based on the elapsed time since the supply of the resin material M began.

[0039] The resin material M is then hardened by cooling the pilot hole shaft 9 while it is inserted in the resin material M. After the resin material M has hardened, the pilot hole shaft 9 is retracted and pulled out of the resin material M, thereby forming a pilot hole 5 at the position where the pilot hole shaft 9 was inserted. Thereafter, the hardened resin material M is removed from the fixed mold 2 and the movable mold 3, and a punching process is performed in which a cylindrical punch is inserted and pressed into the pilot hole 5 in the removed resin material M, thereby forming a resin molded product having a through hole.

[0040] As described above, the pilot hole shank 9 is configured to be inserted into the resin material M from the design surface side of the resin molded product, and the end face of the pilot hole shank 9 is shaped to function as a surface for forming the design surface of the resin molded product if no through hole is formed in the resin molded product. Therefore, by inserting the pilot hole shank 9 into the filled resin material M, the pilot hole 5 can be formed. Conversely, by maintaining the pilot hole shank 9 in a retracted state, in other words, by not inserting it into the resin material M, the design surface of the resin molded product without a through hole can be formed. That is, by advancing or retracting the pilot hole shank 9, it is possible to select between forming a resin molded product with a through hole and a resin molded product without a through hole. Furthermore, by maintaining the pilot hole shank 9 in a retracted state, even when a resin molded product without a through hole is molded, the pilot hole shank 9 has a shape that follows the design surface of the resin molded product, thereby preventing unintended irregularities from forming on the design surface of the resin molded product, thereby preventing the appearance of the resin molded product from being impaired.

[0041] Furthermore, a protrusion 19 having an inner diameter slightly larger than the outer diameter of the pilot hole shaft 9 is formed on the movable die 3, and a thin-walled portion 18 is formed between the pilot hole shaft 9 and the protrusion 19. Therefore, by applying a pressing force to the pilot hole 5 by punching as a secondary process, the thin-walled portion 18 can be easily broken.

[0042] Furthermore, because the pilot hole shank 9 and the protruding portion 19 are formed in a substantially straight line, the gap between them remains substantially constant even if the overlap amount between the pilot hole shank 9 and the protruding portion 19 changes in the vertical direction. Therefore, even if the thickness of the bottom surface of the pilot hole 5 varies due to changes in the filling pressure of the resin material M or variations in the filling pressure, the fractured portion is the thin-walled portion 18, and the cross-sectional area of ​​the thin-walled portion 18 remains almost constant. In other words, the resistance force against the pressing force (punching force) generated by the punching process remains constant. As a result, there is no need to set a high pressing force during punching, taking into account variations in the pressing force required to form a through hole, and punching defects can be reduced. This means that the time required to set the pressing force during punching can be shortened during the production preparation process, and the robustness of the manufacturing process can be improved.

[0043] Furthermore, by forming the pilot hole shaft 9 into a cylindrical shape, it is possible to reduce the resistance force received from the filled resin material M, thereby reducing the pressing force required to insert the pilot hole shaft 9 into the resin material M, in other words, it is possible to reduce the thrust required of each of the actuators 14, 16. As a result, it is possible to reduce the size of each of the actuators 14, 16, and therefore the injection molding machine 1.

[0044] The injection molding machine according to the embodiment of the present invention may have a curved design surface and be configured to form a through hole in the curved design surface. In this case, the end face of the pilot hole shaft may be formed into a curved surface with a predetermined radius of curvature that matches the curved design surface. The lifting mechanism that drives (presses) the pilot hole shaft is not limited to the above-described mechanism and may be configured, for example, to drive the pilot hole shaft using a single actuator. Furthermore, the design surface is not limited to being formed using a fixed mold, but may be formed using a movable mold. In this case, the pilot hole shaft may be provided in the movable mold and a notch may be provided in the fixed mold. Furthermore, the injection molding machine described above has been described using an example in which the movable mold is movable in the vertical direction. However, the injection molding machine may also be configured in such a way that the fixed mold and the movable mold are horizontally opposed to each other and the movable mold is horizontally movable. Furthermore, the pilot holes formed by the injection molding machine of this invention, i.e., the through holes in the resin molded product, are not limited to those with a circular cross section, but may also be through holes with a polygonal cross section, in which case the outer shape of the pilot hole shaft can be formed to match the shape of the through hole. [Explanation of symbols]

[0045] 1 injection molding machine 2 Fixed type 2a Bottom side 3 Movable type 5 Pilot holes 7 Guide shaft 9 Pilot hole shaft 18 Thin-walled section 19 Protrusion C cavity M Resin material

Claims

1. An injection molding machine comprising a fixed mold and a movable mold disposed opposite to each other, the injection molding machine molding a resin molded product by filling a cavity formed by the fixed mold and the movable mold with a resin material, one of the fixed mold and the movable mold, which forms a design surface of the resin molded product, has a molding surface conforming to the design surface of the resin molded product, and also has a pilot hole shaft which is inserted from the molding surface toward the resin material filled in the cavity to form a pilot hole in the resin material; The end surface of the prepared hole shaft is formed in a shape that follows the design surface of the resin molded product, The other of the fixed die and the movable die has a tubular portion protruding toward the one die so as to surround the periphery of the tip end of the pilot hole shaft at a predetermined interval when the pilot hole shaft is inserted into the resin material. An injection molding machine characterized by:

2. 2. The injection molding machine according to claim 1, The pilot hole shaft is formed in a cylindrical shape. An injection molding machine characterized by:

3. 3. The injection molding machine according to claim 2, a retaining shaft into which the pilot hole shaft is fitted, The end face of the retaining shaft is formed in a shape that follows the design surface of the resin molded product. An injection molding machine characterized by:

4. 4. The injection molding machine according to claim 3, When the pilot hole shaft is recessed from the resin material, the molding surface, the end face of the pilot hole shaft, and the end face of the holder shaft are configured to form a continuous surface. An injection molding machine characterized by:

5. 2. The injection molding machine according to claim 1, The predetermined interval is determined based on the breaking strength of the thin-walled portion to be filled and molded in the predetermined interval. An injection molding machine characterized by:

Images