JP2012061622A - Mold device and molding device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold device easily adjustable of the difference of resin pressure generating among a plurality of cavities, and to provide a molding device having the same.SOLUTION: The mold device 101, that an injection-molding machine 100 has, includes: a fixed mold 1, a movable mold 2 and a core 3, and a plurality of cavities 5 are mounted between the mutual molds. The core 3 has: a major mold making a runner 7 leading a molten resin into a plurality of the cavities 5 between itself and a runner-forming part 13 of the fixed mold 1; and a plurality of gate molds 33 each having a gate 33a letting the runner 7 communicate with a plurality of the cavities 5 respectively and connectively mounted on the major mold 31 corresponding to a plurality of the cavities 5. The core 3 has a plurality of micro heaters 35 independently mounted on the respective gates 33a so that the micro heaters 35 can heat the resin in the runner 7 to a predetermined temperature in every gate 33a of a plurality of the gate molds 33.

Description

  The present invention relates to a mold apparatus used for molding a multi-piece resin molded article and a molding apparatus having the mold apparatus, and in particular, has a mold apparatus used for molding a resin molded article requiring high accuracy and the same. The present invention relates to a molding apparatus.

  For example, in an electrophotographic image forming apparatus such as a copying machine or a printer, an electrostatic latent image is formed on a photosensitive member using an optical system including a laser diode (LD) and the electrostatic latent image is formed. Image formation is performed by developing with toner and fixing the toner on recording paper or the like.

  An example of the optical system as described above is shown in FIG. The light beam L emitted from the LD 811 is collimated by the aspherical lens 812, passes through the aperture 813, and is focused on the polygon mirror 815 by the cylindrical lens 814. The light beam L is reflected by the polygon mirror 815 so as to move in the main scanning direction, passes through the scanning lens (fθ lens) 816 and the long lens 817, and then is reflected by a reflecting mirror (not shown) to be photosensitive. The body is irradiated, thereby forming an electrostatic latent image on the photoreceptor.

  A resin-molded part used in such an optical system of an image forming apparatus, for example, a cylindrical lens 814 is once formed by injection molding using a runnerless mold as a mold apparatus as shown in Patent Document 1. A plurality of them were molded.

  As shown in FIG. 10, the runnerless mold 900 of Patent Document 1 includes a fixed mold 901 and a movable mold 902, and a plurality of cavities 918 are formed between them. A hot nozzle 910 is provided at the center of the fixed die 901, and a bottomed cylindrical runner forming portion 911 is provided outside the hot nozzle 910. A bottom surface 911b on the movable mold 902 side of the runner forming portion 911 is formed in a conical concave shape having a required depth, and a conical core 912 (that is, a runner type) can be contacted and separated from the bottom surface 911b. Is fitted. The outer peripheral edge of the bottom surface 911b of the runner forming portion 911 is formed in a wall shape over the entire periphery, and a plurality of gates 913 respectively corresponding to the plurality of cavities 918 are provided.

  In the runnerless mold 900, when filling of a synthetic resin (hereinafter also simply referred to as resin) as a molding material melted through a hot nozzle 910 from a filling portion (not shown) is started, the runnerless mold 900 is fitted to the bottom surface 911b of the runner forming portion 911. The combined core 912 is pushed back by the filled resin to form a runner between the surface of the core 912 and the bottom surface 911b. At the same time, the core 912 opens the gate 913 to fill the plurality of cavities 918 with resin. Then, after the filling of each cavity 918 is completed, the core 912 is fitted again with the runner forming portion 911 and the gate 913 is closed. And the resin with which each cavity 918 was filled is cooled, and the cylindrical lens as a some molded article is completed.

  Components such as those used in the optical system and image reading system of the image forming apparatus described above are required to have high dimensional accuracy in order to realize high-definition image formation. For example, the cylindrical lens 814 having the shape shown in FIG. 11A is made of a transparent resin and has a total length (length in the main scanning direction) of 18 mm, a width (length in the sub scanning direction) of 5 mm, and a thickness of 2 mm. Molded. The cylindrical lens 814 has an incident surface formed in a stepped cross section (FIG. 11B) or a planar shape (FIG. 11C), and a refracting surface formed in a curved surface having an arcuate cross section. Yes. The accuracy (allowable error) in the main scanning direction is required to be less than 0.5 μm on the incident surface, less than 0.15 μm on the waviness, less than 0.5 μm on the refracted surface, and less than 0.15 μm on the waviness. Further, the accuracy in the sub-scanning direction is required to be less than 4 μm on the incident surface, less than 0.1 μm on the waviness, less than 1.2 μm on the refracted surface, and less than 0.1 μm on the waviness.

  In such a cylindrical lens 814, for example, it is known that when the dimension is changed by 1 μm, warping or undulation of about 0.05 μm occurs. For this reason, it is necessary to suppress variations in dimensions among the plurality of cylindrical lenses 814 that are obtained using the above-described runnerless mold 900 or the like.

  However, since a mold used for injection molding or the like such as the above-described runnerless mold needs to have a dimensional tolerance in its processing, the dimensional tolerance causes, for example, a difference in opening diameters between a plurality of gates. It sometimes happened. Also, in molds, the temperature on the top side (upper mold side) generally tends to be higher, so the cavity placed on the top side is the cavity placed on the ground side (lower mold side). There was a tendency to fill the resin earlier. Therefore, due to these factors, a time difference occurs in filling a plurality of cavities provided in the mold, and this time difference sometimes causes a difference in resin pressure between the plurality of cavities. When a difference in resin pressure occurs between a plurality of cavities, a difference occurs in the filling state of the resin in the cavities, resulting in variations in the dimensions of a plurality of molded products formed at the same time.

  In the above-described runnerless mold 900, in order to suppress such dimensional variations, the opening diameter of the gate 913 corresponding to the cavity 918 that takes time to fill is widened, or a runner leading to the gate 913 is formed. The difference in the resin pressure generated between the plurality of cavities 918 in the resin filling is adjusted by changing the surface shape of the bottom surface 911b and the core 912, for example.

  However, in order to widen the opening diameter of the gate 913 or change the surface shape of the core 912, it is necessary to disassemble the runnerless mold 900 and remove the runner forming portion 911 and the core 912. Each time, it is necessary to perform a machining operation using a cutting device or the like, and the operations are complicated. For this reason, a time difference that occurs in filling the plurality of cavities 918, that is, a resin pressure that occurs between the plurality of cavities 918 in filling the resin. There is a problem that it is difficult to adjust the difference between the two.

  The present invention aims to solve the above problems. That is, an object of the present invention is to provide a mold apparatus and a molding apparatus having the same that can easily adjust a difference in resin pressure generated between a plurality of cavities.

  In order to achieve the above object, the invention described in claim 1 includes: (a) a pair of molds provided with a plurality of cavities between one mold and the other mold; and (b) A main body mold in which a runner for guiding the molten resin into the plurality of cavities is formed between the one mold and a gate that communicates with the runner and the plurality of cavities, and is connected to the main body mold. A plurality of gate molds, each having a runner mold provided with each of the gate molds, so that the resin in the runner is heated to a predetermined temperature for each gate in the plurality of gate molds. The mold apparatus is provided with a plurality of resin heating means arranged independently of each other.

  The invention described in claim 2 is characterized in that, in the invention described in claim 1, the plurality of resin heating means are provided in the main body mold.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the main body mold is provided so as to be divided into a plurality of partial molds each having a single gate mold. It is characterized by that.

  The invention described in claim 4 is the invention described in any one of claims 1 to 3, wherein the plurality of gate dies are individually detachably provided on the body die. It is a feature.

  The invention described in claim 5 is the invention described in any one of claims 1 to 4, wherein the runner is formed by moving away from the one mold and is in contact with the one mold. Thus, the runner mold is provided so as to be able to contact and separate from the one mold so that the runner disappears.

  In order to achieve the above object, the invention described in claim 6 is a molding apparatus having a mold apparatus and a filling portion for filling a resin in a cavity of the mold apparatus. A molding apparatus comprising the mold apparatus according to any one of claims 1 to 5.

  According to the first aspect of the present invention, the plurality of resin heating means are provided independently of each other corresponding to each of the gates of the plurality of gate molds, and the resin in the runner is provided by these resin heating means. Can be heated to a predetermined temperature for each gate. Therefore, the resin fluidity is obtained by independently heating the resin flowing into the corresponding cavities through the respective gates to a predetermined temperature (predetermined temperature) for each gate by a plurality of resin heating means. Can be adjusted appropriately for each gate.

  According to the invention described in claim 2, the plurality of resin heating means are provided in the main body mold. That is, a plurality of resin heating means are provided in the vicinity of the runner formed by the main body mold.

  According to the invention described in claim 3, since the main body mold is provided so as to be divided into a plurality of partial molds each having one gate mold arranged in series, one partial mold is replaced with another partial mold. Dividing from the mold, the one partial mold can be exchanged individually.

  According to the fourth aspect of the present invention, since the plurality of gate molds are individually detachably attached to the main body mold, the plurality of gate molds can be individually detached from the main body mold and replaced.

  According to the invention described in claim 5, the runner mold forms the runner by separating from one of the pair of molds, and extinguishes the runner by contacting one of the molds. Since it is provided so as to be able to contact and separate from one mold, the runner can be formed when the resin is filled into the plurality of cavities, and the runner can be extinguished after the filling.

  According to the sixth aspect of the present invention, since the mold apparatus included in the molding apparatus includes the plurality of resin heating means described above, the plurality of resin heating means allows the corresponding cavity through each gate. By heating the resin flowing into the substrate independently of each other so as to be a predetermined temperature (predetermined temperature) for each gate, the fluidity of the resin can be appropriately adjusted for each gate.

  As described above, according to the first aspect of the present invention, the resin that flows into the corresponding cavity through each gate by the plurality of resin heating means has a predetermined temperature (predetermined temperature) for each gate. Since the flowability of the resin can be appropriately adjusted for each gate by heating independently of each other, the resin flowing through the corresponding gate is heated to a predetermined temperature for the cavity that takes time to fill. The fluidity is moderately good, the filling time of the cavity can be shortened, and the difference in resin pressure between multiple cavities can be easily done without disassembling the mold and expanding the gate opening diameter. Can be adjusted. Therefore, it is possible to easily suppress variations in dimensions of the plurality of molded products.

  According to the invention described in claim 2, since the plurality of resin heating means are provided close to the runner formed by the main body mold, the resin heating means is provided away from the runner. In comparison, the resin in the runner can be heated more efficiently.

  According to the third aspect of the present invention, one partial mold can be divided from another partial mold, and the one partial mold can be individually replaced. (1) Opening of the gate type gates connected to each other A plurality of partial molds having different calibers, (2) a plurality of partial molds having different shapes of portions for forming runners in the partial mold, and (3) a plurality of partial molds having different opening diameters and shapes of the positions. Etc. are prepared in advance, and the time for filling the resin in each cavity can be easily adjusted by replacing the partial mold with the appropriate opening diameter or the shape of the location according to the filling time of the cavity. Therefore, the difference in the resin pressure among the plurality of cavities can be adjusted more easily.

  According to the invention described in claim 4, since the plurality of gate molds can be individually removed from the main body mold and replaced, a plurality of gate molds having different gate opening diameters are prepared in advance and the cavity is filled. By replacing the gate type with the appropriate opening diameter according to the time, the time for filling the resin in each cavity can be easily adjusted, so that the difference in the resin pressure among the plurality of cavities can be further increased. It can be adjusted easily.

  According to the invention described in claim 5, since the runner can be formed when the resin is filled into the plurality of cavities and the runner can be extinguished after the filling, the resin is guided to the plurality of cavities by the runner at the time of filling. In addition, after filling, the resin does not remain in the runner, and therefore, it is possible to prevent wasteful resin that is not used as a molded product.

  According to the sixth aspect of the present invention, the resins flowing into the corresponding cavities through the gates by the plurality of resin heating means are independent from each other so as to have a predetermined temperature (predetermined temperature) for each gate. Since the fluidity of the resin can be appropriately adjusted for each gate by heating the resin, the resin flowing through the corresponding gate is heated to a predetermined temperature for the cavity that takes a long time for filling, and the fluidity is moderately adjusted. The filling time of the cavity can be improved, and the difference in the resin pressure among the plurality of cavities can be easily adjusted without disassembling the mold and widening the opening diameter of the gate. Therefore, it is possible to suppress variation in the dimensions of the plurality of molded products.

It is sectional drawing of the injection molding machine of one Embodiment of the shaping | molding apparatus of this invention. (A) is the figure which looked at the fixed mold | type with which the metal mold apparatus of the injection molding machine of FIG. 1 was seen from the metal mold | die division surface, (b) is a movable mold | type with which the metal mold | die apparatus of the injection molding machine of FIG. It is the figure which looked at from the metal mold | die division surface. It is sectional drawing to which the periphery of the core with which the metal mold apparatus of the injection molding machine of FIG. (A) is a front view of a core, (b) is a rear view, (c) is sectional drawing which follows the III-III line of (a). It is sectional drawing in the state before the stationary mold | type and movable mold | type of the injection molding machine of FIG. 1 close. It is sectional drawing in the filling process of the resin in the injection molding machine of FIG. It is sectional drawing in the gate cut state after completion of filling of the resin in the injection molding machine of FIG. It is sectional drawing in the state which has taken out the molded article from the cavity in the injection molding machine of FIG. 1 is a diagram illustrating an example of a configuration of an optical system of an image forming apparatus. It is sectional drawing of the conventional metal mold apparatus. (A) is a perspective view of a cylindrical lens used in the optical system of FIG. 9, (b) is a diagram showing an example of a cross section along the sub-scanning direction of the cylindrical lens of (a), and (c). These are figures which show the other example of the cross section along the subscanning direction of the cylindrical lens of (a).

  Below, the injection molding machine as one Embodiment of the shaping | molding apparatus of this invention is demonstrated with reference to FIGS. The injection molding machine of this embodiment is a molding apparatus used for molding a large number of small and high-precision resin molded products. For example, it is a molding apparatus for injection molding of a cylindrical lens 814 shown in FIG.

  As shown in FIG. 1, the injection molding machine 100 includes a mold apparatus 101, an injection machine 102 as a filling unit, and a control device (not shown).

  The mold apparatus 101 includes a fixed mold 1 and a movable mold 2 as a pair of molds, and a core 3 as a runner mold. The fixed mold 1 and the movable mold 2 are overlapped with each other on the mold dividing surface PL, thereby forming a plurality of cavities 5 therebetween. In the present embodiment, these cavities 5 are arranged radially about the centers of the fixed mold 1 and the movable mold 2, and four cavities 5 are formed. Is determined as appropriate.

  As shown in FIGS. 1 and 2A, the fixed mold 1 includes a fixed base part 11, a fixed mold main body part 12, a runner forming part 13, a hot nozzle part 14, a guide pin hole 16, It has.

  The fixed base portion 11 is formed in a rectangular plate shape, and is fixed together with, for example, a later-described injection machine 102 by a fixing means (not shown) on a factory floor or a work table.

  The fixed mold main body 12 includes a rectangular plate mold 12 a, a transfer piece 12 b, and inserts 12 c and 12 d, and is fixed by being overlapped on the fixed base 11. The transfer piece 12b and the inserts 12c and 12d are fitted into locations corresponding to the plurality of cavities 5 in the rectangular plate mold 12a. The transfer piece 12b is formed in accordance with the shape of the incident surface of the cylindrical lens 814 (for example, a stepped step shape or a planar shape). Further, the inserts 12c and 12d are formed in accordance with the end shape of the cylindrical lens 814 in the full length direction (main scanning direction).

  The runner forming portion 13 is formed in a substantially bottomed cylindrical shape, and its bottom surface 13a (that is, one runner forming surface) is a surface on the movable mold 2 side of the fixed mold main body portion 12 (that is, a mold dividing surface). PL is fixed through the center of the fixed base portion 11 and the fixed mold main body portion 12 so as to be exposed to (PL). The bottom surface 13a of the runner forming portion 13 is formed in a substantially conical concave shape (that is, a mortar shape). In addition, a notch 13b into which a gate mold 33 of the core 3 described later is inserted is provided at a location corresponding to each of the plurality of cavities 5 on the outer peripheral edge of the bottom surface 13a.

  The hot nozzle portion 14 is formed in a syringe (injection cylinder) shape, and is disposed in the runner forming portion 13 such that its outer peripheral surface closely overlaps the inner peripheral surface of the runner forming portion 13. The tip 14 a of the hot nozzle portion 14 is exposed at the center of the bottom surface 13 a of the runner forming portion 13. The injection hole 14b of the hot nozzle portion 14 is disposed so as to open at the end opposite to the tip 14a.

  Each of the runner formation part 13 and the hot nozzle part 14 is provided with a runner formation part heater 13c and a hot nozzle part heater 14c that are controlled independently from each other by a control device (not shown).

  The guide pin holes 16 are provided at the four corners of the fixed mold main body 12, and guide pins 26 described later provided in the movable mold 2 are inserted when the fixed mold 1 and the movable mold 2 are joined.

  As shown in FIGS. 1 and 2B, the movable mold 2 includes a movable base portion 21, a movable mold main body portion 22, an extrusion rod 23, an extrusion plate 24, an extrusion pin 25, and a guide pin 26. And a return pin 27.

  The movable base portion 21 is configured by sequentially superposing three rectangular plate portions 21a, 21b, and 21c. The movable base portion 21 is attached to a mold driving means (not shown) such as a hydraulic cylinder device connected to the control device, for example. Thereby, the movable mold | type 2 can be approached or separated from the fixed mold | type 1, ie, the movable mold | type 2 is provided so that contact / separation with the fixed mold | type 1 is possible.

  The movable body 22 includes a rectangular plate 22a, a transfer piece 22b, and nestings 22b and 22c. The movable body 22 is stacked and fixed on the movable base 21. The rectangular plate mold 22a is formed in substantially the same shape as the rectangular plate mold 12a of the fixed mold main body 12 described above. The transfer piece 22b and the inserts 22c and 22d are fitted into locations corresponding to the plurality of cavities 5 in the rectangular plate mold 22a. The transfer piece 22b is formed in accordance with the refractive surface shape (for example, a circular arc shape) of the cylindrical lens 814. Further, the inserts 22c and 22d are formed in accordance with the end shape of the cylindrical lens 814 in the full length direction. The fixed mold main body 12 and the movable mold main body 22 are joined to each other at a surface (die division surface PL) facing each other, whereby a cavity 5 is formed at a place where each transfer piece and insert are arranged.

  The push rod 23 passes through the centers of the movable base portion 21 and the movable mold main body 22 and can move in this penetrating direction (the left-right direction in FIG. 1 and coincides with the joining direction of the fixed mold 1 and the movable mold 2). Is provided. The push rod 23 is urged in the pull-in direction (left direction in FIG. 1) by a spring 23 a provided on the movable base portion 21. The push rod 23 is pushed in the push direction (right direction in FIG. 1) by an actuator (not shown) connected to the control device, thereby pressing the core 3 described later against the bottom surface 13 a of the runner forming portion 13.

  The extrusion plate 24 is provided in the rectangular plate-like portion 21b at the center of the movable base portion 21 so as to be movable in the penetrating direction. The push plate 24 moves in the push direction as the push rod 23 moves in the push direction.

  The push pin 25 is provided so as to pass through the rectangular plate-like portion 21c on the fixed mold 1 side of the movable base portion 21 and the movable mold main body portion 22 and to be movable in the penetrating direction in parallel with the push rod 23. One end 25a of the push pin 25 is fixed to the push plate 24, and the other end 25b is located at a position corresponding to the plurality of cavities 5 in the movable body portion 22 when the push plate 24 is moved in the push direction. It is arranged to protrude.

  The guide pins 26 are cylindrical fixed pins that protrude from the four corners of the movable main body 22. The guide pin 26 is inserted into the guide pin hole 16 of the fixed mold 1 and fitted to each other when the fixed mold 1 and the movable mold 2 are joined, and the fixed mold 1 and the movable mold 2 are centered. .

  The return pins 27 are columnar movable pins arranged alongside the guide pins 26 at the four corners of the movable main body 22. One end of the guide pin 26 is fixed to the above-described extrusion plate 24, and the other end is fixed to the fixed mold 1 of the movable mold main body 22 when the extrusion plate 24 is moved in the extrusion direction. It is provided so as to protrude from the side surface (mold separation surface PL). When the fixed mold 1 and the movable mold 2 are joined, the return pin 27 hits the fixed mold main body 12 before the above-described push pin 25 and pushes back the push plate 24 to fix the return pin 27 to the push plate 24. The pushing pin 25 is returned, and the pushing pin 25 is prevented from being damaged.

  As shown in FIG. 3 and FIGS. 4A to 4C, the core 3 includes a main body mold 31 including a plurality of partial molds 32, and a plurality of integrally connected one to each of the partial molds 32. A gate mold 33, a base portion 34 to which a main body mold 31 (that is, a plurality of partial molds 32) is fixed, and a micro heater 35 as a plurality of resin heating means are provided.

  The main body mold 31 is formed in a substantially conical shape whose bottom surface diameter is the same as the outer diameter of the runner forming portion 13, and the tapered surface 31 a (that is, the other runner forming surface) is the above-described fixed mold 1. The runner forming portion 13 is formed so as to be in close contact with the bottom surface 13a. The runner 7 is formed between the surface 31 a of the main body mold 31 and the bottom surface 13 a of the runner forming portion 13. That is, the fixed mold 1 provided with the runner forming portion 13 corresponds to one mold in the claims. The movable mold 2 corresponds to the other mold in the claims. The fixed mold 1 and the movable mold 2 correspond to a pair of molds in the claims.

  The plurality of partial molds 32 are formed in a shape obtained by equally dividing the main body mold 31 along the central axis of the conical shape. In the present embodiment, the main body mold 31 is divided into four to form a plurality of partial molds 32a to 32d.

  Each of the plurality of gate dies 33 is formed in a single piece (that is, in a short strip shape) so that it can be fitted into the notch 13 b of the runner forming portion 13. In the central part of the gate mold 33, one gate 33a which is a hole penetrating the gate mold 33 is provided. The gate mold 33 is provided integrally with the partial mold 32 and is erected in parallel with the central axis at the center of the arc-shaped outer edge of the partial mold 32.

  The base portion 34 is formed in a disk shape that is the same as the bottom shape of the main body mold 31 in plan view. On one surface 34 a of the base portion 34, the partial molds 32 a to 32 d are fixed so as to form a conical main body mold 31 by being combined with each other. Specifically, these four partial molds 32 a to 32 d are fitted to each other, for example, with a screwing structure or a fitting structure (the bottom surface of the partial mold 32 (that is, the main body mold 31) and one surface 34 a of the base portion 34. Etc.), and the like is fixed to one surface 34a of the base portion 34 using fixing means (not shown) that can be individually detached. A cylindrical portion 34 c that is pushed by the push rod 23 is integrally provided on the other surface 34 b of the base portion 34.

  The plurality of micro heaters 35 are well-known small heating means, and are embedded in the vicinity of the gate 33 a included in the gate mold 33 in the partial mold 32. Each of the plurality of micro heaters 35 is provided for each of the partial molds 32a to 32d. Each microheater 35 is connected to the control device by a wiring provided in the core 3 so that it can be controlled independently. The micro heater 35 generates heat under the control of the control device, and heats the resin in the runner 7 formed by the surface 31a to a predetermined temperature through the surface of each of the partial molds 32a to 32d (that is, the surface 31a of the main body mold 31). To do. That is, the plurality of micro heaters 35 are provided independently of each other corresponding to each of the gates 33a so that the resin in the runner 7 can be heated to a predetermined temperature for each of the gates 33a of the plurality of gate molds 33. .

  The core 3 is fixed so that each of the gates 33a of the plurality of gate molds 33 is opposed to the plurality of cavities 5 corresponding thereto, and the surface 31a is opposed to the bottom surface 13a of the runner forming portion 13. It is arranged between the mold 1 and the movable mold 2. Moreover, the core 3 is provided so that it can contact the runner formation part 13 between the fixed mold | type 1 and the movable mold | type 2, or can leave | separate from the runner formation part 13, that is, the runner formation part 13 can contact and separate Yes. And when the core 3 leaves | separates from the runner formation part 13, as shown in FIG. 3, space will be formed between the surface 31a of the main body type | mold 31 of the core 3, and the bottom face 13a of the runner formation part 13, ie, resin A runner 7 is formed for guiding the air to the plurality of cavities 5. The runner 7 and the plurality of cavities 5 are communicated with each other by gates 33 a provided in the gate molds 33 of the core 3. Further, when the core 3 approaches the runner forming portion 13, the surface 31 a of the main body mold 31 of the core 3 and the bottom surface 13 a of the runner forming portion 13 are in close contact with each other, and the runner 7 disappears, and each gate die 33 is connected to the runner forming portion 13. Each gate 33a is closed by being inserted into the notch 13b of the forming portion 13.

  Like the fixed mold 1 of the mold apparatus 101, the injection machine 102 is fixed to, for example, a factory floor or a work table by fixing means (not shown). The injection machine 102 includes a heating cylinder 53 as a cylinder, a screw 54 as a pressing member, and a pressing cylinder.

  The heating cylinder 53 is formed in a cylindrical shape. The heating cylinder 53 is arranged such that its longitudinal direction (axial center direction) is parallel to the joining direction of the fixed mold 1 and the movable mold 2. One end portion 53 a of the heating cylinder 53 is formed in a taper shape so that it gradually becomes thinner toward the tip of the heating cylinder 53. The heating cylinder 53 is attached to the fixed mold 1 in a state where the opening 55 of the one end 53 a of the heating cylinder 53 has entered the injection hole 14 b of the hot nozzle section 14 of the fixed mold 1. The inner surface of the injection hole 14b and the one end 53a of the heating cylinder 53 are in close contact with each other.

  The heating cylinder 53 accommodates the screw 54 inside. A plurality of heating heaters are attached to the outer surface of the heating cylinder 53. A cylindrical hopper is attached to the heating cylinder 53. The heating cylinder 53 is filled with a solid chip-shaped synthetic resin G (that is, a resin) as a molding material through a hopper. The heating cylinder 53 heat-fluidizes (plasticizes) the filled chip-shaped synthetic resin G. Thus, the heating cylinder 53 is filled with the plasticized synthetic resin G. Further, the heating cylinder 53 can inject the plasticized synthetic resin G through the opening 55 into the plurality of cavities 5 through the injection hole 14 b, the hot nozzle portion 14, and the runner 7 in order.

  The screw 54 is formed in a rod shape and is accommodated in the heating cylinder 53. When the screw 54 is accommodated in the heating cylinder 53, the longitudinal direction (axial core direction) is parallel to the longitudinal direction (axial core direction) of the heating cylinder 53. The screw 54 is provided so as to be movable along the longitudinal direction of the heating cylinder 53. On the outer peripheral surface of the screw 54, a protrusion 57 is provided in a spiral shape.

  The screw 54 moves along the longitudinal direction of the heating cylinder 53, thereby moving the synthetic resin G in the heating cylinder 53 toward the opening 55, that is, one end portion 53 a of the heating cylinder 53. The plasticized synthetic resin G is pushed out toward the injection hole 14b.

  The pressing cylinder includes a cylinder body and a rod that can be extended and contracted from the cylinder body. The rod is attached to the screw 54. The pressing cylinder moves the screw 54 along the longitudinal direction of the heating cylinder 53 by expanding and contracting the rod. Of course, the pressing cylinder extends the rod to bring the screw 54 closer to the opening 55 and contracts the rod to release the screw 54 from the opening 55.

  The injection machine 102 having the above-described configuration moves the screw 54 along the longitudinal direction of the heating cylinder 53 by expanding and contracting the rod of the pressing cylinder, and plasticized (melted) synthetic resin in the heating cylinder 53. G is filled (injected) into the plurality of cavities 5 through the injection hole 14 b, the hot nozzle portion 14, and the runner 7.

  The control device is a computer including a known RAM, ROM, CPU, and the like. The control device stores a program for operating the injection molding machine 100. The control device is connected to the mold device 101, the injection machine 102, and the like, and controls them based on the program described above to control the entire injection molding machine 100.

  Next, the operation of the above-described injection molding machine 100 will be described with reference to FIGS. FIG. 5 is a cross-sectional view in a state before the fixed mold and the movable mold are closed. FIG. 6 is a cross-sectional view in the resin filling process. FIG. 7 is a cross-sectional view in a gate cut state after completion of resin filling. FIG. 8 is a cross-sectional view of the molded product taken out from the cavity. 5 to 8, the description of the injection machine 102 is omitted, but in practice, one end portion 53a of the heating cylinder 53 is brought into close contact with the inner surface of the injection hole 14b of the hot nozzle portion 14 to form a mold. It is fixed together with the fixed mold 1 of the device 101.

  First, as shown in FIG. 5, in a state before the fixed mold 1 and the movable mold 2 are closed, the core 3 has the surface 31 a of the main body mold 31 in close contact with the bottom surface 13 a of the runner forming portion 13, thereby forming the runner. It is heated by the part heater 13c. Further, the plurality of gate dies 33 of the core 3 are inserted into the plurality of notches 13b of the runner forming portion 13, and the gates 33a of the gate dies 33 are in a closed state.

  In the resin filling process shown in FIG. 6, filling of the plurality of cavities 5 with the synthetic resin G is started by the injector 102, and the surface 31 a is in close contact with the bottom surface 13 a of the runner forming portion 13. The core 3 is pushed by the injected synthetic resin G and moves in the pulling direction to form the runner 7 between the bottom surface 13a and the surface 31a. At the same time, the gates 33a face the cavities 5, the cavities 5 and the runners 7 are communicated with each other by the gates 33a (that is, the gates 33a are opened), and the cavities 5 are filled with resin. At this time, the core 3 is separated from the runner forming portion 13 which is a heat source, but is further heated by the filled synthetic resin G, so the synthetic resin G in the runner 7 formed between the runner forming portion 13 and the core 3. Will not solidify.

  In addition, a plurality of micro heaters 35 embedded in the main body mold 31 of the core 3 (that is, each of the partial molds 32a to 32d) are filled into a plurality of cavities 5 corresponding thereto through a plurality of gates 33a as necessary. The synthetic resin G is heated to a predetermined temperature independently of each other for each gate 33a.

  This predetermined temperature is determined as follows. For example, the resin pressure at the time of filling in each of the plurality of cavities 5 is measured by preforming using the injection molding machine 100 or molding simulation using a computer. This resin pressure is measured, for example, by providing a strain gauge in the vicinity of each cavity 5 and straining the mold during resin filling. If the measured resin pressure variation (for example, the difference between the maximum value and the minimum value or the standard deviation) exceeds a predetermined allowable reference value, the resin pressure is reduced to the gate 33a that leads to the cavity 5. The synthetic resin G in the runner 7 filled in the cavity 5 is heated through the gate 33a by the corresponding micro heater 35, and the temperature is increased to change the fluidity, and the preforming is performed again. This is repeated until the resin pressure variation finally falls within the allowable reference value. And the heating temperature by each micro heater 35 at this time is memorize | stored in a control apparatus as said predetermined temperature, and the micro heater 35 is controlled so that it may become this predetermined temperature in the said filling process. In the above description, the resin pressure variation at the time of filling in each cavity 5 is obtained and adjusted so that these resin pressures are equal. However, the present invention is not limited to this. And the predetermined temperature may be determined so that these dimensions fall within a predetermined reference range.

  Also, it corresponds to the cavity 5 in which the resin pressure is farthest from the average value when the variation in the resin pressure cannot be kept within the allowable reference value only by heating with the micro heater 35 or when the variation is very large. The partial mold 32 (any one of the partial molds 32a to 32d) connected to the gate mold 33 to be connected is individually removed, and the gate mold 33 having the gate 33a having a different opening diameter is prepared. A partial mold 32 is newly attached. Alternatively, the opening diameter of the gate 33a is the same, and the partial mold 32 having a different surface shape (a part of the surface 31a of the body die 31, that is, the shape of the runner 7), or the opening diameter and the surface Partial molds 32 having different shapes may be newly attached. Then, the predetermined temperature is determined again in the same manner as described above. Of course, not only in the above case, the resin pressure variation may be finely adjusted by replacing the partial mold 32. The resin pressure adjustment operation as described above is performed in advance.

  Next, in the gate cut state after completion of the resin filling shown in FIG. 7, after the cavity 5 is filled with the synthetic resin G, the core 3 is pressed to the predetermined extrusion position by the extrusion rod 23, and the main body mold The surface 31a of 31 is brought into close contact with the bottom surface 13a of the runner forming portion 13 and the runner 7 disappears, and each gate mold 33 is inserted into the notch 13b and the gate 33a is closed. At this time, the molten synthetic resin G in the runner 7 (see FIG. 6) formed by the runner forming portion 13 and the core 3 is pushed back to the injection machine 102 via the hot nozzle portion 14. Further, the molten synthetic resin G in the hot nozzle portion 14 flows out of the hot nozzle portion 14 by closing the tip 14a of the hot nozzle portion 14 when the core 3 is in close contact with the runner forming portion 13. Can be prevented.

  When the molded product 814 (that is, the cylindrical lens 814) is taken out from the cavity 5 shown in FIG. 8 (molded product protruding state), the fixed mold 1 and the movable mold 2 of the mold are opened and extruded. The rod 23 is further advanced from the above-mentioned predetermined extrusion position (position shown in FIG. 7), and the extrusion plate 24 is pushed out, so that the extrusion pin 25 protrudes into the cavity 5 of the movable mold 2 and the molded product 814 is cavityd. Remove from 5.

  As described above, according to the present embodiment, the plurality of micro heaters 35 are provided independently of each other corresponding to each of the gates 33 a of the plurality of gate molds 33, and the runners are provided by these micro heaters 35. 7 can be heated to a predetermined temperature for each gate 33a. Therefore, the synthetic resin G flowing into the corresponding cavities 5 through the gates 33a is heated by the plurality of micro heaters 35 independently of each other so as to have a predetermined temperature (predetermined temperature) for each gate 33a. The fluidity of the synthetic resin G can be adjusted appropriately for each gate 33a.

  For this reason, for the cavity 5 that takes time to fill, the synthetic resin G flowing through the corresponding gate 33a is heated to a predetermined temperature so that the fluidity is appropriately good, and the filling time of the cavity 5 can be shortened. The difference in the resin pressure among the plurality of cavities 5 can be easily adjusted without disassembling the mold and increasing the opening diameter of the gate. Therefore, it is possible to suppress variation in the dimensions of the plurality of molded products.

  A plurality of micro heaters 35 are provided in the main body mold 31 (that is, the partial molds 32a to 32d). That is, a plurality of micro heaters 35 are provided in proximity to the runner 7 formed by the main body mold 31. For this reason, compared with the case where the micro heater 35 is provided away from the runner 7, the resin in the runner 7 can be heated more efficiently.

  Further, since the main body mold 31 is provided so as to be divided into a plurality of partial molds 32 a to 32 d each having one gate mold 33 arranged in series, one partial mold 32 is divided from the other partial mold 32. Thus, the one partial mold 32 can be individually replaced. For this reason, (1) a plurality of partial dies 32 having different opening diameters of the gates 33a of the connected gate dies 33, and (2) a surface on which the runners 7 of the partial dies 32 are formed (that is, the surface 31a of the body die 31). A plurality of partial molds 32 having different shapes), (3) a plurality of partial molds 32 having different opening diameters and surface shapes, and the like, depending on the filling time of the cavity 5 By replacing the partial mold 32 with an appropriate opening diameter or surface shape, the time for filling the resin into the cavities 5 can be easily adjusted. The difference in pressure can be adjusted more easily.

  In addition, the runner 7 is formed so that the core 3 is separated from the runner formation portion 13 (that is, the fixed mold 1), and the runner 7 is extinguished by being in contact with the runner formation portion 13. Since it is provided so that contact / separation is possible, the runner 7 can be formed at the time of filling the resin into the plurality of cavities 5, and the runner 7 can be extinguished after filling. For this reason, the synthetic resin G can be guided to the plurality of cavities 5 by the runner 7 at the time of filling, and the synthetic resin G does not remain in the runner 7 after the filling, and is therefore used as a molded product. It is possible to prevent unnecessary synthetic resin G from being generated.

  Although this embodiment demonstrated the runner-less mold apparatus which does not contain a runner part in a molded article, it is not limited to this, The runner-less by which the molded article containing a runner part is shape | molded The present invention may be applied to a normal mold apparatus that is not.

  In the present embodiment, in the core 3, the main body mold 31 is provided so as to be divided into a plurality of partial molds 32 a to 32 d in which one gate mold 33 is integrally connected. However, the present invention is limited to this. The main body mold 31 may be provided so as not to be divided. In this case, since the partial mold 32 cannot be replaced, the difference in the resin pressure among the plurality of cavities 5 is adjusted only by the micro heater 35. Moreover, the gate mold | type 33 may be provided in the main body mold | type 31 (when division is impossible) or each partial mold | type 32 so that attachment or detachment is possible. In this way, since the plurality of gate dies 33 can be individually removed from the main body die 31 or the partial die 32 and replaced, a plurality of gate dies 33 having different opening diameters of the gates 33a are prepared in advance. By replacing the gate mold 33 with the appropriate opening diameter according to the filling time of the cavities 5, the time for filling the resin into the cavities 5 can be easily adjusted. The difference in resin pressure can be adjusted more easily.

  Moreover, in this embodiment, although it was the structure which provided the micro heater 35 as the resin heating means in each partial type | mold 32a-32d of the core 3, instead, for example, each partial type | mold 32a in the movable type main-body part 22 is provided. To 32d (indicated by reference numeral 22a1 in FIG. 3) or the like may be provided with a plurality of electromagnetic induction heating devices as resin heating means for separately heating the partial molds 32a to 32d. . By doing in this way, the wiring in the core 3 etc. can be abbreviate | omitted and it can be set as a simple structure. As described above, the type of the resin heating means and the place where the resin heating means is provided are arbitrary as long as the object of the present invention is not violated.

  Moreover, in this embodiment, although the cone-shaped runner 7 was formed by the runner formation part 13 and the core 3, it is not limited to this, For example, the runner 7 is a flat plate. It may have a shape, or one of the runner forming portion 13 and the core 3 is provided with a groove extending from the tip 14a of the hot nozzle portion 14 to each gate 33a, and the other is provided with a convex portion that fits into this groove. Thus, a tubular runner may be formed, and the shape of the runner is arbitrary as long as it does not contradict the purpose of the present invention.

  Moreover, in this embodiment, although the core 3 was provided so that contact / separation was possible to the runner formation part 13, it is not limited to this, The core 3 formed the runner 7 between the runner formation part 13 It may be fixed in a state.

  The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the scope of the present invention.

1 Fixed mold (one mold)
2 Movable mold (the other mold)
3 core (runner type)
5 Cavity 7 Runner 13 Runner formation part (molding die)
13a Bottom (runner forming surface)
31 Main body type 31a Surface (runner forming surface)
32 (32a to 32d) Partial type 33 Gate type 33a Gate 35 Micro heater (resin heating means)
100 Injection molding machine (molding equipment)
101 Mold device 102 Injection machine (filling part)
G Synthetic resin (resin)

JP 2010-17882 A

Claims (6)

(A) a pair of molds provided with a plurality of cavities between one mold and the other mold; and (b) a runner for guiding the molten resin into the plurality of cavities. And a runner mold having a gate communicating with the runner and the plurality of cavities and a plurality of gate molds connected to the body mold, respectively. In mold equipment,
A plurality of resin heating means arranged independently of each other are provided corresponding to each of the gates so as to heat the resin in the runner to a predetermined temperature for each gate in the plurality of gate types. Mold device characterized.   The mold apparatus according to claim 1, wherein the plurality of resin heating means are provided in the main body mold.   3. The mold apparatus according to claim 1, wherein the main body mold is provided so as to be divided into a plurality of partial molds in which the gate molds are arranged one by one. 4.   The mold apparatus according to any one of claims 1 to 3, wherein the plurality of gate molds are individually detachably attached to the main body mold.   The runner mold is provided detachably from the one mold so that the runner is formed by separating from the one mold and the runner disappears by contacting the one mold. The mold apparatus according to any one of claims 1 to 4, wherein the mold apparatus is provided. In a molding apparatus having a mold apparatus and a filling portion for filling a resin in a cavity of the mold apparatus,
The molding apparatus is configured by the mold apparatus according to any one of claims 1 to 5.

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