Melting heater and method for manufacturing molded product

Abstract

To provide a melting heater requiring low repair costs in the event of wire breakage.SOLUTION: There is provided a melting heater (25) that is composed of a plurality of element heaters (28) arranged in a flat plate-shaped unit. The element heaters (28) are arranged in a straight line parallel to each other, two adjacent heaters form one set of paired heaters, and for each paired heater, one end of each of the two element heaters (28) is wired together to connect in series. The melting heater (25) is configured so that the element heaters (28) are energized by supplying power from one end thereof.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a melting heater used to melt the joining end surfaces of a pair of semi-molded resin products when melting and joining the joining end surfaces of the products to obtain a molded product, and to a manufacturing method for manufacturing a molded product using the melting heater. [Background technology]

[0002] To manufacture a molded product by melting the joining end surfaces of a pair of semi-molded resin parts and pressing them together, a melting heater is required to melt the joining end surfaces. The melting heater is made of a carbon heater or a halogen heater, which can heat the joining end surfaces non-contact and in a short time. The carbon heater or halogen heater is shaped to fit the shape of the joining end surfaces, allowing for efficient melting of the joining end surfaces. However, since the shape of the joining end surfaces varies depending on the type of molded product, a melting heater must be prepared for each type of molded product.

[0003] In response to this, Patent Document 1 proposes a melting heater in which a carbon heater or a halogen heater is processed to have a flat plate shape. Specifically, the carbon heater or halogen heater is bent multiple times to form multiple straight sections. The multiple straight sections are then arranged parallel to each other, evenly spaced, and on the same plane. In this way, the melting heater is formed in a flat plate shape. This melting heater is inserted in a non-contact manner between a pair of semi-molded products whose joining end surfaces are arranged facing each other. Then, by oscillating the melting heater, the joining end surfaces can be uniformly melted. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-116712 Summary of the Invention [Problem to be solved by the invention]

[0005] The melting heater described in Patent Document 1 does not need to be formed to fit the shape of the joining end face. In other words, there is no need to prepare a melting heater for each type of molded product, and it is excellent in that it can be used for general purposes. However, One issue is that if a wire breaks in one place, the repair costs are high.

[0006] In the present disclosure, the joining end surface of the semi-molded product appropriately Can be heated , and low repair costs in the event of a break A melting heater and a method for manufacturing a molded article are provided.

[0007] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0008] The melting heater is composed of a plurality of element heaters arranged in a flat plate-shaped unit. Each of the element heaters is linear and arranged parallel to each other, and two adjacent heaters form a pair of heaters, and one end of each pair of heaters is connected to each other, so that they are connected in series. The power supplied to each heater pair is The power supply is configured to be energized. [Effects of the Invention]

[0009] This disclosure If an element heater breaks, it is sufficient to replace only the pair of heaters to which the broken element heater belongs, thereby reducing repair costs. . [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a front view showing a part of an injection molding machine and a heater device, which are manufacturing devices according to an embodiment of the present invention. [Figure 2] 1 is a side view showing a part of an injection molding machine and a heater device according to an embodiment of the present invention. [Figure 3] 1 is a front view of a melting heater according to a first embodiment of the present invention. [Figure 4]4 is a cross-sectional top view of the melting heater according to the present embodiment, shown at cross section XX in FIG. 3. FIG. [Figure 5] FIG. 2 is a front view showing a pair heater consisting of a pair of element heaters. [Figure 6] 1 is a front cross-sectional view showing a mold according to the present embodiment, a part of an injection molding machine, and a melting heater, which are a manufacturing device for a molded product according to the present embodiment. [Figure 7A] 1 is a front cross-sectional view showing a mold according to an embodiment of the present invention and a part of an injection molding machine in a part of a process of a manufacturing method of a molded product according to an embodiment of the present invention. FIG. [Figure 7B] 1 is a front cross-sectional view showing a mold according to an embodiment of the present invention and a part of an injection molding machine in a part of a process of a manufacturing method of a molded product according to an embodiment of the present invention. FIG. [Figure 7C] 1 is a front cross-sectional view showing a mold according to an embodiment of the present invention and a part of an injection molding machine in a part of a process of a manufacturing method of a molded product according to an embodiment of the present invention. FIG. [Figure 7D] FIG. 2 is a front cross-sectional view showing a mold according to the embodiment of the present invention, a part of an injection molding machine, and a melting heater in a part of a process of a manufacturing method of a molded product according to the embodiment of the present invention. [Figure 7E] 1 is a front cross-sectional view showing a mold according to an embodiment of the present invention and a part of an injection molding machine in a part of a process of a manufacturing method of a molded product according to an embodiment of the present invention. FIG. [Figure 7F] 1 is a front cross-sectional view showing a mold according to an embodiment of the present invention and a part of an injection molding machine in a part of a process of a manufacturing method of a molded product according to an embodiment of the present invention. FIG. [Figure 8] FIG. 4 is a front view of a melting heater according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a cross-sectional top view of a melting heater according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional top view of a melting heater according to a fourth embodiment of the present invention. [Figure 11] FIG. 10 is a cross-sectional top view of a melting heater according to a fifth embodiment of the present invention. [Figure 12]FIG. 10 is a cross-sectional top view of a melting heater according to a sixth embodiment of the present invention. [Figure 13] FIG. 13 is a cross-sectional top view of a melting heater according to a seventh embodiment of the present invention. [Figure 14] FIG. 13 is a cross-sectional top view of a melting heater according to an eighth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Specific embodiments will be described in detail below 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 have been simplified as appropriate. In each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary. Furthermore, hatching has been omitted in some areas to avoid cluttering the drawings.

[0012] The present embodiment will be described. <Molded product manufacturing equipment> 1, the molded product manufacturing apparatus 1 according to this embodiment is composed of an injection molding machine 2 and a heater device 3 according to this embodiment. As will be described later, a pair of semi-molded products is molded in the injection molding machine 2, the joining end surfaces of the pair of semi-molded products are melted by the heater device 3, and the semi-molded products are crimped together to obtain a molded product.

[0013] <Injection molding machine> The injection molding machine 2 according to this embodiment is composed of a mold clamping unit 5 and an injection unit 6. The mold clamping unit 5 is equipped with a fixed platen 8 fixed on a bed B, a mold clamping housing 9 that slides on the bed B, and a movable platen 11 that similarly slides on the bed B. The fixed platen 8 and the mold clamping housing 9 are connected by a plurality of tie bars 12, 12, ..., for example, four tie bars. The movable platen 11 is slidable between the fixed platen 8 and the mold clamping housing 9. A mold clamping mechanism 14 consisting of a toggle mechanism is provided between the mold clamping housing 9 and the movable platen 11. The mold clamping mechanism 14 may be composed of a direct pressure type mold clamping cylinder.

[0014] The fixed platen 8 and the movable platen 11 are provided with a fixed mold 16 and a movable mold 17 according to this embodiment, respectively, and the molds are opened and closed when the mold clamping mechanism 14 is driven. The mold clamping housing 9 slides in accordance with the thickness of these molds 16 and 17, and is adapted to adjust the distance between the fixed platen 8 and the movable platen 11 when the molds are opened. These molds 16 and 17 will be described later. The heater device 3 according to this embodiment is disposed adjacent to these molds 16 and 17, and is provided in the depth direction of the paper in FIG. 1.

[0015] The injection device 6 is composed of a heating cylinder 19, a screw 20 placed in the heating cylinder 19, and a screw drive device 21 that drives the screw 20. The heating cylinder 19 is provided with a hopper 22 and an injection nozzle 23. When the screw 20 is rotated and resin material is supplied from the hopper 22, the resin material is melted and measured inside the heating cylinder 19. When the screw 20 is driven in the axial direction, the melted resin is injected from the injection nozzle 23.

[0016] <Heater device> As shown in Fig. 2, heater device 3 according to this embodiment is provided on the side of injection molding machine 2. Heater device 3 is generally composed of melt heater 25 according to this embodiment, which will be described next, drive mechanism 26 that drives melt heater 25 horizontally, and base 24 that supports drive mechanism 26. Drive mechanism 26 enables melt heater 25 to be driven toward mold 16 or to be retracted from mold 16. Heater device 3 is also provided with a power supply device that supplies power to melt heater 25, but this is not shown in Fig. 2.

[0017] <Melting heater> 3 and 4 show a melting heater 25A according to a first embodiment of the present invention as a melting heater 25 according to the present embodiment. The melting heater 25A is composed of a rectangular metal frame 27, a plurality of linear element heaters 28, 28, ... made of carbon heaters, halogen heaters, etc., which radiate infrared rays or far-infrared rays, and two glass plates 30, 30. The element heaters 28, 28, ... are arranged in parallel within the frame 27, and the whole forms a flat unit. The two glass plates 30, 30 are provided on the frame 27 so as to cover the element heaters 28, 28, ...

[0018] To explain the first embodiment in more detail, each pair of element heaters 28, 28, ... is made up of two heater pairs 32, 32. As shown in FIG. 5, the heater pairs 32 are made up of a quartz glass tube 33 and two heater elements 28, 28 housed in the quartz glass tube 33. These heater elements 28, 28 are connected at one end of each element heater. Therefore, when power is supplied from the other end, a current flows in series through the two heater elements 28, 28. As shown in FIG. 3, these heater pairs 32, 32, ... are provided vertically and arranged in parallel horizontally at a predetermined interval.

[0019] In the first embodiment, if one of the element heaters 28, 28, ... breaks, it is sufficient to replace only the broken element heater 28. Alternatively, it is sufficient to replace only the pair heater 32 consisting of one set of element heaters 28, 28. This is because there is no need to process the element heaters 28, 28, ..., such as bending their shapes to fit the heating target. In other words, the present disclosure has the effect of reducing repair costs and facilitating the management of spare heaters.

[0020] The melting heater 25A is characterized by the provision of two glass plates 30, 30, and the surface treatment of these glass plates 30, 30. Infrared rays from the multiple element heaters 28, 28 are emitted uniformly in a plane, but the surface treatment is applied to control this infrared radiation. In the first embodiment, the surface treatment is a masking treatment that blocks or reduces the infrared radiation. As will be explained later, the masking treatment is applied in a predetermined pattern to match the shape of the joining end surface so that only the joining end surface of the semi-molded product can be selectively heated.

[0021] Specifically, in this embodiment, a coating process is employed as a masking process. Specifically, a light-blocking paint is applied to the surfaces of the glass plates 30, 30, as indicated by reference numerals 35, 35, ... in FIG. 4 . Other coating processes may include plating or coating, or colored glass may be bonded. Furthermore, the masking process may also include sanding or edging. Specifically, the surfaces of the glass plates 30, 30 may be sanded to create frosted glass that scatters and attenuates infrared light in a predetermined pattern. By using glass plates that have undergone such masking, even if the molded product shape changes, the heating area of ​​the heater can be easily changed by simply replacing them with glass plates that have undergone masking to match the pattern of the molded product shape.

[0022] 3, the electric wires provided for each of the multiple element heaters 28, 28, ... are not shown in the middle. These electric wires are connected to a power supply device (not shown), and power is supplied at the required timing so that infrared rays are radiated from the element heaters 28, 28.

[0023] <Mold> The fixed mold 16 and the movable mold 17 according to this embodiment will now be described. As shown in FIG. 6, the fixed mold 16 is in contact with the injection nozzle 23 of the injection unit 6 from its rear surface, so that resin is injected. The movable mold 17 is composed of a fixed plate 17A fixed to the movable platen 11 and a slide mold 17B provided so as to be slidable relative to this fixed plate 17A. The slide mold 17B is slid up and down by a piston cylinder unit 38. As will be explained later, the slide mold 17B is slid between a molding position and a crimping position.

[0024] The fixed mold 16 and the slide mold 17B have recesses and protrusions formed at the parting line for molding a molded product. That is, the fixed mold 16 has a first recess 40 formed on its upper side and a first protrusion 41 formed on its lower side. The slide mold 17B has a second protrusion 42 formed on its upper side and a second recess 43 formed on its lower side. Therefore, when the slide mold 17B is in the molding position and the molds 16 and 17 are clamped, cavities are formed by the first recess 40 and the second protrusion 42, and by the first protrusion 41 and the second recess 43, respectively.

[0025] <Method of manufacturing molded products> A method for manufacturing a molded product using the molded product manufacturing apparatus 1 according to this embodiment will be described. As shown in FIG. 6, the piston cylinder unit 38 is driven to slide the slide mold 17B downward, i.e., to the molding position. The mold clamping device 5 is driven to clamp the mold. As a result, as shown in FIG. 7A, cavities are formed by the first recess 40 of the fixed mold 16 and the second protrusion 42 of the slide mold 17B, and by the first protrusion 41 of the fixed mold 16 and the second recess 43 of the slide mold 17B, respectively. Next, the injection molding process is carried out. That is, resin is injected from the injection device 6. This results in the molding of first and second semi-molded products 45 and 46.

[0026] The mold opening step is carried out after the first and second semi-molded products 45, 46 have cooled and solidified. As shown in Fig. 7B, the molds are opened with the first semi-molded product 45 remaining in the fixed mold 16 and the second semi-molded product 46 remaining in the slide mold 17B. The first semi-molded product 45 and the second semi-molded product 46 have joining end surfaces 45A, 46A, respectively.

[0027] An alignment step is carried out. That is, as shown in Fig. 7C, the piston cylinder unit 38 is driven to slide the slide mold 17B to the upper crimping position. At this time, the joining end surfaces 45A and 46A of the first and second semi-molded products 45 and 46 face each other. In other words, they are aligned.

[0028] A melting step is carried out. That is, the drive mechanism 26 (see FIG. 2) is driven to insert the melting heater 25A according to this embodiment between the first and second semi-molded products 45, 46 as shown in FIG. 7D. If necessary, the mold opening amount is adjusted by the mold clamping device 5 (see FIG. 1) to reduce the distance between the joining end surfaces 45A, 46A. However, the melting heater 25A remains out of contact with the joining end surfaces 45A, 46A. When current is supplied to the multiple element heaters 28, 28, ... (see FIGS. 3 and 4), infrared rays are emitted. The masking treatments 35, 35 applied to the glass plate 30 allow the infrared rays to selectively irradiate the joining end surfaces 45A, 46A, melting them.

[0029] The pressure-bonding step is carried out. That is, the drive mechanism 26 (see FIG. 2) is driven to retract the melting heater 25A. Next, as shown in FIG. 7E, the mold clamping unit 5 is driven to close the mold. This causes the joining end surfaces 45A and 46A of the first and second semi-molded products 45 and 46 to be pressure-bonded together, that is, joined. When the mold clamping unit 5 is driven to open the mold, a molded product 47 is obtained as shown in FIG. 7F.

[0030] <Melting heater according to the second embodiment> The melting heater 25 can be modified in various ways. Fig. 8 shows a melting heater 25B according to a second embodiment. In this embodiment, the multiple element heaters 28, 28, ... are not paired but are independent of each other. That is, each of these element heaters 28, 28, ... is provided for each of the quartz glass tubes 33', 33', .... Such element heaters 28, 28, ... are provided horizontally and are spaced equally apart in the vertical direction.

[0031] Note that while most of the heating by the element heaters 28, 28, ... is due to infrared radiation, there is also a small proportion of heating due to air convection. The heated air rises as indicated by reference numeral 50 in Figure 8, so the upper part is more likely to be heated. Therefore, adjustments may be made by shortening the energization time or reducing the magnitude of the current supplied to the element heaters 28, 28, ... located on the upper side compared to the element heaters 28, 28, ... located on the lower side.

[0032] <Melting heater according to the third embodiment> FIG. 9 shows a melting heater 25C according to a third embodiment. In this embodiment, the surface treatment applied to the two glass sheets 30′, 30′ is a textured treatment that partially changes the thickness of the sheets to form unevenness on the surface. Specifically, the glass sheets 30′, 30′ are formed with convex portions 51, 51, ... and concave portions 52, 52. Because of this textured treatment, infrared rays irradiated from the element heaters 28, 28, ... are refracted. That is, the infrared rays are concentrated at the convex portions 51 and diverged at the concave portions 52. This allows selective heating of the joining end surfaces 45A, 46A of the semi-molded products 45, 46 (see FIG. 7C).

[0033] <Fusing heater according to the fourth embodiment> FIG. 10 shows a melting heater 25D according to a fourth embodiment. In this embodiment, the element heaters 28 are arranged in two layers, a first layer and a second layer. That is, a two-layer structure is formed. A reflector 55 is provided between the element heaters 28 in the first layer and the element heaters 28 in the second layer. The reflector 55 separates the infrared rays from the element heaters 28 in the first layer from the element heaters 28 in the second layer, enabling the infrared rays to be irradiated evenly onto one glass plate 30 side and the other glass plate 30 side. The reflector 55 is not essential and may be provided as needed.

[0034] In some cases, multiple injection units 6, 6 are installed in a single injection molding machine 2 to mold semi-molded products 45, 46 of different colors or resins. In this case, differences in the infrared absorption rates and melting temperatures of the semi-molded products 45 and 46 may result in differences in the melted states of the two, and when the two are heated to a temperature at which they can be welded, the resin that melted first may begin to decompose. In such cases, the melted states of the two products may be adjusted by varying the energization times or the magnitude of the current supplied to the element heaters 28, 28, ... arranged in the first and second layers.

[0035] <Fusing heater according to the fifth embodiment> Fig. 11 shows a melting heater 25E according to a fifth embodiment. In this embodiment, as in the fourth embodiment, element heaters 28, 28, ... are arranged in a two-layer structure. In this embodiment, each of the quartz glass tubes 33, 33 has a reflective film 56, 56, ... formed on one surface by aluminum deposition or the like. This provides the same effect as the reflector 55 (see Fig. 10) in the fourth embodiment.

[0036] <Melting heater according to the sixth and seventh embodiments> In the melting heater 25 according to this embodiment, there are no restrictions on the direction in which the element heaters 28, 28, ... are arranged. Various modifications are possible, such as arranging the heaters in an oblique direction, or arranging part or all of the element heaters 28 bent the minimum number of times required. As such modifications, Figs. 12 and 13 show a melting heater 25F according to a sixth embodiment and a melting heater 25G according to a seventh embodiment.

[0037] <Melting heater according to eighth embodiment> FIG. 14 shows a melting heater 25H according to an eighth embodiment. In this embodiment, the welded portion of the molded product has a shape that protrudes laterally in part on both sides. The frame 27 and the glass plate 30 also have a shape that protrudes laterally to match the shape of the welded portion. In this embodiment, element heaters 28, 28, ... are provided, but curved heaters 58, 58 whose shape is modified to correspond to the protruding portion in the laterally direction are also employed. By employing curved heaters 58, 58, it is possible to accommodate even complex shapes of welded portions.

[0038] The invention made by the inventor has been specifically described above based on the embodiments, but it goes without saying that the present invention is not limited to the above-described embodiments 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]

[0039] 1 Molded product manufacturing equipment 2 Injection molding machine 3 Heater unit 5 Clamping unit 6 Injection device 8 Fixed plate 9. Mold clamping housing 11. Movable platen 12 tie bar 14 mold clamping mechanism 16 Fixed side mold 17 Movable side mold 17A Fixed plate 17B Slide mold 19 Heating cylinder 20 Screw 21 screw drive device 22 hopper 23 Injection nozzle 24 Base 25, 25A, 25B, 25C, 25D, 25E, 25F, ... Melting heater 26 Drive mechanism 27 Frame 28 element heater 30 glass plate 32 Pair heater 33 Quartz glass tube 35 Masking treatment 38 Piston cylinder unit 40 First concave portion 41 First convex portion 42 Second protrusion 43 Second recess 45 First semi-molded product 45A Joint end surface 46 Second semi-molded product 46A Joint end surface 47 Molded product 51 Convex part 52 Recess 55 Reflector 56 Reflective film 58 Curved heater B Bed

Claims

1. A melting heater for melting the joining end surfaces of a pair of semi-molded products when melting and joining the joining end surfaces of the semi-molded products to produce a molded product, The melting heater is composed of a plurality of element heaters arranged in a flat plate-shaped unit, each of the plurality of element heaters is linear and arranged parallel to one another, two adjacent heaters form a pair of heaters, and one end of each of the two element heaters in each pair of heaters is connected to each other in series, The melting heater is configured so that power supplied from one end of the melting heater is supplied to each of the pair heaters.

2. A melting heater as described in Claim 1, wherein the multiple element heaters are fixed to a frame body connected to a drive mechanism.

3. A melting heater as described in claim 1 or 2, wherein the multiple element heaters are capable of controlling the flow of electricity to each pair of heaters.

4. The melting heater is a melting heater described in any one of claims 1 to 3, wherein multiple element heaters are arranged in a single planar layer.

5. The melting heater according to any one of claims 1 to 3, wherein the melting heater has a two-layer structure in which a planar first layer is formed from approximately half of the element heaters, each of which is made up of a plurality of pairs of heaters, and a planar second layer is formed from the remaining element heaters.

6. The melting heater according to claim 5 , further comprising a reflecting member for reflecting infrared rays provided between the first layer and the second layer.

7. 6. The melting heater according to claim 5, wherein each of the plurality of element heaters of the melting heater is subjected to a surface treatment that reflects infrared rays on a surface on which the first layer and the second layer face each other.

8. A method for manufacturing a molded product using a melting heater, The melting heater is composed of a plurality of element heaters arranged in a flat plate-shaped unit, each of the plurality of element heaters is linear and arranged parallel to one another, two adjacent heaters form a pair of heaters, and one end of each of the two element heaters in each pair of heaters is connected to each other in series, The electric power supplied from one end of the melting heater is supplied to each of the pair heaters, The method for manufacturing the molded product includes an injection molding step of molding a pair of semi-molded products using a pair of molds; a mold opening step in which one half-molded article is left in one mold and the other half-molded article is left in the other mold; an alignment step of bringing the joining end surfaces of the pair of semi-molded products close to each other and facing each other; a melting step of inserting the melting heater between the joining end surfaces of the pair of semi-molded products in a non-contact manner to melt the joining end surfaces; and a crimping step of retracting the melting heater, closing the mold, and crimping the joining end surfaces together.

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