JP3951243B2 - Window manufacturing method in in-mold molding - Google Patents

Description

The present invention relates to a method for manufacturing a window portion in in-mold molding used for an instrument panel such as a speedometer, a tachometer, an air conditioner panel, and a shift indicator of an automobile, a front panel of an audio product, or a control panel of a home appliance.

  In in-mold molding, in which the synthetic resin sheet is mounted on an injection mold, the mold is closed and the molten resin is injection-molded, and the mold is opened after cooling, a hole is made in the synthetic resin sheet. As a method, there is a method of making a hole in the synthetic resin sheet in advance, a method of making a hole in the synthetic resin sheet by a press machine or the like after in-mold molding.

  However, when the synthetic resin sheet is pre-drilled and attached to the injection mold, and the mold is closed and the molten resin is injection-molded, the molten resin leaks from the hole of the synthetic resin sheet and There is a possibility that the periphery is blocked and a complete hole cannot be formed. Further, the synthetic resin sheet may shrink and the molten resin may be exposed, causing light leakage.

  In addition, if holes are not formed in the synthetic resin sheet in advance, and the holes are formed by a press machine after in-mold molding, there is a disadvantage that the number of processes increases and the cost increases accordingly.

  In addition, the invention of Patent Document 1 relates to a method of providing a window part that needs to wrap a picture sheet from the outer periphery to the inner periphery of a decorative laminated product to be obtained by the simultaneous injection molding method. As shown in FIG. 7, the configuration of the present invention includes a female mold 31 and a male mold 32, a clamping means 35 that presses and holds the picture sheet S against the parting surface 34 of the female mold 31, and a picture sheet S. A vacuum suction means (such as a vacuum suction hole 36 and a vacuum suction passage 38) that extends along the cavity 33 of the female die 31 and the male die 32 in the cavity 33 formed between the female die 31 and the male die 32. Resin injection means (gate 39, runner 40, etc.) for injecting and filling resin in a fluid state from the side, and the cavity 33 is formed in the female die 31 in order to form the window portion 42 etc. of the decorative laminated product to be obtained. A projecting isolated portion 43 protruding from the bottom of the projecting isolated portion 43 is provided, and the suction of the picture sheet S by the vacuum suction means is preferentially performed from the outer peripheral corner portion of the projecting isolated portion 43.

  By the way, the invention of this document was made to prevent wrinkles from occurring in the vicinity of the base 44 of the outer peripheral corner of the convex isolated portion 43, and the picture sheet S is placed along the cavity 33 in the cavity 33. A plurality of vacuum suction holes 36 for vacuum suction are opened in the vicinity of the corner portion, and the vacuum suction holes 36, 36... Are externally connected via a vacuum suction passage 38 and a conduit 45. It is configured to be connected to a vacuum source such as a vacuum pump.

As described above, the invention of Patent Document 1 is such that the window is formed in the entire thickness of the molded product formed in the cavity 33, and complicated vacuum suction means are provided. become. Also, the picture sheet S remains at the bottom of the hole, and it is necessary to punch the picture sheet S with a press after forming to make a hole penetrating the hole. Molds and presses are required, which increases costs.
JP 2001-79883 A

The present invention has been made to solve the above-described problems, and in in-mold molding in which a synthetic resin sheet is mounted in an injection mold and then the mold is closed and a molten resin is injection-molded. An object of the present invention is to provide a method for manufacturing a window part in in-mold molding, which enables the window part to be formed in a molded product simultaneously with the in-mold molding .

In order to achieve the above object, the method for manufacturing a window part in in-mold molding according to claim 1 of the present invention is to mount a pre-formed and decorated synthetic resin sheet in an injection mold. In in-mold molding in which the mold is closed and mounted in the injection mold, and then the mold is closed and the molten resin is injection-molded, a window formed as an opening of the synthetic resin sheet is provided. And the edge of the mold corresponding to the portion where the peripheral edge of the window portion formed by projecting the synthetic resin sheet toward the molten resin side and the inner peripheral portion of the window portion has a flat surface By closing the mold and injection-molding the molten resin, a concave portion having a thickness of the synthetic resin sheet of 0.02 to 0.15 mm is provided at the periphery of the window portion of the preformed synthetic resin sheet. rear The mold is opened, the molded product is taken out , and then the inner peripheral portion in the concave portion of the window portion is pushed out to remove the synthetic resin sheet on the inner peripheral portion .

  According to the present invention, in the in-mold molding in which the synthetic resin sheet is mounted on the injection mold and the mold is closed and the molten resin is injection molded, the thickness of the synthetic resin sheet at the periphery of the window portion of the synthetic resin sheet By providing a recess with 0.02 to 0.15 mm, the mold is closed and the molten resin is injection-molded, then the mold is opened and the molded product is taken out. The window can be easily removed by being pushed out by work, and the window can be a complete opening.

  In the formation of such a window part, the inner peripheral part of the window part is easily pushed out and removed manually by providing a concave part with a thickness of the synthetic resin sheet of 0.02 to 0.15 mm at the periphery of the window part. In addition, the appearance of the opening end portion as a trace of the removal of the inner peripheral portion of the window portion is also beautiful and can be used as it is, and a molded product that does not require post-processing can be obtained. .

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 4, the method for manufacturing a window portion in in-mold molding according to the present invention trims a pre-formed and decorated synthetic resin sheet 2 into a shape that can be mounted in an injection mold 3. In the in-mold molding in which the mold 3 is closed and the molten resin 4 is injection-molded after being mounted in the injection-molding mold 3, the window portion 6 is provided at a predetermined position of the molded product 5 (see FIG. 1). It is to be formed.

  Further, in the method of manufacturing a window portion in in-mold molding according to the present invention, as shown in FIG. 5, a decorated synthetic resin sheet 2 that is preformed or not preformed is provided on the parting surface of the injection mold 3. In in-mold molding in which the mold 3 is closed and the molten resin 4 is injection-molded after trimming into a shape that can be mounted in the digging recess 16 and mounting in the digging recess 16, the molded product 5 (see FIG. 1). The window portion 6 is formed at a predetermined position.

  A molded product 5 in FIG. 1 shows an example in which a window portion 6 is formed in a car tachometer 8 by the manufacturing method of the present embodiment. This window part 6 is an opening part for displaying time, and as shown in FIG. 2 or FIG. 3, it has a peripheral edge 9 protruding in the back direction of the tachometer 8, and the inside of the peripheral edge 9 is a complete opening. It needs to be formed as a part.

  In order to form such a window portion 6, the structure of the injection mold 3 according to the present invention has a common mold in any in-mold molding shown in FIG. 4 or FIG. That is, as shown in FIG. 6 (a) or FIG. 6 (b), in order to provide a recess 10 in which the thickness G of the synthetic resin sheet 2 is 0.02 to 0.15 mm at the peripheral edge 9 of the window 6 of the synthetic resin sheet 2. The portion of the injection mold 3 is a blade mold 12 having a flat surface 11 at the tip.

  This configuration will be described in more detail. As shown in FIG. 6 (a), the fixed-side mold 13 is formed in the split mold 13a along the peripheral edge 9 of the window portion 6, and the movable-side mold 14 is formed. As shown in FIG. 6 (b), the lowermost bottom portion of the peripheral edge 9 of the window portion 6 is formed in a blade die 12 having a flat surface 11 at the tip, and the movable die 14 is fixed to the fixed die. 13, the peripheral edge 9 of the window portion 6 and the inner peripheral portion 6 a of the window portion 6 are left, leaving the recess 10 where the thickness of the synthetic resin sheet 2 along the peripheral edge 9 of the window portion 6 is 0.02 to 0.15 mm. And keep it connected.

  The tip of the blade mold 12 provided in the injection mold 3 has the flat surface 11 as described above, and this is different from the blade mold used for punching the synthetic resin sheet. It is. This conventional blade type mold has an acute angle at the tip, and punches out the synthetic resin sheet 2 to the last. On the other hand, the blade mold 12 of the injection mold 3 of the present invention is formed so that the tip has a flat surface 11 so as to form the recess 10 leaving a predetermined thickness on the synthetic resin sheet 2. Is.

  After the window portion 6 of the synthetic resin sheet 2 is formed by the injection mold 3 described above, when the mold 3 is opened and a molded product in the mold 3 is taken out, as shown in FIG. 9 and the inner peripheral portion 6a are taken out in a state where they are joined by the concave portion 10, and then, as shown in FIG. 3, the synthetic resin sheet 2 in the inner peripheral portion 6a of the window portion 6 is pushed out and removed manually. Thereby, the shape which the window part 6 opened completely can be obtained.

  As described above, in the present invention, the concave portion 10 having the thickness of the synthetic resin sheet 2 of 0.02 to 0.15 mm is provided on the peripheral edge 9 of the window portion 6, thereby opening the mold 3 and taking out the molded product 5. The inner peripheral part 6a in the recessed part 10 of the window part 6 can be easily removed by manual extrusion.

  Here, the reason why the concave portion 10 in which the thickness of the synthetic resin sheet 2 is 0.02 to 0.15 mm is provided in the peripheral edge 9 of the window portion 6 of the synthetic resin sheet 2 in order to form the window portion 6 will be described.

  First, in FIG. 6A or 6B, the thickness of the concave portion 10 of the synthetic resin sheet 2 at the peripheral edge 9 of the window portion 6 formed by the blade mold 12 of the injection mold 3 is in the range of 0.02 to 0.15 mm. And The thinner the recess 10 is, the easier it is to remove the inner peripheral portion 6a by manually extruding, but the thickness is limited to 0.02 mm. If the concave portion 10 is thinner than 0.02 mm, the inner peripheral portion 6a of the window portion 6 may be partially or entirely broken, and the fragment may remain in the mold even after the mold is opened. A tool is required to take it out, but there is a risk of scratching the mold when using this tool.

  Therefore, in order not to make such a scratch on the mold, a part or all of the inner peripheral portion 6a of the window 6 remaining in the mold must be taken out very carefully. Takes time and leads to cost increase. Further, as described above, taking out a part or all of the inner peripheral portion 6a of the window portion 6 remaining in the mold itself increases one step and increases the injection molding cycle, thereby increasing the cost. It becomes.

  On the contrary, when the thickness of the concave portion 10 on the peripheral edge 9 of the window portion 6 is 0.15 mm or more, a considerable amount of force is required to push out the inner peripheral portion 6a of the window portion 6 remaining in the molded product by hand. As a result, workability is deteriorated, work efficiency is lowered, productivity is lowered, and cost is increased.

  Furthermore, when the thickness of the concave portion 10 is 0.15 mm or more, the opening end 15 (see FIG. 3) as a trace of the removal of the inner peripheral portion 6a of the window portion 6 leaves a jagged roughness and only looks bad. However, post-processing such as cutting with a cutter or the like is required, leading to an increase in cost.

  As described above, when the thickness of the concave portion 10 in the peripheral edge 9 of the window portion 6 of the synthetic resin sheet is 0.02 mm or more and 0.15 mm or less, the inner peripheral portion 6a of the window portion 6 can be easily pushed out by hand, Also, the appearance of the open end 15 is beautiful, can be used as it is, and does not require post-processing.

  As a comparative example with respect to the above embodiment, when the thickness of the concave portion 10 of the synthetic resin sheet 2 by the blade mold 12 of the injection mold 3 is 0.01 mm, the window portion 6 of the synthetic resin sheet 2 is the synthetic resin. As a result, the molten resin leaks from the end portion of the window portion 6 toward the inner peripheral portion 6a, and partially closes the inner peripheral portion 6a.

  In addition, when the thickness of the concave portion 10 is 0.19 mm, the trace (opening end portion 15) from which the inner peripheral portion 6a of the window portion 6 is removed becomes a saw-tooth shape, looks bad, and requires post-processing. It became.

The present invention forms a window part in in-mold molding used for an instrument panel such as an automobile speedometer, tachometer, air conditioner panel, shift indicator, front panel for audio products, control panel for home appliances, etc. at the same time as in-mold molding. It can be used as a method for manufacturing a window portion in in-mold molding .

It is a top view which shows the condition which formed the window part in the tachometer of the motor vehicle which is a molded article formed by this invention. It is the sectional view on the AA line of FIG. The state which has removed the inner peripheral part of the window part in the sectional view on the AA line of FIG. In the present invention, it is a sectional view of an injection mold when a trimmed synthetic resin sheet is mounted. In this invention, it is sectional drawing of the injection mold at the time of mounting | wearing with the synthetic resin sheet trimmed so that it could mount | wear with the digging recessed part of a parting surface. (a) is an expanded sectional view in the injection mold in this invention, (b) is a principal part expanded sectional view which shows the front-end | tip of the blade type | mold in an injection mold. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Synthetic resin sheet 3 ... Injection mold 4 ... Molten resin 5 ... Molded product 6 ... Window part 6a ... Inner peripheral part 7 ... Cavity 8 ... Tachometer 9 ... Perimeter 10 ... Concave 11 ... Flat surface 12 ... Blade type 13 ... fixed side mold 13a ... split mold 14 ... movable side mold 15 ... open end 16 ... digging recess G ... thickness of synthetic resin sheet in recess

Claims (1)

After trimming the pre-formed and decorated synthetic resin sheet into a shape that can be mounted in an injection mold and mounting it in the injection mold, the mold is closed and the molten resin is In in-mold molding for injection molding, the window has a window portion formed as an opening of the synthetic resin sheet, and the synthetic resin sheet protrudes toward the molten resin side, and the window portion has a peripheral edge. The tip of the mold corresponding to the portion where the inner peripheral portion is coupled is formed into a blade mold having a flat surface, and the mold is closed and the molten resin is injection-molded . By providing a recess with a thickness of the synthetic resin sheet of 0.02 to 0.15 mm at the periphery of the window, and then opening the mold and taking out the molded product, and then extruding the inner peripheral part in the recess of the window The inner periphery A method for manufacturing a window portion in in-mold molding , wherein the synthetic resin sheet is removed.

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