JPH0759384B2 - Method for molding resin box, mold used in the method, and resin box molded by the method - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

TECHNICAL FIELD The present invention relates to molding of a resin box body, and in particular, a method, a mold, and a resin for molding an upper member and a lower member into two parts and joining them to form one resin box body. It relates to a box manufacturing body.

[Prior art]

Conventionally, an upper member and a lower member, which form a resin box body having one opening, are separately molded by an upper molding die and a lower molding die, respectively, and then joined. Then, when the resin is injected by the tie gate or the pin gate, a weld line and a flow mark are generated, so that the deep upper member cannot be molded and the joint portion is brought to the upper portion. For example, in the case of a box used as a cover for a certification device provided on a ceiling or a wall surface, that is, a so-called certification instrument glove, in order to make the weld line and the flow mark inconspicuous, the upper side of the glove (joint part) is made ( The position was close to the opening). It should be noted that resin was injected into the lower molding die from a direct gate or a pin gate provided in a portion of the die corresponding to the center of the bottom surface of the lower member.

[Problems to be Solved by the Invention]

As in the past, if a direct gate or pin gate is used for the upper mold, weld lines and flow marks will occur unless the joint is on the top, so there is a design constraint that the joint cannot be on the bottom. It was In addition, when the resin is injected from the bottom of the lower molding die by a direct gate or a pin gate, there is a problem in that a mark of the gate remains on the molded product, which is not preferable in appearance. Therefore, it is an object of the present invention to provide a resin box body capable of preventing a trace of a gate, a weld line, a flow mark, and the like from being generated and bringing a joint portion to a desired position, a molding method thereof, and a mold thereof. I am trying.

[Means for Solving the Problems]

Therefore, in the method for molding a resin box body according to the present invention, a resin box body having one opening is divided into an upper member including an opening and a lower member, and the upper member is formed. In a method for molding a resin-made box body in which a lower member and a lower member are joined to each other, the upper member injects resin through a film gate from a portion of a mold corresponding to the opening, and the lower member includes the joining portion. A means for injecting a resin from a portion of the mold corresponding to the above with a film gate and joining the upper member and the lower member taken out from the mold to form a resin box body was taken. The mold used in the molding method according to claim (1) of the present invention comprises an upper mold for molding an upper member including an opening and a lower mold for molding a lower member. The molding die is a die corresponding to the opening and the side surface, and a film gate is provided in a portion of the die corresponding to the opening, and the lower molding die is a die having a side surface and a bottom surface. As a result, a film gate is provided in the mold portion corresponding to the upper edge portion of the side surface portion. And, in the resin box body according to the present invention, in the resin box body in which an upper member including an opening and a lower member are joined, the upper member is a film from the opening by the method of claim (1). An upper member molded by injecting resin at the gate, and the lower member being a lower member molded by injecting resin at the film gate from the upper edge portion of the side surface by the method according to claim (1). I took the measure.

[Action]

According to the resin box molding method of the present invention, the upper member,
Since resin is injected from the film gate provided in the mold part corresponding to the position of the opening, the amount of resin injected per unit time increases and it is evenly injected in the entire circumferential direction, so that the resin does not have to cool down. It spreads uniformly in the space of the mold and descends evenly in the space of the side surface. Therefore, it is not easily affected by temperature changes, and a vertically long upper member can be formed without forming weld lines or flow marks. Then, since the film is injected from the film gate provided in the portion corresponding to the position of the joint portion of the lower member, the trace of the gate does not remain on the bottom surface unlike the conventional pin gate. The traces of the film gate disappear when the joint part is finished. The upper member and the lower member thus formed are joined together to form an integral resin box body. Then, according to the mold used in the molding method of the present invention, since the resin is injected from the film gate provided in the opening of the upper molding die, the amount of the resin injected per unit time is large and the resin is injected in the entire circumferential direction. Since the resin is uniformly injected, the resin spreads evenly in the space of the mold shortly after cooling, and also rapidly descends uniformly in the space of the side surface. Therefore, it is not easily affected by temperature changes, and a vertically long upper member can be formed without forming weld lines or flow marks. Further, since the film is injected from the film gate provided in the portion corresponding to the position of the bonding portion of the lower molding die, the trace of the gate does not remain on the bottom surface unlike the conventional pin gate. Further, the traces of the gate disappear when the finishing process is performed on the junction. Then, in the resin box body molded by the method according to the present invention, the upper member molded by injecting the resin at the film gate from the opening portion and the resin injected at the film gate from the upper edge portion of the side surface portion. Since the molded and formed lower member is joined at the side surface portion, no weld line or flow mark is generated, and the trace of the gate does not extend to the bottom surface. Further, since the upper member can be formed in a deep box shape by lengthening the length thereof, the joint portion can be formed at a desired position in the upper portion or the lower portion.

【Example】

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view of an example of a resin box body molded by the method for molding a resin box body of the same embodiment, FIG. 2 is a sectional view of an upper molding die used in the molding method, and FIG. It is sectional drawing of the lower mold used for the method. In FIG. 1, A is a globe for a lighting fixture as a resin box body in which the upper member A1 and the lower member A2 are joined, and A3 is an opening portion as a mounting portion having a screw formed on the outer peripheral surface. , A4 is a side surface portion of the upper member A1, A7 is a joint portion in which the joint portion A5 of the upper member A1 and the joint portion A6 of the lower member A2 are fused and joined, A8 of this lighting fixture globe At the bottom. In FIG. 2, 1 is an upper mold for molding the upper member A1, 3 is a disc film gate which is an injection portion of the upper mold 1, 11 is a space for molding the opening A3 of the upper member A1, Reference numeral 12 is a space for molding the joint portion A5 at the lower end of the upper member A1, and 13 is a space for molding the side surface portion A4 of the upper member A1. When the resin is injected from the disk gate 3 of the upper mold 1, the resin is quickly injected into the upper mold 1 from the entire circumference of the disc gate 3, so that the inside of the space 11 of the upper mold 1 is injected. Is uniformly spread in the entire circumferential direction, quickly reaches the space 12 through the space 13, and is hardly affected by temperature change. Therefore, even if the space 13 is deep, it is injected to the lower end without flow marks or weld lines. Then, after the injection is completed, after cooling, the upper mold 1 is opened and the molded upper member A1 is taken out. After this, the injection marks by the disk gate 3 are shaved off for finishing.
At this time, since the disc gate 3 injects from the inside of the opening, the strength of the screw thread on the outside does not decrease. The lower end of the upper member A2 becomes the joint portion A5. In FIG. 3, 2 is a lower mold for molding the lower member A2, 4 is a film gate which is an injection portion of the lower mold 2, and 21 is a joining portion at the upper end of the lower member A2. A space for molding A6, 22 is a space for molding the bottom portion A8 of the lower member A2. When the resin is injected from the film gate 4 of the lower mold 2, the resin uniformly descends the space 21 on the side surface of the lower mold 2 and fills the space 22 on the bottom surface. Here, since the space 21 is shallow and is injected from the film gate 4, the injected resin quickly fills the space 22 at the bottom. Therefore, it is not easily affected by the temperature change, so that the molding is performed uniformly without flow marks or weld lines. Then, after the injection, after cooling, the lower mold 2 is opened and the molded lower member A2 is taken out. After this, the injection marks by the film gate 4 are shaved off for finishing.
The portion of this injection mark becomes the joint portion A6 of the lower member A2. By forming small irregularities on the inner surfaces of the upper molding die 1 and the lower molding die 2, it is possible to mold the surface of the globe in a satin-finished state and obtain a lighting fixture that can obtain soft light. In this way, by molding with the mold A, it is possible to obtain an effect that it is possible to provide a glove for a lighting fixture in which the marks of the flow mark, the weld line, and the injection portion are inconspicuous. Further, since the joining portion between the upper member and the lower member can be brought to a desired position, the effect of increasing the degree of freedom in design can be obtained.

【The invention's effect】

As described above, according to the method for molding the resin box body according to the present invention, by using the film gate, the trace of the injection portion, the weld line, the flow mark, etc. do not appear, and the resin box has an excellent appearance. The effect is that the body can be molded. Then, according to the mold used in the above method, it is possible to mold a resin box body that achieves the above effects. Further, according to the resin box body according to the present invention molded by the above method, since the joint portion can be brought to a desired position, the effect that the joint portion is not limited to the upper portion can be obtained. Can be done.

[Brief description of drawings]

FIG. 1 is a perspective view of a resin box body molded by the method for molding a resin box body of the present invention, FIG. 2 is a sectional view of an upper molding die used in the molding method, and FIG. 3 is used in the molding method. It is sectional drawing of a lower mold. 1 ... Upper mold, 2 ... Lower mold, 3 ... Disc film gate, 4 ... Film gate, A ... Resin box, A1 ... Upper member, A2 ... Lower member, A3 …… Aperture, A4 …… Side, A5 …… Upper member joint, A6 …… Lower member joint, A7 …… Join.

Claims (3)

[Claims] 1. A resin box body having one opening,
In a molding method of a resin box body, which is divided into an upper member including an opening and a lower member and molded, and the upper member and the lower member are joined and molded, the upper member corresponds to the opening. Resin is injected from a mold part by a film gate, the lower member is injected resin from a mold part corresponding to the joint part by a film gate, and the upper member and the lower member taken out from the mold are joined. A method for molding a resin box body, which comprises molding a resin box body using 2. A mold used in the molding method comprises an upper mold for molding an upper member including an opening and a lower mold for molding a lower member, wherein the upper mold has an opening. And a film gate is provided in the part of the mold corresponding to the side part and corresponding to the opening, the lower molding mold,
The mold used in the method of claim (1), wherein a film gate is provided on a mold portion having a side surface portion and a bottom surface, the mold portion corresponding to an upper edge portion of the side surface portion. 3. A resin box body obtained by joining an upper member including an opening and a lower member together, wherein the upper member is an upper member molded by injecting a resin from a film gate through the opening, The resin box body molded by the method according to claim (1), wherein the lower member is a lower member molded by injecting resin from a film gate from an upper edge portion of a side surface portion.