This application claims the benefit of priority from the prior Japanese Patent Application Nos. 2006-42374 and 2006-42375, the entire contents of which are incorporated by reference herein.
1. Field of the Invention
The present invention relates to a method of manufacturing resin molded product for double molding by injecting two kinds of synthetic resins each having a different material and color tone.
2. Description of the Related Art
Conventionally, double molding has been performed by injecting two kinds of synthetic resins each having a different material and color tone. (see, for example, Japanese Patent Application Laid-Open Nos. 9-183139, 9-183140, 9-183141 and 9-183142).
According to these conventional technologies, an injection molding machine is disposed on the side of a fixed mold and a carrying unit for a decorating sheet is disposed integrally on the side of a movable mold. The resin molded product is formed as follows. First, a primary resin molded product is obtained by injecting resin on a primary side, thereafter, the movable mold is rotated to a position in which resin for a secondary side is to be injected. Next, after the molds are closed, the resin for the secondary side is injected so as to obtain a secondary resin molded product.
However, if a heavy construction such as the decorating sheet carrying unit is disposed on the side of the movable mold which is rotated as described above, a large rotary driving force is needed.
Although it can be considered to use a small decorating sheet carrying unit as described in the patent document in order to solve this problem, the decorating sheet itself becomes small so that the freedom of the decorating sheet may be deteriorated. If the driving force of a driving means is increased, the driving means itself becomes large to lead enlargement in the size of the manufacturing apparatus thereby worsening efficiency.
Further, when the movable mold is rotated together with the decorating sheet carrying unit, the position of the decorating sheet and the position of a cavity in the mold may deflect from each other with a motion thereof. If positions of decoration and cavity deflect from each other, decoration cannot be performed accurately on a resin molded product.
An object of the present invention is to provide a manufacturing method for obtaining a resin molded product having a high design property by double molding system.
To achieve the above-described object, according to an aspect of the present invention, there is provided a method of manufacturing resin molded product using a manufacturing apparatus including: a movable mold in which a pair of a movable side cavity and a side gate are formed symmetrically with respect to an axis; a fixed mold in which a fixed side primary cavity and a fixed side secondary cavity are formed; a primary resin injecting means and a secondary resin injecting means disposed on the side of a fixed mold; and a decorating film carrying means disposed on the side of the fixed mold, the method including: a primary forming step of closing the movable mold with respect to the fixed mold and injecting primary resin into the fixed side primary cavity by the primary resin injecting means so as to form a primary resin molded product; a rotating step of opening the molds to separate the movable mold from the fixed mold with the primary resin molded product held and rotating the movable mold around the rotation axis symmetrically with respect to the axis; and a secondary forming step of, with a decorating film of the decorating film carrying means placed on the fixed side secondary cavity, closing the movable mold with respect to the fixed mold and injecting secondary resin from the side gate between the movable side cavity and the fixed side secondary cavity by the secondary resin injecting means so as to form a decorated secondary resin molded product.
According to another aspect of the present invention, there is provided a method of manufacturing resin molded product using a manufacturing apparatus including: a movable mold in which a pair of a movable side cavity and a side gate are formed symmetrically with respect to an axis; a fixed mold in which a fixed side primary cavity and a fixed side secondary cavity are formed; a primary resin injecting means and a secondary resin injecting means disposed on the side of a fixed mold; and a decorating film carrying means disposed on the side of the fixed mold, the method including: a primary forming step of closing the movable mold with respect to the fixed mold and injecting primary resin from a pin gate connected to the fixed side primary cavity by the primary resin injecting means so as to form a primary resin molded product; a rotating step of opening the molds to separate the movable mold from the fixed mold with the primary resin molded product held and rotating the movable mold around the rotation axis symmetrically with respect to the axis; and a secondary forming step of, with a decorating film of the decorating film carrying means placed on the fixed side secondary cavity, closing the movable mold with respect to the fixed mold and injecting secondary resin from the side gate between the movable side cavity and the fixed side secondary cavity by the secondary resin injecting means so as to form a decorated secondary resin molded product.
According to still another aspect of the present invention, there is provided a method of manufacturing resin molded product using a manufacturing apparatus including: a movable mold in which a movable side cavity, primary side gate and secondary side gate are formed on each side symmetrically with respect to the axis; a fixed mold in which a fixed side primary cavity and a fixed side secondary cavity are formed; a primary resin injecting means and a secondary resin injecting means disposed on the side of a fixed mold; and a primary decorating film carrying means and secondary decorating film carrying means disposed on the side of the fixed mold, the method including: a primary forming step of, with a primary decorating film of the primary decorating film carrying means placed on the fixed side primary cavity on the fixed mold, closing the movable mold with respect to the fixed mold and injecting primary resin from the primary side gate between the movable side cavity and the fixed side primary cavity by the primary resin injecting means so as to form a primarily decorated primary resin molded product; a rotating step of opening the molds to separate the movable mold from the fixed mold with the primary resin molded product held and rotating the movable mold around the rotation axis symmetrically with respect to the axis; and a secondary forming step of, with a secondary decorated film of the secondary decorated film carrying means placed on the fixed side secondary cavity on the fixed side mold, closing the movable mold with respect to the fixed mold and injecting secondary resin from the secondary side gate between the movable side cavity and the fixed side secondary cavity by the secondary resin injecting means so as to form a secondarily decorated secondary resin molded product.
According to the method of manufacturing resin molded product of the present invention, as described above, by providing the heavy resin injecting means and decorating film carrying means on the side of the fixed mold, the weight of the movable mold is small thereby facilitating a rotation of the movable mold. Consequently, the driving force can be reduced and the resin molded product can be obtained efficiently.
Further, by closing the molds and injecting resin, two resin molded products of primary resin molded product and secondary resin molded product can be formed at the same time. Because the side gate is used on the secondary side, resin can be injected into the cavity with the decorating film placed on the cavity. Thus, a resin molded product having a high design property can be obtained.
To achieve the above object, the method of manufacturing resin molded product of the present invention may use any one of the primary decorating film carrying means and the secondary decorating film carrying means.
As described above, according to the method of manufacturing resin molded product of the present invention, the design property of the resin molded product can be adjusted by using any one of the primary decorating film carrying means and the secondary decorating film carrying means.
The embodiment of the present invention will be described with reference to the accompanying drawings. (Manufacturing apparatus) The structure of the manufacturing apparatus will be described with reference to FIGS. 1 to 3B.
As shown in FIGS. 1 to 3B, the manufacturing apparatus 1 for resin molded product includes a movable mold 10 each having two movable side cavities 11 and side gates 12 and a fixed mold 20 having a fixed side primary cavity 21 and a fixed side secondary cavity 22. The fixed mold 20 includes a forming mold 20a having the cavities 21, 22 and resin introduction paths 23, 24 and a pouring mold 20b having resin pouring ports 25, 26.
As shown in
As shown in FIGS. 1 to 3B, a plurality of cavities are formed in the movable mold 10 and the fixed mold 20. Next, the detail of the manufacturing apparatus will be described.
The movable side cavity 11 for forming a primary resin molded product is formed in the movable mold 10 symmetrically with a rotation axis X. The side gate 12 which does not communicate directly with the movable cavity 11 is formed sideway of the movable cavity 11.
The fixed side primary cavity 21 for forming a primary resin molded product and the fixed side secondary cavity 22 for forming a secondary resin molded product are disposed in the fixed mold 20. The fixed side primary cavity 21 is disposed at a position opposing the movable side cavity 11 on the primary side. Further, the fixed side secondary cavity 22 is disposed to oppose the movable side cavity 11 on the secondary side and communicate with the movable side cavity 11 and the side gate 12 at the same time.
As shown in FIGS. 1 to 3B, a primary resin introduction path 23 and a primary resin pouring port 25 for introducing primary resin to the fixed side primary cavity 21 are formed on the primary side of the fixed mold 20. A secondary resin introduction path 24 and a secondary resin pouring port 26 for introducing secondary resin to the fixed side secondary cavity are formed on the secondary side of the fixed mold 20. Consequently, resin is poured into the cavity.
As shown in
The decorating film carrying means 40 is fixedly disposed on both side faces of the fixed mold 20. The decorating film carrying means 40 has a feeding side roller and a receiving side roller and carries the decorating film 41 on which a pattern 51 is printed continuously in the direction of an arrow indicated in the figure.
(Manufacturing Method)
The method of manufacturing the resin molded product will be described with reference to
Primary forming process for forming the primary resin molded product will be described with reference to
First, as shown in
Rotating step for rotating the primary resin molded product 61a will be described with reference to
As shown in
When the movable mold 10 and the forming mold 20a are separated from each other, the primary resin molded product 61a is separated from the primary sprue 61b at the exit 23a in which the primary resin introduction path 23 is squeezed. Further, when the forming mold 20a and the pouring mold 20b are separated, space is generated between the primary resin introduction path 23 and the pouring mold 20a, so that the primary sprue 61b can be brought out of the fixed mold 20. Consequently, the primary resin molded product 61a is molded.
Next, as shown in
Secondary forming step for forming the secondary resin molded product will be described with reference to
With the decorating film 41 placed on the fixed side secondary cavity 22 in the fixed mold 20 (see
Next, as shown in
The pattern 51 (see
After the secondary forming, as shown in
When the movable mold 10 and the forming mold 20a are separated, the secondary resin portion 62a and the secondary sprue 62b are separated at the exit 24a in which the secondary resin introduction path 24 is squeezed. When the molds are separated in this procedure, the secondary sprue 62b is removed from the secondary resin molded product in which the primary resin molded product 61a and the secondary resin portion 62a are integrated.
When the forming mold 20a and the pouring mold 20b are separated, space is generated between the secondary resin introduction path 24 and the pouring mold 20b, so that the secondary sprue 62b can be taken out of the fixed mold 20.
A pushing member 70 disposed adjacent the movable side cavity 11 and the side gate 12 is pressed by a pressing means 80 shown in
As described above, according to this embodiment, diversified resin molded products can be obtained by combining the two resin members 61a, 61b. Specifically, if any one or both of the primary resin member 61a and the second resin portion 62a are composed of transparent or translucent member, further diversified patterns can be formed.
According to this embodiment, resin is poured into the cavity in the secondary side through the side gate 12. Consequently, the resin molded product can be formed using the decorating film 41. As a result, the pattern of the resin molded product is diversified thereby improving design property.
In this embodiment, the resin injecting means 31, 32 having a heavy weight and the decorating film carrying means 40 are disposed on the side of the fixed mold 20. Because no heavy means is disposed on the side of the movable mold 10, the movable mold 10 is light so that the driving force of the driving means for rotating or moving the movable mold 10 can be reduced. Thus, the movable mold 10 can be moved efficiently by a small driving force and consequently, the resin molded product can be obtained effectively.
In this embodiment, the decorating film carrying means 40 is disposed on the side of the fixed mold 20. If the decorating film 41 is carried and positioned at a predetermined position by the decorating film carrying means 40, the position of the decorating film 41 is fixed securely until resin is injected. Then, the accuracy of a pattern transferred position is raised compared with a case where the decorating film carrying means is rotated together with the movable mold. As a result, the position of the pattern to be transferred to resin becomes accurate thereby securing high design property of the resin molded product.
Although the configuration of the gate to the cavity in the secondary side is of the side gate 12 in the first embodiment, that gate is not limited to this example. For example, it is permissible to adopt a submarine gate 112 by squeezing part of the aforementioned side gate 12. In this case, if the movable mold 10 and the fixed mold 20 are separated, the secondary resin is separated at the squeezed portion. Consequently, step of removing a runner after the secondary resin molded product is obtained can be omitted thereby making the manufacturing process more effective.
Although in the first embodiment, the two cavities 21, 22 and the two introduction paths 23, 24 are constructed integrally in one fixed mold 20, this embodiment is not restricted thereto. For example, as shown in
Further, although in the first embodiment, the two cavities 11 and the two gates 12 are constructed integrally in the movable mold 10, this embodiment is not restricted thereto For example, as shown in
By constituting the mold with a plurality of independent templates, temperature control on each template can be performed. If the temperature control of the primary side and secondary side templates is carried out individually, the temperature of each template can be controlled to a temperature suitable for each step. As a result, a precision, more stable resin molded product can be obtained.
The embodiment of the present invention will be described with reference to the accompanying drawings.
(Manufacturing Apparatus)
The structure of the manufacturing apparatus will be described with reference to FIGS. 9 to 11B.
As shown in FIGS. 9 to 11B, the manufacturing apparatus 201 for resin molded product includes a movable mold 210 having two cavities 211 and gates 212, 213 and a fixed mold 220 having cavities 221, 222.
As shown in
As shown in FIGS. 9 to 11B, the movable mold 210 and the fixed mold 220 include a plurality of cavities.
The movable side cavities 211 for forming the primary resin molded product are disposed in the movable mold 210 symmetrically with respect to the rotation axis X. Two side gates are disposed on the sides of the movable side cavity 211. That is, the primary side gate 212 is disposed on a far side relative to the rotation axis X and the secondary side gate 213 is disposed on a near side relative to the rotation axis X.
A fixed side primary cavity 221 for forming the primary resin molded product and a fixed side secondary cavity 222 for forming the secondary resin molded product are disposed in the fixed mold 220. The positions of the respective cavities 221, 222 are opposite to the two movable side cavities 211 in the aforementioned movable mold 210.
As shown in FIGS. 9 to 11B, the fixed mold 220 has a primary resin introduction port 223 for introducing primary resin to the fixed side primary cavity 221 through the primary side gate 212 and a secondary resin introduction port 224 for introducing secondary resin to the fixed side secondary cavity through the secondary side gate 213. Further, as shown in
As shown in
Two decorating film carrying means 241, 242 are disposed on both side faces of the fixed mold 220 as shown in
As shown in
(Manufacturing Method)
The method of manufacturing resin molded product will be described with reference to
Primary forming step of forming the primary resin molded product will be described with reference to
First, as shown in
Next, as shown in
The pattern 251 (see
Rotating step for rotating the primary resin molded product 261 us explained with reference to
As shown in
Next, as shown in
Secondary forming step of forming the secondary resin molded product will be described with reference to
First, with the secondary decorating film 242a placed on the fixed side secondary cavity 222 on the fixed mold 220, as shown in
Next, as shown in
The secondary side pattern 252 (see
The secondary resin molded product 260 is obtained by integrating the primary resin molded product 261 with the secondary resin member 262 through the secondary forming step. After the secondary forming step, with the cooled secondary resin molded product 260 held, as shown in
A pushing member 270 disposed adjacent the movable side cavity 211, the primary side gate 212 and the secondary side gate 213 is pressed by a pressing means 280 as shown in
As described above, diversified resin molded products can be obtained by overlaying the secondary resin member 262 on the primary resin molded product 261. Particularly, more diversified patterns can be formed by constituting any one or both of the primary resin molded product 261 and the secondary resin member 262 of transparent or translucent member.
In this embodiment, resin is poured into the primary side cavity and the secondary side cavity through the side gates 212, 213. As a result, a resin molded product can be formed by using the two decorating films 241a, 242a.
If the primary side pattern 251 is interposed between the primary resin molded product 261 and the secondary resin member 262 and the primary resin or the secondary resin is composed of transparent member or the like as shown in
In this embodiment, the heavy resin injecting means 231, 232 and the decorating film carrying means 241, 242 are disposed on the side of the fixed mold 220. Because any heavy means is not disposed on the side of the movable mold 210, the weight of the movable mold 210 is small so that the driving force of the driving means for rotating or moving the movable mold 210 can be lowered. Thus, the movable mold 210 can be moved effectively with a small driving force and a resin molded product can be obtained efficiently.
In this embodiment, the decorating film carrying means 241, 242 are disposed on the side of the fixed mold 20. Thus, if the decorating films 241a, 242a are carried and positioned at a predetermined position by the primary decorating film carrying means 241, 242, the positions of the films 241a, 242a are fixed securely until resin is injected. Consequently, the accuracy of a pattern transfer position becomes higher than a case where the decorating film carrying means is rotated and moved together with the movable mold. As a result, the accuracy of the position of the pattern to be transferred to resin is improved thereby maintaining a high design property of the resin molded product.
Although in the third embodiment, the decorating film carrying means is used on both the primary side and the secondary side, the embodiment is not limited to this example. For example, a decorating film carrying means 241 may be used on only the primary side as shown in
Although in the third embodiment, the side gates are used for both the gates 212, 213 to the cavity, the embodiment is not restricted thereto. For example, as shown in
Although in the third embodiment, the two cavities 221, 222 and introduction ports 223, 224 are integrally constructed in one fixed mold 220, the embodiment is not restricted thereto. For example, as shown in
Further, although in the third embodiment, the two cavities 211 and two gates 212 are integrally formed in the movable mold 210, the embodiment is not restricted thereto. For example, as shown in
Here, the reference numeral 301 denotes rotating disk.
By constructing the mold with plural independent templates, the temperature control of each template can be achieved. If the temperature control of the primary side and secondary side templates is carried out independently, the temperature of each template can be controlled to a temperature suitable for each step. As a result, more accurate, stable resin molded product can be obtained.
X: rotation axis, 1: manufacturing apparatus, 10: movable mold, 11: movable side cavity, 12: side gate, 20: fixed mold, 20a: forming mold, 20b: pouring mold, 21: fixed side primary cavity, 22: fixed side secondary cavity, 23: primary side resin introduction path, 23a: exit, 24: secondary resin introduction path, 24a: exit, 25: primary resin pouring port, 26: secondary resin pouring port; 31: primary resin injecting means, 32: secondary resin injecting means, 40: decorating film carrying means, 41: decorating film, 51: pattern, 60: secondary resin molded product, 61: primary resin member, 61a: primary resin molded product, 61b: primary sprue, 62: secondary resin member, 62a: secondary resin portion, 62b: secondary sprue, 70: pushing member, 80: pressing means, 101: rotating disk, 102: base, 110: movable mold, 110a: template, 112: submarine gate, 120: fixed mold, 120a: fixed side primary template, 120b: fixed side secondary template, 201: manufacturing apparatus, 210: movable mold, 211: movable side cavity, 212: primary side gate, 213: secondary side gate, 220: fixed mold, 221: fixed side primary cavity, 222: fixed side secondary cavity, 223: primary resin introduction port, 224: secondary resin introduction port, 225: recessed hole, 231: primary resin injecting means, 232: secondary resin injecting means, 241: primary decorating film carrying means, 241a: primary decorating film, 242: secondary decorating film carrying means, 242a: secondary decorating film, 251: primary side pattern, 252: secondary side pattern, 260: secondary resin molded product, 261: primary resin molded product, 262: secondary resin member, 270: pushing member, 280: pressing means, 301: rotating disk, 302: base, 310: movable mold, 310a: movable side template, 312: submarine gate, 313: submarine gate, 320: fixed mold, 320a: fixed side secondary template, 320b: fixed side primary template
Number | Date | Country | Kind |
---|---|---|---|
2006-042374 | Feb 2006 | JP | national |
2006-042375 | Feb 2006 | JP | national |