Metal mold for molding and method for manufacturing the same

Abstract

The present invention relates to a molding die. The present invention aims to sufficiently support a shell mold by a support mold, and prevent deformation of the shell mold. The present invention aims to improve the vacuum suction efficiency by connecting all the vacuum suction holes of the shell mold to the air passage. The molding die of the present invention includes a shell mold having a plurality of vacuum suction holes (5), and a support mold. The back surface of the shell mold body (3) and the surface of the support mold body (11) are formed in the same shape and fitted together. A receiving surface (14) for receiving the mating surface is left on the surface of the support mold body (11) and the back surface of the shell mold body (3), and an air passage (13) is formed. A plurality of score lines (6) having a feed pitch of 0.5 to 5.0 mm and a machining depth of 0.01 to 0.4 mm, and a ridge (7) between the score lines are formed on the back surface of the shell mold body (3) or the surface of the support mold body (11). The vacuum suction holes (5) and the air passage (13) are connected via the score lines (6).

Description

Technical Field

[0001] This invention relates to a forming metal mold with a vacuum suction function. Background Technology

[0002] Metal forming molds that have the function of vacuum-suctioning sheet material onto the mold surface are mostly configured as a relatively thin shell mold with multiple vacuum suction holes and a support mold supporting the shell mold. This is because it is easier to form multiple vacuum suction holes on a relatively thin shell mold. On the other hand, it is necessary to provide a ventilation channel on the support mold that supports the shell mold and communicates with the vacuum suction holes.

[0003] Patent Document 1 describes a support mold with a receiving recess that is larger than the back of the shell mold, and multiple support protrusions protruding from the receiving recess, which support the back of the shell mold. The receiving recess, which serves as a vent, communicates with the vacuum suction hole of the shell mold, allowing pressure to be released from outside the mold. However, in this support mold, there is a risk that under high pressure during molding, the support protrusions may be insufficient to support the shell mold, causing deformation of the shell mold.

[0004] Patent Document 2 describes a support mold with a surface that matches the back of the shell mold. Multiple receiving surfaces are provided on the surface, and venting grooves are recessed therein. These receiving surfaces support the back of the shell mold. The venting grooves, serving as venting channels, communicate with the vacuum suction holes of the shell mold, allowing pressure to be reduced from outside the mold through the venting holes. Even under high pressure during molding, this support mold is sufficient to support the shell mold and prevent deformation. However, since not all vacuum suction holes of this support mold are connected to the venting grooves, sometimes the receiving surfaces completely block some of the vacuum suction holes, which can sometimes reduce the overall vacuum suction efficiency.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 61-14922

[0008] Patent Document 2: Japanese Patent Application Publication No. 2021-53920 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] Therefore, the purpose of this invention is to fully support the shell mold using a support mold to prevent deformation of the shell mold, and to connect all the vacuum suction holes of the shell mold with the ventilation grooves to improve vacuum suction efficiency.

[0011] Methods for solving problems

[0012] [1] Metal mold for forming

[0013] A forming metal mold includes: a shell mold having multiple vacuum suction holes, and a support mold supporting the shell mold, wherein the back surface of the shell mold and the surface of the support mold form the same shape and fit together, characterized in that...

[0014] On the surface of the support mold or the back of the shell mold, there is a receiving surface for the mating surface, and a venting groove is formed.

[0015] On the back of the shell mold or the surface of the support mold (where the surface with the vent groove is called the "receiving surface"), multiple marks with a feed pitch of 0.5 to 5.0 mm and a machining depth of 0.01 to 0.4 mm, and protrusions located between the marks, are formed.

[0016] The vacuum suction hole and the ventilation groove are connected by a groove.

[0017] <Function>

[0018] Since the back of the shell mold forming the same shape abuts against the surface of the support mold with protrusions, the support mold can fully support the shell mold and prevent deformation of the shell mold.

[0019] Since the vacuum suction holes and the ventilation grooves are connected through the grooves, all the vacuum suction holes and ventilation grooves of the shell mold can be connected, thereby improving the vacuum suction efficiency.

[0020] By setting the feed pitch of multiple grooves to 0.5–5.0 mm and the machining depth to 0.01–0.4 mm, both vacuum suction efficiency and shell mold rigidity can be balanced. When the feed pitch is less than 0.5 mm and the machining depth is less than 0.01 mm, the vacuum suction efficiency decreases. When the feed pitch exceeds 5.0 mm and the machining depth exceeds 0.4 mm, the shell mold will slightly deform due to the pressure during forming, affecting the dimensional accuracy of the formed product and the durability of the metal mold.

[0021] [2] Method for manufacturing metal molds for forming

[0022] A method for manufacturing a forming metal mold, the forming metal mold comprising: a shell mold having a plurality of vacuum suction holes, and a support mold supporting the shell mold, wherein the back surface of the shell mold and the surface of the support mold form the same shape and are fitted together, characterized in that...

[0023] On the surface of the support mold or the back of the shell mold, a receiving surface with a mating surface is provided, and ventilation grooves are machined there.

[0024] The back of the shell mold or the surface of the support mold (where the surface with the ventilation groove is machined is called the "receiving surface") is machined using an end mill with a non-flat end. As cutting marks, multiple marks with a feed pitch of 0.5 to 5.0 mm and a machining depth of 0.01 to 0.4 mm, as well as protrusions located between the marks, are left.

[0025] <Function>

[0026] By using an end mill with a non-flat end to cut the back of the shell mold or the surface of the support mold in one direction as cutting marks, multiple marks with a feed pitch of 0.5 to 5.0 mm and a machining depth of 0.01 to 0.4 mm, as well as protrusions located between the marks, can be formed efficiently.

[0027] The effects of the invention

[0028] According to the metal mold for forming according to the present invention, the shell mold can be fully supported by the support mold to prevent deformation of the shell mold, and all vacuum suction holes of the shell mold can be connected to the ventilation groove to improve vacuum suction efficiency. Attached Figure Description

[0029] Figure 1 The surface of the shell mold in the forming metal mold of Example 1 is shown in (a) perspective view and (b) enlarged perspective view.

[0030] Figure 2 The back side of the shell mold is shown in (a) as a perspective view and (b) as a partially enlarged perspective view.

[0031] Figure 3 The diagrams depict cutting processes. (a) is a 3D view during roughing, (b) is a 3D view during semi-finishing, and (c) is a 3D view during finishing.

[0032] Figure 4 The surface of the support mold in the forming metal mold of Example 1 is shown in (a) perspective view and (b) enlarged perspective view.

[0033] Figure 5 This is a cross-sectional view of the support mold.

[0034] Figure 6 The metal mold for forming in Example 1, which is formed by mounting the shell mold onto the support mold, is shown in (a) perspective view and (b) sectional view.

[0035] Figure 7 (a) is an enlarged sectional view of the main part of the molding metal mold of the comparative example, (b) is an enlarged sectional view of the main part of the molding metal mold of Example 1, and (c) is an enlarged sectional view of the main part of the molding metal mold of Example 1 cut from another direction.

[0036] Figure 8 This is a cross-sectional view of the resin sheet being vacuum-formed using the molding metal mold of Example 1.

[0037] Figure 9 This is a perspective view showing the surface side of the support mold in the forming metal mold of Example 2.

[0038] Specific implementation method

[0039] <1> Shell mold

[0040] Shell molds can be exemplified by those formed through electroforming, casting, cutting, or electrical discharge machining. Shell molds formed by electroforming are preferred due to their advantages, such as high manufacturing efficiency, ease of forming raised and recessed patterns through model transfer, and the ability to create vacuum suction holes during electroforming.

[0041] There are no specific limitations on the thickness of the shell mold, but it is preferably 2 to 6 mm, more preferably 2.5 to 5 mm. This is because it is easy to manufacture by electroforming or the like, and it is also easy to form vacuum suction holes.

[0042] There are no specific restrictions on the materials used for shell molds, but examples include metals (nickel, steel, etc.) and ceramics.

[0043] By forming a raised or recessed pattern on the surface of a shell mold (mold surface), the surface of the skin, which is attracted to the surface by a vacuum, can be given a shape that transfers the raised or recessed pattern. There are no specific limitations on the raised or recessed pattern; examples include leather wrinkle patterns, stitch patterns, and repeated arrangements of multiple geometric unit patterns.

[0044] Preferably, the shell mold can be interchangeably installed relative to the support mold. Examples of its installation structure include installation by bolts and fitting using a fitting shape.

[0045] <2> Vacuum suction port

[0046] There are no specific limitations on the vacuum suction hole. Examples include vacuum suction holes formed during electroforming using the methods described in Japanese Patent Application Publication No. 60-152692 and Japanese Patent Application Publication No. 9-249987, vacuum suction holes formed by machining (drilling, etc.), and vacuum suction holes formed by high-energy beam processing (laser processing, electron beam processing, ion beam processing, etc.).

[0047] There is no specific limitation on the diameter of the vacuum suction hole, but preferably it is 0.1 to 0.3 mm on the surface side of the shell mold and 0.1 to 5 mm on the back side of the shell mold.

[0048] <3> Support mold

[0049] There are no specific limitations on the support mold; examples include support molds formed by casting, cutting, electrical discharge machining, etc.

[0050] There is no specific limitation on the thickness of the support mold, but it is preferably 10 mm or more, and more preferably 20 mm or more. This is because it results in high rigidity.

[0051] There are no specific restrictions on the materials used as support molds; examples include metals (aluminum alloys, steel, etc.) and ceramics.

[0052] Ventilation channel

[0053] Ventilation grooves can be formed on either or both of the surface of the support mold or the back of the shell mold. However, from the viewpoint of processing efficiency, it is preferable to form them on only one of them. From the viewpoint of reducing the risk of mold strength reduction, it is more preferable to form them on only the surface of the support mold.

[0054] Ventilation channels can be exemplified by those formed through machining (cutting, etc.), electrical discharge machining, etching, etc.

[0055] There are no specific restrictions on the pattern of the ventilation channel. Examples include one or more linear or mesh-like patterns (quadrilateral mesh, triangular mesh, hexagonal mesh, and other mesh patterns as described in Patent Document 2).

[0056] Preferably, it includes a venting groove extending in a direction intersecting the direction of the scratches. This is because the venting groove is connected to multiple scratches.

[0057] There is no specific limitation on the depth of the ventilation groove, but it is preferably 0.2 to 3 mm, more preferably 0.2 to 2 mm, and most preferably 0.3 to 1 mm. When the depth of the ventilation groove is 0.2 mm or more, the ventilation is good, and when it is less than 3 mm, the strength of the support mold is not easily reduced.

[0058] There are no specific limitations on the width (opening width) of the venting groove, but it is preferably 1 to 7 mm, and more preferably 1 to 5 mm. When the width of the venting groove is greater than 1 mm, the air permeability is good, and when it is less than 7 mm, the strength of the support mold is not easily reduced.

[0059] <5> Marks and ridges

[0060] Scratches and protrusions can be formed on either or both of the back of the shell mold or the surface of the support mold. However, since the fitting accuracy of the two molds is reduced when they are formed on both, it is preferable that they are formed on only one of them. From the viewpoint of reducing the amount of machining required for the shell mold, it is more preferable that they are formed only on the back of the shell mold.

[0061] The direction of the scratches and ridges can be one direction on the entire surface forming the scratches and ridges (the back of the shell mold or the surface of the support mold), or the direction can be changed between multiple areas set on that surface.

[0062] There are no specific limitations for end mills with non-flat ends; examples include ball end mills and rounded end mills.

[0063] There is no specific limitation on the cutting diameter of this ball end mill; for example, it can be 15 to 20 mm.

[0064] As mentioned above, the feed pitch for multiple scratches is 0.5–5.0 mm, and the machining depth is 0.01–0.4 mm. More preferably, the feed pitch is 1.0–3.0 mm, and the machining depth is 0.02–0.15 mm.

[0065] There are no specific restrictions on the relationship between feed pitch and machining depth, but preferably, the feed pitch is 20 to 50 times the machining depth.

[0066] <6> Metal mold for forming

[0067] The metal mold for forming according to the present invention can be specifically implemented as a metal mold for various forming processes (without specific limitations, examples of which include vacuum forming, air forming, internal injection molding, blow molding, stamping, pressure forming, coating molding, etc.) that use vacuum suction to form polymer materials. Example

[0068] The following description, with reference to the accompanying drawings, details specific embodiments of the present invention. Furthermore, the materials, structures, and numerical values ​​described in the embodiments are merely exemplary and may be appropriately modified.

[0069] [Example 1]

[0070] Figures 1 to 8 The metal mold 1 used for forming in Example 1 shown is a metal mold for vacuum forming.

[0071] The forming metal mold 1 includes: a shell mold 2 having multiple vacuum suction holes 5, and a support mold 10 supporting the shell mold 2. The back surface of the shell mold and the surface of the support mold have the same shape, such as... Figure 6 and Figure 7 Fitted as shown in (b) and (c).

[0072] like Figure 1 and Figure 2 As shown, the shell mold 2 is a shell-shaped mold with a thickness of 2 to 6 mm formed by nickel electroforming, including a female mold (concave) shell body part 3 and a flange part 4 around the shell body part 3.

[0073] Multiple vacuum suction holes 5 are formed dispersedly throughout the entire area of ​​the shell-shaped body portion 3, but no vacuum suction holes 5 are formed on the flange portion 4. The vacuum suction holes 5 are formed during nickel electroforming. The diameter of the vacuum suction holes 5 is 0.1 to 0.3 mm on the surface side of the shell-shaped mold 2, and increases towards the back side, reaching 3 to 5 mm on the back side of the shell-shaped mold 2. Alternatively, the vacuum suction holes can also be formed through subsequent processing (machining, high-energy beam processing, etc.).

[0074] like Figure 1 As shown, a raised pattern 8 is formed on the surface (mold surface) of the shell-shaped body 3 during electroforming. The raised pattern 8 in the example shown in the figure is a leather wrinkle pattern.

[0075] like Figure 2 As shown, multiple grooves 6 with a feed pitch of 0.5–5.0 mm and a machining depth of 0.01–0.4 mm, and protrusions 7 located between these grooves are formed on the back side of the shell mold 2. Figure 3 As shown in (a) and (b), the marks 6 and the protrusions 7 are formed as cutting marks by cutting the back side of the shell mold 2 using an end mill 20 with a non-flat end. The method will be described in detail after the support mold 10 is explained.

[0076] like Figure 4 and Figure 5 As shown, the support mold 10 includes a support body 11 cast from aluminum alloy with a thickness of 10 to 30 mm, and a box-shaped shell 17 that covers the back side of the support body in a space-separated manner.

[0077] The surface of the support body 11 is formed into a concave shape that is identical to the convex shape of the back side of the shell-shaped body 3. A temperature regulating pipe 12 is cast on the back side of the support body 11, and a temperature regulating fluid flows through the temperature regulating pipe 12. For example, a flexible SUS pipe is used for the temperature regulating pipe 12.

[0078] On the surface of the supporting body 11, there is a receiving surface 14 for receiving the back of the shell-type body 3, and a ventilation groove 13, for example, connected in a quadrilateral grid pattern, is recessed therein through machining. This ventilation groove 13 includes ventilation grooves extending parallel to the direction of the groove 6. Figure 7 (b) and a ventilation groove extending in a direction intersecting the direction of the scratch 6. Figure 7 (c)). For example, the venting groove 13 has a depth of 0.2 to 3 mm and a width of 1 to 7 mm, and the receiving surface 14 is a quadrilateral group of 5 mm square to 20 mm square.

[0079] The support body 11 has a plurality of vent holes 15 that connect to the space on the rear side through the vent groove 13. The diameter of the vent holes 15 is, for example, 5 to 10 mm.

[0080] In the shell 17, there is a vent plug 18 that connects the space to the outside of the mold and can be connected to a vacuum suction device (omitted in the figure) outside the mold.

[0081] like Figure 6 As shown, the shell-shaped body 3 and the support body 11 are fitted and abutted together, and the flange 4 is fitted into the countersunk hole of the support body 11 and screwed in with bolts. The shell mold 2 can be interchangeably installed relative to the support mold 10. In this installed state, as Figure 7 As shown in (b) and (c), all the vacuum suction holes 5 are connected to the ventilation grooves 13 via the grooves 6.

[0082] The forming metal mold 1 constructed in the above manner is manufactured by the method described below.

[0083] The back of the shell-shaped body part 3 and the surface of the support body part 11 must be the same shape for fitting together. Fitting accuracy is ensured by machining one or both of them.

[0084] Therefore, usually, via Figure 3 The three steps—roughing (a), semi-finishing (b), and finishing (c)—ultimately approach a smooth surface to improve fitting accuracy. Specifically, for example, using a ball end mill with a 16mm cutting diameter, in roughing, the feed pitch P1 exceeds 5.0mm and the machining depth H1 exceeds 0.4mm; in the subsequent semi-finishing, the feed pitch P2 is 0.5–5.0mm and the machining depth H1 is 0.01–0.4mm; and in the subsequent finishing, the feed pitch P3 is less than 0.5mm and the machining depth H1 is less than 0.01mm.

[0085] However, when both the back surface of the shell-shaped body portion 3 and the surface of the supporting body portion 11 are finished to near a smooth surface in step (c), such as in Figure 7 As shown in (a) as a comparative example, there is a vacuum suction hole 5 (in the center of the figure) that is completely blocked by the receiving surface 14.

[0086] Therefore, in this embodiment, the cutting process is performed as described below.

[0087] The surface of the support body 11 is made to Figure 3 (c) is finished to be close to a smooth surface.

[0088] The back side of the support body 3 is not machined after roughing (a) and semi-finishing (b), and finishing (c) is not performed. As a result, multiple marks 6 with a feed pitch P2 of 0.5 to 5.0 mm and a machining depth H1 of 0.01 to 0.4 mm, and protrusions 7 located between these marks are left as cutting marks. Even with these cutting marks, the necessary fitting accuracy can be ensured.

[0089] Therefore, as Figure 7 As shown in (b) and (c), since all vacuum suction holes 5 are connected to the ventilation groove 13 via the groove 6, there are no vacuum suction holes completely blocked by the receiving surface 14. Therefore, the suction efficiency in vacuum forming can be improved. In particular, as Figure 7 As shown in (c), multiple grooves 6 are connected to a ventilation groove 13 extending in a direction intersecting the direction of the grooves 6.

[0090] Using the metal mold 1 configured as described above, the resin sheet can be vacuum-formed using the method described below.

[0091] like Figure 8 As shown, a thermoplastic resin sheet 21, softened by heating, is placed in a molding metal mold 1, and the surface of the shell-shaped body 3 is pressed by a male mold 22. Next, the space within the support mold 10 is depressurized using a vacuum suction device (omitted in the figure), and the resin sheet 21 is vacuum-suctioned onto the surface of the shell-shaped body 3 via vent holes 15, vent grooves 13, and grooves 6, and then formed using vacuum suction holes 5. At this time, the raised and recessed pattern 8 of the shell-shaped body 3 is faithfully transferred onto the resin sheet 21 with the high suction efficiency described above, giving it a realistic raised and recessed pattern.

[0092] [Example 2]

[0093] Secondly Figure 9 The forming metal mold of Embodiment 2 shown only has a vent groove 13 in the support body 11 that is in the direction of the groove (see reference). Figure 2 The difference from Embodiment 1 lies in the presence of three linear vent grooves 13 extending in the intersecting directions; otherwise, they are the same as in Embodiment 1. Each vent groove 13 communicates with a vent hole 15.

[0094] The ventilation slot 13 is also related to Figure 7 (c) Similarly, it is connected to all the vacuum suction holes 5 via the groove 6. Therefore, using Example 2, the same function and effect as in Example 1 are also obtained.

[0095] Furthermore, the present invention is not limited to the embodiments described above. For example, as described below, appropriate modifications and implementations can be made without departing from the spirit of the invention.

[0096] (1) The ventilation groove 13 and the receiving surface 14 may also be formed on the back side of the shell-shaped body portion 3. In this case, it is preferable that the ventilation groove and the receiving surface are not formed on the surface of the supporting body portion 11.

[0097] (2) Scratches 6 and protrusions 7 may also be formed on the bearing surface 14 of the supporting body portion 11. In this case, preferably, scratches and protrusions are not formed on the back side of the shell-shaped body portion 3. Attached Figure Description

[0099] 1. Metal mold for forming

[0100] 2. Shell mold

[0101] 3. Shell-shaped body section

[0102] 4. Flange portion

[0103] 5 Vacuum suction holes

[0104] 6 marks

[0105] 7 protrusions

[0106] 8. Concave and convex patterns

[0107] 10 Support mold

[0108] 11 Support body section

[0109] 12 Temperature control piping

[0110] 13 Ventilation slots

[0111] 14. Bonding surface

[0112] 15 Vent holes

[0113] 17. Shell

[0114] 18. Vent plug

[0115] 20 End Mills

[0116] 21 Resin Sheets

[0117] 22 positive molds

Claims

1. A forming metal mold, comprising a shell mold (2) having a plurality of vacuum suction holes (5) and a support mold (10) supporting the shell mold (2), wherein the back surface of the shell mold (2) and the surface of the support mold (10) are formed with the same shape and fit together, characterized in that, On the surface of the support mold (10) or the back of the shell mold (2), there is a receiving surface (14) for receiving the matching surface, and a ventilation groove (13) is formed. Multiple grooves (6) with a feed pitch of 0.5 to 5.0 mm and a machining depth of 0.01 to 0.4 mm are formed on the back of the shell mold (2) or on the surface of the support mold (10), as well as protrusions (7) located between the grooves. The back of the shell mold (2) abuts against the surface of the support mold (10) with a protrusion (7). On the back side of the shell mold (2), the vacuum suction hole (5) and the ventilation groove (13) are connected by a groove (6).

2. The forming metal mold as described in claim 1, wherein, Ventilation grooves (13) are formed only on the surface of the support mold (10).

3. The forming metal mold as described in claim 1, wherein, The ventilation groove (13) includes a ventilation groove (13) extending in a direction that intersects the direction of the groove (6).

4. The forming metal mold as described in claim 1, 2, or 3, wherein, The marks (6) and ridges (7) are formed only on the back of the shell mold (2).

5. A method for manufacturing a forming metal mold, the forming metal mold comprising: A shell mold (2) having multiple vacuum suction holes (5) and a support mold (10) supporting the shell mold (2), wherein the back side of the shell mold (2) and the surface of the support mold (10) are of the same shape and fit together, characterized in that, On the surface of the support mold (10) or the back of the shell mold (2), there is a receiving surface (14) for receiving the matching surface, and a ventilation groove (13) is machined. The back of the shell mold (2) or the surface of the support mold (10) is machined by using an end mill (20) with a non-flat end. As a cutting mark, multiple marks (6) with a feed pitch of 0.5 to 5 mm and a machining depth of 0.01 to 0.4 mm are left, as well as protrusions (7) located between the marks. Make the back side of the shell mold (2) abut against the surface of the support mold (10) with a protrusion (7). On the back side of the shell mold (2), make the vacuum suction hole (5) and the ventilation groove (13) connected through the groove (6).

6. The method for manufacturing a metal mold for forming as described in claim 5, wherein, The end mill (20) is a ball end mill or a rounded end mill.

7. The method for manufacturing a forming metal mold as described in claim 5 or 6, wherein, The cutting diameter of the end mill (20) is 15-20 mm.

Images