JP4105335B2 - Mold manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold manufacturing method for manufacturing a mold by a full mold method in which a model of a press mold is embedded in sand, the model is burned with molten metal, and the portion is replaced with a casting.
[0002]
[Prior art]
The full mold method is a method in which a foamed resin block is cut to form a model, the model is embedded in sand, molten metal is poured into the obtained sand mold, and the model portion is replaced with a casting. Hereinafter, a method for producing a press die by the full mold method will be described.
[0003]
FIG. 7 is a flowchart showing a conventional mold manufacturing method, where STxxx denotes a step number.
ST100: A block made of foamed resin (hereinafter referred to as “foamed resin block”) is prepared, and the foamed resin block is precisely cut with an NC (numerical control) machine tool to make a model of a press die.
ST101: A press mold model is embedded in sand to obtain a sand mold.
ST102: The molten metal is poured into the obtained sand mold, the model embedded in the sand is melted with the molten metal, and the portion is replaced with a casting. After releasing the mold, the casting is taken out to obtain a new press mold.
[0004]
FIG. 8 is a diagram for explaining a main part of a conventional mold manufacturing method, and shows ST100 in FIG.
The concave portion 101 of the model 100 is a portion corresponding to the concave molding surface of the press mold. Therefore, when the model 100 is cut, the concave part 101 uses the NC machine tool 102 to precisely cut the three-dimensional product shape surface in order to align the concave part 101 of the model 100 with the concave molding surface of the press die. There is a need.
[0005]
[Problems to be solved by the invention]
However, NC machining data for controlling the NC machine tool 102 is required to precisely finish the concave portion 101 of the model 100 with the NC machine tool 102 in accordance with the concave molding surface of the press die.
For this reason, when manufacturing a mold, NC machining data for cutting a model must be created, and the NC machining data must be used for cutting with an actual NC machine tool. This period becomes longer, which increases the cost.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a mold manufacturing method capable of reducing the cost of a mold by shortening the period from design to manufacture when the mold is manufactured.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, claim 1 of the present invention prepares a molded panel molded with a press mold, and also creates a rough shape model by roughing a foamed resin block, and a concave portion of the model. Or the crowning process of covering and bonding the molded panel on the convex part, the sanding process of embedding the model with the molded panel in sand, and the casting process of injecting molten metal into the obtained sand mold and replacing the model part with casting It is characterized by becoming.
[0008]
The concave or convex portion of the model is roughly cut into the concave or convex portion of the model. Roughly roughened concave portions or convex portions are different in shape from the molding surface of the press mold. However, the model can be made to have the same shape as the molding surface of the press mold by covering the concave or convex portion of the model with the molded panel.
For this reason, the concave portion or the convex portion of the model can be cut manually, for example, without being precisely cut with an NC machine tool.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view of a press mold manufactured by a mold manufacturing method (first embodiment) according to the present invention.
The press die 10 includes a female mold 12 having a concave molding surface 12a and a male mold 20 having a convex molding surface 20a. The male mold 20 is lowered to form a convex molding surface 20a and a concave molding surface 12a. A panel (not shown) is press-molded.
[0010]
The female mold 12 is formed by fusing a molding panel 14 to an upper surface recess 13a of a casting 13 to form a recess molding surface 12a.
As an example, the casting 13 is made of gray cast iron (FC250) so as to have a recess 13a on the upper surface.
[0011]
The forming panel 14 is a member obtained by forming a cold rolled steel plate (SPCC) having a plate thickness t of 0.75 mm with an existing press die. As the molded panel 14, for example, a product panel (that is, a product panel) that constitutes the body of an automobile is used.
[0012]
The male mold 20 is obtained by fusing a molding panel 24 to a lower surface convex portion 23a of a casting 23 to form a convex molding surface 20a.
As with the casting 13, the casting 23 is cast with gray cast iron (FC250) as an example so as to have a recess 23a on the lower surface.
[0013]
The molded panel 24 is the same member as the molded panel 14 and is formed by molding SPCC having a plate thickness t of 0.75 mm with a press die.
Since the female mold 12 and the male mold 20 are the same constituent members made of a casting and a molded panel, the manufacturing method of the female mold 12 will be described below, and the description of the manufacturing method of the male mold 20 will be omitted.
[0014]
FIG. 2 is a flowchart showing a mold manufacturing method (first embodiment) according to the present invention, where STxx denotes a step number.
ST01: (Processing step) A molded panel molded with a press die is prepared in advance, and a rough shape model is created by roughly cutting the foamed resin block. In addition, a foamed resin block forms a block with foamed polystyrene as an example.
[0015]
ST02: (Crowded step) A molded panel is put on the concave portion of the model and bonded with an adhesive.
ST03: (sand filling step) A model with a molded panel is embedded in sand to obtain a sand mold.
ST04: (Casting process) Molten metal is poured into the obtained sand mold to replace the model part with a casting. After releasing the mold, the casting is taken out to obtain a new press mold.
[0016]
According to the casting method of ST01 to ST04, the concave portion of the model can be roughly processed by covering the concave portion of the model with the molded panel. For this reason, for example, the model 30 can be manually cut.
Hereafter, each process of ST01-ST04 is demonstrated in detail.
[0017]
FIGS. 3A to 3C are first explanatory views of a mold casting method (first embodiment) according to the present invention, wherein FIG. 3A shows a processing step (ST01), and FIGS. (C) shows a crowning process (ST02).
In (a), a block formed of foamed resin is prepared, and the prepared foamed resin block is roughly cut to make a model 30. At this time, it is possible to roughly cut the concave portion 31 of the model 30 that had to be precisely cut. The reason why the recess 31 can be cut roughly will be described in (c).
[0018]
In (b), adhesives 34, 34 are applied to the upper ends 32, 33 of the model 30, and the molded panel 14 is lowered toward the recess 31 as indicated by arrows (1), (1).
The application locations of the adhesives 34 and 34 are not limited to the upper ends 32 and 33 of the model 30 and may be applied to arbitrary positions.
In (c), the molded panel 14 is put on the concave portion 31 of the model 30, and the molded panel 14 is bonded with an adhesive.
[0019]
The concavely cut recess 31 has a different shape from the concave molding surface of the existing press mold, but by covering the concave panel 31 with the molding panel 14, the concave portion of the model 30 becomes the same shape as the concave molding surface of the press die. can do. In addition, although the clearance gaps 36 and 37 open between the recessed part 31 and the panel 14, the clearance gaps 36 and 37 can be filled with a molten metal by a casting process.
[0020]
In this manner, by covering the concave portion 31 of the model 30 with the molded panel 14, the concave portion 31 of the model 30 can be particularly processed roughly. For this reason, the model 30 can be cut manually, for example, without using an NC machine tool. Accordingly, since it is not necessary to precisely cut the model 30 with the NC machine tool, it is not necessary to create NC machining data for controlling the NC machine tool.
[0021]
4 (a) and 4 (b) are second explanatory views of a mold casting method (first embodiment) according to the present invention, (a) shows a sand filling step (ST03), and (b) Indicates the middle of the casting process (ST04).
In (a), the model 30 covered with the molded panel 14 is inverted and set in the sand mold frame 40, and then the sand 30 is supplied from the nozzle 42, and the model 30 covered with the molded panel 14 is embedded in the sand 43 to form a sand mold. Get.
[0022]
In (b), the molten metal 46 is poured into the obtained sand mold 45 as indicated by the arrow (2), and the model 30 is melted with the molten metal 46.
At this time, the molten metal 46 also enters the gaps 36 and 37 between the recess 31 and the molded panel 14 to fill the gaps 36 and 37. For this reason, a gap does not occur between the molten metal 46 and the molded panel 14.
[0023]
FIGS. 5 (a) and 5 (b) are third explanatory views of the mold casting method (first embodiment) according to the present invention. FIGS. 5 (a) and 5 (b) are up to the end of the casting step (ST04). Indicates.
In (a), the entire model is melted with the injected molten metal, and the portion is replaced with the casting 13. The molded panel 14 is integrally attached to the concave portion 13a of the casting 13.
As shown in FIG. 4B, the gap between the concave portion of the model and the molded panel 14 is filled with the molten metal, so that no gap is generated between the concave portion 13 a of the casting 13 and the molded panel 14.
[0024]
Since the molded panel 14 is SPCC having a plate thickness t of 0.75 mm, it is in a semi-molten state due to the heat of the injected molten metal, and the portion in contact with the molten metal is alloyed and closely adhered to the casting.
In (b), after casting the mold, the casting 13 is taken out from the sand mold to obtain a female mold 12 (see also FIG. 1) of a press mold. Since the female mold 12 has the concave molding surface 12a formed by the molding panel 14, it can be matched with the concave molding surface of an existing press mold.
[0025]
Next, a second embodiment will be described.
FIG. 6 is an explanatory view of a mold casting method (second embodiment) according to the present invention.
Although the female die 12 manufactured in the first embodiment has a sufficiently precise concave molding surface 12a, there are cases where the concave molding surface 12a has to be made more precise depending on the application. In this case, the concave molding surface 12 a of the female die 12 is cut using the NC machine tool 48.
[0026]
In addition, although the example which shape | molded the shaping | molding panel by SPCC was demonstrated in the said embodiment, changing to the steel plate which performed the surface treatment, other carbon steel, and low alloy steel is OK, and a material is exceptional. It is not limited.
Further, although the thickness t of the molded panel is set to 0.75 mm, the thickness t of the molded panel can be arbitrarily set.
[0027]
Furthermore, although the example using foamed polystyrene as foamed resin was demonstrated, foamed resin is not restricted to this, What is necessary is just a material which melts | dissolves with the heat | fever of the inject | poured molten metal.
Moreover, although the example which casted the castings 13 and 23 with gray cast iron (FC250) was demonstrated, you may cast with another cast iron and cast steel.
Furthermore, as shown in FIG. 1, both the female mold 12 and the male mold 20 of the mold are manufactured by the manufacturing method according to the present invention, but not limited to this, one mold is manufactured by the manufacturing method of the prior art. Also good.
[0028]
【The invention's effect】
The present invention exhibits the following effects by the above configuration.
According to the first aspect of the present invention, the model can be roughly roughened by covering the concave portion or the convex portion of the model with a molded panel. Roughly roughened recesses or projections have a different shape from the molding surface of the press mold, but by covering the recesses or projections with a molding panel, the recesses or projections of the model have the same shape as the molding surface of the press mold. Can be.
[0029]
For this reason, the model can be cut manually, for example, without using an NC machine tool. Therefore, it is possible to omit the work of creating NC machining data necessary for controlling the NC machine tool, and it is not necessary to cut the model with the actual NC machine tool using the NC machining data. As a result, when manufacturing molds, the time from design to production can be shortened to prevent the cost of the mold from increasing.
FIG. 1 is a cross-sectional view of a press mold manufactured by a mold manufacturing method according to the present invention (first embodiment). FIG. 2 shows a mold manufacturing method (first embodiment) according to the present invention. FIG. 3 is a first explanatory diagram of a mold casting method (first embodiment) according to the present invention. FIG. 4 is a second diagram of a mold casting method (first embodiment) according to the present invention. Explanatory view FIG. 5 is a third explanatory view of the mold casting method according to the present invention (first embodiment). FIG. 6 is an explanatory view of the mold cast method according to the present invention (second embodiment). FIG. 7 is a flowchart showing a conventional mold manufacturing method. FIG. 8 is a diagram illustrating a main part of a conventional mold manufacturing method.
DESCRIPTION OF SYMBOLS 10 ... Press mold, 13, 23 ... Casting, 14, 24 ... Molding panel, 30 ... Model, 31 ... Recess, 43 ... Sand, 45 ... Sand mold, 46 ... Molten metal.

Claims (1)

While preparing a molded panel molded with a press mold, a processing step of creating a rough shape model by roughing the foamed resin block,
A crowning step of covering and bonding the molded panel to the concave portion or convex portion of this model,
A sand embedding process of embedding a model with a molded panel in the sand;
A casting method for injecting molten metal into the obtained sand mold and replacing the model portion with a casting, and a method for producing a mold.

Images