JP2002225036A - Mold for molding resin product and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for molding a resin product, easy to manufacture and advantageous from an aspect of cost, and a method for manufacturing the same. SOLUTION: A mold matrix having a dimension slightly larger than the final shape of the mold is manufactured by casting and the molding surface of the mold matrix is subjected to cutting processing until the shape thereof becomes slightly smaller than the final shape of the molding surface of the mold. Subsequently, an iron plating layer having a thickness becoming slightly larger than the cut thickness of the mold matrix is formed on the molding surface of the mold matrix and subjected to finish processing until the molding surface becomes the final shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold used for, for example, injection molding a resin product and a method for producing the same.

[0002]

2. Description of the Related Art As shown in FIG. 10, a general resin product molding die is subjected to a large rough cutting step, a medium rough cutting step, a fine cutting step, and a finishing step. However, since steel is hard, machining is not easy, and there is a problem in cost when molding a resin product having a complicated shape. Therefore, a resin product molding die using a zinc alloy that is easy to machine,
JP-A-11-189893, JP-A-11-268
044 and JP-A-2000-108132.

Japanese Patent Application Laid-Open No. 11-189893 discloses a resin product molding mold in which a mold is manufactured by machining a zinc alloy and the surface of the mold is plated with iron through a nickel plating layer. It has been disclosed.

Japanese Patent Application Laid-Open No. 11-268044 discloses a method in which a mold is manufactured by machining a zinc alloy, the surface of the mold is plated with iron, and the excess thickness of the iron plating is removed by machining. There is disclosed a mold for molding a resin product having a chrome-plated surface.

[0005] JP-A-2000-108132 discloses that
A graphite base material is subjected to NC processing using an end mill to prepare a plating base material, a nickel plating layer is formed on a molding surface of the plating base material, and an iron plating layer is formed on the nickel plating layer. A method is disclosed in which a molten metal of a zinc alloy is poured into a cavity surrounded by a plating layer and solidified to form a backup material, and then the backup material is removed from the nickel plating layer to obtain a resin product molding die. I have.

[0006]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. H11-1898
In Japanese Patent Publication No. 93 and JP-A-11-268044, machining is easier than machining a steel material, but it takes time and effort to machine a zinc alloy block.

In JP-A-2000-108132, the zinc alloy block is not machined,
It is not easy to perform an NC process on a graphite material to produce a plating base material, and it takes time and costs. Further, both the zinc alloy and the graphite material have lower rigidity than the cast steel, and are expensive.

[0008]

Means for Solving the Problems In order to solve the above problems, a resin product molding die according to the present invention has a thickness capable of filling a pinhole in a molding surface of a mold matrix obtained by casting. The configuration was such that an iron plating layer was provided. The material for the matrix is cast iron or cast steel.

In the method of manufacturing a resin product molding die according to the present invention, first, a die having a dimension larger than the final shape of the die is manufactured by casting, and the molding of the die is performed. The surface is cut until it becomes more negative than the final shape, and then an iron plating layer with a thickness that is more positive than the final shape is formed on the molding surface of the mold matrix, after which the molding surface becomes the final shape Finish processing is applied to the iron plating layer up to.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic diagram of a mold manufacturing process according to the present invention, FIG. 2 is a diagram showing a mold at the completion of a casting process,
FIG. 3 is a view showing the mold at the time of completion of the roughing, FIG. 4 is a view showing the mold at the completion of the plating step, and FIG. 5 is a view showing the mold at the time of completion of the finishing. In FIG. 1, the shape of the mold is simplified as compared with FIGS. 2 to 5 for easy understanding.

In order to manufacture the mold according to the present invention, first, the mold matrix 1 is cast using cast iron (FC) or cast steel (FCD) as a material. As shown in FIG. 2, the dimension of the molding surface of the mold master 1 is a plus dimension (about 5 mm) from the final shape in consideration of the machining allowance.

Next, as shown in FIG. 3, the molding surface of the mold 1 is roughened. In this roughing process, the molding surface size is made smaller than the final shape (about-
0.5 mm). As shown in FIG. 6, a pinhole appears on the surface of the molding surface of the mold mother die 1 in this state due to roughing, as shown in FIG.

After the roughing, as shown in FIG.
Is applied with an iron plating layer 2 on the molding surface of. The thickness of the iron plating layer 2 is set to a plus dimension (about 0.5 mm) from the final shape in view of the finishing allowance. The pinholes appearing on the molding surface of the mold 1 in this state are shown in FIGS.
It is filled with iron plating as shown in FIG.

In carrying out the iron plating, it is preferable to improve the adhesion of the plating layer by pre-treating the surface of the molding surface in advance. As the pretreatment agent, hydrochloric acid (concentration: 20%), sulfuric acid (concentration: 5%) or a mixed solution of hydrofluoric acid and sulfuric acid (125%)
ml / L) can be considered, but as a result of the experiment, hydrochloric acid was most effective for activating the surface of the molding surface.

[0015] Thereafter, as shown in FIG.
Finish the surface to the final geometry. As a method of the finishing process, besides the machining process and the process using a sandpaper, an electric discharge process may be performed. In addition, iron plating layer 2
9B, the pinholes are completely filled with the iron plating layer as shown in FIG. 9B, so that the pinholes do not appear again.

[0016]

According to the present invention as described above,
Since the step of roughly cutting the metal block can be omitted, the time required for manufacturing the resin molding die can be greatly reduced. Also, since the die material may be cast iron (FC) or cast steel (FCD), it is more cost effective than a zinc alloy.

Further, since the pinholes on the molding surface can be completely filled by the iron plating layer formed on the molding surface of the mold, the pinholes are not transferred to the resin molded product. Further, since the iron plating layer formed on the molding surface of the mold can be regarded as pure iron, it is relatively soft and easy to process, and is not easily rusted.

[Brief description of the drawings]

FIG. 1 is a schematic view of a mold manufacturing process according to the present invention.

FIG. 2 is a view showing a mold when a casting process is completed.

FIG. 3 is a diagram showing a mold at the time of completion of roughing.

FIG. 4 is a view showing a mold when a plating step is completed.

FIG. 5 is a view showing a mold at the time of finishing processing.

FIG. 6 is a micrograph showing a metal structure on a die surface at the time of completion of roughing.

FIG. 7 is a photomicrograph showing the surface texture of an iron plating.

FIG. 8 is a micrograph showing a surface structure after finishing.

FIGS. 9A and 9B are enlarged cross-sectional views of a pinhole portion before and after finishing processing on an iron plating layer.

FIG. 10 is a schematic view of a conventional mold manufacturing process.

[Explanation of symbols]

 1: mold base, 2: iron plating layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuo Fujikawa, 1-10-1 Shinsayama, Sayama City, Saitama Prefecture Inside Honda Engineering Co., Ltd. (72) Mikihiko Kimura 1-10-1, Shinsayama, Sayama City, Saitama Prefecture Honda Engineering Co., Ltd. (72) Inventor Yuichi Uchiyama 1-10-1 Shinsayama, Sayama-shi, Saitama F-term (reference) 4F202 AJ02 AJ09 CA11 CB01 CD02 CD18 CD22

Claims (2)

[Claims] 1. A mold used for molding a resin product, wherein the mold has an iron plating layer having a thickness capable of filling a pinhole on a molding surface of a mold matrix obtained by casting. A resin product molding die, which is provided. 2. A mold die having a plus dimension with respect to the final shape of the mold is cast, and a molding surface of the cast mold matrix is cut until it becomes more negative than the final shape. A resin product characterized by forming an iron plating layer having a thickness that is more positive than the final shape on the molding surface of the mother die, and thereafter finishing the iron plating layer until the molding surface has the final shape. Manufacturing method of molding die.