JPS61220809A - Mold - Google Patents

Abstract

PURPOSE:To permit to make the mold, high in the hardness thereof, simply by a method wherein the mold is provided with a base body, made by pressurized powder body consisting of metallic powder, ceramics powder and inorganic binding agent, a water absorbing metallic porous layer provided on the surface of the base body and a flat surface metal layer provided on the surface of the metallic porous layer. CONSTITUTION:The principal constituents of the binding agent, constituting the base body 1, are silicates, amorphous silica and colloidal silica and they are bonded through the medium of water. The porous layer 2 is consisting of rough metallic powder having the grain size of 100-200 mesh and the binding agent substantially equal to the metallic powder and is provided with numberless of air holes therein. The surface metal layer 3 is the electro-deposit layer of metal individual or the metal containing ceramic powder in order to increase the headness of the surface of is an electroless plating layer of the same. The thickness of the surface metal layer 3 is preferable to be 0.5-3mm. The surface metal layer 3 is applied on the surface of a matrix 6 formed with a protection film 7. A frame body 4 is filled with the material for forming the porous layer 2 and is filled further with a paste type base body 1 forming material. The frame body is heated and pressurized gradually by a punch to obtain the mold.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a mold for molding plastics, rubber, etc.

≦JIZM specifications In Western countries, quench-hardened materials are used for molds, but in order to create durable molds that do not cause failure, it is necessary to quench-harden them after die carving or to use quench-hardened materials. This is done by mold engraving the material.

However, with this, it takes time to carve only hard materials, and post-processing causes problems with distortion and increases in processing costs, so in Japan, nearly 90% of molds for plastics are made of materials that are not hardened. We only use materials that have been hardened when necessary.Also, general mold processing depends on the differences in the cavity, but manufacturing takes a long time and requires advanced technology. However, recently a method has been developed and put into practical use to reduce processing costs and obtain molds at high speed through mass production of molds, that is, rapid processing. For example, cold working called cold bobbing, the Shico process method, electrical discharge machining, electroforming, fully automatic profile milling machines that do not require human labor, fully automatic drilling machines, etc. have been developed to improve economic efficiency.

However, changes in mold machining methods have been accompanied by changes in the mold steel materials used, with the cold bobbing method using low-carbon alloy steel, and the electrical discharge machining method using pre-tempered high-grade steel. It is also possible to process cemented carbide, regardless of its hardness. In addition, zinc alloy (
ZAS) or beryllium copper is used in some of the molds.

On the other hand, cermet, which is a composite material made of ceramics and metal, is generally manufactured by mixing ceramic powder and metal powder, compression molding the mixture, and then sintering the mixture. Such cermets have the advantage of combining the hardness, wear resistance, corrosion resistance, and heat resistance of ceramics with the strength of metals.

If such a cermet is used in a mold, there is no need to harden the metal to increase its hardness as in the past, and the mold front knee is simplified.

Problems to be Solved by the Invention When making a mold using such cermet, thermal deformation may occur at temperatures of several hundred degrees Celsius or lower depending on the material of the mother mold used for making the mold. Therefore, there was a problem that normal sintering methods could not be used.

Means for Solving the Problems The technical means (structure of the invention) taken by the present invention to solve the above-mentioned problems are as follows.

That is, the mold of the present invention includes a base using a green compact made of metal powder, ceramic powder, and an inorganic binder, a water-absorbing metal porous layer provided on the surface of the base, and a surface of the metal porous layer. It is equipped with a smooth surface metal layer provided on the surface.

According to this invention, since the mold base is composed of a green compact made of metal powder, ceramic powder, and an inorganic binder, it can be heated and pressed at a low temperature of about 400°C or less to give it a metallic luster. The mold base can be easily made. Furthermore, in order to counter the brittleness which is a drawback of ceramics, the metal powder is used and the surface of the base body is sequentially wrapped in a porous metal layer and a surface metal layer, thereby reinforcing the brittleness of ceramics. Further, the porous layer has the function of absorbing liquid such as water that exudes from the substrate when the substrate is heated and pressurized.

Further, the surface metal layer constitutes the mold surface, and has the effect of covering the surface of the porous layer having a large number of pores and smoothing the surface.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 and 2. 1st)! 1, 1 is a mold base, and this base 1 is made of a composite material made by mixing metal powder, ceramic powder, and an inorganic binder and heating and pressing the mixture. Further, a water-absorbing metal porous layer 2 and a smooth surface metal layer 3 are provided in this order on the surface of the base 1 to form a mold surface. 4 is a frame made of steel.

The binder constituting the substrate 1 is mainly composed of silicates, amorphous silica, and colloidal silica, and has an adhesive effect using water as a medium. Such binders are described, for example, in Japanese Patent Publication No. 55-18673 and Japanese Patent Publication No. 56-51) 508A\[Iy D W 'r 4Q
f L% L Furthermore, the porous layer 2 is made of coarse metal powder of 100 to 200 mensier (ASTM) and a binder almost the same as described above, and has numerous pores inside. The thickness of this porous layer 2 is preferably in the range of 20 to 30 mm; if it is larger than that, the compression of the substrate 1 at the boundary between the substrate 1 and the porous layer 2 will be insufficient;
In addition, if it is smaller than that, the base l when heating and pressurizing the base 1
It becomes unable to absorb enough water exuding from the
The remaining water may cause some areas to be insufficiently compressed.
This will create a depression.

The surface metal layer 3 is an electrodeposition layer or an electroless plating layer of a metal alone or a metal containing ceramic powder to increase the hardness of the surface. The thickness of the surface metal layer 3 is 0.5 to 3 f.
i is preferable; if it is larger than this, it is not economical; if it is smaller than that, it will not be able to withstand the heat and pressure applied when compressing the base 1, and it will easily deform.

FIG. 2 is a sectional view showing the manufacturing state of the mold in this embodiment. That is, as shown in the figure, a frame body 4 made of steel (SK3) is erected on a support base 6 around the mother mold 5. Also, the surface of the mother mold 5 is protected in advance! Protection by covering with I7 1) When the matrix 5 is made of a heat-resistant but non-conductive material, it is a metal reduction film or graphite coating, and the conductive matrix made of metal is coated with I7. These include release coatings such as paint, lacquer, and graphite, or release coatings such as metal oxides and sulfides. In this way, the surface metal layer 3 is applied to the surface of the master mold 6 on which the protective film 7 has been formed.

Thereafter, the frame 4 is filled with a porous layer 2 forming material to a predetermined thickness, and a paste-like base 1 forming material is further filled thereon. Then, gradually heat and pressurize it using a punch. The heating temperature may be at room temperature or higher, and from the viewpoint of the binder, it is possible to heat it at 1000°C or higher, but in order to prevent thermal deformation of the matrix 5, it is preferable to heat and press in a low temperature range of 450°C or lower. A mold as shown in FIG. 1 can be obtained.

Next, a method for producing the substrate and the porous layer will be explained in detail by giving an example.

Example 1 (Preparation of substrate): Silicon carbide (average particle size 0.7
um, A-2 type, manufactured by Showa Denko ■) 250° and zinc powder (350 mesh, ASTM) 250g,
The mixture was mixed in a ball mill for an extended period of about 5 days. From this, 260 g was taken and mixed with 740 g of 300 mesh zinc powder to make 1 kg. This mixed powder was thoroughly mixed. On the other hand, as a binder, 120 g of No. 3 sodium silicate, 50 g of No. 2 sodium silicate, 1 potassium silicate,
A mixed solution of 0g of colloidal silica, 120g of amorphous silica, and 35g of colloidal silica was prepared. This was allowed to stand for about 12 hours to separate into an upper layer liquid and a lower layer liquid. Then, the upper layer liquid and the lower layer liquid were mixed at a ratio of 3:1. To 170 g of the blended binder, 35 cc of water, 15 g of glycol, 15 g of oil, and about 2.5% by weight of a hardening agent (sodium fluorosilicide) were added as a bond adjusting liquid. This was mixed with the above powder, the mixed material was filled into a frame, and heated and pressed to produce a molded body.

The water released during this action is not removed suddenly, but
In order to increase the bonding effect by gradually removing the material, it is necessary to remove the moisture between the metal layer and the filler, especially when the shape of the matrix is concave as shown in Figure 2, since moisture tends to accumulate in the concave part when the filler is compressed. A porous layer was provided to provide an escape route for water. However, if the matrix is convex, there is a way for water to escape to the outside, so
A porous layer as an escape route for water is not particularly required.

Example 2 (Creation of porous layer): 70 g of a mixed powder of nickel powder (200 mesh) and iron powder (200 mesh) mixed at a ratio of 1:1 was prepared. On the other hand, 2 cc of water was added to a mixture of 10 g of the same binding solution as in Example 1 and 2.5% by weight of a curing agent (sodium silica), and mixed powder 7 was prepared.
0 g was gradually mixed. After that, the water was evaporated and the mixture was solidified to obtain a porous layer.

Effects of the Invention According to this invention, the disadvantage of brittleness due to the use of ceramics is compensated for by the metal powder, porous layer, and surface metal layer, and a mold with high hardness can be easily produced. .

[Brief explanation of drawings]

Value 1 Stomach FI L+ , w G ■ Sunrise - Invitation Airflow 1 ＾蟇R ii Image Image 1 It is a cross-sectional view showing the manufacturing state of the stomach FI L+ ,w. DESCRIPTION OF SYMBOLS 1... Base body, 2... Metal porous layer, 3... Surface metal layer, 5... Matrix

Claims (3)

[Claims] (1) A base using a green compact made of metal powder, ceramic powder, and inorganic binder, a water-absorbing metal porous layer provided on the surface of this base, and a smooth surface provided on the surface of this metal porous layer. A mold with a metal layer. (2) The mold according to claim (1), wherein the metal porous layer is a green compact of metal powder with large particle size and an inorganic binder. (3) The mold according to claim (1), wherein the surface metal layer is an electrodeposition layer or an electroless plating layer of a metal alone or a metal containing ceramic powder.