JPS5911370B2 - Synthetic resin coated press mold - Google Patents

Description

[Detailed description of the invention] The present invention has excellent compatibility with metal materials, and
1F Kamichi ιRoya', ^・ιds゜1・,,-,He-匡l4G11lrRF ``→；S, Recently, with the development of synthetic resins, synthetic resin mixtures are used for jigs and press molds. has been done.

A press mold whose surface is coated with synthetic resin (hereinafter referred to as
(Resin coated press mold) has the following advantages: Firstly, it is possible to obtain a highly accurate press molding surface with the resin layer on the surface, and secondly, since the press mold surface is made of a resin layer instead of metal, the entire surface is made of metal. This has the advantage that the mold manufacturing cost can be significantly lowered compared to a press mold constructed of. However, in order to use such a resin-coated press mold as a press mold for molding metal materials, the metal must be bent, stretched,
Mechanical properties such as compressive strength and abrasion resistance required for draw forming are insufficient. Therefore, it is generally attempted to strengthen the resin by mixing 15 powders of metal, coal, carbide, glass, etc. as a filler into the resin. Among them, alumina, quartz powder, iron powder, etc. have been commonly used as fillers for forming metal materials. However, as part of recent efforts to save energy, high-strength steel plates (20) have been replaced with conventional mild steel plates to reduce the weight of vehicles.
(Haiti) came to be used as a material for vehicles.

Along with this, the strength required for resin-coated press molds and the ease of sliding between the material and press mold 25 (hereinafter referred to as mold flexibility), which is necessary to avoid breaking the material during molding, have become even more advanced. Things started to be demanded. Therefore,
Inorganic alumina and metallic iron powder were added as fillers to strengthen the resin. However, although the compressive strength is improved, the abrasion resistance and mold smoothness are not sufficient. Also, adding graphite powder, carbon black, or talc as a filler improves mold flexibility, but
It is not possible to improve the strength, especially the pressure resistance strength. Therefore, an attempt was made to add both of these in combination, but the mold flexibility 35 was not sufficient. Therefore, the present inventors conducted various experiments in order to obtain a filler that can improve mold slipperiness as well as strength, and found that "cast iron powder satisfies the purpose. This is a completed resin-coated press mold containing powder as a filler.

That is, the present invention provides a press mold in which a part or all of the contact surface with a metal material on the surface of the press mold is formed with a synthetic resin coating layer, and the synthetic resin coating layer contains cast iron powder, and the synthetic resin coating layer contains cast iron powder. This is a synthetic resin-coated press mold with excellent strength and mold smoothness, characterized in that a part of the powder is exposed on the surface of the coating layer.

Here, the press die is a general term for press forming dies used to perform stretching, deep drawing, stretch flange, and bending of a material.

The press mold of the present invention has a resin layer containing cast iron powder on the mold surface.

The thickness of the resin layer is preferably 50 nm or less, particularly about 10 fins. The thickness is 5011! Exceeding this is undesirable because cracks are likely to occur in the resin layer due to thermal shrinkage distortion during cooling of the resin. The resin coating in the present invention is applied at least to the portion of the mold that comes into contact with the material under high pressure. In order to fully utilize the effects of the present invention, it is desirable to apply a resin coating to the entire contact surface between the material and the mold. The synthetic resin used for the resin coating of the present invention may be of any type as long as it exhibits room temperature or thermosetting properties. Therefore, not only epoxy resin but also phenol and melamine resins may be used. In order to accelerate curing of the synthetic resin, it is preferable to add a curing agent to the resin.

The curing agent differs depending on the type of synthetic resin used, but for example, epoxy resins use organic acid anhydrides or polyamides, and phenolic resins use hexamethylenetetramine - commonly used curing agents. It is used by adding the usual amount of.

Cast iron powder, that is, iron powder containing graphite 5, is added to the resin as a filler.

FIG. 1 shows the state of the resin layer when a metal material is repeatedly press-molded using a resin-coated press mold containing cast iron powder. Since the resin layer on the surface of the mold comes into contact with the metal and metal material 1 under high pressure, the resin and the cast iron powder exposed on the surface of the resin layer are subjected to a load, but first of all, compared to the cast iron powder 2, The resin portion 3 with low strength wears out first, and as a result, the cast iron powder distributed in the resin layer directly receives the load from the material. Then, on the fu side, the iron powder supports the load from the material, and on the other hand, the graphite 4 in the iron powder plays the role of a so-called lubricant between the material and the mold, improving the stability of the mold.

As described above, since the presence of graphite in iron powder is indispensable for improving mold stability, Ashikyura cast iron powder, which has a low graphite content, is not preferred in the present invention. Therefore, cast iron powder containing 0.5% by weight or more of graphite is generally used. In addition, conventionally used fillers and other special additives may be added in combination with the cast iron powder depending on the application and within the range that does not impair the effects of the present invention.

The cast iron powder to be added preferably has a particle size of 100 mesh or less.

If a powder with a large particle size is used, unevenness will occur on the surface of the resin, causing a rough texture in the molded product. The amount of cast iron powder added to the synthetic resin is selected within the range of 10 to 50% by volume based on 100% by volume of the synthetic resin.

If the amount is less than 10%, the amount of cast iron powder distributed in the resin will be small, and the stability of the material and mold will not be sufficiently improved.

However, if the amount added exceeds 50%, the viscosity of the resin becomes undesirable, inhibiting the fluidity of the resin and making mold manufacturing difficult. The mold base material to be coated with resin is appropriately selected from those commonly used as mold materials, such as zinc alloy and cast iron, depending on the purpose. Here, the method for manufacturing the resin-coated press mold of the present invention will be explained with reference to FIG. 3, taking as an example the squeeze mold shown in FIG. 2, which squeezes a material into a cup shape.

A resin injection space 9 is provided between the molding surface 6 of the master model 5 for resin injection placed on a surface plate (not shown) and the resin coating surface 8 of the die base 7, and the die base is fixed to the master model. do. Next, attach a presser plate 10 to the top of the die base.
to seal the resin injection space. A rod-shaped cylinder 13 is attached to the sprue 12 of the runner 11 leading from the resin injection space through the presser plate and the die matrix, and the attachment point is sealed with rubber clay. Next, resin to which cast iron powder and a hardening agent have been added is injected from the sprue to fill the resin injection space with the resin. Thereafter, the resin is left to stand for about 2 to 3 days and nights to allow the resin to harden, and after hardening, the mold is removed to obtain a resin-coated die. That dice 14
and punch 15, wrinkle presser 16, knockout 17
are combined to obtain the diaphragm mold shown in FIG. Since the resin-coated press mold of the present invention contains cast iron powder as a filler, it has high compressive strength and abrasion resistance, and the mold has good sliding properties, so it is an excellent press mold with a long mold life.

Moreover, since the mold surface is formed of a resin layer, an accurate mold surface can be easily obtained, and a press mold can be provided that is cheaper to manufacture than a mold made entirely of metal. Therefore, does the press mold of the present invention necessarily have a high degree of wear resistance? It is suitable for use in prototypes for low-volume production that are not required. Hereinafter, the details of the present invention will be explained with reference to Examples.

Example 1 20% by volume of 1100 mesh flaky graphite cast iron (equivalent to JISFC23) powder was added to a room temperature curable epoxy resin and stirred.

Next, the gas in the resin was defoamed, and 10% by volume of amine (based on 100% by volume of the resin) was added as a curing agent. This resin is injected from the cylinder 13 shown in FIG.
After being left for about 2 days, the mold was demolded to obtain a resin-coated die.
Using this die, a resin-coated drawing die of the present invention shown in FIG. 2 was manufactured. In addition, squeeze molds of the same shape were manufactured under the same mold manufacturing conditions, with one using iron powder as a filler and the other using a mixture of graphite and quartz powder as a filler. Using the above three types of resin-coated drawing dies, drawing was performed 100 times on a circular steel plate JISS pcd (diameter 80 mm, thickness O, 87n1) under a wrinkle pressing load of 950 kg.

The part of the die shoulder 18 shown in FIG. 2 had the largest displacement p due to wear or deformation during machining. FIG. 4 shows an enlarged view of the displacement state before and after processing. In addition,
In the figure, the mold surface 19 before processing is shown by a solid line, and the mold surface 20 after processing is shown by a broken line.

Next, the displacement amount 21 shown in FIG. 4 was measured using a universal shape measuring machine. The average displacement per one time v is shown in the table below in correspondence with the resin filler. The amount of displacement is less than half that of the flat type, indicating that it is less prone to wear and deformation.

In addition, using these three types of drawing dies, four types of high-strength steel plate
A 0 kg class high tensile strength circular material (diameter 807!Ln, thickness 0.8m71L) was subjected to drawing forming under a wrinkle pressing load of 8001<g.

The relationship between the punch load and punch stroke at that time is shown in FIG. In addition, when using a drawing die containing quartz and graphite, the material broke at a punch stroke of more than 10 mm.
As is clear from the figure, the mold of the present invention requires less punch load for molding than other molds. this is,
This shows that the mold of the present invention has the best molding properties.As shown above, the breath mold of the present invention has excellent strength and is resistant to deformation and wear. It has slippery properties.

Example 2 Using a synthetic resin containing cast iron powder prepared under the same conditions as in Example 1, and by the same mold manufacturing method as in Example 1, a press mold for an automobile panel as shown in FIG. 6 was made.

Further, a press mold of the same shape was manufactured under the same conditions by mixing iron powder as a filler. A conventional resin-coated press mold mixed with iron powder is used to press the steel plate JISS pcd material (
20001rLX120c1n) was used to manufacture automobile panels. However, after producing 250 pieces, the mold surface became worn and deformed, losing its precise mold surface, and it could no longer be used as a press mold. However, when using the resin-coated press mold containing cast iron powder of the present invention, the
It is possible to press mold 0 sheets, and the mold life is twice as long as that of conventional press molds.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the state of a resin layer mixed with cast iron powder that is in contact with the material to be molded, Fig. 2 is a diagram showing a drawing die that is an embodiment of the present invention, and Fig. 3 is , Figure 4 shows the die manufacturing method used in the drawing die of the present invention, Figure 4 is an enlarged view of the shoulder part of the die, Figure 5 shows the relationship between the punch load and punch stroke that occur during the drawing process. 6A and 6B are diagrams showing a press mold for automobile panels, which is an embodiment of the present invention. 1... Material, 2... Portable iron powder, 3...
...Resin, 4...Graphite, 5...Master model, 6...Molding surface of master model, 7
...Dice base, 8...Resin-coated surface,
9... Resin pouring space, 10... Holding plate, 11... Runway, 12... Sprue, 13
...Tube, 14...Dice, 15...
...Punch, 16...Formation foot, 17...
... Knock out, 18 ... Dice shoulder, 19.
... Mold surface before processing, 20 ... Mold surface after processing, 21 ... Displacement amount, 22 ... Mold base, 23 ...・Resin coating layer, A...Curve based on the type of addition of quartz powder and graphite powder, B...Curve due to the type of addition of iron powder, C...Curve of the present invention (addition of cast iron powder) type) curve.

Claims (1)

[Claims] 1. A press mold in which part or all of the contact surface with the metal material on the surface of the press mold is formed with a synthetic resin coating layer, the synthetic resin coating layer containing cast iron powder, and a part of the cast iron powder containing the A press mold coated with a synthetic resin that has excellent sliding properties with metal materials and high strength, characterized by the coating layer being exposed on the surface.