JP3212477B2 - Manufacturing method of sheet molding die - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet molding die for extruding resins (including films) from general-purpose plastics, engineering plastics, super engineering plastics, rubbers, elastomers, etc., in particular, molds. A mold obtained by diffusing and joining a material different from the main body material to a resin molding flow path of the mold by hot isostatic pressing (HIP) is used for an extruder or the like.

[0002]

2. Description of the Related Art Conventionally, a molding flow path of a sheet molding die is generally a plating layer. As a method of manufacturing a resin sheet molding die capable of improving the resin fluidity deterioration from the problem of smoothness due to the porosity of the plating layer, corrosion resistance at any thickness by HIP treatment in the resin molding flow path of the mold, The present applicant has proposed a manufacturing method for forming a resin sheet in which an alloy powder having good wear resistance is diffusion-bonded (see Japanese Patent Publication No. 6-61818).

According to this method, after a heat-resistant release material is applied to the outer peripheral surface of a core having an outer shape substantially equal to that of a molding flow path, the core is formed on a mating surface of an upper material and a lower material. The two materials are overlapped in a state where they are accommodated in the upper concave portion and the lower concave portion via the filling gap, and the dividing line portion that appears on the outer periphery of the combined material is welded, and then the filling gap has good corrosion resistance and wear resistance. After filling the alloy powder, degassing and sealing, and performing hot isostatic pressing, the combined material is placed on the front end face of the product mold,
This is a method of cutting along the surfaces corresponding to the rear end face and the split surfaces of both side molds to obtain a pair of upper and lower, left and right materials, take out a core mold, and finish each material.

In this method, the core mold and the alloy powder lining layer which has been densely solidified by the HIP treatment are not diffusion-bonded, but are naturally separated from each other, and the upper concave portion and the lower concave portion approximate to the resin molding flow path. A composite material having a two-dimensional inner surface can be formed, and processing of the molding flow path surface can be almost omitted. Moreover, four mold materials can be obtained at one time by one HIP process, which is economically excellent. Of course, the inner surface formed in the resin molding flow path is firmly covered with a thick, 100% dense lining layer with good corrosion resistance and good abrasion resistance, eliminating all inconveniences caused by plating. I could do it.

[0005]

SUMMARY OF THE INVENTION However, HIP
In the joining of dissimilar materials by processing, stress is generated due to a difference in the coefficient of thermal expansion between joining materials in a cooling process during HIP.
Some resin sheet molding dies manufactured by the above-described technique have a long shape and have a length of 1 m to as long as about 4 m in terms of sheet productivity. In such a shape, the material after the HIP processing is easily deformed by the previously generated stress, and it is necessary to provide a machining allowance to the material in anticipation of the deformation, which lowers the material yield.

[0006] Further, even during machining, the balance of residual stress changes, causing deformation, and it is difficult to secure dimensional accuracy with the present mold requiring high dimensional accuracy. The present invention has been made in order to solve such a problem, and even when a lining material having a different coefficient of thermal expansion is diffusion-bonded to a mold material by HIP processing, deformation is prevented and material yield is reduced. It is an object of the present invention to provide a method for obtaining a mold having high dimensional accuracy without performing the above.

[0007]

In order to achieve the above object, a method for manufacturing a mold according to the present invention comprises a method of forming a corrosion-resistant and abrasion-resistant alloy powder having a desired thickness by a HIP in a resin molding flow path of a mold; And in a method for forming a resin sheet in which these dense alloys are joined, the material of the mold body is a two-phase alloy,
After the diffusion bonding in the HIP is completed, a heat treatment for adjusting the amount of the alloy phase of the main body is performed.

That is, according to the first aspect of the present invention, a laminated material in which the upper material 2 and the lower material 3 are overlapped with each other,
A capsule 4 is manufactured by mounting a core mold 1 having an outer shape substantially equal to that of a molding flow path and subjected to a mold release treatment, and an outer surface of the core mold 1 and inner surfaces of the upper and lower materials 2 and 3 in the capsule 4. The lining powder 17 is filled with the lining powder 17 having good corrosion resistance and abrasion resistance, degassed and sealed, and subjected to a hot isostatic pressing process, thereby bringing the lining powder 17 into upper and lower materials 2. In a method for manufacturing a sheet molding die having a molding flow path for forming a resin into a sheet by diffusion bonding to the inner surface of the upper and lower members 2, 3
After the diffusion bonding is completed, a heat treatment for adjusting the amount of the alloy phase is performed.

[0009] In the present invention according to claim 2, the above-mentioned claim 1 is provided.
In the invention according to the invention, the material of the upper and lower materials 2 and 3 is a two-phase alloy of ferrite / austenite, and the heat treatment adjusts the phase amount of either ferrite / austenite. Things.
According to a third aspect of the present invention, in the first and second aspects of the invention, the heat treatment is performed in the processing chamber 18 of the hot isostatic pressing apparatus or in another furnace 19 which is taken out of the processing chamber 18. It is characterized by the following.

[0010] In the present invention according to claim 4, according to claim 1 of the present invention.
In the inventions according to any one of (1) to (3), after performing the heat treatment, the capsule 4 is cut along a surface corresponding to a division surface of a front end and a rear end of a product mold to obtain a material for upper and lower molds. Type 1
It is characterized by taking out and finishing each material.

[0011]

The operation will now be described with reference to FIGS. FIG. 4 is 1500 mm long and 30 m thick for simplicity.
4.5 mm as resin molding flow path of m mold (material to be joined)
It shows the relationship between the difference in the coefficient of thermal expansion between the joining material and the material to be joined and the amount of change (bending) in the length direction when the dissimilar materials (joining material) are subjected to diffusion joining by HIP processing. 3.5mm even if the difference in thermal expansion coefficient between materials is only 0.5 × 10 ^-6
It is understood that it is necessary to reduce the difference in coefficient of thermal expansion as much as possible to prevent the deformation and prevent the deformation.

FIG. 5 shows a change in the coefficient of thermal expansion due to a change in the amount of ferrite / austenite in a two-phase alloy. In this case, it is understood that the coefficient of thermal expansion varies depending on the amount of the ferrite / austenite phase even with the same material. From these facts, as shown in FIG. 5, the amount of the ferrite / austenite phase of the mold material, that is, the two-phase alloy, which is the same as the thermal expansion coefficient of the joining material is set in advance, and this phase amount is adjusted by heat treatment. HIP processing can be performed with a combination of materials to be joined having the same coefficient of thermal expansion as the joining material, and deformation can be prevented.

Here, since the amount of the two-phase alloy ferrite / austenite varies depending on the heat treatment conditions, it is necessary to examine in advance the relationship between the heat treatment conditions of the alloy used, the amount of ferrite / austenite phase and the coefficient of thermal expansion. It is. Accordingly, in the capsule 4 containing the core mold 1 and the lining powder 17 and formed of the upper material 2 and the lower material 3 which are degassed and sealed, the lining powder 17 is sintered and integrated by the HIP process to form a lining layer. And the upper recess 9 of the upper material 2 and the lower recess 1 of the lower material 3
Diffusion bonding is performed on the inner surface. At this time, since the core mold 1 is formed of a metal material having a larger coefficient of thermal expansion than the upper and lower materials, and the surface thereof is coated with a heat-resistant release material, the core mold, the lining layer, Does not undergo diffusion bonding, and upon cooling, the core mold shrinks more than the upper and lower materials and spontaneously separates from the lining layer. The lining layer is diffusion-bonded to the upper and lower recesses and contracts in accordance with the contraction of the upper and lower materials. However, after the two materials 2 and 3 are made of a two-phase alloy and the diffusion bonding is completed,
By performing the heat treatment for adjusting the amount of the alloy phase, the bending deformation due to the difference in thermal expansion is reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 3 shows an upper mold manufacturing upper material 2 provided with a core mold 1 for forming a molding flow path. FIG. 1 (A) shows the lower material 3 for lower mold manufacturing in the core mold 1. 1 shows a cross-sectional view of a capsule 4 for HIP processing superimposed on an upper material 2 provided with.

The core mold 1 is made of a SUS304 stainless steel thick plate, and has a fixing head 6 and a main body 7 having a three-dimensional convex shape substantially similar to a molding flow path of a product mold. It is formed by milling. In processing the main body 7, the relative thermal expansion coefficient between the upper and lower materials 2 and 3 at room temperature-HIP processing temperature is considered in order to perform the HIP molding to a dimension as close as possible to the product forming flow path. did.

The surface roughness of the main body 7 is Rmax 10 to 6S after machining, the whole surface is polished to 3 to 4S by grinding, and further subjected to electrolytic polishing to finally Rmax 1S or less. I made it. On the other hand, the upper and lower materials 2 and 3 are for accommodating the upper half and the lower half of the core body 7 corresponding to the molding flow paths of the upper mold and the lower mold via the gap 8 for filling the lining powder. An upper concave portion 9 and a lower concave portion 10 are formed on the mating surface of the two materials by NC milling, and a concave portion 11 for fitting and fixing the head 6 of the core mold 1 is provided at the upper center. I have.
Further, a step 12 for slidably holding the lower edge of the core body 7 with the mating surface of the lower material 3 is provided at the lower edge of the upper recess 9. Reference numeral 12 is formed to have a length that allows vertical extension of the core 1 during HIP.

Here, as the material of the upper and lower materials 2 and 3, for example, a two-phase alloy of fetolite / austenite is used. The spacing 8 of the lining powder filling gap may be a value obtained by dividing the thickness of the lining layer of the product die by the powder filling rate (about 0.7). For example, if the lining thickness of the product is 3 mm, the width (thickness) of the filling gap 8 may be about 4.5 mm. Reference numeral 13 denotes a supply hole for the lining powder. In addition, a fitting step (not shown) for accurately overlapping the two materials is fitted on the side and the lower periphery of the mating surface of the upper and lower materials, and the tolerance e7 is fitted.
To e8.

The core 1 and the upper and lower materials 2 and 3
When assembling, the core mold 1 is first degreased, and the
A heat-resistant release material is applied to the entire surface of the substrate. As the heat-resistant release material, a material obtained by using a high melting point oxide powder such as alumina or zirconia as an aggregate and adding an inorganic binder thereto is used. Upon application, it may be diluted by adding a solvent such as water and spray-applied. The coating thickness may be 0.05 mm to 0.5 mm for release from the lining layer,
Since the lower edge of the core mold slides in the step portion when the temperature of the HIP process is increased, it is preferable to set the lower edge to about 0.5 mm to 1.0 mm.
The gap between the steps is formed in a size that allows for the thickness of the heat-resistant release material to be applied.

Next, the core mold 1 is placed in the upper concave portion 9 and the lower concave portion 1.
The upper and lower materials 2 and 3 are overlapped in a state where they are housed in 0, and they are fitted together. As a result, a cavity comprising the lining powder filling gap 8 is formed in the capsule 4 between the core mold body 7 and the upper concave portion 9 and the lower concave portion 10, and the step 12 below the upper concave portion 9 is formed in the lower portion. The sliding surface is closed by the mating surface of the material 3, and the edge of the core body 7 is inserted into the sliding groove 14.

After that, the lining powder 17 is filled from the supply hole 13 of the capsule 4 and heated while being evacuated to about 400 ° C. to seal the supply hole 13 and then treated by the HIP apparatus shown in FIG. 960 ℃ × 1000kg / in the room 18
The lining powder was subjected to HIP treatment for 4 hours under the HIP condition of ² cm ² so that the lining powder was
Diffusion bonding was possible on the inner surface of No. 3.

In the present invention, after the above-mentioned diffusion bonding is completed, the capsule 4 is taken out of the processing chamber 18 of the HIP apparatus, and is heated to 1000 ° C. in air in a furnace 19 shown in FIG.
Heat treatment was performed at 1100 ° C. for 3 hours. This heat treatment
By controlling the amount of ferrite / austenite phases of the upper and lower materials 2 and 3, the amount of bending caused by the difference in the coefficient of thermal expansion is suppressed.

After the heat treatment, as shown in FIG. 3, the capsule 4 is placed on the front end face, the rear end face, and the surfaces corresponding to the divided surfaces of the both molds (XX, YY, ZZ in FIG. 3). To obtain a pair of upper and lower upper and lower mold materials and a pair of left and right side mold materials. The core body 7 was naturally separated and removed from the upper and lower mold materials, and the surface roughness of the molding channel forming surface was Rmax 3 to 6S. Each material is subjected to finish processing to become a product part. In particular, the forming channel forming surface could be processed to a mirror surface of 0.05 to 0.07 S by polishing using diamond abrasive grains.

Next, specific embodiments of the present invention and a conventional method will be described with reference to FIGS. 2A, 2B and 2C and Table 1. FIG. SCM440, SUS329 as mold body material
J1, A material (Ni-17.5wt%) as lining material
Cr-24wt% Mo-3.6wt% B-3wt% Si
-1wt% Cu), B material (Ni-34wt% Cr-2w)
t% Mo-3wt% B-4.3wt% Si-4wt% W
-4.5 wt% Fe-1 wt% Cu-2 wt% Nb),
Using the C material (Fe-1.2C-18Cr-1V), a sheet forming die material 30 having the dimensions shown in FIGS. In addition, the lining layer 31 is diffusion-bonded to one surface of the raw material 30 by the HIP process, and all the prototypes No. 1 to 8 shown in Table 1 have the same dimensions.

Table 1 shows combinations of the material of the mold body and the lining material, and the heat treatment conditions after the HIP treatment.

[0025]

[Table 1]

After HIP and heat treatment, both ends are cut off, and FIG.
The dimensions indicated by the arrow t in (B) were measured and are shown in the deformation amount column of Table 1. The deformation amount when the body material is SCM440 and the lining material is A material and the heat treatment is not performed after HIP as the conventional method, and the body material in the present invention is SUS329J
1. As is clear from the comparison with the amount of deformation in the case where the lining material is material A and the appropriate heat treatment is performed after HIP, the mold material obtained by the method of the present invention has less deformation and is manufactured with a high yield. It is now possible.

In the present invention, the heat treatment after the HIP treatment can be performed in a HIP apparatus, and the amount of ferrite in a ferrite / austenite two-phase alloy can be adjusted. Further, as the material of the mold body (material), two of ferrite / austenite are used.
Other than the phase alloy may be used.

[0028]

As described above in detail, according to the present invention, a lining material having a different coefficient of thermal expansion from that of the mold material is obtained by HIP.
Even when diffusion bonding is performed by the treatment, it is possible to obtain a sheet molding die that prevents deformation and ensures high dimensional accuracy without lowering the material yield.

[Brief description of the drawings]

1A and 1B show an embodiment of the method of the present invention, wherein FIG. 1A is a cross-sectional view of a capsule, and FIG.

FIGS. 2A and 2B show prototype materials for comparing the method of the present invention with the conventional example method, wherein FIG. 2A is a plan view, FIG. 2B is an explanatory diagram of a bending amount, and FIG.

FIG. 3 is a plan view of a capsule used in the method of the present invention.

FIG. 4 is a graph showing the relationship between the difference in the coefficient of thermal expansion and the amount of bending.

FIG. 5 is a graph showing the relationship between the amount of austenite in a two-phase alloy and the coefficient of thermal expansion.

[Explanation of symbols]

 Reference Signs List 1 core type 2 upper material 3 lower material 4 capsule 8 gap 17 lining powder

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Umeda 2-3-1, Shinhama, Arai-machi, Takasago-shi, Hyogo Kobe Steel, Ltd. Inside Takasago Works (56) References JP-A-4-336223 (JP, A) JP-A-6-179234 (JP, A) JP-A-62-294106 (JP, A) JP-A-7-108557 (JP, A) JP-A-6-304992 (JP, A) JP-A-5-338009 (JP, A) JP-A-4-41606 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 47/00-47/96

Claims (4)

(57) [Claims] 1. A core material (1) having an outer shape substantially equal to a molding channel and having been subjected to a release treatment is provided inside a laminated material in which an upper material (2) and a lower material (3) are overlapped. A capsule (4) is manufactured, and a corrosion resistance and abrasion resistance are formed in a gap (8) between the outer surface of the core mold (1) and the inner surfaces of the upper and lower materials (2) and (3) in the capsule (4). The lining powder (1) is filled with a good lining powder (17), degassed and sealed, and subjected to hot isostatic pressing.
7) A method of manufacturing a sheet molding die, wherein diffusion molding is performed on the inner surfaces of the upper and lower materials (2) and (3) to form a molding flow path for molding a resin into a sheet. The material of the lower material (2) (3) is a two-phase alloy,
After the diffusion bonding is completed, a heat treatment for adjusting the amount of the alloy phase is performed. 2. The method according to claim 1, wherein the material of the upper and lower materials (2) and (3) is a two-phase alloy of ferrite / austenite, and the heat treatment adjusts the phase amount of either ferrite / austenite. The method for manufacturing a sheet molding die according to claim 1, wherein: 3. The heat treatment according to claim 1, wherein the heat treatment is performed in a processing chamber of a hot isostatic pressing apparatus or in another furnace taken out of the processing chamber. 3. The method for producing the sheet molding die according to 2. 4. After performing the heat treatment, the capsule (4) is cut along a surface corresponding to a divided surface of front and rear end surfaces of a product mold to obtain upper and lower mold materials. Type (1)
The method for manufacturing a sheet forming die according to any one of claims 1 to 3, wherein the material is taken out and each material is finished.