JPH04336223A - Manufacture of sheet molding die - Google Patents

Abstract

PURPOSE:To manufacture a sheet molding die wherein a lining layer is formed to the inner surface of a resin molding flow passage. CONSTITUTION:After the outer peripheral surface of a core mold 1 having an outer shape almost equal to that of a molding flow passage is coated with a heat-resistant release agent, the core mold 1 is received in the upper and lower recessed parts 9,10 formed to the mating surfaces of upper and lower elements 2,3 through a filling gap 8 and both elements 2,3 are superposed one upon another in this state and the dividing line part appearing on the outer periphery of a ply material 4 is welded. Next, the filling gap 8 is filled with a lining powder 17 having good corrosion resistance and abrasion resistance to be degassed and sealed and, after hot isotropic pressure treatment is applied to said powder, the ply material 4 is cut along the surfaces corresponding to the front and rear end surfaces of a product die and the dividing surfaces of both side molds.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a sheet molding die for extruding resins such as general-purpose plastics, engineering plastics, super engineering plastics, rubber, and elastomers into sheets (including films). It is something that can be installed.

0002

2. Description of the Related Art Resin sheets are usually extruded using a flat die attached to an extruder. The flat die has an outlet corresponding to the cross-sectional shape of the sheet on its front end surface, and includes T-dies, coat hanger dies, and the like. Figure 4
5 shows an example of a T-die, in which a pair of upper and lower molds 21 and a lower mold 22 and a pair of left and right side molds 23 can be divided and assembled freely by fastening means such as bolts, and an opening is provided at the rear end surface of the die. A molding channel 26 for molding the resin into a sheet is formed between the resin inlet 24 and the resin outlet 25 opened at the front end surface on the mating surface of the upper mold 21 and the lower mold 22. A manifold 27 consisting of a relatively large cavity is formed in the molding channel 26 at a substantially right angle to the flow of the resin, and the resin is supplied to the entire width of the die through the manifold 27. In addition, the manifold 27 and the outlet 25
An adjusting body 28 for controlling the resin flow rate is connected to the adjusting bolt 2 between the
9, it is provided to be slightly movable in the vertical direction.

[0003] As shown in FIG. 6, the resin outflowing tip of the die may be attached as a lip part 30 to the die body using bolts or the like so that it can be assembled separately. By replacing lip parts with various outflow gaps, the sheet thickness can be adjusted over a wide range. 31 is a vertical adjustment mechanism for the upper half of the lip component. The T-die and other sheet-forming dies are manufactured using mechanical structural steel materials with excellent machinability because the inner surface of the die that forms the resin molding flow path has a complex shape and needs to be machined smoothly. After the inner surface of the die is polished, it is customary to apply chrome plating or Kanigen plating to improve corrosion resistance and wear resistance.

0004

[Problems to be Solved by the Invention] However, the plating layer has a thin thickness of about 30 μm and is prone to pinholes and peeling, resulting in poor corrosion resistance, abrasion resistance, and durability. . This is particularly noticeable in the extrusion molding of engineering plastics and general-purpose resins containing halogenated flame retardants and high-hardness inorganic fillers for reinforcement or coloring. Furthermore, since the plating layer is porous, it is difficult to smooth it, and even with polishing, the Rmax is 0.2.
The limit was about 0.3, and there was also a limit to the improvement of fluidity and reduction of extrusion pressure loss.

By the way, in order to form a thick lining layer with good corrosion resistance and abrasion resistance on the inner surface of the die, lining powder of a highly corrosion-resistant Ni, Co-based high alloy is placed on the surface of the die material, and then heated. It is conceivable to form a lining layer with a uniform thickness by isostatic pressing (HIP) treatment and carve resin molded channels in this lining layer, but the sintered alloy of the corrosion-resistant lining layer cannot be processed. Furthermore, the inner surface of the die cannot be lined to a uniform thickness, resulting in high costs.

[0006]

[Means for Solving the Problems] The manufacturing method of the present invention, which has been made to solve the above problems, includes a pair of upper and lower molds and a pair of left and right side molds that can be divided and assembled, and a rear end surface. A sheet in which a molding channel is formed on the mating surface of the upper mold and the lower mold for molding the resin flowing from the inlet into a sheet shape between an open resin inlet and a resin outlet opened on the front end surface. In the method for manufacturing a molding die, a core mold 1 having an outer shape approximately equal to the molding flow path is manufactured, and an upper half and a lower part of the core mold 1 corresponding to the molding flow paths of the upper mold and the lower mold are manufactured. Gap 8 for filling half with lining powder
An upper and lower pair of upper and lower blanks 2 and 3 are manufactured, each of which has an upper recess 9 and a lower recess 10 formed on the mating surfaces for storage through the core mold 1, and is made of a metal material with a smaller coefficient of thermal expansion than the core mold 1. After applying a heat-resistant release material to the outer peripheral surface of the core mold 1, the core mold 1 is housed in the upper recess 9 and the lower recess 10 through the filling gap 8, and both materials 2, 3 are placed one on top of the other, and the parting line appearing on the outer periphery of the composite material 4 is welded.Then, the filling gap 8 is filled with a lining powder 17 having good corrosion resistance and wear resistance, degassed and sealed, and heated. After applying isostatic pressure treatment, the laminate material 4 is cut along the front end face, rear end face, and planes corresponding to the splitting surfaces of both side molds of the product die to form a pair of upper and lower mold materials and a lower mold. The structure of the invention is to obtain raw materials for a mold and a pair of left and right side mold materials, take out a core mold 1, and finish each raw material.

[0007]

[Operation] The upper and lower materials can be made of carbon steel or low-alloy steel for machine structures, as in the past, and high precision is not required, so the upper and lower recesses can be easily machined. A gap for filling the lining powder with an arbitrary thickness can be formed along the resin molding channel.

A core mold and lining powder are stored,
The degassed and sealed composite material consisting of the upper material and the lower material is subjected to HIP processing so that the lining powder is sintered and integrated to form a lining layer, and the inner surface of the upper recess of the upper material and the lower recess of the lower material is Diffusion bonding. At this time, the core mold is made of a metal material with a higher coefficient of thermal expansion than the upper and lower materials, and its surface is coated with a heat-resistant mold release material, so the core mold and the lining layer are There is no diffusion bonding, and the core mold shrinks more than the upper and lower materials when cooled, and naturally separates from the lining layer. Note that the lining layer is diffusion bonded to the upper and lower recesses, and contracts as the upper and lower materials contract.

[0009] The material for the core mold should preferably have a coefficient of thermal expansion 5 to 8 x 10-6/°C higher than the material for the upper and lower parts, and when carbon steel is used as the upper and lower parts, It is preferable to use high Mu steel or stainless steel. After HIP processing, the laminate material is cut at a surface corresponding to the plan outline line and parting line of the product die, allowing one HIP process.
Through processing, materials for each component of the product die can be obtained at the same time, and because the inner surface shape that approximates the resin flow path is formed in the lining layer of each material, finishing processing can be easily performed.

0010

EXAMPLE A manufacturing example of the T-die shown in FIGS. 4 and 5 will be described with reference to FIGS. 1 to 3. FIG. 1 shows an upper material 2 for producing an upper mold, which is equipped with a core mold 1 for forming a molding channel, and FIG. 2 shows a lower material 3 for manufacturing a lower mold, which is equipped with the core mold 1. A cross-sectional view (a cross-section corresponding to the line A-A in FIG. 1) of a laminate material 4 for HIP processing superimposed on an upper material 2 is shown.

The core mold 1 is made of a thick SUS304 stainless steel plate, and a head part 6 for fixing and a main body part 7 having a three-dimensional convex shape approximately approximating the molding channel of the product die are formed by NC milling. It is formed by processing. When processing the main body part 7, in order to perform HIP forming to a size as close as possible to the product forming flow path, the temperature of the upper and lower materials 2 and 3 (SCM440 structural alloy steel) is kept at room temperature - HIP processing temperature ( Approximately 1000℃
) Considering the relative thermal expansion coefficient of 8/1000, the dimensions of the finished product were multiplied by (1-8/1000).

Furthermore, the surface roughness of the main body part 7 is machined to Rmax 10 to 6S, then ground to 3 to 4S by polishing the entire surface to crush the processed joints, and then electrolytically polished to a final Rmax of 1S or less. I made it. On the other hand, the upper and lower materials 2 and 3 are stored in the upper and lower halves of the core mold main body 7 corresponding to the molding channels of the upper mold and the lower mold through the gap 8 for filling the lining powder. upper recess 9 for
A lower recess 10 is formed on the mating surfaces of both materials by NC milling, and a recess 11 for fitting and fixing the head 6 of the core mold 1 is provided at the upper center. Furthermore, a step 12 is provided at the lower edge of the upper recess 9 to slidably hold the lower edge of the core mold main body 7 with the mating surface of the lower material 3. 12
is formed to a length that can tolerate the vertical elongation that occurs in the core mold 1 during HIP.

The gap 8 for filling the lining powder is as follows:
The value may be calculated by dividing the thickness of the lining layer of the product die by the powder filling rate (approximately 0.7). For example, if the lining thickness of the product is 3 mm, the width (thickness) of the filling gap 8 may be approximately 4.5 mm. Note that 13 is a supply hole for lining powder. In addition, fitting steps (not shown) are formed on the sides and lower peripheral edges of the mating surfaces of the upper and lower materials to accurately overlap the two materials with a fitting tolerance of e7 to e8.

[0014] The core mold 1 and the upper and lower materials 2,
3, first, the core mold 1 is degreased and a heat-resistant mold release material is applied to the entire surface of the main body part 7. As the heat-resistant mold release material, one in which an aggregate of high-melting point oxide powder such as alumina or zirconia is used as an aggregate and an inorganic binder added thereto is used. When applying it, it is recommended to dilute it by adding a solvent such as water and spray it. The coating thickness may be 0.05 to 0.5 mm in order to release the mold from the lining layer, but since the lower edge of the core mold slides within the stepped portion when the temperature rises during HIP processing, the coating thickness may be 0.05 to 0.5 mm. The thickness is preferably about 5 to 1.0 mm. Note that the gap between the stepped portions is formed to a size that takes into account the coating thickness of the heat-resistant mold release material.

Next, with the core mold 1 housed in the upper recess 9 and the lower recess 10, the upper and lower materials 2 and 3 are overlapped and fitted together. With this, the laminate material 4
The core body 7 has an upper recess 9 and a lower recess 10.
A cavity consisting of a lining powder filling gap 8 is formed between the lining powder filling gap 8 , and the lower step 12 of the upper recess 9 is closed by the mating surface of the lower material 3 to become a sliding groove 14 . The lower edge of the core mold main body 7 is inserted into the hole.

A separation plate 15 made of steel plate shown in FIG. 3 is attached to the upper part of the mating surface, and its lower edge
It is inserted into a sliding groove 16 recessed in the upper edge of. The surface of the separation plate 15 is coated with the heat-resistant mold release material. In addition, in order to prevent lining powder from entering the lower sliding groove 14, it is necessary to
It is advisable to attach a heat-resistant elastic material such as ceramic fiber to the part).

[0017] After that, lining powder 17 is filled through the supply hole 13 and heated to about 400°C while degassing.
After sealing the supply hole 13, 960℃×1000kg/
It was maintained for 5 hours under HIP conditions of cm2. The lining powder has corrosion resistance equivalent to Hastelloy C-276 alloy, and has high hardness and wear resistance (HR) equivalent to tool steel.
c54) Nickel-based high alloy (17.5wt%
Cr-24.0wt% Mo-3.6wt%B-3.0
A gas atomized powder of wt%Si-1.0wt%Cu-remaining Ni was used.

After HIPing, the laminate material 4 is cut along the front end face, rear end face, and planes corresponding to the dividing planes of both side molds (X-X, Y-Y, Z-Z in FIG. 1). , a pair of upper and lower mold materials and a pair of left and right side mold materials are obtained. The core mold body 7 was naturally separated from the upper mold and lower mold materials, and the surface roughness of the molding channel forming surface was Rmax 3 to 6S. Each material is subjected to finishing processing to become product parts. In particular, the molded flow path forming surface is polished to a 0.0
It was possible to process it to a mirror surface of 5 to 0.07S.

In addition, in the case of a T-die to which a lip part is attached as shown in FIG.
1+L2) plus the insertion allowance into the sliding groove 14 and the machining allowance. Further, an adjustment body 28 for resin flow rate control is separately manufactured and incorporated into the upper mold 21. Also,
A heater insertion hole and a temperature measuring element insertion hole are machined in the product die as appropriate.

[0020]

[Effects of the Invention] As explained above, according to the method of manufacturing a die for sheet molding of the present invention, a core mold having an outer shape approximately equal to that of the resin molding flow path has a coefficient of thermal expansion larger than that of the upper and lower materials. Since it is made of a metal material and a heat-resistant mold release material is applied to its surface, the core mold is housed in the upper and lower recesses, and the filling gap around it is filled with a lining material filled with powder for lining. Even with the HIP treatment, the core mold and the lining layer sintered and formed by HIP do not diffuse bond, and the two are naturally separated, with a three-dimensional inner surface approximately resembling the resin molding channel in the upper and lower recesses. The lining layer can be easily formed, and processing of the molding channel surface can be almost omitted. Furthermore, the gap for filling the lining powder can be recessed into the upper and lower materials to a desired thickness, so the thickness of the lining layer can be freely set.

[0021] Furthermore, after the HIP process, the laminate material is cut along the front end surface, rear end surface, and surfaces corresponding to the dividing surfaces of the product die, so that each component material of the die can be cut in one HIP process. It can be obtained all at once and is economically superior. In addition, in the die manufactured according to the present invention, the inner surface where the resin molding channel is formed is coated with a thick lining layer that has good corrosion resistance and wear resistance, eliminating all the inconveniences that occur in the case of plating. can do.

[Brief explanation of drawings]

FIG. 1 is a plan view of an upper material for manufacturing an upper mold equipped with a core mold for forming resin molding channels.

FIG. 2 is a cross-sectional view of a laminate for HIP processing for producing each part of the die.

FIG. 3 is a plan view of a separation plate.

FIG. 4 is a cross-sectional view of the T-die.

FIG. 5 is a front view of the same half.

FIG. 6 shows a sectional view of a main part of a T-die equipped with a lip component.

[Explanation of symbols]

1 Core mold 2 Upper material 3 Lower material 4 Laminating material 8 Filling gap 9 Upper recess 10 Lower recess 17 Powder for lining

Claims (1)

[Claims] 1. A pair of upper and lower molds and a pair of left and right side molds are provided which can be assembled separately, and the flow is disposed between a resin inlet opening at the rear end face and a resin outlet opening opening at the front end face. In a method for manufacturing a sheet molding die, in which a molding channel for molding resin flowing from an inlet into a sheet shape is formed on the mating surfaces of an upper mold and a lower mold, While manufacturing the child mold (1), the upper and lower halves of the core mold (1) corresponding to the molding channels of the upper mold and lower mold are filled through the gap (8) for filling the lining powder. Upper recess (9) and lower recess (1
0) is formed on the mating surface, and a pair of upper and lower upper materials (
2) and the lower material (3) are manufactured, and the core mold (
1) After applying a heat-resistant mold release material to the outer peripheral surface of the core mold (1), the core mold (1) is housed in the upper recess (9) and lower recess (10) through the filling gap (8), and then both Material (2
) and (3), and weld the parting line that appears on the outer periphery of the laminated material (4), and then fill the filling gap (8) with a lining powder (17) with good corrosion resistance and wear resistance.
) is filled, degassed and sealed, and subjected to hot isostatic pressure treatment, and then the laminate material (4) is applied along the front end surface, rear end surface, and surfaces corresponding to the dividing surfaces of both sides of the product die. A sheet forming die characterized in that a pair of upper and lower mold materials and a pair of left and right side mold materials are obtained by cutting, the core mold (1) is taken out, and each material is finished. manufacturing method.