Compression molding mold of composite material and compression molding method thereof

Abstract

The invention discloses a compression molding mold of a composite material and a compression molding method of the compression molding mold, and relates to the technical field of composite material machining, the compression molding mold comprises a lower mold, a transfer mold and an upper mold assembly, and the transfer mold is detachably arranged on the lower mold; a first forming face is arranged on the upper surface of the lower die, a second forming face is arranged on the lower surface of the transfer die, and a third forming face is arranged on the lower surface of the upper die assembly. During mold pressing, a lower laying layer is laid on the first forming face, then an upper laying layer is laid on the second forming face, then a transfer mold is pressed on a lower mold, the second forming face and the first forming face are matched to form a prefabricated mold cavity, and the upper laying layer and the lower laying layer are extruded into a prefabricated laying layer through the prefabricated mold cavity; and then, the transfer mold is removed, the upper mold assembly is pressed on the lower mold, the third forming face and the first forming face are matched to form a forming mold cavity, and the forming mold cavity extrudes the prefabricated laying layer into a molded part. The upper paving layer and the lower paving layer are pre-compacted in advance by virtue of the transfer mold, so that fiber wrinkling, deformation and the like are avoided, and the yield is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material processing, and particularly relates to a compression molding die for composite materials and a compression molding method thereof. Background Art

[0002] In the manufacturing process of continuous fiber composite products, especially for L-shaped flanging structures and parts with complex shapes, due to high requirements for structural accuracy, a full outer surface die face forming process is usually required. Currently, the compression molding process is widely used in the industry to produce such products. The laying operation is carried out on the lower die, and after closing the upper die, pressure is applied for molding. However, there are many problems with this traditional laying method in actual production.

[0003] For example, after the laying process is completed, the initial density of the fiber layup is often insufficient. During the mold closing and pressing stage, when facing a workpiece with complex geometric features, a significant frictional force will be generated between the mold surface and the fiber-reinforced material, resulting in uneven pulling forces on the fibers during the forming process, and further causing adverse phenomena such as fiber wrinkling and deformation. These process defects will be manifested as quality problems such as surface irregularities and fiber orientation deviations after the product is cured, resulting in a decrease in the finished product rate. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a compression molding die for composite materials and a compression molding method thereof. Before mold closing, a transfer die is added to pre-transfer the lower layup to the upper layup in advance, and a preformed layup is pre-pressed. Then, through mold closing, the preformed layup is compression molded into a molded part, reducing quality problems of the molded part and improving the finished product rate, and solving the technical problem of the decrease in the finished product rate caused by uneven stress during the layup compression molding of the existing die.

[0005] To achieve the above purpose, the present invention provides a compression molding die for composite materials, including:

[0006] A lower die, the upper surface of the lower die is provided with a first forming surface, and a lower layup is laid on the first forming surface;

[0007] A transfer die, the lower surface of the transfer die is provided with a second forming surface, and an upper layup is laid on the second forming surface; the transfer die is detachably arranged on the lower die; when the transfer die is pressed on the lower die, the second forming surface and the first forming surface cooperate to form a preformed mold cavity, and the preformed mold cavity squeezes the upper layup and the lower layup into a preformed layup;

[0008] An upper die assembly, the lower surface of the upper die assembly is provided with a third forming surface, and the third forming surface is the same as the second forming surface; when the transfer die is removed and the upper die assembly is pressed on the lower die, the third forming surface and the first forming surface cooperate to form a forming mold cavity, and the forming mold cavity squeezes the preformed layup into a molded part, and the contour shape of the molded part coincides with the contour shape of the forming mold cavity.

[0009] In some embodiments, the upper mold assembly includes:

[0010] An upper mold, the lower surface of the upper mold is provided with an extrusion inclined surface and a third forming surface, and the extrusion inclined surface and the third forming surface are arranged at an angle;

[0011] A wedge-shaped pressing block, the side forming surface of the wedge-shaped pressing block faces the bent surface of the first forming surface, and the side forming surface and the bent surface extrude the bent flange of the molded part; on the side of the wedge-shaped pressing block away from the first forming surface, there is a mating inclined surface, and the mating inclined surface is in wedge-shaped fit with the extrusion inclined surface.

[0012] In some embodiments, a limiting groove is provided at one end of the lower mold, and the wedge-shaped pressing block is in concave-convex fit with the limiting groove.

[0013] In some embodiments, a positioning protrusion and a positioning groove that are mutually engaged are provided between the bottom of the wedge-shaped pressing block and the bottom of the limiting groove.

[0014] In some embodiments, a limiting post and a limiting groove that are mutually matched are provided between the upper mold and the lower mold.

[0015] In some embodiments, a positioning plane is provided on the upper surface of the wedge-shaped pressing block, a mating plane is provided on the lower surface of the upper mold, and the extrusion inclined surface and the third forming surface are connected through the mating plane; when the upper mold is pressed on the lower mold, the positioning plane abuts against the mating plane.

[0016] In some embodiments, a pressure relief groove is provided on the positioning plane.

[0017] In some embodiments, a plurality of positioning posts are fixedly arranged along the outer side of the first forming surface, a plurality of positioning holes are provided on the outer edge of the transfer mold, and all the positioning posts are in one-to-one correspondence and cooperation with all the positioning holes.

[0018] In some embodiments, a plurality of lifting rings are fixedly arranged on the outer side surfaces of both the lower mold and the upper mold.

[0019] The present invention also provides a molding method for a composite material, which is applied to the above-mentioned molding die for a composite material, and the steps include:

[0020] Lay a lower ply on the first forming surface of the lower mold;

[0021] Lay an upper ply on the second forming surface of the transfer mold;

[0022] Press the transfer mold onto the lower mold, and the second forming surface and the first forming surface cooperate to form a preformed cavity, and the preformed cavity extrudes the upper ply and the lower ply into a preformed ply;

[0023] Remove the transfer mold;

[0024] The upper die assembly presses on the lower die. The third forming surface of the upper die assembly cooperates with the first forming surface to form a forming die cavity. The forming die cavity extrudes the prefabricated ply into a molded part, and the contour shape of the molded part coincides with the contour shape of the forming die cavity.

[0025] Compared with the background art, the compression molding die for composite materials provided by the present invention includes a lower die, a transfer die and an upper die assembly. The transfer die is detachably arranged on the lower die. The upper surface of the lower die is provided with a first forming surface, the lower surface of the transfer die is provided with a second forming surface, and the lower surface of the upper die assembly is provided with a third forming surface.

[0026] During compression molding, first lay the lower ply on the first forming surface, then lay the upper ply on the second forming surface, and then press the transfer die on the lower die. The second forming surface cooperates with the first forming surface to form a prefabricated die cavity. The prefabricated die cavity extrudes the upper ply and the lower ply into a prefabricated ply. Then, remove the transfer die, and the upper die assembly presses on the lower die. The third forming surface cooperates with the first forming surface to form a forming die cavity. The forming die cavity extrudes the prefabricated ply into a molded part, and the contour shape of the molded part coincides with the contour shape of the forming die cavity.

[0027] Before the upper die and the lower die assembly of the present invention perform compression molding, the upper ply and the lower ply are pre-compacted in advance by means of the transfer die, and the prefabricated ply is prefabricated by an integral transfer method to ensure the quality of the complex surface of the prefabricated ply, and avoid adverse phenomena such as fiber wrinkling and deformation due to uneven pulling force on the complex surface during the compression molding stage, reduce the risk of quality problems in the molded part, and effectively improve the yield. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for description in the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0029] Figure 1 Schematic diagram of the compression molding die for composite materials provided by a specific embodiment of the present invention;

[0030] Figure 2 For Figure 1 the state diagram when the transfer die is pre-pressed on the upper die in

[0031] Figure 3 For Figure 1 the state diagram before the upper die assembly and the lower die are closed in

[0032] Figure 4 For Figure 1 the state diagram when the upper die assembly and the lower die are closed in

[0033] Figure 5 Schematic diagram of a molded part molded by a compression molding die for a composite material provided by a specific embodiment of the present invention.

[0034] The reference numerals are as follows:

[0035] Lower mold 1, prefabricated ply 2, transfer mold 3, upper mold assembly 4, molded part 5, and lifting ring 6;

[0036] First forming surface 10, limiting groove 11, limiting slot 12, and positioning post 13;

[0037] Bending forming surface 101;

[0038] Positioning groove 111;

[0039] Lower ply 21 and upper ply 22;

[0040] Second forming surface 30 and positioning hole 31;

[0041] Upper mold 41 and wedge-shaped pressing block 42;

[0042] Second forming surface 410, extrusion inclined surface 411, and mating plane 412;

[0043] Side forming surface 421, mating inclined surface 422, positioning plane 423, and pressure relief groove 424;

[0044] Bending flange 51. Detailed implementation manner

[0045] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0046] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0047] An embodiment of the present invention discloses a compression molding die for a composite material, as shown in the attached Figure 1As shown in the figure, it includes a lower mold 1, a transfer mold 3 and an upper mold assembly 4. The upper surface of the lower mold 1 is provided with a first forming surface 10. The first forming surface 10 is an L-shaped structure, that is, the first forming surface 10 is formed by the perpendicular intersection of an annular surface and a bending surface 101. Among them, the annular surface is specifically a rectangular structure. Of course, the contour shape of the first forming surface 10 can be adaptively adjusted according to the outer contour shape of the molded part 5, and no specific limitation is made here. A lower laying layer 21 is laid on the first forming surface 10. Additionally, a reference plane is provided on the lower surface of the lower mold 1 to ensure that the lower mold 1 is placed horizontally based on this reference.

[0048] As shown in the attached Figure 2 figure, the lower surface of the transfer mold 3 is provided with a second forming surface 30. The second forming surface 30 is a convex surface, and the convex surface is in concave-convex fit with the annular surface to form a convex structure of the molded part 5. An upper laying layer 22 is laid on the second forming surface 30. Both the upper laying layer 22 and the lower laying layer 21 can be fiber pre-pregs. The transfer mold 3 is detachably arranged on the lower mold 1; in the pre-pressing stage, the transfer mold 3 is installed on the lower mold 1; in the molding stage, the transfer mold 3 is removed from the lower mold 1. When the transfer mold 3 is pressed on the lower mold 1, the second forming surface 30 and the first forming surface 10 cooperate to form a preform cavity. It should be noted that the bonding force between the upper laying layer 22 and the lower laying layer 21 after pre-pressing is greater than the contact force between the upper laying layer 22 and the second forming surface 30, ensuring that the upper laying layer 22 completely detaches from the transfer mold 3 after pre-pressing.

[0049] As shown in the attached Figure 2 figure, the lower surface of the upper mold assembly 4 is provided with a third forming surface 40. The third forming surface 40 is the same as the second forming surface 30, ensuring that the upper mold assembly 4 completely fits the upper surface of the preform layer 2. The upper mold assembly 4 is pressed on the lower mold 1, and the third forming surface 40 and the first forming surface 10 cooperate to form a forming cavity. The contour shape of the forming cavity completely fits the contour shape of the molded part 5, and a high-quality molded part 5 is molded.

[0050] During molding, first lay the lower laying layer 21 on the first forming surface 10, then lay the upper laying layer 22 on the second forming surface 30, and then press the transfer mold 3 on the lower mold 1. The second forming surface 30 and the first forming surface 10 cooperate to form a preform cavity, and the preform cavity squeezes the upper laying layer 22 and the lower laying layer 21 into a preform layer 2; then, remove the transfer mold 3, press the upper mold assembly 4 on the lower mold 1, and the third forming surface 40 and the first forming surface 10 cooperate to form a forming cavity. The forming cavity squeezes the preform layer 2 into the molded part 5. As shown in the attached Figure 4 and 5 figure, the contour shape of the molded part 5 fits the contour shape of the forming cavity.

[0051] Before the upper mold 41 and the lower mold 1 assembly of the present invention are molded, the upper ply 22 and the lower ply 21 are pre-compacted by means of the transfer mold 3 in advance, and the prefabricated ply 2 is prefabricated by an integral transfer method to ensure the quality of the complex surface of the prefabricated ply 2, and to avoid poor phenomena such as fiber wrinkling and deformation of the complex surface due to uneven pulling force during the molding stage, reduce the risk of quality problems of the molded part 5, and effectively improve the yield rate.

[0052] As a preferred embodiment, as shown in the appendix Figure 3 and 4 shown, the upper mold assembly 4 includes an upper mold 41 and a wedge-shaped pressing block 42. The lower surface of the upper mold 41 is provided with an extrusion inclined surface 411 and a third forming surface 40, and the extrusion inclined surface 411 and the third forming surface 40 are arranged at an angle. The side forming surface 421 of the wedge-shaped pressing block 42 is opposite to the bending surface 101 of the first forming surface 10, and the side forming surface 421 and the bending surface 101 extrude the bending flange 51 of the molded part 5. A mating inclined surface 422 is provided on the side of the wedge-shaped pressing block 42 away from the first forming surface 10, and the mating inclined surface 422 is in wedge-shaped cooperation with the extrusion inclined surface 411, so that the upper mold 41 applies a lateral force to the wedge-shaped pressing block 42, and the wedge-shaped pressing block 42 fully extrudes the prefabricated ply 2, and the quality of the bending flange 51 of the molded part 5 is higher, avoiding problems such as reduced resin deficiency or poor forming, and further improving the yield rate of the molded part 5.

[0053] Remove the transfer mold 3, first place the wedge-shaped pressing block 42 in the limiting groove 11 of the lower mold 1, and then press the upper mold 41 on the wedge-shaped pressing block 42 and the lower mold 1. The side forming surface 421 of the wedge-shaped pressing block 42 and the third forming surface 40 of the lower mold 1 jointly cooperate with the first forming surface 10 to form a forming cavity, and the prefabricated ply 2 is extruded into the molded part 5.

[0054] As a preferred embodiment, as shown in the appendix Figure 1 shown, one end of the lower mold 1 is provided with a limiting groove 11, and the wedge-shaped pressing block 42 is in concave-convex cooperation with the limiting groove 11 to accurately limit the installation position of the wedge-shaped pressing block 42 on the lower mold 1, which is convenient for quickly and accurately installing the wedge-shaped pressing block 42, and improving the forming quality and forming efficiency. Specifically, the two opposite sides of the wedge-shaped pressing block 42 are respectively abutted against the two end surfaces of the limiting groove 11 to limit the movement of the wedge-shaped pressing block 42 relative to the lower mold 1 along the width direction of the lower mold 1. The limiting groove 11 is specifically an L-shaped groove.

[0055] Furthermore, as shown in the appendix Figure 1As shown in the figure, a positioning protrusion and a positioning groove 111 that are fitted with each other are provided between the bottom of the wedge-shaped pressing block 42 and the bottom of the limit groove 11, which restricts the wedge-shaped pressing block 42 from moving relative to the lower mold 1 in the length direction of the lower mold 1, eliminates quality problems caused by the improper installation of the wedge-shaped pressing block 42, and is beneficial to further improving the yield rate of the molded part 5. Specifically, the positioning protrusion is a strip-shaped protrusion provided at the bottom of the limit groove 11, and the positioning groove 111 is a strip-shaped groove provided at the bottom of the wedge-shaped pressing block 42. The strip-shaped groove and the strip-shaped protrusion are in concave-convex fit. Of course, swapping the installation positions of the positioning protrusion and the positioning groove 111, or changing the shapes of the two does not affect the achievement of the purpose of the present invention.

[0056] As a preferred embodiment, as shown in the attached Figure 1 figure, a limiting post and a limiting groove 12 that cooperate with each other are provided between the upper mold 41 and the lower mold 1 to ensure the accurate mold closing of the upper mold 41 and the lower mold 1, and to prevent the upper mold 41 and the lower mold 1 from being misaligned during mold closing and affecting the mold closing quality. Specifically, the limiting groove 12 is a cylindrical groove provided at the outer edge of the lower mold 1, and the limiting post is a circular post provided along the outer edge of the upper mold 41. The circular post and the cylindrical groove are in concave-convex fit. Of course, swapping the installation positions of the limiting post and the limiting groove 12, or changing the shapes of the two does not affect the positioning purpose.

[0057] As a preferred embodiment, as shown in the attached Figure 3 figure, a positioning plane 423 is provided on the upper surface of the wedge-shaped pressing block 42, and a mating plane 412 is provided on the lower surface of the upper mold 41. The extrusion inclined surface 411 and the third forming surface 40 are connected through the mating plane 412; when the upper mold 41 is pressed on the lower mold 1, the positioning plane 423 abuts against the mating plane 412 to ensure full fit between the upper mold 41 and the wedge-shaped pressing block 42 and improve the quality of the molding by pressing.

[0058] Furthermore, as shown in the attached Figure 3 figure, a pressure relief groove 424 is provided on the positioning plane 423. When the wedge-shaped pressing block 42 and the upper mold 41 are closed, the excess exhaust gas is squeezed into the pressure relief groove 424, reducing the pressure between the wedge-shaped pressing block 42 and the upper mold 41, ensuring full fit between the wedge-shaped pressing block 42 and the upper mold 41, improving the assembly efficiency and assembly accuracy between the wedge-shaped pressing block 42 and the upper mold 41, and being beneficial to correspondingly improving the molding efficiency and molding quality.

[0059] As a preferred embodiment, as shown in the attached Figure 1As shown, a number of positioning posts 13 are fixedly arranged along the outer side of the first forming surface 10. A number of positioning holes 31 are provided at the outer edge of the transfer die 3. All the positioning posts 13 are in one-to-one correspondence and cooperation with all the positioning holes 31, which facilitates the quick and accurate disassembly and assembly of the transfer die 3 on the lower die 1, and ensures the accurate mold closing of the transfer die 3 and the lower die 1 during the pre-pressing stage, improving the forming quality of the prefabricated ply 2 and providing conditions for improving the forming quality of the subsequent molded part 5. The head of the positioning post 13 is provided with a tapered guide head, which facilitates the quick installation of the transfer die 3.

[0060] As a preferred embodiment, as shown in the appendix Figure 1 As shown, a number of lifting rings 6 are fixedly arranged on the outer sides of both the lower die 1 and the upper die 41, which facilitates the lifting equipment to lift the upper die 41 and the lower die 1 by means of the lifting rings 6, reducing the labor intensity and improving the mold closing efficiency.

[0061] The present invention also provides a molding method for composite materials, which is applied to the molding die for composite materials as described above. The steps include:

[0062] Lay the lower ply 21 on the first forming surface 10 of the lower die 1;

[0063] Lay the upper ply 22 on the second forming surface 30 of the transfer die 3;

[0064] Press the transfer die 3 onto the lower die 1. The second forming surface 30 and the first forming surface 10 cooperate to form a prefabricated mold cavity, and the prefabricated mold cavity extrudes the upper ply 22 and the lower ply 21 into a prefabricated ply 2

[0065] Remove the transfer die 3;

[0066] Press the upper die assembly 4 onto the lower die 1. The third forming surface 40 of the upper die assembly 4 and the first forming surface 10 cooperate to form a molding cavity, and the molding cavity extrudes the prefabricated ply 2 into a molded part 5. The contour shape of the molded part 5 coincides with the contour shape of the molding cavity.

[0067] The molding method for composite materials provided by the present invention and the technical solution of the molding die for composite materials are essentially the same, both of which improve the finished product rate by adding a transfer die 3.

[0068] It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0069] In this article, specific examples are used to illustrate the principles and implementation modes of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A compression molding die for a composite material, characterized in that, Comprising: Lower die (1), on the upper surface of the lower die (1) there is a first forming surface (10), and a lower laying layer (21) is laid on the first forming surface (10); Transfer die (3), on the lower surface of the transfer die (3) there is a second forming surface (30), and an upper laying layer (22) is laid on the second forming surface (30); the transfer die (3) is detachably arranged on the lower die (1); when the transfer die (3) presses on the lower die (1), the second forming surface (30) and the first forming surface (10) cooperate to form a prefabricated die cavity, and the prefabricated die cavity extrudes the upper laying layer (22) and the lower laying layer (21) into a prefabricated laying layer (2); Upper die assembly (4), on the lower surface of the upper die assembly (4) there is a third forming surface (40), and the third forming surface (40) is the same as the second forming surface (30); when the transfer die (3) is removed, the upper die assembly (4) presses on the lower die (1), the third forming surface (40) and the first forming surface (10) cooperate to form a forming die cavity, and the forming die cavity extrudes the prefabricated laying layer (2) into a molded part (5), and the contour shape of the molded part (5) coincides with the contour shape of the forming die cavity.

2. The compression molding die for the composite material according to claim 1, characterized in that, The upper die assembly (4) includes: Upper die (41), on the lower surface of the upper die (41) there is an extrusion inclined surface (411) and the third forming surface (40), and the extrusion inclined surface (411) and the third forming surface (40) are arranged at an angle; Wedge-shaped pressing block (42), the side forming surface (421) of the wedge-shaped pressing block (42) faces the bending type surface (101) of the first forming surface (10), and the side forming surface (421) and the bending type surface (101) extrude the bending flange (51) of the molded part (5); on the side of the wedge-shaped pressing block (42) away from the first forming surface (10) there is a mating inclined surface (422), and the mating inclined surface (422) is in wedge-shaped fit with the extrusion inclined surface (411).

3. The compression molding die for the composite material according to claim 2, characterized in that, One end of the lower die (1) is provided with a limit groove (11), and the wedge-shaped pressing block (42) is in concave-convex fit with the limit groove (11).

4. The compression molding die for the composite material according to claim 3, characterized in that, Between the bottom of the wedge-shaped pressing block (42) and the bottom of the limit groove (11) there are mutually engaged positioning protrusions and positioning grooves (111).

5. The compression molding die for the composite material according to claim 2, characterized in that, Between the upper die (41) and the lower die (1) there are mutually cooperating limit posts and limit grooves (12).

6. The compression molding die for the composite material according to claim 2, characterized in that, On the upper surface of the wedge-shaped pressing block (42) there is a positioning plane (423), on the lower surface of the upper die (41) there is a mating plane (412), and the extrusion inclined surface (411) and the third forming surface (40) are connected through the mating plane (412); when the upper die (41) presses on the lower die (1), the positioning plane (423) abuts against the mating plane (412).

7. The compression molding die for the composite material according to claim 6, characterized in that, The positioning plane (423) is provided with a pressure relief groove (424).

8. The compression molding die for the composite material according to any one of claims 1 to 5, characterized in that, A plurality of positioning columns (13) are fixedly arranged along the outer side of the first forming surface (10), and a plurality of positioning holes (31) are arranged on the outer edge of the transfer mold (3). All the positioning columns (13) are in one-to-one correspondence and cooperation with all the positioning holes (31).

9. The compression molding die for the composite material according to claim 2, characterized in that, A plurality of lifting rings (6) are fixedly arranged on the outer side surfaces of both the lower mold (1) and the upper mold (41).

10. A compression molding method for a composite material, characterized in that, A compression molding die for a composite material according to any one of claims 1 to 9, the steps comprising: Laying a lower ply on the first forming surface of the lower mold; Laying an upper ply on the second forming surface of the transfer mold; Pressing the transfer mold onto the lower mold, the second forming surface and the first forming surface cooperate to form a prefabricated mold cavity, and the prefabricated mold cavity extrudes the upper ply and the lower ply into a prefabricated ply; Removing the transfer mold; Pressing an upper mold assembly onto the lower mold, the third forming surface of the upper mold assembly and the first forming surface cooperate to form a forming mold cavity, and the forming mold cavity extrudes the prefabricated ply into a compression molded part, and the contour shape of the compression molded part coincides with the contour shape of the forming mold cavity.

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