TWI854638B - Knife mold for forming plastic containers - Google Patents

Abstract

The present invention provides a knife mold for forming plastic containers, including a male knife, a pressing part, and a female knife, wherein the male knife forms a circular first pressing part, the outer circumference of the first pressing part forms a first shear plane, the pressing part forms a circular second pressing part, the first pressing part and the second pressing part are axially opposite; the female knife is looped around the pressing part, and the inner part of the female knife forms a circular second shear plane, the first pressing part forms a circular convex part and a circular first plane facing the direction side of the second pressing part, and the convex part forms a circular surface facing the direction side of the second pressing part; the distance between the circular surface and the first shear plane is 0.05-0.5 mm, the distance between the first plane and the circular surface is 0.15-2.4 mm, and a plastic container that is less likely to cut fingers is formed accordingly.

Description

Die cutter for forming plastic containers

The present invention relates to a tool for forming a plastic container, and in particular to an innovative structural form revealer of a die for forming a plastic container.

The vacuum forming and blow molding technologies utilize the design of the cutter mold to form a sheet of plastic blank into a plastic container. The cutter mold used to form the blank includes a male cutter, a female cutter, and a pressing piece, wherein a mold cavity is formed inside the male cutter, and one end of the male cutter forms a ring-shaped first pressing portion. The mold cavity extends to one end of the male cutter to form the first pressing portion. The mold cavity is used to set a mold core. The shape and size of the mold core are matched with the plastic container to be formed in advance. The pressing piece and the male cutter are opposite to each other, and the pressing piece forms a channel relative to the mold cavity as a path for providing air to flow toward the mold cavity. The pressing piece forms a ring-shaped second pressing portion at one end facing the male cutter. The first pressing portion is provided with a mold core having a shape and size that matches the plastic container to be formed. The pressing piece and the male cutter are opposite to each other, and the pressing piece forms a channel relative to the mold cavity as a path for providing air to flow toward the mold cavity. The pressing piece forms a ring-shaped second pressing portion at one end facing the male cutter. The first pressing part and the second pressing part clamp the embryo sheet relative to each other, and the air is made to flow in the mold core and the channel, forcing the portion of the embryo sheet between the mold core and the channel to deform toward the inside of the mold core and to form a cup-shaped thin shell body against the inner side of the mold core. The portion of the embryo sheet clamped by the first pressing part and the second pressing part forms a lip integrally connected to the radial periphery of the thin shell body. The female knife surrounds the radial periphery of the pressed part, and the female knife and the male knife are respectively driven by the molding machine to move relative to each other in the axial direction. When the female knife and the male knife move relative to each other, a cutting effect is formed on the radial periphery of the lip, so that the lip and the embryo sheet are separated, thereby forming the container.

The air flows in the mold core and the channel. In the case of blow molding, it means providing compressed air to the interior of the mold core through the channel, compressing the embryo sheet to deform toward the interior of the mold core. In the case of vacuum molding, it means sucking the air inside the mold core to form a relative negative pressure inside the mold core, attracting the embryo sheet to deform toward the interior of the mold core.

The plastic container formed by the aforementioned die cutting method comprises a cup-shaped shell and a ring-shaped lip, wherein the interior of the shell forms a space for accommodating articles, the space extends upward to the top of the shell, and the top of the shell radially outwardly forms a thin sheet-shaped lip.

After investigation, it was found that the above-mentioned known knife mold still has the following problems and disadvantages in actual application experience: the female knife and the male knife act relatively to each other, and when cutting the radial periphery of the lip, the annular inner edge of the female knife and the annular outer edge of the male knife are displaced relative to each other, forming a shearing effect on the junction of the blank and the lip. During this process, the female knife and the radial periphery of the lip are in contact and relatively act, and relative friction is formed between the radial periphery of the lip and the female knife, so that the female knife can easily draw the radial periphery of the lip to deform in the relative action direction of the female knife, and the radial periphery of the lip forms a sharp edge that can easily cut the user.

The main purpose of the present invention is to provide a die cutter for molding plastic containers. The technical problem it aims to solve is to explore and innovate a new type of molding die cutter that is more ideal and practical.

Based on the above purpose, the technical features of the present invention to solve the problem are mainly that the die for forming the plastic container includes:

A male knife, a mold cavity is formed inside the male knife, an annular first pressing portion is formed at one end of the male knife, the mold cavity extends to the end of the male knife forming the first pressing portion, and the radial periphery of the first pressing portion forms an annular first shearing surface;

A pressing piece, the pressing piece and the male knife are axially opposite to each other, the pressing piece forms a channel relative to the mold cavity, the channel is connected to the mold cavity, an annular second pressing part is formed at one end of the pressing piece facing the male knife, and the first pressing part and the second pressing part are axially opposite to each other;

A mother knife surrounds the radial periphery of the pressed part, and the mother knife faces the inside of the pressed part to form an annular second shearing surface, and the first shearing surface and the second shearing surface are opposite to each other along the axial direction, and the first shearing surface and the second shearing surface are moved relative to each other to cut the blank for forming a plastic container, thereby forming the plastic container;

The first pressing part forms an annular convex part and an annular first plane on the side facing the second pressing part, the first shearing surface forms the radial periphery of the convex part, the convex part forms an annular annular surface along the radial direction of the first pressing part on the side facing the second pressing part, the distance between the radial inner edge of the annular surface and the first shearing surface is 0.05-0.5 mm, the first plane and The axial distance between the annular surfaces is 0.15-2.4 mm, and along the axial direction of the first pressing portion, the annular surface is located between the first plane and the second pressing portion, the radial inner edge of the protrusion forms an annular first mold surface, the radial cross-section of the first mold surface is arc-shaped, the radial inner side of the first mold surface is tangentially connected to the first plane, and the radial outer side of the first mold surface is connected to the annular surface.

The main effect and advantage of the present invention is that it can be used to form a plastic container with a lip portion having a radial periphery that is not easy to cut fingers.

Please refer to Figures 1 to 5, which are preferred embodiments of the knife die for molding plastic containers of the present invention. However, these embodiments are for illustrative purposes only and are not limited to this structure in patent applications.

The cutting die for forming a plastic container of the present invention is applied in a vacuum forming process or a blow molding process to form a blank 01 made of plastic into a plastic container 02.

The preferred embodiment of the present invention comprises a male knife 10, a pressed part 20 and a female knife 30, wherein a mold cavity 11 is formed inside the male knife 10, and a mold core 12 is arranged inside the mold cavity 11. The mold core 12 is used to define the external shape and size of the thin shell-shaped main body 60 of the plastic container 02, and the replaceable mold core 12 of corresponding size and shape can be selected to be arranged in the mold cavity 11 according to the size and shape requirements of the main body 60. An annular first pressing part 13 is formed at one end of the male knife 10, and the mold cavity 11 extends to one end of the male knife 10 to form the first pressing part 13, and the radial periphery of the first pressing part 13 forms an annular first shearing surface 14; the mold cavity 11 can choose not to be provided with the mold core 12, and the mold cavity 11 is used to form the main body 60.

The pressing part 20 and the male knife 10 are axially opposite to each other. The pressing part 20 forms a channel 21 relative to the mold cavity 11. The channel 21 is connected to the mold cavity 11. The pressing part 20 forms an annular second pressing part 22 at one end facing the male knife 10. The first pressing part 13 and the second pressing part 22 are axially opposite to each other. The blank 01 is formed by the channel 21, which forms a path for air to flow toward the mold cavity 11. The form of the channel 21 can be selectively replaced as needed, and such selective replacement is common knowledge familiar to those skilled in the art to which the present invention belongs. The shape of the channel 21 shown in the diagram and its relative configuration in the pressed part 20 are only a feasible example and cannot be used as a limitation to explain the present invention.

When used in a vacuum forming process, the air inside the mold core 12 is sucked to cause the embryo sheet 01 to deform toward the surface of the mold core 12. External air enters the channel 21 and flows toward the mold core 12 to prevent the embryo sheet 01 from forming a relative negative pressure on the side facing the pressed part 20, thereby affecting the forming of the embryo sheet 01.

When used in a blow molding process, external air enters the channel 21 and then exerts an extrusion effect on the embryo sheet 01 , causing the embryo sheet 01 to deform toward the surface of the mold core 12 .

The mother knife 30 surrounds the radial periphery of the pressed part 20, and the mother knife 30 forms an annular second shearing surface 31 facing the inside of the pressed part 20. The first shearing surface 14 and the second shearing surface 31 are opposite to each other along the axial direction, and the first shearing surface 14 and the second shearing surface 31 are moved relative to each other to cut the embryonic sheet 01, thereby forming the plastic container 02.

The first pressing portion 13 forms an annular convex portion 15 and an annular first plane 16 on the side facing the second pressing portion 22. The first shearing surface 14 forms the radial periphery of the convex portion 15. The convex portion 15 forms an annular annular surface 17 along the radial direction of the first pressing portion 13 on the side facing the second pressing portion 22. The distance between the radial inner edge of the annular surface 17 and the first shearing surface 14 is 0.05-0.5 mm, preferably 0.05-0.15 mm. The first plane The distance between the first die 16 and the annular surface 17 along the axial direction is 0.15-2.4 mm, wherein 0.15-2.4 mm is preferred. Along the axial direction of the first pressing portion 13, the annular surface 17 is located between the first plane 16 and the second pressing portion 22. The radial inner edge of the convex portion 15 forms an annular first die surface 18. The radial cross section of the first die surface 18 is in the shape of an arc. The radial inner side of the first die surface 18 is tangentially connected to the first plane 16, and the radial outer side of the first die surface 18 is connected to the annular surface 17.

In a preferred embodiment of the vacuum forming process or the blow molding process, when the plastic container 02 is formed, the embryo sheet 01 enters between the first pressing part 13 and the second pressing part 22, the male knife 10 and the pressing part 20 act relative to each other, and the first pressing part 13 and the second pressing part 22 clamp the embryo sheet 01 relative to each other. In the process of vacuum forming or blow molding the plastic container 02, the male knife 10 and the female knife 3 0 moves relative to each other along the axial direction, and the first shearing surface 14 and the second shearing surface 31 relatively shear the portion of the embryo 01 located outside the first pressing portion 13 and the second pressing portion 22 to complete the molding of the plastic container 02. The embryo 01 cooperates with the mold core 12 to form the main body 60, and the portion of the embryo 01 relatively clamped by the first pressing portion 13 and the second pressing portion 22 forms the lip 70 of the plastic container 02.

The plastic container 02 formed by the preferred embodiment includes a thin shell-shaped main body 60 and a ring-shaped lip 70, wherein a space 62 is formed inside the main body 60 for accommodating articles, and the space 62 extends upward to the top of the main body 60, and the top of the main body 60 radially outwardly forms the lip 70, and the radial outer periphery of the lip 70 forms a first annular surface 71 and a second annular surface 72, and the diameter of the first annular surface 71 is larger than that of the second annular surface 72. The diameter of the first annular surface 71 is equal to the diameter of the second annular surface 72, and the difference between the radius of the first annular surface 71 and the radius of the second annular surface 72 is 0.05-0.1 mm. A circular connecting surface 73 is formed between the first annular surface 71 and the second annular surface 72. The connecting surface 73 connects the bottom edge of the first annular surface 71 and the top edge of the second annular surface 72. The distance between the bottom edge of the first annular surface 71 and the bottom edge of the lip 70 along the axial direction of the lip 70 is 0.5 mm.

The first annular surface 71 and the second annular surface 72 are relatively configured in space, and the difference between the radius of the first annular surface 71 and the second annular surface 72 is 0.05-0.5 mm. The distance between the bottom edge of the first annular surface 71 and the bottom edge of the lip 70 along the axial direction of the lip 70 is 0.15-2.4 mm. When the user holds the plastic container 02 and grasps the radial periphery of the lip 70, the finger 90 not only contacts the first annular surface 71 and may contact the bottom edge of the lip 70, but the lip 70 is relatively soft to the touch. The soft fingertips of the finger 90 enable the finger 90 to contact the portion of the lip 70 between the second annular surface 72 and the bottom edge of the lip 70. The relative pressure formed by the weight of the object contained in the space 62 acting on the finger 90 will not be concentrated on the portion adjacent to the first annular surface 71 and the joint surface 73, but can be effectively dispersed, thereby reducing the relative force of the portion adjacent to the first annular surface 71 and the joint surface 73 on the finger 90, and the finger 90 is not easily cut by the portion adjacent to the first annular surface 71 and the joint surface 73.

The annular first shearing surface 14 and the annular second shearing surface 31 are staggered relative to each other. In the process of shearing the junction between the embryo sheet 01 and the lip 70, the second shearing surface 31 and the radial periphery of the lip 70 contact and form a relative action, and the radial periphery of the lip 70 and the second shearing surface 31 form a relative friction. Even though the second shearing surface 31 pulls the radial periphery of the lip 70 toward the relative friction of the second shearing surface 31, the second shearing surface 31 is not frictional. The actuating direction is deformed, but the relative structure of the first shearing surface 14, the first plane 16, the annular surface 17 and the first mold surface 18 is matched with the distance between the radial inner edge of the annular surface 17 and the first shearing surface 14 being 0.05-0.5 mm, the distance between the first plane 16 and the annular surface 17 along the axial direction being 0.15-2.4 mm, and the radial periphery of the lip 70 forming a space structure that is not easy to cut the finger 90.

The annular surface 17 is selected as a plane extending along the radial direction of the first pressing portion 13. The annular surface 17 can be selected to be replaced by a conical surface or other regular or irregular surfaces, thereby constituting a modified embodiment based on the modification of the preferred embodiment.

The radial periphery of the second pressing portion 22 cooperates with the second shear surface 31, and the second pressing portion 22 forms a conical second mold surface 23 and an annular second plane 24 on the side facing the first pressing portion 13. The radial periphery of the second mold surface 23 is connected to the radial periphery of the second pressing portion 22, and the diameter of the second mold surface 23 increases from the side of the second pressing portion 22 facing the first pressing portion 13 toward the direction away from the first pressing portion 13. The second plane 24 is connected to the radial inner periphery of the second mold surface 23, and the first plane 16 and the second plane 24 are opposite to each other along the axial direction.

The second mold surface 23 is formed so that a circular protrusion 76 is formed on the top edge of the lip 70 . The radial outside of the protrusion 76 is connected to the first circular surface 71 .

10: Male knife 11: Mold cavity 12: Mold core 13: First pressing part 14: First shearing surface 15: Protrusion 16: First plane 17: Annular surface 18: First mold surface 20: Pressed part 21: Channel 22: Second pressing part 23: Second mold surface 24: Second plane 30: Female knife 31: Second shearing surface 01: Blank 02: Plastic container 60: Main body 62: Space 70: Lip 71: First annular surface 72: Second annular surface 73: Joint surface 76: Convex hillock 90: Finger

FIG. 1 is a partial cross-sectional schematic diagram of a preferred embodiment of the present invention. FIG. 2 is a partial enlarged view of the first pressing portion and the second pressing portion shown in FIG. 1. FIG. 3 is a partial enlarged view of the sheared blank state of the preferred embodiment of the present invention. FIG. 4 is a partial enlarged view of the axial cross-section of a plastic container formed using the preferred embodiment of the present invention. FIG. 5 is a partial enlarged view of a finger touching the lip of a plastic container formed using the preferred embodiment of the present invention.

11: Mold cavity

13: First pressing part

14: First shear plane

15: convex part

16: First plane

17: Toroidal surface

18: First die surface

22: Second pressing part

23: Second mold surface

24: Second plane

31: Second shear plane

01: Embryo

70: Lips

Claims (2)

A knife die for molding plastic containers, comprising: a male knife, the interior of which forms a mold cavity, one end of which forms an annular first pressing portion, the mold cavity extends to one end of the male knife to form the first pressing portion, and the radial periphery of the first pressing portion forms an annular first shearing surface; a pressing part, the pressing part and the male knife are axially opposite to each other, the pressing part forms a channel relative to the mold cavity, the channel is connected to the mold cavity, the pressing part faces the male knife to form an annular second pressing portion, and the first pressing portion and the second pressing portion are axially opposite to each other; A mother knife surrounds the radial periphery of the pressed part, and the mother knife faces the inside of the pressed part to form an annular second shearing surface, and the first shearing surface and the second shearing surface are opposite to each other in the axial direction, and the first shearing surface and the second shearing surface are opposite to each other to cut the embryo sheet used to form a plastic container, thereby forming the plastic container; wherein the first pressing part forms an annular convex part and an annular first plane on the side facing the second pressing part, and the first shearing surface forms the radial periphery of the convex part, and the convex part forms an annular annular surface along the radial direction of the first pressing part on the side facing the second pressing part, and the distance between the radial inner edge of the annular surface and the first shearing surface is 0.05-0.5 mm, and the first plane and the The distance between the annular surfaces along the axial direction is 0.15-2.4 mm, and along the axial direction of the first pressing portion, the annular surface is located between the first plane and the second pressing portion, the radial inner edge of the convex portion forms an annular first mold surface, the radial cross section of the first mold surface is in the shape of an arc, the radial inner side of the first mold surface is tangentially connected to the first plane, and the radial outer side of the first mold surface is connected to the annular surface. A cutting die for molding plastic containers as described in claim 1, wherein the distance between the radial inner edge of the annular surface and the first shear surface is 0.05-0.15 mm, and the distance between the first plane and the annular surface along the axial direction is 0.3-2.3 mm.

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