KR101555619B1 - Mold for flange pipe and molding method of flange pipe using the same - Google Patents

Abstract

The present invention relates to an isostatic press mold for a flange pipe and a method for molding a flange pipe using the same and, more specifically, to an isostatic press mold for a flange pipe and a method for molding a flange pipe using the same, which comprises: an external mold formed with a cylindrical cavity with opened both ends; an internal mold in a rod form arranged in the inner center of the external mold; an interval maintaining body in a ring form for maintaining an interval to form homocentricity of the external mold and the internal mold by being inserted in the upper and lower parts of the external mold, respectively; a cylindrical elastic body mold inserted inside the external mold, and formed with a length shorter than the length of the external mold; and an elasticity interval maintaining body for maintaining an interval to form homocentricity of the internal mold and the elastic body mold by being inserted in the lower part of the elastic body mold.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of forming a flange pipe,

More particularly, the present invention relates to an isostatic pressing mold for a flange pipe, and more particularly, to a method of forming a flange pipe by using an elastic body provided in a mold cavity to uniformly pressurize (vertically and horizontally) And a method of forming a flange pipe using the same. 2. Description of the Related Art

Generally, various parts such as various mechanical products, electronic products, and semiconductor products are being developed that can enhance durability, maintain electrical properties, and provide excellent heat resistance.

Particularly, special systems or equipment such as chemical fields and semiconductor manufacturing facilities use various kinds of pipes (pipes) in which various kinds of gases or fluids are guided or flowed, so that the pipes are subjected to the physical and chemical properties It should have good resistance.

Accordingly, piping used in the semiconductor and physicochemical fields is mainly made of polytetrafluoroethylene (hereinafter referred to as "PTFE"), and polytetrafluoroethylene has a melting point known as Teflon It is a crystalline polymer with a melting point of 327 ° C. It has heat resistance against long-term use at 260 ° C and stability at -196 ° C.

The chemical resistance of PTFE is the most excellent among the organic materials and does not infringe on acids, alkalis and various solvents at all, and has characteristics of non-adhesiveness, electrical insulation, non-adhesiveness, purity and flame retardancy.

Meanwhile, conventionally, a PTFE which is a Teflon material was molded into a tube or plate shape, and then a design shape was manufactured by machining such as milling or turning.

However, when a flange pipe is compression molded by a conventional PTFE forming method, a flange pipe is formed by a manufacturing process in which a crack is generated in a flange inner diameter portion and a cutting process is performed after forming on a cylindrical pipe. Therefore, the conventional flange pipe manufacturing process has a problem in that the cost is reduced because additional thickening and cutting air are required after forming the cylindrical pipe in a thick state and then cutting to the final dimension of the flange state.

An example of a technique for solving such a problem is disclosed in Document 1 below.

The following Patent Document 1 discloses a method for preparing polychlorotrifluoroethylene in powder form by drying the polychlorotrifluoroethylene at a temperature of 120 to 180 DEG C for about 2 to 4 hours to remove moisture and insoluble gas; Preparing a mold having a predetermined shape at a temperature of 350 to 380 占 폚 for 2 to 4 hours; Melting the raw material by sufficiently immersing the polychlorotrifluoroethylene powder in the preheated mold and keeping the temperature at 250 to 280 DEG C for 4 to 6 hours in an open state; Pressing the mold at a pressure of 100 to 200 tons for 20 to 40 minutes in a closed state in which the mold is closed; Adding a pressure of less than 100 tons to the mold for 20 to 40 minutes to solidify the mold; Treating the solidified polychlorotrifluoroethylene at a temperature of 180 to 230 ° C. for about 4 to 6 hours after the mold is removed; And a slow cooling step of spontaneously cooling the solidified polychlorotrifluoroethylene to a room temperature, and a method of molding polychlorotrifluoroethylene.

However, if the PTFE material is replaced with a PCTFE material only, it can not be replaced with a solid material because the temperature range of the PTFE material is different from that of the PCTFE material. The bubbles are included in the molding process, and if it is judged to be defective, it is impossible to regenerate, so that the economic loss is also very large. Therefore, there is a problem that economical efficiency is low and mass production is difficult.

Korean Registered Patent No. 10-0400274 (registered on September 20, 2003)

It is an object of the present invention to solve the above-mentioned problems, and it is an object of the present invention to provide an elastic body in a mold cavity to uniformly pressurize (pressurize) the upper and lower and circumferential directions in a preforming process, The present invention provides a method of forming a flange pipe for a flange pipe and a method for forming a flange pipe using the same, which effectively prevents a pipe from cracking and can manufacture a flange pipe by a molding process in which a cutting part is greatly reduced in a cutting process by a simple mold and apparatus have.

In order to achieve the above object, the present invention provides an isostatic press forming die for a flange pipe, comprising: an outer mold having a cylindrical cavity with both open ends; A rod-shaped inner mold disposed at an inner center of the outer mold; A ring-shaped spacing member inserted in the upper and lower portions of the outer mold to maintain a spacing so that the outer and inner dies are concentric with each other; A cylindrical elastic metal mold inserted into the outer mold and formed to have a length smaller than the length of the outer mold; And an elastic gap retainer inserted into a lower portion of the elastic metal mold to maintain a gap so that the inner mold and the elastic metal mold are concentric with each other.

According to another aspect of the present invention, there is provided a flange pipe forming method including: preparing a mold for forming an isostatic valve for a flange pipe; A compression molding step of filling a polytetrafluoroethylene (PTFE) powder into the cavity of the isostatic pressure forming mold and applying a pressure of 130 to 250 kg / cm 2 to the powder to form a flange pipe molded product corresponding to the cavity of the isostatic pressure forming mold; ; A releasing step of separating the compression-molded article from an isostatic pressing die; A heat treatment step of placing the separated molded article in an electric furnace and heating the molded article at a temperature of 360 to 380 ° C for a predetermined time; A cooling step of cooling the heat-treated molded article to room temperature; And a cutting step of cutting the cooled molded article to a final size.

As described above, according to the iso-pressure forming mold for a flange pipe and the method for forming a flange pipe using the same according to the present invention, an elastic body is provided in the mold cavity, uniform pressure (equal pressure) acts in the upper and lower and circumferential directions, The preformed part of the flange shape can be formed without cracking and the manufacturing part can be manufactured by cutting the cutting part drastically in the cutting process by simple mold and device, thereby improving the productivity by reducing the investment cost of the manufacturing facility, improving the workability and reducing the material cost. .

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view schematically showing an isostatic pressing die for a flange pipe according to the present invention; Fig.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a flange pipe.
3 is a perspective view showing a flange pipe formed by an isostatic forming die for a flange pipe according to the present invention.
4 is a process diagram showing a method of forming a flange pipe according to the present invention.

An iso-pressure forming mold for a flange pipe according to the present invention includes: an outer mold having a cylindrical cavity with both ends opened; A rod-shaped inner mold disposed at an inner center of the outer mold; A ring-shaped spacing member inserted in the upper and lower portions of the outer mold to maintain a spacing so that the outer and inner dies are concentric with each other; A cylindrical elastic metal mold inserted into the outer mold and formed to have a length smaller than the length of the outer mold; And an elastic gap retainer inserted into a lower portion of the elastic metal mold to maintain a gap so that the inner mold and the elastic metal mold are concentric with each other.

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Further, the elastic metal mold and the elastic gap retainer are made of a urethane material, and the Shore A hardness of the elastic metal mold is 50 to 95, and the Shore A hardness of the elastic space retainer is 30 to 80. [

Further, a round is formed in an inner upper corner portion of the elastic metal mold with a radius of 5 to 10 mm.

According to another aspect of the present invention, there is provided a flange pipe forming method including: preparing a mold for forming an isostatic valve for a flange pipe; A compression molding step of filling a polytetrafluoroethylene (PTFE) powder into the cavity of the isostatic pressure forming mold and applying a pressure of 130 to 250 kg / cm 2 to the powder to form a flange pipe molded product corresponding to the cavity of the isostatic pressure forming mold; ; A releasing step of separating the compression-molded article from an isostatic pressing die; A heat treatment step of placing the separated molded article in an electric furnace and heating the molded article at a temperature of 360 to 380 ° C for a predetermined time; A cooling step of cooling the heat-treated molded article to room temperature; And a cutting step of cutting the cooled molded article to a final size.

In the compression molding step, the pressure holding time by the compression molding machine is 5 minutes. While maintaining the pressure by the compression molding machine, the lower punch is raised and maintained for 1 minute, and then the lower punch is lowered and the upper punch is gradually raised The mold pressure inside the mold is removed, and the molding pressure for pressing the upper portion to the upper portion is the same as the pressure applied from the upper portion to the lower portion. The molding space temperature of the mold during molding of the flange pipe molded product is maintained at 28 to 30 ° C, And the temperature of the ethylene (PTFE) powder raw material is maintained at 29 to 33 占 폚.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of an isostatic pressing die for a flange pipe according to the present invention will be described with reference to the accompanying drawings.

2 is a cross-sectional view schematically showing a process of compressing an isostatic pressing metal mold for a flange pipe according to the present invention by a compression molding machine, and Fig. 2 is a cross- 3 is a perspective view showing a flange pipe formed by an isostatic forming die for a flange pipe according to the present invention.

1 to 3, the iso-pressure forming mold for a flange pipe according to the present invention includes an outer mold 1, an inner mold 2, a spacer 3, an elastic metal mold 4, (5).

The outer mold 1 is preferably made of carbon steel or other metal having similar properties, and a cylindrical cavity 11 having both open ends is formed.

The inner mold 2 is preferably made of carbon steel or other metal having similar properties, and is disposed in the center of the inner portion of the outer mold 1 as a rod.

Particularly, the outer mold 1 is located outside the inner mold 2 for forming the flange pipe 6, and forms a space between the outer mold 1 and the inner mold 2 to form the thickness of the flange pipe 6 .

The cavity holding member 3 is preferably made of carbon steel or other metal having similar properties and is inserted into the upper and lower portions of the outer mold 1 as a ring shape so that the outer mold 1 and the inner mold 2 Keep spacing to be concentric.

The elastic metal mold 4 has a cylindrical shape and is inserted into the outer mold 1 and has a length smaller than the length of the outer mold 1. [

The elastic metal mold 4 is disposed between the outer mold 1 and the powder so that a uniform pressure (equal pressure) acts on the upper and lower circumferential and circumferential directions to make the formed structure compact and the flanged preform can be compression- It is.

The elastic metal mold 4 is made of a urethane material and the shore A hardness of the elastic metal mold 4 is preferably 50 to 95. [ If the Shore A hardness of the elastic metal mold 4 is less than 50, the tensile strength is low and the durability is low, which makes it difficult to use for a long period of time.

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Meanwhile, it is preferable that a round is formed at an inner upper corner of the elastic metal mold 4 with a radius of 5 to 10 mm. If the radius of the elastic metal mold 4 is less than 5 mm, the stress is concentrated on the flange edge portion of the preliminarily molded product to affect the crack. If the radius exceeds 10 mm, the thickness of the resin mold becomes thick, The flange is bent.

The elastic space retaining member 5 is inserted into the lower portion of the elastic metal mold 4 to maintain the gap so that the inner mold 2 and the elastic metal mold 4 are concentric with each other.

It is preferable that the elastic space retainer 5 is made of a urethane material and the Shore A hardness of the elastic space retainer 5 is 30 to 80. [

If the Shore A hardness of the elastic space retainer 5 is less than 30, the tensile strength is low and durability is low, which makes it difficult to use for a long period of time. If the Shore A hardness exceeds 80, So that the outer diameter of the preliminarily molded article becomes large, and a crack is generated during the release.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the flange pipe forming method according to the present invention will be described with reference to the accompanying drawings.

The flange pipe forming method of the present invention includes a mold preparing step S100, a compression molding step S200, a mold releasing step S300, a heat treatment step S400, , A cooling step (S500), and a cutting step (S600).

First, in the mold preparing step S100, an outer mold 1 in which a cylindrical cavity 11 having both ends opened is formed, and a rod-shaped inner mold 2 disposed in the center of the inner surface of the outer mold 1, A ring-shaped gap holding member 3 inserted in the upper and lower portions of the outer mold 1 to keep the gap so that the outer mold 1 and the inner mold 2 are concentric with each other, And an elastic metal mold 4 inserted into the lower portion of the elastic metal mold 4 and inserted into the inner mold 2 and the elastic metal mold 4 And an elastic space retaining member 5 for retaining an interval so as to form concentric circles.

Further, a compression molding machine 7 is prepared together with the above-mentioned isobar forming mold for a flange pipe. The compression molding machine 7 is preferably constituted by a vertical reciprocating hydraulic cylinder and includes a fixing plate 71, an upper punch 72 and a lower punch 73.

An outer mold 1, an inner mold 2 and a lower space-holding member 3 are placed on the upper surface of the fixing plate 71 and an elastic metal mold 4 and an elastic space retainer 5 ). At this time, the bottom of the lower space-holding member 3 is aligned on the upper portion of the lower punch 73 provided on the fixing plate 71, and the mold preparation operation is completed.

In the compression molding step S200, polytetrafluoroethylene (PTFE) powder is filled in the cavity of the isostatic pressing mold, and a pressure of 130 to 250 kg / cm2 is applied to the powder to form a flange pipe corresponding to the cavity of the isostatic- Thereby molding the molded article.

When filling the polytetrafluoroethylene powder into the cavity 11 of the outer mold 1 mounted on the upper portion of the fixing plate 71 of the compression molding machine 7, the upper space-holding member 3 is closed, The upper punch 72 of the compression molding machine 7 is lowered and a pressure of 130 to 250 kg / cm2 is applied to the polytetrafluoroethylene powder of the isostatic pressing die.

If the pressure applied to the powder is less than 130 kg / cm 2, the density of the pre-molded article may be lowered and space may be left in the molded article. If the pressure exceeds 250 kg / cm 2, the molded article may be cracked with excessive pressure.

On the other hand, in the compression molding step, the pressure holding time by the compression molding machine is 5 minutes. While maintaining the pressure by the compression molding machine, the lower punch is elevated and maintained for 1 minute. Then, the lower punch is lowered and the upper punch is gradually raised It is preferable that the pressure inside the mold is removed, and the molding pressure for pressing the upper portion from the lower portion is equal to the pressure applied from the upper portion to the lower portion.

It is preferable that the working space temperature of the mold during molding of the flange pipe molded product is maintained at 28 to 30 ° C and the temperature of the polytetrafluoroethylene (PTFE) powder raw material is maintained at 29 to 33 ° C. This is because cracks are generated even at the temperature difference between the raw materials of the powder, so that raw materials at the same temperature should be introduced through the raw material during molding while maintaining the proper temperature.

When the upper punch 72 is lifted, the pressure inside the mold is removed, so that the elastic metal mold 4 is shrunk, and the preliminarily molded product is attached to the additional equipment Can easily be released without.

In the heat treatment step (S400), the separated molded product is placed in an electric furnace and heated at a temperature of 360 to 380 ° C for 4 to 6 hours, preferably at a high temperature of 375 ° C, and the heating time varies depending on the volume, You can change as many as you like.

In the cooling step (S500), the heat-treated molded article is cooled to room temperature, and the flange pipe (6) is taken out from the electric furnace and cooled by air cooling or water cooling.

In the cutting step (S600), the cooled molded product is cut to final dimensions, and the cooled molded product is finished to be a flanged pipe part having an accurate dimension through milling, lathe machining, or the like.

As described above, the isostatic pressing mold for a flange pipe and the method for forming a flange pipe using the same according to the present invention are characterized in that an elastic metal mold 4 is disposed between an outer mold 1 and a cavity 11 to form uniform pressure Uniform pressure) acts to compact the formed structure and form the preliminarily molded flange-shaped article without cracking.

In addition, since a cutting tool can be manufactured with a simple mold and an apparatus in a cutting process, the investment cost can be reduced, the workability can be improved, and the material cost can be reduced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many obvious changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention should therefore be construed in light of the claims set forth to cover many of such variations.

1: Outside mold
11: Cavity
2: Inner mold
3:
4: Elastic mold
5: elastic spacer
6: Flange pipe
7: Compression molding machine
71: Fixed plate
72: upper punch
73: Lower punch

Claims (6)

An outer mold 1 in which a cylindrical cavity 11 having open ends is formed;
An inner mold 2 in the form of a rod disposed at the center of the inner portion of the outer mold 1;
A ring-shaped spacing member 3 inserted in the upper and lower portions of the outer mold 1 to maintain a gap so that the outer mold 1 and the inner mold 2 are concentric with each other;
A cylindrical elastic metal mold 4 inserted into the outer mold 1 and formed to have a length smaller than the length of the outer mold 1;
And an elastic gap retainer (5) inserted in a lower portion of the elastic metal mold (4) to maintain a gap so that the inner mold (2) and the elastic metal mold (4) are concentric with each other. mold.
delete The elastic distance holding body (5) according to claim 1, wherein the elastic metal mold (4) and the elastic gap retaining body (5) are made of a urethane material, the shore A hardness of the elastic metal mold (4) is 50 to 95, Wherein the shore A hardness of the shore A is in the range of 30 to 80.
delete A mold preparing step of preparing an isostatic shaping mold for a flange pipe according to claim 1;
A compression molding step of filling a polytetrafluoroethylene (PTFE) powder into the cavity of the isostatic pressure forming mold and applying a pressure of 130 to 250 kg / cm 2 to the powder to form a flange pipe molded product corresponding to the cavity of the isostatic pressure forming mold; ;
A releasing step of separating the compression-molded article from an isostatic pressing die;
A heat treatment step of placing the separated molded article in an electric furnace and heating the molded article at a temperature of 360 to 380 ° C for a predetermined time;
A cooling step of cooling the heat-treated molded article to room temperature;
And a cutting step of cutting the cooled molded product to final dimensions.
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