阅读说明：本技术 聚四氟乙烯材料密封圈、环类密封元件及其制作方法 (Polytetrafluoroethylene material sealing ring, ring-shaped sealing element and manufacturing method thereof ) 是由 刘铭杰 张车宁 李文文 武明德 于 2019-10-18 设计创作，主要内容包括：本申请涉及聚四氟乙烯密封装置制备领域,具体而言,涉及一种聚四氟乙烯密封圈、环类密封元件及其制作方法。将聚四氟乙烯生料粉末压制成圆筒状毛坯；设置圆筒状毛坯的外径等于密封圈、环类密封元件的外径除以n,其中,n为大于1的奇数。按照预设的模型将圆筒状毛坯铣削加工成包括n圈首尾相连的折叠环的坯体,坯体的相邻两圈折叠环在高度方向有交叉且在径向上有重叠,以使坯体展开后能够变成一个完整的圈环。最后将坯体加温重定型后展开形成密封圈、环类密封元件。该制备方法,不需要大尺寸整体成型的设备,也不需要大体积的烧结炉,极大地降低了设备成本和占地面积,使得大直径聚四氟乙烯密封装置的制备方法简单可行。(The application relates to the field of preparation of polytetrafluoroethylene sealing devices, in particular to a polytetrafluoroethylene sealing ring, a ring-shaped sealing element and a manufacturing method thereof. Pressing polytetrafluoroethylene raw material powder into a cylindrical blank; and setting the outer diameter of the cylindrical blank to be equal to the outer diameter of the sealing ring and the annular sealing element divided by n, wherein n is an odd number larger than 1. Milling the cylindrical blank into a blank body comprising n circles of end-to-end folding rings according to a preset model, wherein two adjacent circles of folding rings of the blank body are crossed in the height direction and overlapped in the radial direction, so that the blank body can become a complete circle after being unfolded. Finally, the blank is heated and reshaped and then is unfolded to form a sealing ring and a ring-shaped sealing element. The preparation method does not need large-size integral molding equipment and a large-volume sintering furnace, greatly reduces the equipment cost and the occupied area, and ensures that the preparation method of the large-diameter polytetrafluoroethylene sealing device is simple and feasible.)

1. A method for manufacturing a polytetrafluoroethylene material sealing ring and a ring-shaped sealing element is characterized by comprising the following steps:

pressing polytetrafluoroethylene raw material powder into a cylindrical blank; setting the outer diameter of the cylindrical blank to be equal to the outer diameter of the sealing ring and the annular sealing element divided by n, wherein n is an odd number larger than 1;

milling the cylindrical blank into a blank body comprising n circles of end-to-end folding rings according to a preset path, wherein two adjacent circles of folding rings of the blank body are crossed in the height direction and overlapped in the radial direction, so that the blank body can become a complete circle after being unfolded;

and heating and reshaping the blank, and then unfolding the blank to form a sealing ring and a ring-shaped sealing element.

2. The method of manufacturing a polytetrafluoroethylene sealing ring or ring-like sealing member according to claim 1,

when the outer diameter of the cylindrical blank is set, adding a processing allowance on the basis of dividing the outer diameters of the sealing ring and the annular sealing element by n;

the processing allowance is 3 mm-5 mm.

3. The method of manufacturing a polytetrafluoroethylene sealing ring or ring-like sealing member according to claim 1,

the wall thickness of the cylindrical blank is equal to one half of the difference value between the outer diameter of the sealing ring and the annular sealing element and the inner diameter of the sealing ring and the annular sealing element, and then the wall thickness is enlarged by 3(n-1) times to 5(n-1) times.

4. The method of manufacturing a polytetrafluoroethylene sealing ring or ring-like sealing member according to claim 1,

the height of the cylindrical blank is equal to 3-5 n times of the height of the sealing ring and the ring-shaped sealing element, and then the machining allowance of 5-10 mm is added.

5. A method of manufacturing a polytetrafluoroethylene sealing ring or ring-like sealing member according to any one of claims 1 to 4,

the step of milling the cylindrical blank comprises:

and placing the cylindrical blank in the center of a working table of a machining center, fixing the cylindrical blank in the axial direction, and then milling the cylindrical blank by adopting a five-axis linkage machining mode.

6. The method of manufacturing a polytetrafluoroethylene sealing ring or ring-like sealing member according to claim 5,

the horizontal machining range of the machining center is greater than or equal to 110% of the diameter of the cylindrical blank, and the machining height of the machining center is greater than or equal to 110% of the height of the cylindrical blank.

7. A method of manufacturing a polytetrafluoroethylene sealing ring or ring-like sealing member according to any one of claims 1 to 4,

the step of milling the cylindrical blank according to a preset path comprises the following steps:

and constructing a three-dimensional model, generating a cutter walking path according to the three-dimensional model, and then milling the cylindrical blank according to the walking path.

8. A method of manufacturing a polytetrafluoroethylene sealing ring or ring-like sealing member according to any one of claims 1 to 4,

and (3) milling the cylindrical blank, and then trimming and cutting to separate the crossed bonding positions of the n circles of the folding rings in the height direction.

9. A method of manufacturing a polytetrafluoroethylene sealing ring or ring-like sealing member according to any one of claims 1 to 4,

the step of heating and reshaping the blank body and then unfolding the blank body to form a sealing ring and a ring-shaped sealing element comprises the following steps:

and heating the blank body, reshaping, keeping the temperature for 3-5 hours, and unfolding to form a sealing ring and a ring-shaped sealing element.

10. A polytetrafluoroethylene sealing ring or an annular sealing member obtained by the method for manufacturing a polytetrafluoroethylene sealing ring or an annular sealing member according to any one of claims 1 to 9,

the diameters of the sealing ring and the ring-shaped sealing element are 3-20 meters.

Technical Field

The application relates to the field of preparation of polytetrafluoroethylene sealing rings and ring-shaped sealing elements, in particular to a polytetrafluoroethylene sealing ring and ring-shaped sealing element and a manufacturing method thereof.

Background

In some large-volume equipment, such as shield tunneling machines, wind power, hydroelectric power, monocrystalline silicon reaction furnaces, coal chemical industry, large wind tunnels and other devices, a polytetrafluoroethylene material sealing ring and an annular sealing element with the diameter of 3-20 meters are required for sealing.

In the traditional method, a large-size integrally formed (non-welding) high polymer material product with the diameter of 3.0-20 m needs to be processed by a corresponding pressure forming machine, a heating reshaping oven, a shaping device and turning equipment. However, such bulky equipment is costly and occupies a large area.

Disclosure of Invention

An object of the embodiments of the present application is to provide a polytetrafluoroethylene sealing ring, an annular sealing element and a manufacturing method thereof, which aim to solve the problems of large-size equipment and high cost required in the preparation of the existing large-diameter polytetrafluoroethylene sealing ring and the annular sealing element.

In a first aspect, the present application provides a technical solution:

a manufacturing method of a polytetrafluoroethylene material sealing ring and a ring sealing element comprises the following steps:

pressing polytetrafluoroethylene raw material powder into a cylindrical blank; setting the outer diameter of the cylindrical blank equal to the outer diameter of the sealing ring and the annular sealing element divided by n, wherein n is an odd number greater than 1;

milling the cylindrical blank into a blank body comprising n circles of end-to-end folding rings according to a preset path, wherein two adjacent circles of folding rings of the blank body are crossed in the height direction and overlapped in the radial direction, so that the blank body can become a complete circle after being unfolded;

heating and reshaping the blank, and then unfolding to form a sealing ring and a ring-shaped sealing element.

The method comprises the steps of preparing a cylindrical blank, milling the cylindrical blank into a polytetrafluoroethylene material comprising n circles of folding rings, heating and reshaping the cylindrical blank into the polytetrafluoroethylene material, and then unfolding the polytetrafluoroethylene material into a sealing ring and a ring sealing element which are approximately n times of the diameter of the cylindrical blank, so as to obtain the large-diameter polytetrafluoroethylene sealing ring and the ring sealing element. The preparation method does not need large-size integral forming equipment and a large-volume heating heavy sizing furnace, greatly reduces the equipment cost and the occupied area, and ensures that the preparation method of the large-diameter polytetrafluoroethylene sealing ring and the ring sealing element is simple and feasible.

In other embodiments of the present application, when the outer diameter of the cylindrical blank is set, a machining allowance is added on the basis of dividing the outer diameter of the sealing ring and the ring-shaped sealing element by n;

the processing allowance is 3 mm-5 mm.

By setting the machining allowance, the required size can be better machined and adjusted.

In other embodiments of the present application, the wall thickness of the cylindrical blank is equal to one-half of the difference between the outer diameter of the seal ring and the ring-like seal member and the inner diameter of the seal ring and the ring-like seal member, and then is enlarged by a factor of 3(n-1) to 5 (n-1).

The wall thickness of the cylindrical blank is set within the range, so that the sufficient milling amount of the wall thickness direction of the sealing ring and the ring sealing element can be ensured, and the processing precision is improved.

In other embodiments of the present application, the height of the cylindrical blank is equal to 3n times to 5n times of the height of the sealing ring and the ring-shaped sealing element, and then a machining allowance of 5mm to 10mm is added.

The height of the cylindrical blank is set within the range, so that the sufficient milling amount in the height direction can be guaranteed, and the processing precision is improved.

In another embodiment of the present application, the milling of the cylindrical blank includes:

the cylindrical blank is placed in the center of a working table of a machining center, the cylindrical blank is axially fixed, and then the cylindrical blank is subjected to milling machining in a five-axis linkage machining mode.

The cylindrical blank is placed in the center of the working table surface of the machining center, so that the machining process is free from obstruction, the cutters in each sequence run according to a set path, and the cutter precisely reaches a specified position to be milled.

In another embodiment of the present application, the horizontal machining range of the machining center is 110% or more of the diameter of the cylindrical blank, and the machining height of the machining center is 110% or more of the height of the cylindrical blank.

By setting the horizontal machining range of the machining center to be greater than or equal to 110% of the diameter of the cylindrical blank and the machining height of the machining center to be greater than or equal to 110% of the diameter of the cylindrical blank, a sufficient machining space can be ensured, and further the milling machining can be performed orderly and stably.

In another embodiment of the present application, the step of milling the cylindrical blank according to a predetermined path includes:

and 3D software is adopted to construct a three-dimensional model, a cutter walking path is generated according to the three-dimensional model, and then the cylindrical blank is milled according to the walking path.

And a three-dimensional model is constructed, so that the operation of the cutter can be ensured to be completely matched with the material size of a designed product, and the accuracy is improved.

In other embodiments of the present application, the cylindrical blank is milled and trimmed and cut to separate the n-turn folded rings from the cross-bonded portion in the height direction.

And separating the bonding part to ensure that the n-circle folding ring forms a large circle after being unfolded.

In another embodiment of the present application, the step of expanding the milled cylindrical blank after heating and reshaping to form the sealing ring or the ring-like sealing element includes:

heating, reshaping, heating and reshaping the milled cylindrical blank, keeping the temperature for 3-5 hours, and unfolding to form a sealing ring and a ring sealing element.

Heating and reshaping to obtain the polytetrafluoroethylene product.

In a second aspect, the present application provides a technical solution:

a polytetrafluoroethylene sealing ring and ring sealing element is prepared by the method:

the diameters of the sealing ring and the annular sealing element are 3-20 meters.

The polytetrafluoroethylene sealing ring and the annular sealing element have large diameters, and can be applied to sealing of devices such as a shield machine, wind power, hydropower, a monocrystalline silicon reaction furnace, coal chemical industry, large wind tunnel and the like, wherein the diameters of the devices are 3-20 meters.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a flowchart of a method for manufacturing a polytetrafluoroethylene sealing ring or a ring-shaped sealing element according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of a cylindrical blank provided in an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a cylindrical blank including three folding rings according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a milled blank including n folded rings connected end to end according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of a sealing ring and a ring-shaped sealing element made of expanded large-diameter polytetrafluoroethylene material according to an embodiment of the present disclosure.

Detailed Description

The polytetrafluoroethylene material and the high polymer polytetrafluoroethylene filling modified material have excellent performance and wide application. The application temperature is-200-260 ℃, the glass does not melt at the high temperature of 375 ℃, and the glass does not crack and is anti-aging at the low temperature of-100 ℃. However, the special engineering plastics have poor high-temperature fluidity and do not have a molten state, so that the complex workpiece cannot be processed by adopting a casting method, an injection method and the like. In addition, the chemical properties of the materials are stable, the materials are not easy to be bonded or welded, and even if the surface is treated by a Nakail reagent, and similar methods such as hot-melt bonding are adopted, the strength of a welding point is greatly reduced, so that the physical properties of the product are influenced.

The inventor finds that under the natural temperature state, the polytetrafluoroethylene material has good flexibility and can be folded back to form a ring, and by utilizing the characteristic, the inventor selects an intelligent five-axis linkage machining center, firstly manufactures a digital model through three-dimensional forming modes of carving, milling, turning and drilling, generates machining data through a program, and then carefully selects functional cutters with multiple angles, so that various cutters move mutually according to program control to manufacture an integral sealing ring folded into a small diameter. And then trimming and cutting, heating at high temperature and shaping to expand the folded sealing ring to form an annular product with an oversized diameter, wherein the diameter of the annular product is three times or more than five times that of the original small annular ring. In this way, small equipment can be used for processing, and theoretically, the required processing equipment only needs 1/3 or 1/5 as the external dimension of the final product. Thus, the equipment cost and the occupied area can be greatly reduced.

Based on the above, the embodiment of the application provides a method for manufacturing a polytetrafluoroethylene sealing ring and an annular sealing element. Referring to fig. 1, the manufacturing method includes:

pressing polytetrafluoroethylene raw material powder into a cylindrical blank; setting the outer diameter of the cylindrical blank equal to the outer diameter of the sealing ring and the annular sealing element divided by n, wherein n is an odd number greater than 1;

milling the cylindrical blank into a blank body comprising n circles of end-to-end folding rings according to a preset path, wherein two adjacent circles of folding rings of the blank body are crossed in the height direction and overlapped in the radial direction, so that the blank body can become a complete circle after being unfolded;

heating and reshaping the blank, and then unfolding to form a sealing ring and a ring-shaped sealing element.

The method comprises the steps of preparing a cylindrical blank, milling the cylindrical blank into a polytetrafluoroethylene material comprising n circles of folding rings, heating and reshaping the cylindrical blank into the polytetrafluoroethylene material, and then unfolding the polytetrafluoroethylene material into a sealing ring and a ring sealing element which are approximately n times of the diameter of the cylindrical blank, so as to obtain the large-diameter polytetrafluoroethylene sealing ring and the ring sealing element. The preparation method does not need large-size integral forming equipment and a large-volume heating heavy sizing furnace, greatly reduces the equipment cost and the occupied area, and ensures that the preparation method of the large-diameter polytetrafluoroethylene sealing ring and the ring sealing element is simple and feasible.

The polytetrafluoroethylene material comprises polytetrafluoroethylene and a high-molecular polytetrafluoroethylene filling modification material.

In some embodiments of the present application, a method of making a polytetrafluoroethylene sealing ring, ring-type sealing element, comprises:

and step S1, pressing the polytetrafluoroethylene raw powder into a cylindrical blank.

By pressing the polytetrafluoroethylene raw powder into a cylindrical blank, a processing foundation is provided for subsequently milling the cylindrical blank into a plurality of sequentially-overlapped folding rings.

Furthermore, the polytetrafluoroethylene raw material powder is pressed into a cylindrical blank by adopting a die to press the polytetrafluoroethylene raw material powder.

Further optionally, the die for pressing the cylindrical blank comprises an outer sleeve, an inner sleeve, upper and lower pressing pads and a pressing sleeve. The cavity is formed by combination, polytetrafluoroethylene raw powder is uniformly distributed and filled into the cavity formed by combining the outer sleeve, the inner sleeve and the lower pressure pad or the upper pressure pad, and then the upper pressure pad or the lower pressure pad and the pressure sleeve are assembled in sequence. And finally, applying a certain pressure to the die by using a hydraulic press, and pressing to obtain a cylindrical blank.

Compared with a large-diameter sealing ring and a ring sealing element to be prepared, the outer diameter of the cylindrical blank obtained by pressing polytetrafluoroethylene raw powder is greatly reduced, so that a die with a smaller diameter can be used for pressing, and the die cost is greatly reduced.

The wall body of cylindric blank can be milled and include n circle folding ring, and processing is simple, and the feasibility is high.

And step S2, milling the cylindrical blank into a blank body comprising n circles of end-to-end folding rings according to a preset path, wherein two adjacent circles of folding rings of the blank body are crossed in the height direction and overlapped in the radial direction, so that the blank body can become a complete circle after being unfolded.

In other words, the cylindrical blank is milled to include n folding rings according to a preset path.

The cylindrical blank is milled into n-circle folding rings by preparing the cylindrical blank, so that the diameters of the sealing ring and the ring sealing element are reduced by n times during subsequent heating and reshaping. The cylindrical blank is adopted for heating and reshaping, large-volume heating and reshaping equipment is not needed, and the processing cost and the occupied area are greatly reduced.

Further, the outer diameter of the cylindrical blank is equal to the outer diameter of the sealing ring and the annular sealing element divided by n, wherein n is an odd number larger than 1. For example, n may be selected to be 3, 5 or 7.

By setting the outer diameter of the cylindrical blank equal to the outer diameter of the seal ring or the ring-shaped seal element divided by n, a large-diameter seal ring or ring-shaped seal element with a diameter n times can be manufactured.

Further, when the outer diameter of the cylindrical blank is set, a machining allowance is added to the outer diameter of the seal ring or the ring-like seal member divided by n.

By setting the machining allowance, the required size can be better machined and adjusted.

Further optionally, the processing allowance is 3mm to 5 mm.

Illustratively, the machining allowance can be selected to be 3mm, 4mm or 5 mm.

Further optionally, the processing allowance is selected to be 3.5-4.5 mm.

Further optionally, the processing allowance is selected to be 3.6-4.6 mm.

Within the above range, the accuracy of the processing can be ensured.

Further, the wall thickness of the cylindrical blank is equal to one half of the difference between the outer diameter of the sealing ring and the ring-shaped sealing element and the inner diameter of the sealing ring and the ring-shaped sealing element, and then the wall thickness is multiplied by 3(n-1) times to 5(n-1) times. Illustratively, the difference between the outer diameter of the seal ring, ring-like sealing element and the inner diameter of the seal ring, ring-like sealing element is multiplied by 3(n-1), 3.5(n-1), 4(n-1), 4.5(n-1), or 5 (n-1).

The wall thickness of the cylindrical blank is set within the range, and sufficient machining allowance can be provided, so that the milling amount in the wall thickness direction is guaranteed, and the machining accuracy is improved.

Further optionally, the difference between the outer diameter of the sealing ring and the annular sealing element and the inner diameter of the sealing ring and the annular sealing element is half, and then the difference is enlarged by 3.2(n-1) to 4.8(n-1) times.

Further optionally, the difference between the outer diameter of the sealing ring and the annular sealing element and the inner diameter of the sealing ring and the annular sealing element is half, and then the difference is enlarged by 3.5(n-1) to 4.5(n-1) times.

Illustratively, the wall thickness of the cylindrical blank is equal to one-half of the difference between the outer diameter of the seal ring, the ring-like sealing member and the inner diameter of the seal ring, the ring-like sealing member, and then expanded by a factor of 3.1 (n-1). When the outer diameter of the seal ring and the ring-shaped seal element is 10mm, the inner diameter of the seal ring and the ring-shaped seal element is 9mm, and n is 3, the wall thickness of the cylindrical blank is (10-9)/2 x 3.1 x (3-1) 3.1 mm.

Further, the height of the cylindrical blank is equal to 3n times to 5n times of the height of the sealing ring and the ring-shaped sealing element, and then a machining allowance of 5-10 mm is added.

Illustratively, the height of the cylindrical blank is equal to 3n times, 3.5n times, 4n times, 4.5n times or 5n times the height of the sealing ring, ring-like sealing element, to which a machining allowance of 5mm, 6mm, 7mm, 8mm, 9mm or 10mm is added.

The height of the cylindrical blank is set within the range, and sufficient machining allowance can be provided, so that the milling amount in the height direction is guaranteed, and the machining accuracy is improved.

Further optionally, the height of the cylindrical blank is equal to 3.2n times to 4.8n times of the height of the sealing ring and the ring-shaped sealing element, and then a machining allowance of 5.5mm to 9.5mm is added.

Further optionally, the height of the cylindrical blank is equal to 3.5n times to 4.5n times of the height of the sealing ring and the ring-shaped sealing element, and then a machining allowance of 5.6-9.6 mm is added.

Illustratively, the height of the cylindrical blank is equal to 3.6n times the height of the sealing ring, ring-like sealing element, plus a machining allowance of 5 mm. The height of the sealing ring and the ring-shaped sealing element is 3.3mm, n is equal to 3, and then the height of the cylindrical blank is 3.6 × 3.3+5mm, namely 40.64 mm.

Further, the step of milling the cylindrical blank comprises:

first, the outer diameter, wall thickness and height of the blank tube material used are accurately calculated according to the dimensions of the cylindrical blank given above.

Then, a three-dimensional model is constructed by adopting 3D software, a cutter walking path is generated according to the three-dimensional model, and then the cylindrical blank is milled according to the walking path.

Further alternatively, a three-dimensional model can be constructed by using 3D software such as solidworks. Then the program-controlled digital equipment transmitted into the processing center is converted into an execution statement, then a simulation cutter walking track demonstration diagram is carried out, verification, proofreading and verification are carried out, the fact that the program operation is completely matched with the material size of a designed product is ensured, and the accuracy of 100% is guaranteed.

And then, placing the cylindrical blank in the center of a worktable of a machining center, fixing the cylindrical blank in the axial direction of the cylindrical blank, and then milling the cylindrical blank by adopting a five-axis linkage machining mode.

The cylindrical blank is placed in the center of the working table surface of the machining center, so that the machining process is free from obstruction, the cutters in each sequence run according to the generated path, and the cutter precisely reaches the specified position to be milled.

Furthermore, the cylindrical blank can be fixed in the axial direction by selectively adopting a clamping and pressing mode, and pressure is applied to the axial direction of the cylindrical blank to fix the cylindrical blank on the worktable. Through fixing cylindric blank from the axial, can avoid cylindric blank to take place not hard up in milling process, guarantee that milling process goes on steadily.

Further, the horizontal machining range of the machining center is 110% or more of the diameter of the cylindrical blank, and the machining height of the machining center is 110% or more of the height of the cylindrical blank.

By setting the horizontal machining range of the machining center to be greater than or equal to 110% of the diameter of the cylindrical blank and the machining height of the machining center to be greater than or equal to 110% of the height of the cylindrical blank, a sufficient machining space can be ensured, and further the orderly and stable milling machining can be ensured.

Further alternatively, the machining center may be a five-axis numerical control machining center.

During machining, a cylindrical blank is placed in the center of a table top of a machining center of a five-axis numerical control machining center, a cutter is assembled, a program is input, the operation is started, the trial operation is slowly carried out, the observation is noticed, and the operation speed is gradually increased.

Further optionally, a rod-shaped multifunctional special-shaped forming five-axis linkage processing mode and a special-shaped forming five-axis linkage processing mode are adopted for a processing cutter during milling, and the shape of the cutter and the length of a cutter rod need to be elaborately and finely ground and are mutually fused with a design and editing program and practical operation.

It should be noted that, during milling, it is necessary to arrange the tool bit order reasonably, for example, a simple part is machined first, a complex part is machined later, a thin point is machined first, and a thick point is machined second.

Finally, the cylindrical blank is subjected to milling processing and then trimming and cutting so as to separate the crossed bonding positions of the n-turn folding rings in the height direction.

When the cylindrical blank is milled and processed into the folded rings with n circles, the folded rings at the intersecting positions in the height direction are still bonded together, at the moment, the bonded positions need to be separated, and the n circles of folded rings are enabled to form a complete large circle ring after being unfolded.

And step S3, heating and reshaping the blank obtained by milling, and then unfolding the blank to form a sealing ring and a ring-shaped sealing element.

The cylindrical blank after milling is heated and reshaped and then is unfolded to form the sealing ring and the ring-shaped sealing element, so that the volume of the heating and reshaping equipment is greatly reduced, and the cost is effectively saved.

Further, the step of expanding the milled cylindrical blank after heating and reshaping to form a sealing ring and a ring-shaped sealing element comprises the following steps:

heating and reshaping the milled cylindrical blank, preserving heat for 3-5 hours, and unfolding to form a sealing ring and a ring sealing element.

Illustratively, the milled cylindrical blank is heated and reshaped, and then is kept for 3 hours, 3.5 hours, 4 hours, 4.5 hours or 5 hours.

Further optionally, after the milled cylindrical blank is cured at a high temperature, heated and reshaped, the temperature is preserved for 3.5 to 4.5 hours, and the milled cylindrical blank is unfolded to form a sealing ring and a ring-shaped sealing element.

Further optionally, after the milled cylindrical blank is heated and reshaped, the cylindrical blank is insulated for 3.6 to 4.6 hours and is unfolded to form a sealing ring and a ring-shaped sealing element.

Further optionally, the temperature for heating the cylindrical blank after milling is selected to be over 380 ℃, and the temperature can be adaptively adjusted according to actual conditions. Illustratively, the warming temperature is selected to be 380 ℃, 390 ℃, or 400 ℃.

Furthermore, the folded sealing ring and the ring-shaped sealing element after being heated and reshaped are unfolded quickly when the temperature is high.

It should be noted that, in the process of unfolding, the force application needs to be uniform, and twisting cannot be performed.

Further, after the sealing ring and the ring-shaped sealing element are unfolded, the sealing ring and the ring-shaped sealing element are placed into a shaping tire mold for shaping treatment, and the natural cooling time is 16-24 hours.

Illustratively, the natural cooling time is 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, or 24 hours.

Further optionally, the natural cooling time is 17-23 hours.

Further optionally, the natural cooling time is 18-22 hours.

And further, after the final product is completely cooled and has stable shape, taking out the final product by using a mould, and thus completing the preparation of the large-diameter sealing ring and the ring-shaped sealing element.

Furthermore, when the shaping mould is selected, a metal annular mould matched with the size of the final product piece and a large-scale combined platform are manufactured according to the corresponding size of the final product piece.

In other alternative embodiments, a non-metallic platform may be selected.

The manufacturing method of the polytetrafluoroethylene material sealing ring and the ring-shaped sealing element solves the problem of manufacturing large-size high polymer material products by using small equipment. In particular, the bottleneck of large-scale sealing rings and ring-type sealing elements widely existing in the high-end equipment manufacturing industry and the large-scale equipment manufacturing industry is solved. The sealing device can be applied to the sealing of 3-20 m in devices such as shield machines, wind power, hydroelectric power, monocrystalline silicon reaction furnaces, coal chemical industry, large wind tunnels and the like. The technical problem that the large-diameter sealing and supporting assembly cannot be integrally machined at present is solved.

The method can greatly save cost, the traditional process can be adopted for early pressing, the process is simple, large-scale asset injection is not needed, and the milling process at the middle stage is novel and unique. The product processing cycle is short, the cost is recycled quickly, and the risk of bearing is low.

Some embodiments of the present application further provide a polytetrafluoroethylene sealing ring, a ring-like sealing element, the sealing ring, the ring-like sealing element having a diameter of 3-20 meters.

Illustratively, the sealing ring, ring-like sealing element has a diameter of 3 meters, 4 meters, 5 meters, 6 meters, 7 meters, 8 meters, 10 meters, 11 meters, 12 meters, 13 meters, 14 meters, 15 meters, 16 meters, 17 meters, 18 meters, 19 meters, or 20 meters.

Further optionally, the diameter of the sealing ring and the ring-shaped sealing element is 5-20 meters.

Further optionally, the diameter of the sealing ring and the ring-shaped sealing element is 8-20 meters.

Further optionally, the diameter of the sealing ring and the ring-shaped sealing element is 10-20 meters.

Furthermore, the sealing ring and the ring-shaped sealing element adopt the manufacturing method of the polytetrafluoroethylene sealing ring and the ring-shaped sealing element provided by the embodiment, and the manufacturing method is simple and feasible and has low cost.

A specific example is given below.

Referring to fig. 2-5, the illustrated embodiment provides a ptfe seal ring, ring-type seal element, made by:

the specifications of final sealing rings and ring sealing elements are as follows: outer diameter phi 10 m/inner diameter phi 9.92 m/height 0.03 m;

the cylindrical blank specification is then selected as: the outer diameter phi is 3.5 m/wall thickness 0.32 m/height 0.36 m. As shown in fig. 2.

1. And calculating the specification of the cylindrical blank.

(1) And calculating the outer diameter of the cylindrical blank:

the outer diameter of the sealing ring and the ring-shaped sealing element is divided by 3, for example, phi 10m/3 turns is phi 3.33 m. As shown in fig. 3.

(2) And calculating the wall thickness of the cylindrical blank:

the difference of the outer diameter and the inner diameter of the final product is divided by 2 to be equal to the wall thickness, the wall thickness is multiplied by 4 to be used as the reserved processing amount, and then the product is multiplied by the folding layer 2, and the product is the wall thickness of the blank tube material. I.e., (10-9.92)/2 × 4 ═ 0.32 m.

(3) Calculating the height dimension of the blank cylinder material: the height of the sealing ring and the ring-shaped sealing element is multiplied by 4 to obtain the reserved machining amount, and is multiplied by 3 circles, for example (the height is 0.03m multiplied by 4 to obtain the reserved machining amount multiplied by 3 circles), and the height dimension is equal to (0.36 m). 0.03 × 4 × 3 ═ 0.36 m. Then a processing reserve of 5mm is added, equal to 0.41 mm.

2. And (5) milling.

The method comprises the steps of constructing a three-dimensional model by using solidworks, then transferring the three-dimensional model into program-controlled digital equipment to be converted into an execution statement, then performing simulation of a tool walking track demonstration diagram, performing verification, correction and verification, ensuring that the sizes of program operation and designed product materials are completely matched with each other, and ensuring 100% accuracy.

The cutter position sequence is reasonably arranged, the simple part is machined firstly, the complex part is machined secondly, the thin point is machined firstly, and then the thick point is machined.

Placing and clamping blank tube materials on a workbench: the milling cutter is placed in the center of the working table, so that the placement is beneficial to the processing process without obstruction, and the milling cutter is milled in place according to program operation instructions. The clamping and pressing means that a blank barrel material is firmly clamped and compacted, and the phenomenon of looseness cannot occur in the machining process, so that the product workpiece can be stably milled until the milling is finished.

The five-axis numerical control machining center is used for machining products, placing blank barrel material workpieces, assembling cutters, inputting programs, starting to run, slowly trying, paying attention to observation, and gradually increasing the running speed.

The processed workpiece is trimmed and cut, so that the adhesion part of the folding ring is separated to form a folding 3 folding ring, and the protruding part of the folding 3 folding ring is smooth and easy to further trim and cut, so that the product part of the folding 3 folding ring is formed. A schematic illustration of a blank milled to include n turns of folded rings end to end is shown in fig. 4.

3. Heating, reshaping and unfolding.

According to the corresponding size of the final product part, a metal annular tire mold matched with the size of the final product part and a large-scale combined platform are manufactured.

And (3) putting the corrected and cut cylindrical blank into a high-temperature furnace to be heated at 400 ℃, setting the heat preservation time to be 5 hours, taking out the product after the process conditions are met, quickly unfolding the product at high temperature (paying attention to the fact that the product cannot be twisted), putting the product into a shaping tire mold, and carrying out shaping treatment, wherein the natural cooling time is 20 hours.

And after the final product is completely cooled and the shape is stable, taking out the final product by using a mould, and thus finishing. The expanded large-diameter fluororubber material sealing ring and ring-shaped sealing element is shown in fig. 5.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.