Extruder head for synchronous production of multi-layer optical cable sheath, preparation method and application

Abstract

The invention belongs to the field of optical cable manufacturing, and particularly discloses an extruding machine head for synchronous production of multi-layer optical cable sheaths and a preparation method and application thereof.The extruding machine head comprises an extruding section and a stable section, an optical cable through hole is formed in the center of the extruding section and used for allowing a cable core to penetrate through, and at least two sheath runners are formed in the outer side of the optical cable through hole from inside to outside at intervals; same or different sheath materials are introduced into the cable cores, so that multiple layers of optical cable sheaths can be synchronously produced outside the cable cores; the stable section is connected with the outlet of the extrusion section, and an extension through hole is formed in the stable section and used for providing extension shaping for the optical cable coated with the multi-layer optical cable sheath, so that the smoothness of the outer surface of the optical cable is ensured. According to the invention, the stable section is arranged on the extruder head, so that extension molding can be provided for an optical cable coated with multiple layers of optical cable sheaths, and the problem of poor smoothness of the outer surface of the optical cable caused by different shrinkage properties of sheath materials is avoided, so that synchronous production of the multiple layers of optical cable sheaths is realized; and the production efficiency of the optical cable with the multi-layer optical cable sheath is effectively improved.

Description

Technical Field

[0001] The present application belongs to the field of optical cable manufacturing, and more specifically, to an extruder head for synchronous production of multi-layer optical cable sheaths, a preparation method and an application thereof. Background Art

[0002] At present, optical cables are usually produced with a single-layer extruder head for single-layer sheathing, but customers and actual application scenarios usually require optical cables covered with multiple layers of sheathing. For example, in Sichuan and Yunnan, rat infestation is rampant, so it is necessary to add rat-proof sheathing materials on the surface of the optical cable, but the rat-proof sheathing materials are not enough to provide the protection performance of the outermost layer of the optical cable, so traditional sheathing materials are generally required inside the rat-proof sheathing materials.

[0003] Considering the different shrinkage properties of each layer of sheath material, the existing technology usually adopts the method of coating the sheath material from the inside to the outside to ensure that each layer of sheath material shrinks sufficiently, thereby ensuring good performance of the outer surface. However, this production method has low production efficiency and cannot be applied industrially. At the same time, although the existing technology provides some multi-layer extruder heads, when applied to the production of optical cables, there is also the problem that the shrinkage properties of each material are different, resulting in an uneven outer surface of the product. In addition, considering that the external dimensions of the extruder head are fixed, designing multi-layer flow channels on this basis will result in thinner walls between the flow channels, greatly reducing the service life of the extruder head. In addition, the temperature of the materials in each flow channel in the extruder head is different, so it is necessary to select appropriate tube wall materials and processing technology to minimize the temperature impact between each flow channel. Summary of the invention

[0004] In view of the defects of the prior art, the present application provides an extruder head for the synchronous production of multi-layer optical cable sheaths, a preparation method and an application thereof, aiming to solve the problems of the existing synchronous production of multi-layer optical cable sheaths.

[0005] According to one aspect of the present application, an extruder head for synchronous production of multi-layer optical cable sheaths is provided, specifically comprising an extrusion section and a stable section, wherein the center of the extrusion section is provided with an optical cable through hole for passing a cable core, and at the same time, the extrusion section is provided with at least two sheath flow channels spaced from the inside to the outside around the outer side of the optical cable through hole, which are respectively used to introduce the same or different sheath materials to synchronously produce multi-layer optical cable sheaths on the outside of the cable core; the stable section is connected to the outlet of the extrusion section, and an extension through hole is provided inside the stable section for providing extension shaping for the optical cable coated with the multi-layer optical cable sheath to ensure a smooth outer surface of the optical cable.

[0006] Through the above technical scheme conceived by the present application, compared with the prior art, the present application can provide extension shaping for optical cables coated with multi-layer optical cable sheaths by arranging a stable section on the extruder head, thereby avoiding the problem of poor smoothness of the outer surface of the optical cable caused by different shrinkage properties of each layer of sheath materials, thereby realizing the synchronous production of multi-layer optical cable sheaths.

[0007] As further preferred, the length of the plateau section is determined according to the following formula:

[0008] Where L is the length of the stationary segment, P is the allowable pressure of the stable section, a is the number of each sheath flow channel, and the value is 1, 2, 3..., is the melt consistency of the sheath material in each sheath flow channel, is the non-Newtonian index of the sheath material in each sheath flow channel, R is the radius of the extended through hole, is the volume flow rate of each sheath flow channel, It is the proportion of the optical cable sheath formed by each sheath flow channel in the optical cable.

[0009] As further preferred, the diameter of the plateau section is 3.0 mm to 50.0 mm.

[0010] As a further preference, the width of one end of the sheath flow channel close to the stable section gradually decreases along the flow direction.

[0011] As a further preference, the minimum width of the sheath flow channel is 1.0 mm to 8.0 mm.

[0012] As further preferred, the number of the sheath flow channels is 2 to 4.

[0013] As a further preference, a water cooling mechanism is provided outside the stable section to accelerate cooling of the optical cable.

[0014] According to another aspect of the present application, a method for preparing the extruder head is provided, specifically, the method comprises: pouring molten metal into a mold to obtain a casting, and then sequentially annealing, quenching and tempering the casting to obtain the extruder head.

[0015] As further preferred, the preparation method further comprises machining the optical cable through hole, the sheath flow channel and the extension through hole of the extruder head to reduce their roughness.

[0016] According to yet another aspect of the present application, an extrusion device including the above extruder head is provided.

[0017] In general, the above technical solutions conceived by this application have the following technical advantages compared with the prior art: 1. This application can provide extension shaping for optical cables coated with multi-layer optical cable sheaths by setting a stable section on the extruder head, avoiding the problem of poor smoothness of the outer surface of the optical cable caused by different shrinkage properties of each layer of sheath materials, thereby realizing the synchronous production of multi-layer optical cable sheaths and effectively improving the production efficiency of optical cables with multi-layer optical cable sheaths; 2. In particular, the present application optimizes the method for determining the length of the stable section, taking into full account the performance parameters of each sheath material and the size parameters of the optical cable, thereby ensuring that each layer of sheath material shrinks evenly and further improving the smoothness of the outer surface of the optical cable; 3. In addition, the present application optimizes the preparation method of the extruder head, and adopts a casting combined with heat treatment method for production, so as to obtain an extruder head with a longer service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a cross-sectional view of an extruder head for synchronous production of multi-layer optical cable sheaths provided in an embodiment of the present application.

[0019] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-extrusion section, 11-optical cable through hole, 12-sheath flow channel, 2-stable section, 21-extension through hole. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] like Figure 1 As shown, according to one aspect of the present application, an extruder head for synchronous production of multi-layer optical cable sheaths is provided, specifically comprising an extrusion section 1 and a stable section 2. An optical cable through hole 11 is provided at the center of the extrusion section 1 for passing through a cable core; at the same time, the extrusion section 1 is provided with at least two sheath flow channels 12 spaced from the inside to the outside around the outer side of the optical cable through hole 11, which are respectively used to pass the same or different sheath materials, and the sheath materials are adhered around the cable core by extrusion, thereby synchronously producing a multi-layer optical cable sheath on the outside of the cable core; The stable section 2 is connected to the outlet of the extrusion section 1, and an extended through hole 21 is opened inside the stable section 2, so that the optical cable coated with the multi-layer optical cable sheath passes through the extended through hole 21 for extension shaping, thereby utilizing the limiting effect of the extended through hole 21 to ensure that each layer of sheath material avoids bubbling and other problems while shrinking, thereby ensuring the smooth outer surface of the optical cable and improving the production efficiency of the optical cable with the multi-layer optical cable sheath.

[0022] In actual production, the number of sheath flow channels 12 and the required sheath material can be determined as needed. Too many sheath flow channels 12 will result in an extruder head that is too large and cannot be used in existing production devices. It will also result in the wall thickness of each sheath flow channel in the extruder head being too thin, resulting in difficulty in forming or a short service life. Therefore, the number of sheath flow channels 12 is preferably 2 to 4.

[0023] In a preferred embodiment of the present application, the number of sheath flow channels 12 is two, and different sheath materials, namely PE-A and PE-B, are respectively passed through. In another preferred embodiment of the present application, the number of sheath flow channels 12 is three, the innermost layer and the outermost layer are passed through the same sheath material, namely PE-A, and the middle layer is passed through another sheath material, namely PE-B. In another preferred embodiment of the present application, the number of sheath flow channels 12 is three, and different sheath materials, namely PE-A, PE-B, and PE-C, are respectively passed through each layer.

[0024] More preferably, a water cooling mechanism is provided outside the stable section 2 for accelerating the cooling of the optical cable by forced water cooling, so that the optical cable can be stably formed in the stable section 2 and defects on the surface of the optical cable caused by later shrinkage can be avoided.

[0025] Furthermore, if the length of the plateau section 2 is too short, the sheaths of each layer of the optical cable will not shrink sufficiently, making the outer surface of the optical cable not smooth enough, while if the length of the plateau section 2 is too long, the equipment processing will be difficult, which is not conducive to industrial production and application. Therefore, the length of the plateau section 2 is determined according to the following formula:

[0026] Where L is the length of plateau 2, P is the allowable pressure of the stable section 2, a is the number of each sheath flow channel 12, which is determined by the number of sheath flow channels 12 in the extruder head and can be sequentially recorded as 1, 2, 3, etc. from the inside to the outside. is the melt consistency of the sheath material in each sheath flow channel 12, is the non-Newtonian index of the sheath material in each sheath flow channel 12, R is the radius of the extended through hole 21, is the volume flow rate of each jacket flow channel 12, It is the proportion of the optical cable sheath formed by each sheath flow channel 12 in the optical cable, that is, the thickness of each layer of the optical cable sheath / the radius of the optical cable.

[0027] The present application optimizes the method for determining the length of the plateau section 2, taking full account of the performance parameters of each sheath material and the size parameters of the manufactured optical cable, thereby ensuring uniform shrinkage of each layer of sheath material and further improving the smoothness of the outer surface of the optical cable.

[0028] Furthermore, the diameter of the stable section is 3.0 mm to 50.0 mm. The width of the sheath flow channel 12 at one end close to the stable section 2 gradually decreases along the flow direction, and the minimum width of the sheath flow channel is 1.0 mm to 8.0 mm, preferably 4.0 mm.

[0029] According to another aspect of the present application, a method for preparing the above-mentioned extruder head is provided, specifically: preparing a mold that matches the structure of the extruder head to be produced, then pouring molten metal into the mold to obtain a casting, and finally annealing, quenching and tempering the obtained casting in sequence to obtain the extruder head. Considering that there are a large number of sheath flow channels in the extruder head, the use of machining to prepare it will lead to increased costs due to high machining precision requirements. Therefore, the present application adopts a casting method to prepare a casting with a preset flow channel. At the same time, considering that the size of the extruder head has been controlled, setting up multi-layer flow channels will result in a thinner wall thickness between the flow channels. In order to increase the service life of the head, the obtained casting needs to be heat treated including annealing, quenching and tempering to increase the service life of the extruder head.

[0030] Furthermore, since each layer of the extruder head is sensitive to temperature, in order to ensure that it can withstand impact force and alternating stress at high temperature and minimize the temperature influence between each flow channel, 3Cr2W8V steel is preferably used to prepare the extruder head, so that the extruder head can work normally between 400℃ and 700℃, and can even work in an environment above 700℃. The specific heat treatment process is: the casting is subjected to three cycles of spheroidizing annealing, followed by rapid pre-cooling annealing, first quenching at 1060℃ for 20min, then quenching at 550℃ for 2h, and finally tempering at about 680℃ to obtain the extruder head.

[0031] Furthermore, considering that the optical cable through hole 11, the sheath flow channel 12 and the extended through hole 21 of the extruder head after heat treatment have a high roughness, the optical cable through hole 11, the sheath flow channel 12 and the extended through hole 21 can be processed by machining to reduce the roughness and ensure their smooth surface.

[0032] According to another aspect of the present application, an extrusion device including the above-mentioned extrusion head is provided. The extrusion head provided by the present application can replace the extrusion device in the prior art, and a corresponding number of sheath material supply components can be matched. The extrusion device can be used to realize the synchronous production of multi-layer optical cable sheaths.

[0033] In the description of the present application, it should be understood that, in the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically limited. In addition, references to "one embodiment" throughout this specification; "one embodiment", "one example" or similar language indicate that a particular feature, structure or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present application. Therefore, the phrase "in one embodiment;" appears throughout this specification, "in one embodiment" and similar language may but do not necessarily refer to the same embodiment.

[0034] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. Extruder head for synchronous production of multi-layer optical cable sheath, characterized in that: The invention comprises an extrusion section (1) and a stable section (2); the center of the extrusion section (1) is provided with an optical cable through hole (11) for passing a cable core; at the same time, the extrusion section (1) is provided with at least two sheath flow channels (12) spaced from the inside to the outside around the outer side of the optical cable through hole (11), respectively used for passing the same or different sheath materials to simultaneously produce a multi-layer optical cable sheath outside the cable core; the stable section (2) is connected to the outlet of the extrusion section (1); an extension through hole (21) is provided inside the stable section (2) for providing extension shaping for an optical cable coated with a multi-layer optical cable sheath, thereby ensuring a smooth outer surface of the optical cable.

2. The extruder head according to claim 1, characterized in that The length of the plateau (2) is determined according to the following formula: Where L is the length of the stationary segment, P is the allowable pressure of the stable section, a is the number of each sheath flow channel, and the value is 1, 2, 3..., is the melt consistency of the sheath material in each sheath flow channel, is the non-Newtonian index of the sheath material in each sheath flow channel, R is the radius of the extended through hole, is the volume flow rate of each sheath flow channel, It is the proportion of the optical cable sheath formed by each sheath flow channel in the optical cable.

3. The extruder head according to claim 1, characterized in that The diameter of the stable section (2) is 3.0 mm to 50.0 mm.

4. The extruder head according to claim 1, characterized in that The width of one end of the sheath flow channel (12) close to the stable section (2) gradually decreases along the flow direction.

5. The extruder head according to claim 4, characterized in that The minimum width of the sheath flow channel (12) is 1.0 mm to 8.0 mm.

6. The extruder head according to claim 1, characterized in that The number of the sheath flow channels (12) is 2 to 4.

7. The extruder head according to claim 1, characterized in that A water cooling mechanism is arranged outside the stable section (2) to accelerate the cooling of the optical cable.

8. The method for preparing an extruder head according to any one of claims 1 to 7, characterized in that: Specifically, the molten metal is poured into a mold to obtain a casting, and then the casting is sequentially annealed, quenched and tempered to obtain an extruder head.

9. The preparation method according to claim 8, characterized in that The preparation method further comprises machining the optical cable through hole (11), the sheath flow channel (12) and the extension through hole (21) of the extruder head to reduce their roughness.

10. An extrusion device comprising the extruder head according to any one of claims 1 to 7.

Images