Bonded neodymium iron boron flexible strip extrusion die

Abstract

An injection part and an extrusion part are matched to form an extrusion cavity, a drainage section, a compression section, a transition section and a straight section are formed in the extrusion cavity in the flowing direction, the drainage section is distributed in a horn mouth shape, and the compression section and the transition section are distributed in a conical shape. The taper angle of the compression section is larger than that of the transition section, the straight section is horizontally distributed in an equal-diameter mode, extruded materials flow into the drainage section in a loose state, the compression section can convert the extruded materials into a dense state from the loose state, the extrusion pressure is increased to the peak value, and the transition section can conduct pressure and flowing transition adjustment on the extruded materials. And the extrusion pressure can be preliminarily reduced, the straight section can convert the extrusion material from a compact state to a forming state and then extrude the extrusion material, and the extrusion pressure is reduced to the outlet pressure along the flowing direction, so that the extrusion pressure in the mold is reduced, the extrusion speed and the production efficiency are improved, and meanwhile, the forming quality of the bonded neodymium iron boron flexible strip is ensured.

Description

Technical Field

[0001] This invention relates to the field of molding die technology, specifically to an extrusion die for bonding NdFeB flexible strip. Background Technology

[0002] Bonded NdFeB flexible tapes are composed of an elastomer substrate (TPU, TPE, etc.) and NdFeB magnetic powder composite material, and are typically manufactured by extrusion through an extrusion die. Chinese Patent No. CN201189714Y discloses a bonding NdFeB magnet extrusion molding die, comprising a main body with a main channel open at one end, a preformed body with a pre-die cavity located close to one side of the main body, the pre-die being placed in the pre-die cavity, and a main forming body with a main die cavity located close to one side of the preformed body, the main die being placed in the main die cavity. The inner hole of the pre-die is conical, and the material is extruded through the pre-die.

[0003] However, existing extrusion dies suffer from problems such as high extrusion pressure and uneven material output from the die, resulting in slow extrusion speed, low efficiency, and negatively impacting the forming quality of bonded NdFeB flexible strips.

[0004] Therefore, how to effectively reduce the extrusion pressure in the mold, improve the extrusion speed and production efficiency, and ensure the molding quality of bonded NdFeB flexible strips has become an urgent problem to be solved in this field. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide an extrusion die for bonded NdFeB flexible strip, which reduces the extrusion pressure in the die, improves the extrusion speed and production efficiency, and ensures the forming quality of bonded NdFeB flexible strip.

[0006] To achieve the above objectives, the present invention provides an extrusion die for bonded NdFeB flexible strip, comprising an injection section and an extrusion section. The injection section and the extrusion section cooperate to form continuously distributed extrusion cavities. Each extrusion cavity has a guiding section, a compression section, a transition section, and a straight section along the flow direction of the extruded material. The guiding section is funnel-shaped, the compression section and the transition section are conical, and the conical angle of the compression section is greater than that of the transition section. The straight sections are horizontally distributed with equal diameters. The extruded material flows into the guiding section in a loose state. The guiding section guides the extruded material. The compression section changes the extruded material from a loose state to a compact state and increases the extrusion pressure to a peak value. The transition section adjusts the pressure and flow of the extruded material and initially reduces the extrusion pressure. The straight section changes the extruded material from a compact state to a shaped state before extrusion and reduces the extrusion pressure along the flow direction to the outlet pressure. The injection section and the extrusion section are respectively equipped with a heating device and a temperature measuring device, which can perform zoned temperature control of the extrusion cavity.

[0007] Furthermore, the extrusion section includes a first extrusion section and a second extrusion section, the first extrusion section includes a first housing and a first neutron built into the first housing, the second extrusion section includes a second housing and a second neutron built into the second housing, and the injection section includes a third housing.

[0008] Furthermore, the first housing end is provided with an extrusion port, the third housing end is provided with an injection port, and the extrusion cavity is continuously distributed along the injection port to the extrusion port.

[0009] Furthermore, a heat insulation plate is provided between the first extrusion section and the second extrusion section.

[0010] Furthermore, the heat insulation plate is provided with through holes connecting the transition section and the compression section.

[0011] Furthermore, the heating devices are distributed around the first housing, the second housing, and the third housing, respectively.

[0012] Furthermore, the heating device maintains a decreasing temperature gradient along the flow direction from the diversion section, compression section, transition section to the straight section.

[0013] Furthermore, the temperature measuring device extends into the first housing, the second housing, and the third housing, respectively.

[0014] Furthermore, along the flow direction, the lengths of the diversion section, compression section, transition section, and straight section decrease sequentially.

[0015] Furthermore, the diameter of the compression section is smaller than that of the drainage section, and the cross-section of the compression section gradually decreases from the drainage section to the transition section.

[0016] The bonding NdFeB flexible strip extrusion die provided by this invention forms a flow guide section, a compression section, a transition section, and a straight section in the extrusion cavity along the flow direction of the extruded material. This allows each section to work together to ensure stable flow and compression molding of the extruded material. It can also gradually reduce the extrusion pressure in the die, thereby improving the extrusion speed and production efficiency, while ensuring the molding quality of the bonding NdFeB flexible strip.

[0017] Furthermore, the heating and temperature measuring devices can perform zoned temperature control of the extrusion cavity, allowing for independent temperature adjustment of each section, thereby further improving the forming quality of the bonded NdFeB flexible strip. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] Figure 1A cross-sectional schematic diagram of the extrusion die for bonding NdFeB flexible strip provided by the present invention; Figure 2 A side view schematic diagram of the extrusion die for bonding NdFeB flexible strip provided by the present invention; Figure 3 This is a schematic diagram of the extrusion cavity in this invention; Figure 4 This is a schematic diagram of the in-mold pressure of each section of the extrusion cavity in this invention.

[0020] 1. Injection section; 11. Injection port; 12. Third housing; 2. Extrusion section; 21. Extrusion port; 22. First extrusion section; 221. First housing; 222. First neutron; 23. Second extrusion section; 231. Second housing; 232. Second neutron; 3. Extrusion cavity; 31. Drainage section; 32. Compression section; 33. Transition section; 34. Straight section; 4. Heating device; 41. First annular heater; 42. Second annular heater; 43. Third annular heater; 5. Temperature measuring device; 51. First temperature measuring coupler; 52. Second temperature measuring coupler; 53. Third temperature measuring coupler; 6. Insulation board; 61. Through hole. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0022] See Figure 1 and Figure 2 The image shows an example of an extrusion die for bonded NdFeB flexible strip provided by the present invention.

[0023] As shown in the figure, the NdFeB flexible strip extrusion die in this example mainly includes an injection section 1 and an extrusion section 2. The injection section 1 and the extrusion section 2 cooperate to form a continuously distributed extrusion cavity 3. The extrusion cavity 3 is formed along the injection port 11 of the injection section 1 to the extrusion port 21 of the extrusion section 2, respectively forming a guide section 31, a compression section 32, a transition section 33, and a straight section 34. The guide section 31 is distributed in a trumpet shape, the compression section 32 and the transition section 33 are distributed in a conical shape, and the conical angle of the compression section 32 is larger than that of the transition section 33. The straight section 34 is distributed horizontally. The injection section 1 and the extrusion section 2 are respectively equipped with a heating device 4 and a temperature measuring device 5, so that the extrusion pressure in the die is reduced by the cooperation of each section, thereby improving the extrusion speed and production efficiency, while ensuring the forming quality of the bonded NdFeB flexible strip.

[0024] Combination Figure 1The extrusion section 2 includes a first extrusion section 22 and a second extrusion section 23. The second extrusion section 23 is disposed between the first extrusion section 22 and the injection section 1. The first extrusion section 22 includes a first housing 221 and a first neutron 222 built into the first housing 221. The end of the first housing 221 is provided with an extrusion port 21. The second extrusion section 23 includes a second housing 231 and a second neutron 232 built into the second housing 231. The injection section 1 includes a third housing 12. The end of the third housing 12 is provided with an injection port 11.

[0025] Furthermore, the third shell 12, the second neutron 232 and the first neutron 222 are respectively formed with cavities for containing and extruding the NdFeB flexible strip raw material, so that the first extrusion section 22, the second extrusion section 23 and the injection section 1 are connected to form a continuously distributed extrusion cavity 3 inside.

[0026] Combination Figure 3 Furthermore, the extrusion cavity 3 is formed with a guide section 31, a compression section 32, a transition section 33, and a straight section 34 along the injection port 11 of the injection section 1 to the extrusion port 21 of the extrusion section 2. Specifically, the guide section 31 is formed by a cavity formed inside the third shell 12, the compression section 32 is formed by a cavity formed inside the second neutron 232, and the transition section 33 and the straight section 34 are formed by a cavity formed inside the first neutron 222.

[0027] Therefore, the extruded material enters the flow section 31 from the injection port 11, enters the transition section 33 along the compression section 32, and finally passes through the straight section 34 and is extruded from the extrusion port 21.

[0028] Furthermore, along the flow direction, the lengths of the diversion section 31, compression section 32, transition section 33, and straight section 34 decrease sequentially.

[0029] Combination Figure 3 The guide section 31 is shaped like a funnel, with its diameter gradually decreasing from the injection port 11 to the compression section 32. It can guide the loose extruded material and ensure that the extruded material (e.g., loose melt) can flow smoothly from the injection port 11 into the extrusion cavity 3, thus achieving the initial convergence and flow guidance of the extruded material.

[0030] In conjunction with this, the compression section 32 is tapered, with a diameter that is further reduced compared to the guide section 31, and the cross-section of the compression section 32 gradually decreases from the guide section 31 to the transition section 33, so that the compression section 32 applies shearing and compression to the extruded material through cross-sectional shrinkage, transforming the extruded material from a loose state to a dense state.

[0031] Furthermore, the transition segment 33 is also tapered, and the tapered angle (transition angle) of the transition segment 33 is... The cone angle (compression angle) is less than 32° of the compression section. This allows the transition section 33 to mitigate flow channel changes, ensuring that the extruded material smoothly transitions to the straight section 34 in a compacted state, thereby ensuring stable flow of the extruded material.

[0032] Furthermore, the straight section 34 is a horizontally distributed flow channel with equal diameter, which can stabilize the flow of the extruded material, allowing the extruded material to flow stably along the straight section 34 while cooling and solidifying uniformly, and finally being extruded from the extrusion port 21 in a shaped state.

[0033] Therefore, the extruded material can enter the extrusion chamber 3 from the injection port 11 and flow along the guide section 31, compression section 32, transition section 33 and straight section 34, and finally be extruded from the forming extrusion port 21.

[0034] Meanwhile, the funnel-shaped distribution structure of the flow guide section 31 enables the extruded material to accelerate smoothly from the large-diameter injection port 11, avoiding pressure spikes caused by the sudden contraction of the extruded material at the injection port 11, thereby establishing a good initial flow field for the overall flow channel of the extrusion cavity 3.

[0035] Furthermore, the compression section 32 and the transition section 33 work together. The compression section 32, with its large cone angle, compresses and densifies the extruded material, increasing the extrusion pressure in the die to its peak. After being compressed and densified in the compression section 32, the extruded material enters the transition section 33, which has a smaller cone angle and a gentler flow. The transition section 33 reduces the contraction speed of the flow channel, ensuring that the extruded material flows at a slower speed in the transition section 33 and smoothly redistributes or dissipates the kinetic and pressure energy of the extruded material. This allows the extrusion pressure in the die to gradually decrease from the peak value of the compression section 32.

[0036] In conjunction with this, the uniform diameter distribution structure of the straight section 34 can further eliminate the compression of the flow channel, so that the flow velocity of the extruded material decreases linearly and uniformly along the flow direction, while the extrusion pressure in the die decreases smoothly to the pressure at the extrusion port 21 along the flow direction.

[0037] Therefore, the flow section 31, compression section 32, transition section 33 and straight section 34 can work together to ensure the stable flow and compression molding of the extruded material in the extrusion cavity 3. At the same time, they can gradually reduce the extrusion pressure in the die to avoid quality defects caused by excessive pressure and rapid release of the extruded material at the extrusion port 21, thereby improving the extrusion speed and production efficiency, while ensuring the molding quality of the bonded NdFeB flexible strip.

[0038] Therefore, the extrusion pressure P inside the mold is:

[0039] Combination Figure 2 and Figure 3In the formula, K represents the extrusion material parameters, W represents the width of the extrusion port 21 (straight section 34), H represents the height of the extrusion port 21 (straight section 34), and V represents the extrusion speed of the extruded material entering the guide section 31 from the injection port 11. The conical angle of the compression section 32, L1 is the conical angle of the transition section 33, L2 is the length of the drainage section 31, L3 is the length of the compression section 32, L4 is the length of the transition section 33, and L5 is the length of the straight section 34.

[0040] Preferably, 30≤L1≤60, 20≤L2≤30, 15≤L1≤25, 5≤ ≤10, 10≤ ≤30, to ensure stable coordination among all segments.

[0041] Furthermore, the injection section 1 and the extrusion section 2 are respectively equipped with a heating device 4 and a temperature measuring device 5. The heating device 4 can heat the extrusion cavity 3, while the temperature measuring device 5 can measure the temperature data of each section of the extrusion cavity 3.

[0042] Combination Figure 1 Specifically, the heating device 4 includes a first annular heater 41, a second annular heater 42, and a third annular heater 43. The first annular heater 41, the second annular heater 42, and the third annular heater 43 are respectively arranged around the first housing 221, the second housing 231, and the third housing 12. The first annular heater 41 can heat the diversion section 31, the second annular heater 42 can heat the compression section 32, and the third annular heater 43 can heat the straight section 34, thereby controlling the temperature of each section.

[0043] In conjunction with this, the temperature measuring device 5 includes a first temperature measuring coupler 51, a second temperature measuring coupler 52, and a third temperature measuring coupler 53. The first temperature measuring coupler 51, the second temperature measuring coupler 52, and the third temperature measuring coupler 53 extend into the first housing 221, the second housing 231, and the third housing 12, respectively. The first temperature measuring coupler 51 can measure the temperature data of the drainage section 31 in real time, the second temperature measuring coupler 52 can measure the temperature data of the compression section 32 in real time, and the third temperature measuring coupler 53 can measure the temperature data of the transition section 33 and the straight section 34 in real time, and feed back the temperature data of each section to the heating device 4.

[0044] Furthermore, the heating device 4 also includes a control system, which can receive temperature data fed back by the temperature measuring device 5 and adjust the working state of the first annular heater 41, the second annular heater 42 and the third annular heater 43 accordingly to adjust the heating temperature of each section.

[0045] To ensure the molding quality of the extruded material, preferably, the control system sets a decreasing temperature gradient in the flow direction. For example, the temperature of the inlet section 31 and the compression section 32 is set to be higher to promote the plasticization and flow of the extruded material, while the temperature of the transition section 33 and the straight section 34 is set to be lower to ensure the shaping and cooling of the extruded material.

[0046] Furthermore, the first annular heater 41, the second annular heater 42, and the third annular heater 43 respectively raise the temperature of the flow section 31, the compression section 32, the transition section 33, and the straight section 34. At the same time, the first temperature measuring coupler 51, the second temperature measuring coupler 52, and the third temperature measuring coupler 53 respectively measure the temperature data of each section and feed it back to the control system. The control system compares the current temperature of each section to adjust the working state of the first annular heater 41, the second annular heater 42, and the third annular heater 43 to ensure that the temperature of the flow section 31 and the compression section 32 is higher than that of the transition section 33 and the straight section 34, thereby improving the molding quality of the extruded material.

[0047] Combination Figure 1 and Figure 3 Since there is a temperature difference between the compression section 32 and the transition section 33, a heat insulation plate 6 is provided between the first extrusion section 21 and the second extrusion section 22 to block the temperature transfer between the first extrusion section 21 and the second extrusion section 22, so that the temperature between the first extrusion section 21 and the second extrusion section 22 remains relatively independent and no heat exchange occurs, thus ensuring the molding quality of the extruded material.

[0048] Furthermore, in order to ensure the continuous distribution of the extrusion chamber 3, the heat insulation plate 6 is provided with a through hole 61 connecting the transition section 33 and the compression section 32, so that the extruded material in the compression section 32 can enter the transition section 33 through the through hole 61.

[0049] The extrusion die thus formed, through the cooperation of the flow section 31, compression section 32, transition section 33 and straight section 34 in the extrusion cavity 3, and the interaction with the extruded material, can effectively reduce the extrusion pressure in the die, thereby improving the extrusion speed and production efficiency, and ensuring the forming quality of the bonded NdFeB flexible strip.

[0050] like Figure 4 The figure shows the in-mold pressure of each section of the extrusion cavity 3, namely the guide section 31, the compression section 32, the transition section 33, and the straight section 34. As can be seen from the figure, along the flow direction, the in-mold pressure of each section gradually decreases from 3.700e+06Pa in the guide section 31 to 3.193e+03Pa in the straight section 34, which can effectively reduce the extrusion pressure.

[0051] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A bonding neodymium-iron-boron flexible strip extrusion die comprising an injection portion and an extrusion portion, characterized in that, The injection part and the extrusion part are matched to form a continuously distributed extrusion cavity, the extrusion cavity is provided with a flow guiding section, a compression section, a transition section and a straight section along the flow direction of the extrusion material, the flow guiding section is distributed in a trumpet shape, the compression section and the transition section are distributed in a tapered shape, the taper angle of the compression section is greater than that of the transition section, and the straight section is distributed in a horizontal equal diameter. The extrusion material flows into the flow guiding section in a loose state, the flow guiding section can guide the extrusion material, the compression section can change the extrusion material from a loose state to a dense state and increase the extrusion pressure to a peak value, the transition section can adjust the pressure and flow of the extrusion material and preliminarily reduce the extrusion pressure, and the straight section can extrude the extrusion material from a dense state to a forming state and reduce the extrusion pressure to an outlet pressure along the flow direction. The injection part and the extrusion part are respectively provided with heating devices and temperature measuring devices, which can control the temperature of the extrusion cavity in different zones.

2. The bonded NdFeB flexible strip extrusion die of claim 1 wherein, The extrusion part includes a first extrusion part and a second extrusion part, the first extrusion part includes a first shell and a first neutron built in the first shell, the second extrusion part includes a second shell and a second neutron built in the second shell, and the injection part includes a third shell.

3. The bonded NdFeB flexible strip extrusion die of claim 1 wherein, The first shell is provided with an extrusion outlet, the third shell is provided with an injection inlet, and the extrusion cavity is continuously distributed along the injection inlet to the extrusion outlet.

4. The bonded NdFeB flexible strip extrusion die of claim 2 wherein, The first extrusion part and the second extrusion part are provided with a heat insulation plate.

5. The bonded NdFeB flexible strip extrusion die of claim 4 wherein, The heat insulation plate is provided with a through hole communicating the transition section and the compression section.

6. The bonded NdFeB flexible strip extrusion die of claim 2 wherein, The heating devices are respectively distributed around the first shell, the second shell and the third shell.

7. The bonded NdFeB flexible strip extrusion die of claim 6 wherein, The heating devices maintain a temperature gradient decreasing from the flow guiding section to the straight section along the flow direction.

8. The bonded NdFeB flexible strip extrusion die of claim 2 wherein, The temperature measuring devices respectively extend into the first shell, the second shell and the third shell.

9. The bonded NdFeB flexible strip extrusion die of claim 1 wherein, The lengths of the flow guiding section, the compression section, the transition section and the straight section decrease in turn along the flow direction.

10. The bonded NdFeB flexible strip extrusion die of claim 1 wherein, The diameter of the compression section is smaller than that of the flow guiding section, and the cross section of the compression section gradually decreases from the flow guiding section to the transition section.

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