Extrusion apparatus and material extrusion method

Abstract

This application provides extrusion equipment and a material extrusion method. The extrusion equipment includes a barrel and a screw. The barrel includes a main feed section, a feeding section, and an extrusion section. The main feed section includes a first feeding port for adding main material into the barrel to form a main melt. The feeding section includes a second feeding port for adding auxiliary material into the barrel to mix with the main melt to form a mixture. The extrusion section includes a discharge port to extrude the mixed melt formed by the mixture into the barrel. The screw includes a first section, a second section, and a third section. The first section includes a first screw channel, which forms a first material space with the inner wall of the main feed section and generates a first pressure on the main material when the screw rotates. The second section includes a second screw channel, which forms a second material space with the inner wall of the feeding section and generates a second pressure on the main melt and auxiliary material when the screw rotates; the second pressure is less than the first pressure. The extrusion equipment provided by this application facilitates the smooth addition of auxiliary material into the barrel and improves the reliability of material switching.

Description

Technical Field

[0001] This specification relates to the field of material extrusion molding technology, and in particular to extrusion equipment and material extrusion methods. Background Technology

[0002] Extrusion equipment melts materials and extrudes the molten material to obtain extruded products such as wires or other shapes. To meet application requirements, some extruded products need different material compositions in different parts, thus requiring the addition of multiphase materials to the extrusion equipment. This often involves material switching, requiring changes to the material composition during the extrusion process. For example, in the process of preparing rainbow-colored wires with sequentially changing colors, different colored materials are switched sequentially, resulting in corresponding color changes on the extruded wire.

[0003] However, when switching materials, the material being switched often leaves significant residue within the extrusion equipment, which can mix with the new material and negatively impact its performance. For example, in the process of producing rainbow-colored wire, substantial material residue remains throughout the extrusion equipment, causing intermittent appearance of previous colors in subsequent colors during color switching. Existing solutions involve increasing the feeding interval between the two colors, adding the next color only after the previous color has been largely emptied. However, this approach leads to discontinuous extrusion and significant dimensional fluctuations in the extruded product.

[0004] Therefore, there is a need to provide a new extrusion equipment that can reduce the residue of the previous material and improve the reliability and stability of the material switching process.

[0005] The information in the background section is merely information known only to the inventor and does not imply that such information had entered the public domain before the date of this application, nor does it imply that it can be considered prior art in this disclosure. Summary of the Invention

[0006] This manual provides extrusion equipment and material extrusion methods that can solve the problems existing in related technologies.

[0007] In a first aspect, this specification provides an extrusion apparatus, comprising a barrel and a screw. The barrel includes a main feed section, a feeding section, and an extrusion section. The main feed section is located at one end of the barrel and includes a first feeding port for adding main material into the barrel to form a main melt. The feeding section is adjacent to the main feed section along the axial direction of the barrel and includes a second feeding port for adding auxiliary material into the barrel to mix with the main melt to form a mixture. The extrusion section is adjacent to the feeding section along the axial direction and includes a discharge port for extruding the mixed melt formed by the mixture into the barrel. The screw is rotatably located within the barrel. The screw includes a first section, a second section, and a third section. The first section is located in the main feed section and includes a first screw channel, which forms a helical first material space with the inner wall of the main feed section and generates a first pressure on the main material when the screw rotates. The second section is located in the feeding section and includes a second screw channel, which forms a helical second material space with the inner wall of the feeding section and generates a second pressure on the main melt and auxiliary material when the screw rotates, the second pressure being less than the first pressure. The third section is located in the extrusion section and includes a third spiral channel. The third spiral channel and the inner wall of the extrusion section form a spiral third material space to convert the mixture into a mixed melt.

[0008] In some embodiments, the depth of the first screw groove is less than the depth of the second screw groove, so as to facilitate the addition of auxiliary materials into the cylinder through the second feed port.

[0009] In some embodiments, the lead of the second screw channel is less than the lead of the first screw channel.

[0010] In some embodiments, the screw further includes a flow control section. The flow control section is located between the first and second sections and is configured to limit the flow rate of the main material such that the flow rate of the main material passing through the flow control section is less than or equal to a preset flow rate threshold.

[0011] In some embodiments, the flow control section includes a flow-limiting screw ridge, a first flow-limiting screw groove, and a second flow-limiting screw groove. The first and second flow-limiting screw grooves are located on opposite sides of the flow-limiting screw ridge, with the first flow-limiting screw groove communicating with the first screw groove and the second flow-limiting screw groove communicating with the second screw groove. The diameter of the inner wall of the cylinder is larger than the outer diameter of the flow-limiting screw ridge, so as to form a gap between the inner wall of the cylinder and the flow-limiting screw ridge.

[0012] In some embodiments, the extrusion apparatus includes a pressure sensor. The pressure sensor is disposed in the barrel and adjacent to the front end of the second section, and measures the material pressure at the front end of the second section. The front end is located at one end of the second section adjacent to the first section.

[0013] In some embodiments, when the screw rotates at the operating speed, the material pressure at one end of the first section near the front end is greater than 2 MPa. At the front end, the material pressure is less than or equal to 2 MPa.

[0014] In some embodiments, in the axial direction, the second feeding port and the first feeding port have a first interval distance, and the second feeding port and the discharge port have a second interval distance, wherein the first interval distance is greater than or equal to the second interval distance.

[0015] In some embodiments, the ratio of the threaded section length to the outer diameter of the screw ranges from 20 to 35. The first spacing distance is greater than 10 times the outer diameter of the screw, and the second spacing distance is greater than 4 times the outer diameter of the screw.

[0016] In some embodiments, the operating speed of the screw is configured such that the material transfer speed generated in the first material space is greater than the feeding speed of the main material at the first feed port.

[0017] Secondly, this specification provides a material extrusion method applied to the extrusion equipment of the first aspect. The extrusion method includes: controlling the screw to rotate; adding a main material into a main material section through a first feeding port, so that the main material forms a main melt in the main material section; adding a first auxiliary material into a feeding section through a second feeding port, thereby forming a first mixed melt in the extrusion section that mixes the main melt and the first auxiliary material.

[0018] In some embodiments, after the extrusion method adds the first auxiliary material into the feeding section through the second feeding port, it includes: stopping the addition of the first auxiliary material through the second feeding port and adding the second auxiliary material into the feeding section through the second feeding port, thereby forming a second mixed melt in the extrusion section that mixes the main melt and the second auxiliary material.

[0019] In some embodiments, after the extrusion method adds the second auxiliary material into the feeding section through the second feeding port, it further includes:

[0020] The addition of the second auxiliary material is stopped at the second feed port, and at least the third auxiliary material is added into the feeding section through the second feed port, thereby forming at least a third mixed melt in the extrusion section. The third mixed melt is formed by mixing the main melt and the third auxiliary material under the drive of the screw.

[0021] In some embodiments, the main material accounts for more than 80% by weight in the first mixed melt and / or more than 80% by weight in the second mixed melt.

[0022] In some embodiments, the main material and the first and second auxiliary materials are different in color.

[0023] In some embodiments, the first auxiliary material includes at least one of color masterbatch, color oil, color powder, fiber, or foaming agent.

[0024] In some embodiments, the second auxiliary material includes at least one of color masterbatch, color oil, color powder, fiber, or foaming agent.

[0025] As can be seen from the above technical solutions, the extrusion equipment and material extrusion method provided in this specification enable the distance between the first feed port and the discharge port to be greater than the distance between the second feed port and the discharge port. This means that the main material, after being added to the cylinder from the first feed port, will travel a longer path and time to reach the discharge port, while the auxiliary material, after being added to the cylinder from the second feed port, will travel a shorter path and time to reach the discharge port. This allows the main material to achieve a more complete melting and dispersion effect. When switching from the first auxiliary material to the second auxiliary material at the second feed port, less of the first auxiliary material remains, which can be quickly flushed away during the extrusion process, thereby reducing the risk of contamination of the second mixed melt by the first auxiliary material and improving the reliability and stability of the material switching process. A pressure difference will be generated between the first material space and the second material space, which can reduce the risk of material overflowing from the second feed port in the second material space and also facilitate the smooth addition of the auxiliary material into the cylinder.

[0026] Other features of the extrusion equipment and material extrusion methods provided in this specification will be partially listed in the following description. The figures and examples presented below will be readily apparent to those skilled in the art. The inventive aspects of the extrusion equipment and material extrusion methods provided in this specification can be fully understood through practice or use of the methods, apparatus, and combinations described in the detailed examples below. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of the structure of an extrusion apparatus provided according to some embodiments of this specification is shown;

[0029] Figure 2 An exploded structural schematic diagram of an extrusion apparatus provided according to some embodiments of this specification is shown;

[0030] Figure 3 A schematic diagram of extruded products from an extrusion apparatus provided according to some embodiments of this specification is shown;

[0031] Figure 4 A schematic diagram of the flow control section of an extrusion apparatus provided according to some embodiments of this specification is shown; and

[0032] Figure 5 A flowchart of an extrusion method provided according to some embodiments of this specification is shown. Detailed Implementation

[0033] The following description provides specific application scenarios and requirements for this specification, intended to enable those skilled in the art to make and use the contents of this specification. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0034] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not restrictive. For example, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used herein may also include the plural forms. When used in this specification, the terms “comprising,” “including,” and / or “containing” mean that the associated feature, integer, step, operation, element, and / or component is present, but do not preclude the presence of one or more other features, integers, steps, operations, elements, components, and / or groups, or that other features, integers, steps, operations, elements, components, and / or groups may be added to the system / method.

[0035] Considering the following description, these and other features of this specification, as well as the operation and function of the related components of the structure, and the economy of assembly and manufacture of the parts, can be significantly improved. All of these form part of this specification with reference to the accompanying drawings. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not drawn to scale.

[0036] The flowcharts used in this specification illustrate operations implemented according to some embodiments of this specification. It should be clearly understood that the operations in the flowcharts may not be implemented in a sequential order. Instead, the operations may be implemented in reverse order or simultaneously. Furthermore, one or more additional operations may be added to the flowcharts. One or more operations may be removed from the flowcharts.

[0037] In this specification, "X includes at least one of A, B, or C" means that X includes at least A, or X includes at least B, or X includes at least C. That is, X may include only one of A, B, and C, or any combination of A, B, and C, as well as other possible content / elements. The arbitrary combination of A, B, and C can be A, B, C, AB, AC, BC, or ABC.

[0038] In this specification, unless explicitly stated otherwise, the relationships between structures can be direct or indirect. For example, when describing "A is adjacent to B," unless it is explicitly stated that A and B are directly adjacent, it should be understood that A can be directly adjacent to B or indirectly adjacent to B, meaning that there are other elements between A and B. Similarly, when describing "A is above B," unless it is explicitly stated that A is directly above B (AB is adjacent and A is above B), it should be understood that A can be directly above B or indirectly above B (AB is separated by other elements, and A is above B). And so on.

[0039] Extrusion equipment melts materials and extrudes the molten material to obtain extruded products such as wires or other shapes. To meet application requirements, some extruded products need different material compositions in different parts, thus requiring the addition of multiphase materials to the extrusion equipment. This often involves material switching, requiring changes to the material composition during the extrusion process. For example, in the process of preparing rainbow-colored wires with sequentially changing colors, different colored materials are switched sequentially, causing the colors on the extruded wire to change accordingly.

[0040] However, after material replacement, a significant amount of the replaced material remains inside the extruder barrel. Therefore, for a period of time, the extruder will continue to extrude wire containing the replaced material. Simultaneously, before the replaced material is completely discharged from the extruder, new material entering the extruder will mix with it. This may adversely affect the wire's performance or cause the wire quality to fail to meet standards. For example, in the process of producing rainbow-colored wire, significant material residue at various points on the screw can cause intermittent appearances of previous colors when switching colors.

[0041] One existing solution is to increase the feeding interval between the two materials. For example, in the case of changing the color of an extrusion line, the current method is to stop adding the material of the previously colored one, and only add the material of the new color after all the material of the previously colored one has been discharged from the extrusion equipment. However, this solution leads to a discontinuous extrusion process and large fluctuations in the size of the extruded product.

[0042] Therefore, during feeding, the materials can be divided into main materials and auxiliary materials, and the inlet of the auxiliary materials can be separated from that of the main materials, with the auxiliary material inlet designed to be closer to the outlet. The main materials, after being added to the cylinder, need to travel a longer path and time to reach the outlet. This allows the main materials to be fully melted and dispersed. The auxiliary materials, after being added to the cylinder, need to travel a shorter path to reach the outlet, resulting in a smaller distribution area.

[0043] During extrusion, the main material can remain unchanged as the base material, while auxiliary materials can be added and replaced. This method reduces the residue of old auxiliary materials in the barrel when replacing them with new ones, allowing for rapid flushing and mitigating the risk of old auxiliary material residue affecting the performance of subsequent extruded products. Taking wire as an example, the wire segments where old and new auxiliary materials mix can be shortened, and the extruded wire segments can be switched from containing old auxiliary materials to containing new ones more quickly.

[0044] Accordingly, an extrusion apparatus is required, comprising a barrel and a screw. The screw is rotatably located within the barrel. The barrel includes a main feed section, a feeding section, and an extrusion section. The main feed section is located at one end of the barrel and includes a first feeding port for adding main material into the barrel to form a main melt. The feeding section is adjacent to the main feed section along the axial direction of the barrel and includes a second feeding port for adding auxiliary material into the barrel to mix with the main melt to form a mixture. The extrusion section is adjacent to the feeding section along the axial direction and includes a discharge port for extruding the mixed melt formed from the mixture into the barrel.

[0045] This extrusion equipment can be used to switch between different auxiliary materials. When switching from the first auxiliary material to the second auxiliary material at the second feeding port, the first auxiliary material has a smaller distribution area and less residue, and can be quickly washed away during the extrusion process, thereby reducing the risk of the subsequent second mixed melt being contaminated by the first auxiliary material.

[0046] For example, in the process of preparing rainbow-colored wire, the materials can be divided into a base material (main material) and various color-enhancing materials (first auxiliary material, second auxiliary material, third auxiliary material, etc., with other colors). With the base material unchanged, the wire color is changed by adding different color-enhancing materials. Especially when the main material differs in color from both the first and second auxiliary materials, the first auxiliary material leaves less residue and can be quickly washed away during the switch between them. This reduces the risk of the first auxiliary material's color mixing into the second melt mixture, resulting in high color purity in each segment of the extruded product and preventing intermittent mixing of different colors.

[0047] Therefore, this extrusion equipment can reduce the residue of the previous material and improve the reliability and stability of the process of changing auxiliary materials.

[0048] Furthermore, when the main material is conveyed inside the cylinder, the main melt formed by the main material is subjected to significant pressure caused by the screw rotation, affecting the smooth addition of auxiliary materials. Therefore, when adding auxiliary materials at the second feed port, it is also necessary to overcome the problem of significant pressure on the main melt.

[0049] In view of this, embodiments of this specification provide extrusion equipment and a material extrusion method. The extrusion equipment includes a barrel and a screw. A main material section, a feeding section, and an extrusion section are sequentially arranged on the barrel along its extension direction (i.e., the axial direction of the barrel). Furthermore, the barrel is also provided with a first feeding port, a second feeding port, and a discharge port. The first feeding port is located on the main material section; the second feeding port is located on the feeding section; and the discharge port is located at one end of the extrusion section, i.e., the extrusion end of the barrel. Along the axial direction of the barrel, the second feeding port is located between the first feeding port and the discharge port. The first feeding port is for adding the main material into the barrel, and the second feeding port is for adding at least a first auxiliary material and a second auxiliary material sequentially into the barrel. The screw is located within the barrel and is provided with a first section, a second section, and a third section corresponding to the main material section, the feeding section, and the extrusion section, respectively. Through the design of the screw ribs and screw grooves, a first material space is formed between the first section of the screw and the barrel, a second material space is formed between the second section of the screw and the barrel, and a third material space is formed between the third section of the screw and the barrel. Because the spiral edges in the first, second, and third segments are all spiral-shaped, the first material space, the second material space, and the third material space are all spiral-shaped.

[0050] As the screw rotates, the main material melts into a main melt within the first material space and is conveyed towards the discharge port, thus generating significant pressure at the main melt. When the main melt moves from the first material space into the second material space, the space becomes more expansive, and the pressure decreases. Because the pressure in the second material space is lower than in the first material space, auxiliary materials can be added through the second feed port only by overcoming a relatively low pressure.

[0051] The technical solutions of the embodiments of this specification will now be described in detail with reference to the accompanying drawings.

[0052] Figure 1 A schematic diagram of the structure of an extrusion apparatus provided according to some embodiments of this specification is shown. Figure 2 An exploded structural schematic diagram of an extrusion apparatus provided according to some embodiments of this specification is shown. For example... Figure 1 and Figure 2 As shown, the extrusion apparatus 100 may include a drive motor 160, a screw 140, a barrel 110, and an outlet flow channel 170. The screw 140 is rotatably located within the barrel 110. The drive motor 160 is connected to the screw 140 and can drive the screw 140 to rotate relative to the barrel 110.

[0053] The screw 140 includes screw ridges 145 and a shaft structure 146, with the screw ridges 145 located on the outer circumferential surface of the shaft structure 146. A screw groove is formed between two screw ridges 145. Through the screw groove, a material space can be formed between the barrel 110 and the screw 140 to accommodate the material. When the screw 140 rotates relative to the barrel 110, the material in the material space can be driven towards the discharge port 113 via the screw ridges 145. The barrel 110 is connected to the outlet flow channel 170 through the discharge port 113. After the material flows into the outlet flow channel 170 from the discharge port 113, it is extruded through the outlet flow channel 170 to form extruded products 150 such as wires.

[0054] The material added into the barrel 110 can be in the form of particles, powder, liquid, fiber, or a combination thereof. Further, the extrusion equipment 100 includes a heating device. The heating device is used to heat the screw 140 or the barrel 110, thereby heating the material inside the barrel 110. The material can enter the barrel 110 in a solid form and be converted to a molten state upon heating. Furthermore, the shearing action experienced by the material when the screw 140 rotates also helps to fully melt and homogenize the material.

[0055] The cylinder 110 may include a main material section 1110, a feeding section 1120, and an extrusion section 1130. The main material section 1110 is located at one end of the cylinder 110 and includes a first feeding port 111 for adding main material 120 into the cylinder 110 to form a main melt. The feeding section 1120 is adjacent to the main material section 1110 along the axial direction D1 of the cylinder 110 and includes a second feeding port 112 for adding auxiliary material into the cylinder 110 to mix with the main melt to form a mixture. The extrusion section 1130 is adjacent to the feeding section 1120 along the axial direction D1 and includes a discharge port 113 for extruding the mixed melt formed by the mixture into the cylinder 110.

[0056] That is, a main material section 1110, a feeding section 1120, and an extrusion section 1130 are sequentially arranged on the cylinder 110 along its extension direction (i.e., the axial direction D1 of the cylinder). The main material section 1110 is located at one end of the cylinder 110, and the extrusion section 1130 is located at the other end of the cylinder 110. The discharge port 113 can be located at the end of the extrusion section 1130 to extrude the mixed melt from the cylinder 110. In some embodiments, there is one second feeding port 112. In other embodiments, there can be two or more second feeding ports 112.

[0057] The structure of the screw 140 corresponds to the structure of the barrel 110. For example, the screw 140 includes a first section 141, a second section 142, and a third section 143. The second section 142 is located between the first section 141 and the third section 143. These three sections correspond to the main material section, the feeding section 1120, and the extrusion section 1130 of the barrel 100, respectively. Each screw section includes spaced-apart screw ridges 145 and screw grooves. The screw 140 has an outer diameter D2. The screw outer diameter D2 is also the outer diameter of the screw ridges, and its size can be approximately equal to the inner diameter of the barrel 110. For example, the outer diameter of the screw ridge 145 is 45 mm, and the inner diameter of the barrel 110 is also 45 mm, so the screw 140 fits tightly with the barrel 110.

[0058] The first segment 141 of the screw 140 is located in the main material segment 1110 and includes a helical first screw ridge 1451 and a first screw groove 1411. The first screw groove 1411 and the inner wall of the main material segment 1110 form a helical first material space 1412. The main function of the first material space 1412 is to melt the solid main material 120 into a first melt. Therefore, the length of the first segment 141 is designed to be relatively long so that there is sufficient time to melt the main material 120. For example, in some embodiments, the length of the first segment 141 is 11 to 22 times the outer diameter D2 of the screw 140.

[0059] The second section 142 of the screw 140 is located in the feeding section 1120 and includes a helical second screw ridge 1452 and a second screw groove 1421. The second screw groove 1421 forms a helical second material space 1423 with the inner wall of the feeding section 1120. The main function of the second material space 1423 is to accommodate auxiliary materials and mix them with the main material 120. Therefore, the length of the second section 142 is designed to be shorter than that of the first section 141. For example, in some embodiments, the length of the second section 142 is 6 to 12 times the outer diameter D2 of the screw.

[0060] The third section 143 of the screw 140 is located in the extrusion section 1130 and includes a helical third screw ridge 1453 and a third screw groove 1431. The third screw groove 1431 forms a helical third material space 1432 with the inner wall of the extrusion section 1130 to convert the mixture into a mixed melt. In the third section 143, the auxiliary material and the main material 120 are thoroughly mixed to form a mixed melt, which is finally extruded at the outlet. This section is the shortest. For example, in some embodiments, the length of the third section 143 is 3 to 7 times the screw outer diameter D2.

[0061] The main material 120 is added to the first material space 1412 through the first feeding port 111; the auxiliary material is added to the second material space 1423 through the second feeding port 112. The first feeding port 111 is opposite to the first section 141. The second feeding port 112 is opposite to the second section 142. Further, along the axial direction D1 of the cylinder 110, the length of the first feeding port 111 is smaller than the length of the first section 141, and the length of the second feeding port 112 is smaller than the length of the second section 142.

[0062] Since both the first material space 1412 and the second material space 1423 are spiral-shaped, the screw 140 compresses the materials in both the first material space 1412 and the second material space 1423 when it rotates. Accordingly, when the screw 140 rotates, it can generate a first pressure on the main material 120 in the first material space 1412, and a second pressure on the main melt and auxiliary materials formed by the main material 120 in the second material space 1423.

[0063] However, if the pressure at the second feed port 112 is greater than or equal to the first pressure, there is a risk that the material in the second material space 1423 will overflow from the second feed port 112, which is detrimental to the addition of auxiliary materials. Therefore, in this disclosure, the screw 140 has a special structure that makes the second pressure less than the first pressure. A pressure difference will be generated between the first material space 1412 and the second material space 1423, which can reduce the risk of the material in the second material space 1423 overflowing from the second feed port 112 and facilitate the smooth addition of auxiliary materials into the second material space 1423.

[0064] The following section details the pressure reduction structure of screw 140.

[0065] In some embodiments, the depth of the first screw groove 1411 is less than the depth of the second screw groove 1421, so as to facilitate the addition of auxiliary materials into the cylinder 110 through the second feed port 112.

[0066] After the main material 120 is added into the cylinder 110, it first enters the first screw groove 1411 (first material space 1412) and moves towards the second section 142 under the drive of the first screw ridge 1451. Then, the main material 120 can enter the second screw groove 1421 (second material space 1423). At this time, auxiliary material is added to the main material 120, increasing its volume. The main material 120 and auxiliary material move together towards the discharge port 113 under the drive of the second screw ridge 1452. The second screw groove 1421 is set to a larger depth, thus having a stronger capacity to hold materials. This reduces the pressure of the main material 120 flowing through the second section 142, making it easier to add materials into the cylinder 110 through the second feed port 112.

[0067] For example, the upper limit of the conveying capacity of the first section 141 is a material flow rate of 8 kg / h to 9 kg / h, and the upper limit of the conveying capacity of the second section 142 can be a material flow rate of 10 kg / h.

[0068] In existing single-screw extrusion technology, the screw groove depth of the screw 140 tends to gradually decrease along the material conveying direction, which causes the material pressure to gradually increase. This is obviously not conducive to the formation of a low-pressure zone.

[0069] In some embodiments, the outer diameter of the threaded rib 145 remains unchanged along the axial direction D1 of the cylinder 110. The outer diameter of the shaft structure 146 in the first segment 141 is greater than the outer diameter of the shaft structure 146 in the second segment 142, such that the depth of the first threaded groove 1411 is less than the depth of the second threaded groove 1421.

[0070] In some embodiments, the lead of the second spiral groove 1421 is less than the lead of the first spiral groove 1411. This is beneficial for improving the mixing effect of the material at the second section 142, increasing the separation between the mixed melts at different positions of the second spiral groove 1421, and reducing interference between the first and second mixed melts. The lead refers to the axial distance between adjacent corresponding points on the same spiral line.

[0071] In some embodiments, the lead of the third screw groove 1431 is greater than the lead of the second screw groove 1421, which is beneficial to improving the material conveying capacity of the third screw groove 1431.

[0072] In some embodiments, such as Figure 1 and Figure 2 As shown, the screw 140 also includes a flow control section 144. The flow control section 144 can be configured as a barrier structure. The flow control section 144 is located between the first section 141 and the second section 142 and is configured to limit the flow rate of the main material 120 so that the flow rate of the main material 120 passing through the flow control section 144 is less than or equal to a preset flow rate threshold.

[0073] The preset flow rate threshold allowed for passage at flow control section 144 is less than the upper limit of the conveying capacity of the first section 141 and also less than the upper limit of the conveying capacity of the second section 142. For example, the upper limit of the conveying capacity of the first section 141 is a material flow rate of 8 kg / h to 9 kg / h, the upper limit of the conveying capacity of the second section 142 is a material flow rate of 10 kg / h, and the preset flow rate threshold allowed for passage at flow control section 144 is 6 kg / h.

[0074] Within the cylinder 110, the material conveying process is dynamic. Therefore, the material flow rate fluctuates. The flow control section 144 controls the flow rate of the main material 120, ensuring a stable flow rate. This way, when the main material 120 reaches the second section 142 after passing through the flow control section 144, the flow rate will not be excessive, which helps maintain a low-pressure state at the second section 142, facilitating the addition of new material at that point.

[0075] Furthermore, the flow control section 144 is adjacent to the front end 1422 of the second section 142, so that the material can reach the front end 1422 of the second section 142 after passing through the flow control section 144. This helps to improve the flow stabilization effect of the flow control section 144 on the material at the second section 142.

[0076] Figure 4 A schematic diagram of the flow control section of an extrusion apparatus provided according to some embodiments of this specification is shown.

[0077] In some embodiments, such as Figure 1 , Figure 2 and Figure 4 As shown, the flow control section 144 includes a flow-limiting screw ridge 1443, a first flow-limiting screw groove 1441, and a second flow-limiting screw groove 1442. The flow-limiting screw ridge 1443, the first flow-limiting screw groove 1441, and the second flow-limiting screw groove 1442 are all helical. The first flow-limiting screw groove 1441 and the second flow-limiting screw groove 1442 are parallel and located on both sides of the flow-limiting screw ridge 1443.

[0078] The flow control section 144 is divided into two ends. Its first end 144a is adjacent to the first section 141 of the screw 140, and its second end 144b is adjacent to the second section 142 of the screw 140. The diameter of the first end 144a and the second end 144b of the flow control section 144 is D2, and it is fitted with the inner wall of the cylinder 110 with a clearance. On the one hand, it can rotate freely in the cylinder, and on the other hand, it can seal the flow of materials.

[0079] The first flow-limiting screw groove 1441 is divided into two ends. Its first end starts at the first end 144a of the flow control section 144 and is connected to the first screw groove 1411, that is, connected to the main material section 1110 of the cylinder 110; its second end stops in the flow control section 144 and is isolated by the second end 144b of the flow control section 144, so that it is not connected to the feeding section 1120 of the cylinder 110.

[0080] The second flow-limiting screw groove 1442 also has two ends. Its second end starts at the second end 144b of the flow control section 144 and is connected to the second screw groove 1421, that is, it is connected to the feeding section 1120 of the cylinder 110; its first end stops in the flow control section 144 and is isolated by the first end 144a of the flow control section 144, so that it is not connected to the main material section 1110 of the cylinder 110.

[0081] The flow-limiting screw ridge 1443 is located between the first end 144a and the second end 144b of the flow control section 144. The diameter of the inner wall of the cylinder 110 is larger than the outer diameter of the flow-limiting screw ridge 1443, thus forming a gap between the inner wall of the cylinder 110 and the flow-limiting screw ridge 1443. This gap allows the first flow-limiting screw groove 1411 and the second flow-limiting screw groove 1442 to communicate.

[0082] During extruder operation, the main material 120 in the first screw channel 1411 can enter the first flow-limiting screw channel 1441 from the first end of the first flow-limiting screw channel 1441, then pass through the gap between the inner wall of the barrel 110 and the flow-limiting screw ridge 1443, and then reach the second flow-limiting screw channel 1442. It can then enter the second screw channel 1421 through the second end of the second flow-limiting screw channel 1442. Thus, during the flow control section 144, the flow-limiting screw ridge 1443 can restrict the flow rate of the main material 120. Simultaneously, the structure of the flow control section 144 can compress the main material 120, further dispersing and melting it, thereby increasing the degree of dispersion and melting of the main material 120.

[0083] In some embodiments, the pitch of the flow control section 144 is smaller than that of the first section 141 and the second section 142, and the lead of the flow control section 144 is greater than that of the first section 141 and the second section 142.

[0084] The end of the second segment 142 adjacent to the first segment 141 is its front end 1422. In some embodiments, when the screw 140 rotates at its operating speed, the material pressure at the end of the first segment 141 adjacent to the front end 1422 of the second segment 142 is greater than 2 MPa. At the front end 1422 of the second segment 142, the material pressure is less than or equal to 2 MPa. Further, the material at the front end 1422 of the second segment 142 is the main material 120 that has just arrived at the second segment 142. For example, the pressure range of the main material 120 at the front end 1422 of the second segment 142 can be 1.4 MPa to 1.6 MPa or 1.6 MPa to 2 MPa.

[0085] The material pressure at the front end 1422 can be used to measure the material fullness of the entire second section 142. If the fullness of the main material 120 is too high when it flows through the second section 142, internal pressure will be generated, which may cause the main material 120 to overflow from the second feed port 112. Therefore, it is necessary to control the pressure of the main material 120 when it flows through the second section 142 so that it does not exceed the preset pressure threshold.

[0086] By controlling the pressure at the front end 1422 of the second section 142 to be less than or equal to 2 MPa, the operator can ensure that the pressure of the main material 120 flowing through the second section 142 does not exceed a preset pressure threshold. This creates a cavity in the second section 142, forming a low-pressure zone. At this time, the main material 120 will not overflow from the second feed port 112, and the second auxiliary material 02 is allowed to be added to the second section 142 through the second feed port 112.

[0087] For example, the maximum conveying capacity of the second section 142 is a material flow rate of 10 kg / h. If the addition rate of the main material 120 and its flow rate within the cylinder 110 are 6 kg / h, the main material 120 cannot fill the second section 142, resulting in a low-pressure zone at the second section 142. If the addition rate of the main material 120 and its flow rate within the cylinder 110 reach or approach 9 kg / h, the pressure at the second section 142 exceeds a preset pressure threshold.

[0088] In some embodiments, such as Figure 1 As shown, the extrusion apparatus 100 includes a pressure sensor 180. The pressure sensor 180 is disposed in the barrel 110 and adjacent to the front end of the second section 142, and measures the material pressure at the front end of the second section 142.

[0089] Using pressure sensor 180, the operator can measure the pressure value of the main material 120 when it arrives at the second stage 142. Based on the measurement results of pressure sensor 180, the operator or controller can easily and accurately control the pressure of the main material 120 as it flows through the second stage 142.

[0090] In some embodiments, the pressure value of the main material 120 when it reaches the second stage 142 is affected by the rotational speed of the screw 140 and the feeding speed of the main material 120. When the pressure value of the main material 120 does not meet the requirements, the operator or controller can adjust the rotational speed of the screw 140 and the feeding speed of the main material 120 to make the pressure value of the main material 120 meet the requirements. For example, when the pressure sensor 180 measures a pressure of 2.3 MPa, the operator or controller can increase the rotational speed of the screw 140 and decrease the feeding speed of the main material 120, thereby reducing the pressure value of the main material 120 to less than or equal to 2 MPa.

[0091] Materials can be fed into the cylinder 110 by a feeder. For example, the feeder can use a pump to input materials into the cylinder 110. Alternatively, the feeder can use its own screw to push materials into the cylinder 110.

[0092] The feeder can add material into the barrel 110 using either starve feeding or flood feeding. Starve feeding sets the material supply rate below the extruder's current theoretical capacity, preventing the screw from being completely filled with raw material. In starve feeding of the main material 120, the main material 120 falls directly into the barrel 110, with no material accumulation in the hopper at the first feed port 111, and the space between the barrel 110 and the screw 140 is partially filled. In flood feeding, the material first enters the hopper at the first feed port 111, where material accumulates, and then gradually falls into the barrel 110. In this way, the extruder 100 draws in as much material as possible, and the space between the barrel 110 and the screw 140 is filled.

[0093] In some embodiments, the operating speed of the screw 140 is configured such that the material transfer speed generated in the first material space 1412 is greater than the feeding speed of the main material 120 at the first feed port 111.

[0094] This configuration of the feeding speed of the main material 120 and the operating speed of the screw 140 allows the main material 120 to be fed into the cylinder 110 in a starved state. This makes it easier for the feeder to measure the feeding speed of the material and effectively control the feeding speed, which helps to maintain a stable material flow rate in the cylinder 110 and also helps to maintain a low-pressure state for the material at the second feeding port 112 in the cylinder 110.

[0095] For example, when the screw 140 rotates at 25 rpm, the material flow rate in the saturated state of the cylinder 110 is 12 kg / h. If the feeder provides material at a rate of 8 kg / h, then at the first feed port 111, the melt does not fill the cylinder 110 and is in a state of starvation.

[0096] Furthermore, the operating speed of the screw 140 is configured such that the material transfer speed generated in the second material space 1423 is greater than the sum of the feeding speeds of the main material 120 and the auxiliary material. This configuration of the feeding speeds of the main material 120 and the auxiliary material, as well as the operating speed of the screw 140, allows both the main material 120 and the auxiliary material to be fed into the cylinder 110 in a state of starvation.

[0097] In the scenario of changing auxiliary materials, the first feeding port 111 supplies the main material 120 into the cylinder 110, and the second feeding port 112 supplies at least the first auxiliary material 01 and the second auxiliary material 02 into the cylinder 110 in sequence. When the screw 140 rotates, the main material 120 and the first auxiliary material 01 first form a first mixed melt and leave the cylinder 110 through the discharge port 113, and then the main material 120 and the second auxiliary material 02 form a second mixed melt and leave the cylinder 110 through the discharge port 113.

[0098] Along the axial direction D1 of the cylinder 110, the second feed port 112 is located between the first feed port 111 and the discharge port 113. That is, the distance between the first feed port 111 and the discharge port 113 is greater than the distance between the second feed port 112 and the discharge port 113. Thus, material added to the cylinder 110 from the first feed port 111 will travel a longer path and take longer to reach the discharge port 113, while material added to the cylinder 110 from the second feed port 112 will travel a shorter path and take shorter time to reach the discharge port 113. Therefore, when switching the material added to the cylinder 110 from the second feed port 112, less residue of the first mixed melt remains, which is beneficial for the first mixed melt to be thoroughly washed away by the second mixed melt.

[0099] Based on the addition process of the first auxiliary material 01 and the second auxiliary material 02, the time period corresponding to the extrusion process can have a first time window and a second time window. The first time window roughly corresponds to the time period when the first auxiliary material 01 is added; the second time window roughly corresponds to the time period when the second auxiliary material 01 is added. The first time window precedes the second time window.

[0100] Within the first time window, main material 120 is continuously added through the first feeding port 111, and first auxiliary material 01 is continuously added through the second feeding port 112. The rotation of the screw 140 causes both the main material 120 and the first auxiliary material 01 within the cylinder 110 to move towards the discharge port 113. Upon encountering each other, the main material 120 and the first auxiliary material 01 mix under the influence of the screw 140. After mixing and melting, the main material 120 and the first auxiliary material 01 form a first mixed melt, which then exits the cylinder 110 through the discharge port 113.

[0101] During the transition period between the first and second time windows, the main material 120 can continue to be added at the first feeding port 111, while the addition of the main material 120 stops at the second feeding port 112.

[0102] During the second time window, the main material 120 can continue to be added through the first feeding port 111, and the second auxiliary material 02 can continue to be added through the second feeding port 112. The rotation of the screw 140 causes both the main material 120 and the second auxiliary material 02 within the cylinder 110 to move towards the discharge port 113. After the main material 120 and the second auxiliary material 02 meet, they mix under the influence of the screw 140. The mixture and melt of the main material 120 and the second auxiliary material 02 form a second mixed melt, which then exits the cylinder 110 through the discharge port 113.

[0103] Therefore, during the extrusion process, the material switching at the first feed port 111 is not required. When the material switching from the first auxiliary material 01 to the second auxiliary material 02 at the second feed port 112, the distribution area of ​​the first auxiliary material 01 is small and there is less residue. It can be quickly washed away during the extrusion process, thereby reducing the risk of the second mixed melt being contaminated by the first auxiliary material 01.

[0104] In some embodiments, the main material 120 is different in color from both the first auxiliary material 01 and the second auxiliary material 02. For example, when the extruded product 150 is a color-gradient 3D printing filament, the main material 120 can serve as the base material of the extruded product 150, the first color pigment can serve as the first auxiliary material 01, and the second color pigment can serve as the second auxiliary material 02. The base material and pigment can have corresponding colors after mixing. When the first auxiliary material 01 is switched to the second auxiliary material 02, the color of the mixed melt in the cylinder 110 also changes accordingly. The residue of the first auxiliary material 01 is small and can be quickly washed away, which reduces the risk of the color of the first auxiliary material 01 mixing into the second mixed melt, so that the color of each segment of the extruded product 150 has high purity and is not mixed with different colors. In this way, the transition zone of the color switching of the obtained 3D printing filament is narrow, a single roll of filament can be used to print models with color changes, and the printed models have distinct colors without the need to switch between different colored filament rolls during the 3D printing process.

[0105] For example, Figure 3 A schematic diagram of extruded products from an extrusion apparatus provided according to some embodiments of this specification is shown. For example... Figure 1 and Figure 3 As shown, the first auxiliary material 01 is black, and correspondingly, the first mixed melt is black after extrusion and solidification. The second auxiliary material 02 is white, and correspondingly, the second mixed melt is white after extrusion and solidification. In extruded products obtained by the prior art, when the first auxiliary material is switched to the second auxiliary material, there is a wide transition zone, and some black first mixed melt is mixed in the second mixed melt, affecting the appearance of the second mixed melt after solidification. In the extruded product 150 obtained in the embodiments of this specification, when the first auxiliary material 01 is switched to the second auxiliary material 02, the transition zone is narrower, and the appearance color of the second mixed melt after solidification is purer.

[0106] In some embodiments, the pigment may include at least one of masterbatch, color oil, or color powder. Masterbatch is convenient to add and easy to measure. Color oil provides vibrant colors and facilitates accurate measurement. Color powder contains the highest concentration of active ingredients, which helps reduce the amount of material added and is easier to disperse.

[0107] In some embodiments, the temperature at the second feed port 112 inside the cylinder 110 is higher than the temperature at the first feed port 111. The higher temperature results in lower material viscosity, making it easier for the material to be driven by the screw 140 and less prone to residue buildup. Furthermore, the higher temperature facilitates the formation of a mixed melt between the second auxiliary material 02 and the first auxiliary material 01. For example, the temperature at the first feed port 111 inside the cylinder 110 is 150°C to 180°C, and the temperature at the second feed port 112 is 200°C to 210°C.

[0108] In some embodiments, the main material 120 may be a single substance or a mixture of at least two substances. The first auxiliary material 01 may be a single substance or a mixture of at least two substances. The second auxiliary material 02 may be a single substance or a mixture of at least two substances.

[0109] In some embodiments, the main material 120 can be continuously added to the first feeding port 111, and at least one material can be added to the second feeding port 112 in a preset order after the first auxiliary material 01 and the second auxiliary material 02 are added in sequence.

[0110] For example, when the extruded product 150 is a rainbow-colored wire, the first auxiliary material 01, the second auxiliary material 02, the third auxiliary material, and the fourth auxiliary material can be added sequentially at the second feeding port 112. The main material 120 itself may or may not have color. For example, the main material 120 may be yellow. The first auxiliary material 01, the second auxiliary material 02, the third auxiliary material, and the fourth auxiliary material may be pigments of different colors. For example, the colors of the first auxiliary material 01, the second auxiliary material 02, the third auxiliary material, and the fourth auxiliary material may be red, green, blue, and white, respectively.

[0111] In some embodiments, auxiliary materials may also be periodically added to the cylinder 110 at the second feed port 112.

[0112] The following are some examples of the order of adding auxiliary materials at the second feeding port 112. The first auxiliary material 01, the second auxiliary material 02, the third auxiliary material and the fourth auxiliary material can be represented as 01, 02, 03 and 04 respectively. The gap period when the first auxiliary material 01, the second auxiliary material 02, the third auxiliary material and the fourth auxiliary material are not added is represented by 00.

[0113] Example 1: 01→02→01→02.

[0114] Example 2: 01→02→03→04.

[0115] Example 3: [01→02]→00→[01→02]→00→[01→02]→……00→[01→02].

[0116] Example 4: [01→02→03]→[01→02→03]→……[01→02→03].

[0117] Example 5: [01→02→03→04]→[01→02→03→04]→……[01→02→03→04].

[0118] Example 6: [01→02→03→04→03→02]→[01→02→03→04→03→02]→……[01→02→

[0119] 03→04→03→02).

[0120] Example 7: [01→02→01→03→01→04]→[01→02→01→03→01→04]→……[01→02→

[0121] 01→03→01→04).

[0122] In some embodiments, the main material 120 is the sum of the material added to the cylinder 110 at the first feeding port 111. In other embodiments, the main material 120 is a portion of the material added at the first feeding port 111.

[0123] In some embodiments, the main material 120 is added continuously at a constant rate. In other embodiments, the main material 120 is added at a variable rate or intermittently.

[0124] The first auxiliary material 01 can be added within a first time window. In some embodiments, within the first time window, the first auxiliary material 01 is the sum of the material added to the cylinder 110 at the second feeding port 112. In other embodiments, within the first time window, the first auxiliary material 01 is a portion of the material added at the second feeding port 112.

[0125] In some embodiments, the first auxiliary material 01 is added continuously at a constant rate. In other embodiments, the first auxiliary material 01 is added at a variable rate or intermittently.

[0126] The second auxiliary material 02 can be added within a second time window. In some embodiments, within the second time window, the second auxiliary material 02 is the sum of the material added to the cylinder 110 at the second feeding port 112. In other embodiments, within the second time window, the second auxiliary material 02 is a portion of the material added at the second feeding port 112.

[0127] In some embodiments, during the extrusion process, most of the material can be added to the cylinder 110 from the first feed port 111, and a small portion of the material can be added to the cylinder 110 from the second feed port 112.

[0128] Material added to cylinder 110 through the first feed port 111 will travel a longer path and take longer to reach discharge port 113. Consequently, material added to cylinder 110 through the first feed port 111 will experience a more thorough homogenization and melting effect. Therefore, most of the material is added to cylinder 110 through the first feed port 111, which is beneficial for the complete melting and homogenization of the overall material.

[0129] Material added to the cylinder 110 through the second feeding port 112 will travel a shorter path and take a shorter time to reach the discharge port 113. Consequently, the homogenization and melting effect of material added to the cylinder 110 through the second feeding port 112 is weaker. Therefore, adding a small portion of the material to the cylinder 110 through the second feeding port 112 is beneficial for the material added to the cylinder 110 through the second feeding port 112 to fully melt and homogenize. Furthermore, when switching materials at the second feeding port 112, it helps to reduce the residue of the previous material.

[0130] For example, the first auxiliary material 01 and the second auxiliary material 02 are pigments of different colors. A small amount of pigment can color a large amount of main material 120. The small amount of pigment particles are relatively few and easily dispersed after being added to the cylinder 110. Therefore, the small amount of pigment can fully integrate with the main material 120 through a shorter path and time, achieving the coloring of the main material 120. Along the material conveying direction, the pigment is located in the part of the cylinder 110 after the second feed port 112, making it easier to completely discharge the previous pigment during pigment switching.

[0131] In some embodiments, the weight percentage of the main material 120 in the first mixed melt is greater than 80%. That is, within the first time window, the weight ratio of the main material 120 to the first auxiliary material 01 added into the cylinder 110 can be greater than 4:1. Further, within the first time window, the ratio of the feeding rate (feeding weight per unit time) of the main material 120 to the first auxiliary material 01 is greater than 4:1.

[0132] In some embodiments, within a first time window, the weight of the main material 120 added to the cylinder 110 accounts for 90% to 97% of the sum of the weights of the main material 120 and the first auxiliary material 01. That is, within the first time window, the weight ratio of the main material 120 to the first auxiliary material 01 added to the cylinder 110 is 9:1 to 32.3:1.

[0133] In some embodiments, the volume percentage of the main material 120 in the first mixed melt is greater than 80%. That is, within the first time window, the volume ratio of the main material 120 to the first auxiliary material 01 added into the cylinder 110 can be greater than 4:1. Further, within the first time window, the ratio of the feeding rate (feeding volume per unit time) of the main material 120 to the first auxiliary material 01 is greater than 4:1.

[0134] In some embodiments, the weight percentage of the main material 120 in the second mixed melt is greater than 80%. That is, within the second time window, the weight ratio of the main material 120 to the second auxiliary material 02 added into the cylinder 110 can be greater than 4:1. Further, within the second time window, the ratio of the feeding rate (feeding weight per unit time) of the main material 120 and the second auxiliary material 02 is greater than 4:1.

[0135] In some embodiments, within the second time window, the weight of the main material 120 added to the cylinder 110 accounts for 90% to 97% of the sum of the weights of the main material 120 and the second auxiliary material 02. That is, within the second time window, the weight ratio of the main material 120 to the second auxiliary material 02 added to the cylinder 110 is 9:1 to 32.3:1.

[0136] In some embodiments, the volume percentage of the main material 120 in the second mixed melt is greater than 80%. That is, within the second time window, the volume ratio of the main material 120 to the second auxiliary material 02 added into the cylinder 110 can be greater than 4:1. Further, within the second time window, the ratio of the feeding rate (feeding volume per unit time) of the main material 120 and the second auxiliary material 02 is greater than 4:1.

[0137] In some embodiments, the first auxiliary material 01 includes at least one of fiber or foaming agent. The second auxiliary material 02 includes at least one of fiber or foaming agent.

[0138] Fibers are easily damaged when subjected to shear forces. The first auxiliary material 01 and the second auxiliary material 02 travel a shorter path and time to reach the discharge port 113, and are subjected to weaker shear forces. Therefore, by adding the fiber into the cylinder 110 from the second feed port 112, the operator can help maintain a longer fiber length, which can improve the mechanical properties of the extruded product 150.

[0139] In some embodiments, the fibers may include carbon fibers and glass fibers.

[0140] The foaming agent is prone to structural decomposition when heated. The first auxiliary material 01 and the second auxiliary material 02 will travel a shorter path and time to reach the discharge port 113, and will be subjected to a weaker heating effect. Therefore, the foaming agent is added to the cylinder 110 from the second feed port 112, which is beneficial for the preservation of the foaming agent and results in a foamable extruded product 150.

[0141] In some embodiments, such as Figure 2 As shown, on the axial direction D1 of the cylinder 110, the second feeding port 112 and the first feeding port 111 have a first interval distance L1, and the second feeding port 112 and the discharge port 113 have a second interval distance L2. The first interval distance L1 is greater than or equal to the second interval distance L2.

[0142] Furthermore, the first interval distance L1 is greater than or equal to twice the second interval distance L2. For example, the first interval distance L1 can be three times the second interval distance L2.

[0143] This arrangement of the second feeding port 112 ensures that the travel distance of the material fed into the cylinder 110 through the second feeding port 112 is not too large, which is beneficial for the material fed into the cylinder 110 through the second feeding port 112 to be quickly flushed clean.

[0144] In some embodiments, the ratio (length-to-diameter ratio) of the threaded section length L0 of the screw 140 to the outer diameter D2 of the screw 140 ranges from 20 to 35. Specifically, along the axial direction D1 of the cylinder 110, the threaded section of the screw 140 can be defined as starting from the point where the thread begins to appear and ending at the point where the thread completely ends.

[0145] For example, the length-to-diameter ratio of screw 140 is 30.

[0146] For example, the outer diameter D2 of the screw 140 can be 30mm, and the thread length L0 can be 600mm to 1050mm. Another example is that the outer diameter D2 of the screw 140 can be 45mm, and the thread length L0 can be 900mm to 1350mm.

[0147] Furthermore, the outer diameter D2 of the screw 140 can be greater than or equal to 40 mm. For example, the outer diameter D2 of the screw 140 can be equal to 45 mm. This allows the screw 140 to obtain a larger conveying capacity, increase the material conveying volume, and thus increase the output of the extruded product 150.

[0148] In some embodiments, the first interval L1 is greater than 10 times the outer diameter D2 of the screw 140, and the second interval L2 is greater than 4 times the outer diameter D2 of the screw 140. Further, the first interval L1 is greater than 15 times the outer diameter D2 of the screw 140, and the second interval L2 is greater than 5 times the outer diameter D2 of the screw 140.

[0149] In this way, after the main material 120 is added to the cylinder 110, it can be fully dispersed and melted. After the first auxiliary material 01 is added to the cylinder 110, it will be fully mixed with the main material 120, thereby improving the overall melting and mixing effect of the material in the cylinder 110.

[0150] The above is a schematic representation of the extrusion apparatus 100 according to an embodiment of this specification. It should be noted that the schematic representation of the extrusion apparatus 100 and the technical solution of the extrusion method described below belong to the same concept. Details in the schematic representation of the extrusion apparatus 100 and the technical solution of the extrusion method can be referred to each other.

[0151] This specification also provides a material extrusion method P100. The extrusion method P100 can be implemented manually by an operator, automatically by a controller, or by both.

[0152] The controller includes at least one storage medium and at least one processor. The storage medium stores at least one set of instructions for material extrusion. The processor is communicatively connected to the storage medium. When the extrusion equipment is running, the processor reads the at least one set of instructions and executes the extrusion method P100 described herein according to the instructions of the at least one set of instructions.

[0153] Storage media may include one or more of disks, read-only storage media, or random access storage media. Storage media may also include non-volatile random access memory.

[0154] The processor may take the form of one or more processors. According to some embodiments of this specification, the processor may include one or more hardware processors, such as microcontrollers, microprocessors, reduced instruction set computers (RISC), application-specific integrated circuits (ASICs), application-specific instruction set processors (ASIPs), central processing units (CPUs), microprocessors (MCUs), graphics processing units (GPUs), physical processing units (PPUs), microcontroller units, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), advanced RISC machines (ARMs), programmable logic devices (PLDs), any circuit or processor capable of performing one or more functions, etc., or any combination thereof.

[0155] Figure 5 A flowchart of an extrusion method provided according to some embodiments of this specification is shown.

[0156] like Figure 5 As shown, extrusion method P100 is applied to the extrusion equipment 100 described above, and extrusion method P100 includes:

[0157] S100: Controls screw rotation;

[0158] S200: The main material is added into the main material section through the first feeding port, so that the main material forms the main melt in the main material section;

[0159] S300: The first auxiliary material is added into the feeding section through the second feeding port, thereby forming a first mixed melt in the extrusion section that combines the main melt and the first auxiliary material.

[0160] In some embodiments, after the first auxiliary material is added into the feeding section through the second feeding port, the extrusion method P100 further includes:

[0161] S400: Stop adding the first auxiliary material at the second feeding port and add the second auxiliary material into the feeding section through the second feeding port, thereby forming a second mixed melt in the extrusion section that mixes the main melt and the second auxiliary material.

[0162] In some embodiments, after the second auxiliary material is added into the feeding section through the second feeding port, the extrusion method P100 further includes:

[0163] S500: The addition of the second auxiliary material is stopped at the second feed port, and at least the third auxiliary material is added into the feeding section through the second feed port, thereby forming at least a third mixed melt in the extrusion section. The third mixed melt is formed by mixing the main melt and the third auxiliary material under the drive of the screw.

[0164] The specific implementation methods for steps S100, S200, S300, S400 and S500 have been described in the aforementioned implementation methods of the extrusion equipment, and will not be repeated here.

[0165] In summary, the main material 120 and the first auxiliary material 01 form a first mixed melt in the feeding section 1120 and the extrusion section 1130, and exit the barrel 110 from the discharge port 113. When changing the auxiliary material, the operator of the extrusion equipment 100 replaces the first auxiliary material 01 with the second auxiliary material 02 at the second feeding port 112. The main material 120 and the second auxiliary material 02 form a second mixed melt and exit the barrel 110 from the discharge port 113. The main material 120 added to the barrel 110 from the first feeding port 111 will travel a longer path and take longer to reach the discharge port 113, while the auxiliary material added to the barrel 110 from the second feeding port 112 will travel a shorter path and take longer to reach the discharge port 113. When switching from the first auxiliary material 01 to the second auxiliary material 02 at the second feeding port 112, less of the first auxiliary material 01 remains, which can be quickly washed away during the extrusion process, thereby reducing the risk of the second mixed melt being contaminated by the first auxiliary material 01. Especially when the main material 120 is different in color from the first auxiliary material 01 and the second auxiliary material 02, when switching between the first auxiliary material 01 and the second auxiliary material 02, the residue of the first auxiliary material 01 is less and can be quickly washed away. This can reduce the risk of the color of the first auxiliary material 01 mixing into the second mixed melt, so that the color of each segment of the extruded product 150 has high purity and will not be intermittently mixed with different colors.

[0166] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0167] In summary, after reading this detailed disclosure, those skilled in the art will understand that the foregoing detailed disclosure is presented by way of example only and is not restrictive. Although not explicitly stated herein, those skilled in the art will understand that this specification requires various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this specification and are within the spirit and scope of the exemplary embodiments described herein.

[0168] Furthermore, certain terms in this specification have been used to describe embodiments of this specification. For example, "an embodiment," "an embodiment," and / or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of this specification. Therefore, it is to be emphasized and understood that two or more references to "an embodiment" or "an embodiment" or "alternative embodiment" in various parts of this specification do not necessarily refer to the same embodiment. Moreover, specific features, structures, or characteristics may be suitably combined in one or more embodiments of this specification.

[0169] It should be understood that in the foregoing description of the embodiments in this specification, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the description and aiding in the understanding of a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art may readily identify some of the devices as separate embodiments when reading this specification. That is, the embodiments in this specification can also be understood as an integration of multiple secondary embodiments. It is also valid when each secondary embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0170] Every patent, patent application, publication of a patent application, and other material, such as articles, books, specifications, publications, documents, and literature (excluding any related historical examination documents), cited in this disclosure is incorporated herein for all purposes, including, for example, in the specification and claims of this disclosure. However, in the event of any inconsistency or conflict between the descriptions, definitions, and / or terms used in the foregoing and those used in this disclosure, the descriptions, definitions, and / or terms used in this disclosure shall prevail.

[0171] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments described in this specification. Other modified embodiments are also within the scope of this specification. Therefore, the embodiments disclosed in this specification are merely examples and not limitations. Those skilled in the art can implement the applications described in this specification using alternative configurations based on the embodiments in this specification. Therefore, the embodiments in this specification are not limited to the embodiments precisely described in the applications.

Claims

1. An extrusion apparatus, characterized in that, include: The cylindrical body includes: The main material section, located at one end of the cylinder, includes a first feed port for adding the main material into the cylinder to form the main melt. The feeding section, adjacent to the main material section along the axial direction of the cylinder, includes a second feeding port for adding auxiliary materials into the cylinder to mix with the main melt into a mixture. The second feeding port allows at least a first auxiliary material and a second auxiliary material to be sequentially added into the cylinder. An extrusion section, adjacent to the feeding section along the axial direction, and including a discharge port for extruding the mixed melt formed by the mixture into the cylinder; and A screw, rotatably located within the cylinder, includes: The first segment, located in the main material section and including a first screw groove, forms a spiral first material space with the inner wall of the main material section. This first material space exerts a first pressure on the main material when the screw rotates. The second section, located in the feeding section and including a second screw channel, forms a spiral second material space with the inner wall of the feeding section. This second material space exerts a second pressure on the main melt and the auxiliary material when the screw rotates. This second pressure is less than the first pressure. The third section, located in the extrusion section and including a third screw channel, forms a spiral third material space with the inner wall of the extrusion section to convert the mixture into the mixed melt. A flow control section, located between the first section and the second section, has a first end adjacent to the first section and a second end adjacent to the second section, and includes a flow-limiting screw ridge, a first flow-limiting screw groove, and a second flow-limiting screw groove. The flow-limiting screw ridge, the first flow-limiting screw groove, and the second flow-limiting screw groove are all helical. The first flow-limiting screw groove and the second flow-limiting screw groove are located on opposite sides of the flow-limiting screw ridge. The first end of the first flow-limiting screw groove begins at the first end of the flow control section and communicates with the first screw groove. The second end of the first flow-limiting screw groove ends within the flow control section and is isolated by the second end of the flow control section. The second end of the second flow-limiting screw groove begins at the second end of the flow control section. The second end is connected to the second screw groove, and the first end of the second flow-limiting screw groove stops within the flow control section and is isolated by the first end of the flow control section; the diameter of the inner wall of the cylinder is larger than the outer diameter of the flow-limiting screw ridge, so as to form a gap between the inner wall of the cylinder and the flow-limiting screw ridge, the gap connecting the first flow-limiting screw groove and the second flow-limiting screw groove; the main material enters the first flow-limiting screw groove from the first screw groove through the first end of the first flow-limiting screw groove, passes through the gap between the inner wall of the cylinder and the flow-limiting screw ridge, reaches the second flow-limiting screw groove, and enters the second screw groove through the second end of the second flow-limiting screw groove.

2. The extrusion equipment according to claim 1, characterized in that, The depth of the first screw groove is less than the depth of the second screw groove, so as to facilitate the addition of auxiliary materials into the cylinder through the second feeding port.

3. The extrusion equipment according to claim 1 or 2, characterized in that, The lead of the second screw groove is less than the lead of the first screw groove.

4. The extrusion equipment according to claim 1 or 2, characterized in that, Including pressure sensors, The pressure sensor is installed in the cylinder, near the front end of the second section, to measure the material pressure at the front end of the second section. The front end is located at one end of the second segment adjacent to the first segment.

5. The extrusion equipment according to claim 4, characterized in that, When the screw rotates at its operating speed, At one end of the first segment adjacent to the front end, the material pressure is greater than 2 MPa; At the aforementioned front end, the material pressure is less than or equal to 2 MPa.

6. The extrusion equipment according to claim 1 or 2, characterized in that, In the axial direction, the second feeding port has a first interval distance from the first feeding port, and the second feeding port has a second interval distance from the discharge port, wherein the first interval distance is greater than or equal to the second interval distance.

7. The extrusion equipment according to claim 6, characterized in that, The ratio of the threaded section length to the outer diameter of the screw ranges from 20 to 35. The first interval is greater than 10 times the outer diameter of the screw, and the second interval is greater than 4 times the outer diameter of the screw.

8. The extrusion equipment according to claim 1 or 2, characterized in that, The screw's operating speed is configured such that the material transfer speed it generates in the first material space is greater than the feeding speed of the main material at the first feeding port.

9. A material extrusion method, characterized in that, Applied to the extrusion apparatus as described in any one of claims 1 to 8, the extrusion method comprises: Control the rotation of the screw; The main material is added into the main material section through the first feeding port, so that the main material forms the main melt in the main material section; The first auxiliary material is added into the feeding section through the second feeding port, thereby forming a first mixed melt in the extrusion section that combines the main melt and the first auxiliary material.

10. The extrusion method according to claim 9, characterized in that, After the first auxiliary material is added into the feeding section through the second feeding port, the process includes: The first auxiliary material is stopped being added at the second feeding port, and the second auxiliary material is added into the feeding section through the second feeding port, thereby forming a second mixed melt in the extrusion section that combines the main melt and the second auxiliary material.

11. The extrusion method according to claim 10, characterized in that, After the second auxiliary material is added into the feeding section through the second feeding port, the method further includes: The addition of the second auxiliary material is stopped at the second feeding port, and at least the third auxiliary material is added into the feeding section through the second feeding port, thereby forming at least a third mixed melt in the extrusion section; the third mixed melt is formed by mixing the main melt and the third auxiliary material under the drive of the screw.

12. The extrusion method according to claim 10, characterized in that, In the first mixed melt, the main material accounts for more than 80% by weight; and / or In the second mixed melt, the main material accounts for more than 80% by weight.

13. The extrusion method according to claim 10, characterized in that, The main material is different in color from both the first auxiliary material and the second auxiliary material.

14. The extrusion method according to claim 10, characterized in that, The second auxiliary material includes at least one of color masterbatch, color oil, color powder, fiber, or foaming agent.

15. The extrusion method according to any one of claims 9 to 14, characterized in that, The first auxiliary material includes at least one of color masterbatch, color oil, color powder, fiber, or foaming agent.

Images