Semi-automatic mirror polishing device for extruder

Abstract

The invention discloses a semi-automatic mirror polishing device for an extruder, which belongs to the technical field of extruder screw polishing and comprises a polishing table, and a mirror polishing unit consisting of a thread polishing mechanism and a screw polishing mechanism is arranged on the polishing table. According to the arranged thread polishing mechanism, the rotating freedom degree of a polishing ring is limited through sliding of a connecting rod and a polishing sliding frame, a similar thread pair movement mechanism is formed in combination with a polishing seat with the adjustable axial position, a polishing wheel set is dynamically attached to the threaded face of an extruder screw, and the situation that the threaded face of the screw is not damaged due to non-equidistant arrangement of threads is avoided. And the screw rod polishing mechanism is linked with a multi-stage grinding belt based on a variable-diameter arc-shaped sliding block, is driven by a servo motor, realizes continuous adjustment of the transmission radius of the grinding belt, and is matched with the mesh number gradient configuration of the multi-stage grinding belt, so that the single-pass progressive polishing process of the screw rod part of the extruder screw rod can be realized. And the effect of improving the surface polishing quality and efficiency of the extruder screw is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of extruder screw polishing, in particular to a semi-automatic mirror polishing device for an extruder. Background Art

[0002] After the extruder screw is processed, its surface needs to be polished to improve its smoothness, reduce the friction resistance between the material inside the extruder and the screw, make the melt flow more smoothly, and improve the conveying efficiency of the extruder.

[0003] At present, the polishing equipment for extruder screws generally adopts two methods, hard polishing and soft polishing, and gradually increases the frosting mesh number and polishing speed of the polishing equipment to improve the polishing finish of the extruder screw. However, such a polishing method will result in a large number of polishing times during polishing. In addition, the traditional polishing of the extruder screw is generally carried out step by step on the thread and the screw, and the two cannot be carried out synchronously. Therefore, when polishing the extruder screw, it is necessary to polish its various parts multiple times, which will prolong the overall polishing time of the extruder screw and reduce the overall polishing efficiency. In addition, the pitch of the current extruder screw thread part needs to be set to a non-equidistant state in order to cope with the different thrusts of materials of different densities injected into the pipeline. When conventional extruder polishing equipment is used to polish the extruder screw with non-equidistant threads, it can only perform equidistant polishing on the thread part through a flexible polishing abrasive belt, and cannot polish it in accordance with the thread changes of the screw. As a result, the screw thread part after polishing has orange peel and pitting phenomena, which reduces the polishing quality of the extruder screw. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems raised in the prior art and to provide a semi-automatic mirror polishing device for an extruder.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A semi-automatic mirror polishing device for an extruder comprises a polishing table for polishing a screw of the extruder, wherein the polishing table is provided with a mirror polishing unit, and the mirror polishing unit is composed of a thread polishing mechanism and a screw polishing mechanism; The thread polishing mechanism includes a polishing slide frame arranged on a polishing table, the polishing slide frame is connected to a thread polishing ring via a connecting rod, a strip polishing seat is fixedly arranged on the thread polishing ring, and the strip polishing seat is provided with a pair of polishing wheels slidingly arranged via a slider, and each pair of polishing wheels is movably connected via an elastic contraction component; The screw polishing mechanism consists of a differential polishing assembly and a differential polishing drive assembly. The differential polishing assembly includes a screw polishing seat arranged on the polishing table, a frosting stabilization frame is arranged on the screw polishing seat, a frosting driving wheel is arranged on the frosting stabilization frame, a servo motor is arranged at one end of the frosting driving wheel, and the frosting driving wheel is connected to an equal-diameter driven wheel through a multi-stage frosting belt transmission.

[0006] Preferably, one end of the extruder screw is rotatably arranged on the polishing table by a stepping motor, and the other end of the extruder screw is provided with a rotating ejector rod rotatably connected to the polishing table.

[0007] Preferably, a polishing groove is provided on the inner wall of the strip-shaped polishing seat, a rotating seat fixed to a slider is provided on the top of the polishing wheel, and the rotating seat is slidably connected to the strip-shaped polishing seat.

[0008] Preferably, the elastic contraction component includes a rotating sleeve and an elastic contraction rod sleeved on the surface of each pair of polishing wheels, and a tension spring is provided in the elastic contraction rod. The polishing wheel is contracted by the tension spring and always fits the threaded part of the extruder screw.

[0009] Preferably, the spacing between each pair of polishing wheels is determined by the pitch of adjacent threads of the extruder screw, and the outer surfaces of the multiple pairs of polishing wheels are all provided with frosted surfaces with the same mesh size.

[0010] Preferably, the grinding driving wheels are arranged in pairs, and one opposite side of each pair of the grinding driving wheels is radially slidably connected to a variable diameter arc slider through a variable diameter slide groove, and the multi-stage grinding belt is sleeved on the outer surface of the variable diameter arc slider.

[0011] Preferably, the multi-stage sanding belt consists of a primary sanding belt, a secondary sanding belt and a tertiary sanding belt with increasing mesh sizes, and the linear speeds of the primary sanding belt, the secondary sanding belt and the tertiary sanding belt are driven by variable-diameter arc sliders of different diameters and gradually increase.

[0012] Preferably, the differential polishing drive assembly includes a drive screw arranged on the polishing table, one end of the drive screw is rotatably connected to the polishing table through a drive motor, and the drive screw is threadedly connected to the inner wall of the screw polishing seat.

[0013] Preferably, the screw polishing seat is arranged at an angle, and the inclination direction is adapted to the inclination direction of the adjacent threads on the upper surface of the extruder screw, and the axis of the driving screw is arranged parallel to the axis of the extruder screw.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention designs a thread polishing mechanism that limits the rotational freedom of the polishing ring by sliding a connecting rod and a polishing slide frame. Combined with a polishing seat with adjustable axial position, a thread pair-like motion mechanism is formed, so that the polishing wheel group and the thread surface of the extruder screw are dynamically fitted. The screw thread surface will not be interrupted in the polishing and fitting due to the non-equidistant setting of the thread, thereby achieving the effect of improving the polishing quality and efficiency of the extruder screw thread part.

[0015] 2. The screw polishing mechanism is based on the linkage between the variable diameter arc slider and the multi-stage abrasive belt. It is driven by a servo motor to achieve continuous adjustment of the transmission radius of the abrasive belt. Combined with the mesh gradient configuration of the multi-stage abrasive belt, it can realize a single-pass progressive polishing process for the screw part of the extruder screw.

[0016] 3. When the mirror polishing unit is driven in reverse, the present invention configures the mesh size of the reverse multi-stage abrasive belt, adopts the radius gradient flipping technology in the reverse stroke, and combines the polishing ring phase synchronization adjustment mechanism to form a forward and reverse angle polishing cycle, thereby improving the polishing efficiency and polishing quality of the extruder screw. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the three-dimensional structure of a semi-automatic mirror polishing device for an extruder proposed by the present invention; Figure 2 For the present invention Figure 1 A magnified view of the structure at center A; Figure 3 For the present invention Figure 1 A magnified view of the structure at B in the middle; Figure 4 This is an overall structural assembly view of a semi-automatic mirror polishing device for an extruder proposed by the present invention; Figure 5 This is a schematic structural diagram of a thread polishing ring in a semi-automatic mirror polishing device for an extruder proposed by the present invention; Figure 6 This is a structural schematic diagram of the polishing wheel and the rotating sleeve in the semi-automatic mirror polishing device for an extruder proposed by the present invention; Figure 7 This is a structural schematic diagram of the differential polishing drive assembly in the semi-automatic mirror polishing device for an extruder proposed by the present invention.

[0018] Figure numerals: 1. Polishing table; 11. Stepper motor; 12. Rotating ejector; 2. Extruder screw; 3. Polishing slide frame; 31. Threaded polishing ring; 32. Strip polishing seat; 33. Polishing wheel; 331. Rotating seat; 34. Rotating sleeve; 341. Elastic shrinkage rod; 4. Screw polishing seat; 41. Frosting stabilizing frame; 42. Frosting driving wheel; 421. Servo motor; 43. Multi-stage frosting belt; 431. First-stage frosting belt; 432. Second-stage frosting belt; 433. Third-stage frosting belt; 44. Equal-diameter driven wheel; 45. Variable-diameter arc slider; 5. Driving motor; 51. Driving screw. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "mounted / connected," and "connected" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention in specific circumstances.

[0022] Example, see Figures 1 to 7 , a semi-automatic mirror polishing device for an extruder, comprising a polishing table 1 for polishing an extruder screw 2, a mirror polishing unit being provided on the polishing table 1, and the mirror polishing unit being composed of a thread polishing mechanism and a screw polishing mechanism; Furthermore, one end of the extruder screw 2 is rotatably mounted on the polishing table 1 by a stepper motor 11, and the other end of the extruder screw 2 is provided with a rotating push rod 12 rotatably connected to the polishing table 1, and a rotating frame fixed by bolts is provided at the rotating push rod 12, which can lock the other end of the extruder screw 2 after it is mounted on the output shaft of the stepper motor 11; It should be noted that when the extruder screw 2 is driven to rotate by the stepper motor 11, the threaded part and the screw part can produce relative movement relative to the mirror polishing unit. At this time, the thread polishing mechanism can always fit the threaded part with changing pitch, and polish the threads at various parts of the screw. At the same time, the screw polishing mechanism following the thread polishing mechanism can gradually increase the mesh count and polishing speed during the screw polishing process, so that the surface of the extruder screw 2 can be quickly polished, and the polishing mechanism will not be unable to always perform fit polishing due to the non-equidistant threads on its surface, thereby improving the polishing quality of the extruder screw 2 and accelerating the polishing speed.

[0023] like Figure 2 and Figures 4 to 6 As shown, the thread polishing mechanism includes a polishing slide 3 set on the polishing table 1, the polishing slide 3 is connected to the thread polishing ring 31 through a connecting rod, the thread polishing ring 31 is fixedly provided with a strip polishing seat 32, and the strip polishing seat 32 is provided with a pair of polishing wheels 33 slidingly arranged through a slider, and each pair of polishing wheels 33 is movably connected by an elastic contraction component; Furthermore, a polishing groove is provided on the inner wall of the strip-shaped polishing seat 32, and a rotating seat 331 fixed to the slider is provided on the top of the polishing wheel 33, and the rotating seat 331 is slidably connected to the strip-shaped polishing seat 32; Furthermore, the elastic contraction assembly includes a rotating sleeve 34 and an elastic contraction rod 341 sleeved on the surface of each pair of polishing wheels 33. A tension spring is provided in the elastic contraction rod 341. The polishing wheel 33 is contracted by the tension spring and always fits the threaded portion of the extruder screw 2. The elastic contraction rod 341 can also be made of other similar materials with a pull-back force, such as a buffer cylinder and a connecting rod made of an elastic material. Furthermore, the spacing between each pair of polishing wheels 33 is determined by the pitch of adjacent threads of the extruder screw 2, and the outer surfaces of the multiple pairs of polishing wheels 33 are provided with a frosted surface with the same grit as the polishing requirement of the threaded portion, so that when the extruder screw 2 is driven to rotate by the stepper motor 11, a driving force is generated to move the strip-shaped polishing seat 32 along the axis of the screw, so that the multiple pairs of polishing wheels 33 are always in contact with the threaded portion to polish the extruder screw 2; It should be noted that: the threaded polishing ring 31 is slidably connected to the polishing slide frame 3 through a connecting rod, which can limit the rotation angle of the threaded polishing ring 31, making it similar to a threaded rod driving a threaded sleeve structure, pushing the strip polishing seat 32 to move along the axial direction of the screw, always fitting on the threaded part of the extruder screw 2, and by setting multiple pairs of polishing wheels 33 to polish the threaded parts at the same time, the polishing speed of the threaded part of the extruder screw 2 can be accelerated, and its polishing efficiency can be improved.

[0024] like Figure 3 、 Figure 4 and Figure 7 As shown, the screw polishing mechanism consists of a differential polishing assembly and a differential polishing drive assembly. The differential polishing assembly includes a screw polishing seat 4 arranged on the polishing table 1, a frosting stabilizing frame 41 is provided on the screw polishing seat 4, a frosting driving wheel 42 is provided on the frosting stabilizing frame 41, a servo motor 421 is provided at one end of the frosting driving wheel 42, and each pair of frosting driving wheels 42 is connected to an equal-diameter driven wheel 44 through a multi-stage frosting belt 43.

[0025] Furthermore, the grinding driving wheels 42 are arranged in pairs, and the opposite side of the grinding driving wheels 42 is radially slidably connected to a variable diameter arc slider 45 through a variable diameter slide groove, and the multi-stage grinding belt 43 is sleeved on the outer surface of the variable diameter arc slider 45, wherein the variable diameter arc slider 45 is driven by the existing claw driving structure to change the diameter. The diameter changing driving process is the same as the diameter changing principle of the existing three-jaw chuck movable claw, which is the existing technology. The diameter changing drive of the variable diameter arc slider 45 will not be described in detail later. Furthermore, the multi-stage sanding belt 43 is composed of a primary sanding belt 431, a secondary sanding belt 432, and a tertiary sanding belt 433, each having an increasing mesh size. The linear speeds of the primary sanding belt 431, the secondary sanding belt 432, and the tertiary sanding belt 433 are driven by variable-diameter arc-shaped sliders 45 of different diameters, gradually increasing. The multi-stage sanding belt 43 is a flexible sanding belt. Driven by the servo motor 421, the lower surface of the sanding belt is always in contact with the screw portion of the upper surface of the extruder screw 2, whereby the screw portion can be polished step by step, thereby accelerating the polishing speed of the extruder screw 2. like Figure 4 As shown, the differential polishing drive assembly includes a driving screw 51 provided on the polishing table 1, one end of the driving screw 51 is rotatably connected to the polishing table 1 through the driving motor 5, and the driving screw 51 is threadedly connected to the inner wall of the screw polishing seat 4, the screw polishing seat 4 is tilted, and the tilting direction is adapted to the tilting direction of the adjacent threads on the upper surface of the extruder screw 2, the axis of the driving screw 51 is arranged parallel to the axis of the extruder screw 2, wherein the rotation speed of the driving motor 5 is adapted to the rotation speed of the stepping motor 11, so that when the threads on the upper surface of the extruder screw 2 rotate, the lower surface of the abrasive belt is fitted with the screw portion at the thread interval; It should be noted that the variable-diameter arc slider 45 located between two adjacent frosting driving wheels 42 can change the transmission radius of the multi-stage frosting belt 43 set therein by changing the distance from the axis of the frosting driving wheel 42. According to the fact that the linear speed of the transmission belt is equal to the linear speed of the driving wheel, it can be known that the linear speed of the transmission belt depends on the angular velocity and the rotation radius of the driving wheel. Since the frosting driving wheels 42 are driven by the output shaft of the same servo motor 421, their angular velocities are the same. When the variable-diameter arc slider 45 changes the transmission radius of the multi-stage frosting belt 43, the transmission speed of the frosting belt can be changed, so that different polishing speeds of the screw part of the extruder screw 2 can be achieved by the same motor, thereby achieving the effect of polishing the screw part step by step, and then there is no need to repeat the process of performing different frosting mesh numbers and polishing speeds on the screw part multiple times, thereby improving the polishing efficiency of the screw part of the extruder screw 2. Based on the above, when the extruder screw 2 moves the mirror polishing unit to the rotating top rod 12 through the stepper motor 11, the multi-stage frosting belt 43 on the frosting driving wheel 42 can be replaced so that the mesh number of the frosting belt that first contacts the extruder screw 2 is greater than that of the original three-stage frosting belt 433, and the subsequent frosting belts are replaced step by step. That is, at this time, the mesh number of the first-stage frosting belt 431 in the reverse movement process is the largest compared with the second-stage frosting belt 432 and the third-stage frosting belt 433; Based on the above, in the process of the differential polishing assembly moving in the opposite direction toward the stepping motor 11, the variable diameter arc slider 45 can be adjusted to be aligned with the stepping motor 11. Figure 7 As shown, the radius distribution when moving toward the rotating push rod 12 is opposite. At the same time, the thread polishing mechanism can polish the threaded parts of the extruder screw 2 in reverse by inserting multiple pairs of polishing wheels 33 one by one into the threaded parts of the extruder screw 2, so that the surface of the extruder screw 2 can be quickly polished in this way in a reciprocating manner.

[0026] Working principle: The present invention divides the polishing process of the extruder screw 2 into a thread polishing process and a screw polishing process, wherein the thread polishing process is as follows: when polishing the threaded portion of the extruder screw 2, the thread polishing ring 31 is slidably connected to the polishing slide 3 through a connecting rod, which can limit the rotation angle of the thread polishing ring 31, making it similar to a threaded rod driving a threaded sleeve structure, pushing the strip polishing seat 32 to move along the axial direction of the screw, always fitting on the threaded portion of the extruder screw 2, and by providing multiple pairs of polishing wheels 33 to polish the threaded portion simultaneously, the polishing speed of the threaded portion of the extruder screw 2 can be accelerated, thereby improving its polishing efficiency; The screw polishing process is as follows: when polishing the screw portion of the extruder screw 2, the variable diameter arc slider 45 located between the two adjacent frosting driving wheels 42 changes the distance from the axis of the frosting driving wheel 42, so that the transmission radius of the multi-stage frosting belt 43 correspondingly set here can be changed. According to the fact that the linear speed of the transmission belt is equal to the linear speed of the driving wheel, it can be known that the linear speed of the transmission belt depends on the angular velocity and rotation radius of the driving wheel. Since the frosting driving wheel 42 is driven by the output shaft of the same servo motor 421, its angular velocity is the same. When the variable diameter arc slider 45 changes the transmission radius of the multi-stage frosting belt 43, the transmission speed of the frosting belt can be changed, so that different polishing speeds of the screw portion of the extruder screw 2 can be achieved by the same motor, thereby achieving the effect of polishing the screw portion step by step, and then there is no need to repeat the process of performing different frosting mesh numbers and polishing speeds on the screw portion multiple times, thereby improving the polishing efficiency of the screw portion of the extruder screw 2. Based on the above, when the extruder screw 2 moves the mirror polishing unit to the rotating top rod 12 through the stepper motor 11, the multi-stage frosting belt 43 on the frosting driving wheel 42 can be replaced so that the mesh number of the frosting belt that first contacts the extruder screw 2 is greater than that of the original three-stage frosting belt 433, and the subsequent frosting belts are replaced step by step. That is, at this time, the mesh number of the first-stage frosting belt 431 in the reverse movement process is the largest compared with the second-stage frosting belt 432 and the third-stage frosting belt 433; Based on the above, in the process of the differential polishing assembly moving in the opposite direction toward the stepping motor 11, the variable diameter arc slider 45 can be adjusted to be aligned with the stepping motor 11. Figure 7 As shown, the radius distribution when moving toward the rotating push rod 12 is opposite. At the same time, the thread polishing mechanism can polish the threaded parts of the extruder screw 2 in reverse by inserting multiple pairs of polishing wheels 33 one by one into the threaded parts of the extruder screw 2, so that the surface of the extruder screw 2 can be quickly polished in this way in a reciprocating manner.

[0027] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A semi-automatic mirror polishing device for an extruder, comprising a polishing table (1) for polishing an extruder screw (2), characterized in that: The polishing table (1) is provided with a mirror polishing unit, and the mirror polishing unit is composed of a thread polishing mechanism and a screw polishing mechanism; The thread polishing mechanism comprises a polishing slide frame (3) arranged on a polishing table (1), the polishing slide frame (3) being connected to a thread polishing ring (31) via a connecting rod, a strip polishing seat (32) being fixedly arranged on the thread polishing ring (31), the strip polishing seat (32) being provided with polishing wheels (33) arranged in pairs slidingly via a slider, and each pair of polishing wheels (33) being movably connected via an elastic contraction assembly; The screw polishing mechanism is composed of a differential polishing assembly and a differential polishing drive assembly. The differential polishing assembly comprises a screw polishing seat (4) arranged on a polishing table (1). A frosting stabilizing frame (41) is arranged on the screw polishing seat (4). A frosting driving wheel (42) is arranged on the frosting stabilizing frame (41). A servo motor (421) is arranged at one end of the frosting driving wheel (42). The frosting driving wheel (42) is connected to an equal-diameter driven wheel (44) through a multi-stage frosting belt (43).

2. The semi-automatic mirror polishing device for an extruder according to claim 1, characterized in that: One end of the extruder screw (2) is rotatably arranged on the polishing table (1) via a stepping motor (11), and the other end of the extruder screw (2) is provided with a rotating top rod (12) rotatably connected to the polishing table (1).

3. The semi-automatic mirror polishing device for an extruder according to claim 1, characterized in that: A polishing groove is provided on the inner wall of the strip-shaped polishing seat (32), and a rotating seat (331) fixed to the slider is provided on the top of the polishing wheel (33), and the rotating seat (331) is slidably connected to the strip-shaped polishing seat (32).

4. The semi-automatic mirror polishing device for an extruder according to claim 3, characterized in that: The elastic contraction assembly comprises a rotating sleeve (34) and an elastic contraction rod (341) sleeved on the surface of each pair of polishing wheels (33). A tension spring is provided in the elastic contraction rod (341). The polishing wheels (33) are contracted by the tension spring and always adhere to the threaded portion of the extruder screw (2).

5. The semi-automatic mirror polishing device for an extruder according to claim 1, characterized in that: The spacing between each pair of polishing wheels (33) is determined by the pitch of adjacent threads of the extruder screw (2), and the outer surfaces of the multiple pairs of polishing wheels (33) are all provided with frosted surfaces of the same mesh size.

6. The semi-automatic mirror polishing device for an extruder according to claim 1, characterized in that: The grinding driving wheels (42) are arranged in pairs, and one opposite side of each pair of the grinding driving wheels (42) is radially slidably connected to a variable diameter arc slider (45) via a variable diameter slide groove, and the multi-stage grinding belt (43) is sleeved on the outer surface of the variable diameter arc slider (45).

7. The semi-automatic mirror polishing device for an extruder according to claim 1, characterized in that: The multi-stage grinding belt (43) is composed of a first-stage grinding belt (431), a second-stage grinding belt (432), and a third-stage grinding belt (433) with mesh sizes increasing in sequence, and the linear speeds of the first-stage grinding belt (431), the second-stage grinding belt (432), and the third-stage grinding belt (433) are driven by variable-diameter arc-shaped sliders (45) of different diameters and gradually increase.

8. The semi-automatic mirror polishing device for an extruder according to claim 7, characterized in that: The differential polishing drive assembly comprises a driving screw (51) arranged on the polishing table (1), one end of the driving screw (51) is rotationally connected to the polishing table (1) via a driving motor (5), and the driving screw (51) is threadedly connected to the inner wall of the screw polishing seat (4).

9. The semi-automatic mirror polishing device for an extruder according to claim 8, characterized in that: The screw polishing seat (4) is arranged tilted, and the tilting direction is adapted to the tilting direction of the adjacent threads on the upper surface of the extruder screw (2), and the axis of the driving screw (51) is arranged parallel to the axis of the extruder screw (2).

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