An injection molding machine for preparing plastic injection molded parts

Abstract

The present invention relates to the technical field of injection molding machines, and discloses an injection molding machine for preparing plastic injection molded parts, which includes a workbench and a barrel installed on the top of the workbench. A screw is installed in the barrel, a heating part is installed on the outer wall of the barrel, and a feed trough is also installed on the outer wall of the barrel. It further includes: a reflux hopper installed on the outer wall of the barrel away from the injection port and above, with balls contained in the reflux hopper. An electric switch is provided at the discharge port of the reflux hopper. When the balls enter the barrel, the height of the balls piled up in the screw grooves of the screw is equal to or greater than the radius of the screw. By arranging the reflux hopper above, the present invention can make the height of the balls falling and piled up in the screw grooves of the screw equal to or greater than the radius of the screw, so as to ensure that the balls in the barrel can keep in contact with the screw in different sections, and further improve the cleaning effect of the screw in different sections.

Description

Technical Field

[0001] The present invention relates to the technical field of injection molding machines, and specifically relates to an injection molding machine for preparing plastic injection molded parts. Background Art

[0002] An injection molding machine, also known as an injection molding machine or an injection machine, is the main molding equipment for making various shaped plastic products from thermoplastic or thermosetting plastics using plastic molding dies, and can be specifically divided into vertical, horizontal, etc.

[0003] For example, Chinese Patent CN117507249B discloses a uniformly heated injection molding machine barrel. After use, through the cooperation of components such as a cleaning mechanism, a conveying mechanism, and a separating mechanism, it can automatically clean the outer wall of the screw feed rod inside the barrel, solving the problem that the traditional screw feed rod needs to be removed from the inside of the barrel for cleaning, and effectively improving the convenience of cleaning the screw feed rod.

[0004] However, since the groove depth of the screw of the injection molding machine is different in different sections, the gap between the screw and the barrel in different sections is different. In the above-mentioned disclosed document, the method of transferring the balls from below the barrel by the supporting block cannot ensure that the balls in the barrel can maintain contact with the screw in different sections, resulting in different cleaning effects of the screw in different sections, and thus poor cleaning effect of the screw. Summary of the Invention

[0005] The purpose of the present invention is to provide an injection molding machine for preparing plastic injection molded parts to solve at least one of the technical problems existing in the above-mentioned prior art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: An injection molding machine for preparing plastic injection molded parts, including a workbench and a barrel installed on the top of the workbench. A screw is installed inside the barrel, a heating part is installed on the outer wall of the barrel, and a feed trough is also installed on the outer wall of the barrel. It further includes:

[0007] A return hopper installed on the outer wall of the barrel away from the injection port and above it. The return hopper contains balls, and an electric switch is provided at the discharge port of the return hopper. When the balls enter the barrel, the height of the balls piled up in the screw groove is equal to or greater than the radius of the screw;

[0008] A drainage part connected and installed on the outer wall of the barrel near the injection port below, and the balls can be discharged out of the barrel from the drainage part;

[0009] A return part for re - returning the balls discharged from the drainage part to the return hopper to form a circulating loop for the balls.

[0010] Preferably, the drainage part includes a mounting bracket fixed to the outer wall below the barrel. A drainage pipe is mounted on the mounting bracket. The drainage pipe includes a vertical pipe and an inclined pipe that are connected to each other. The vertical pipe is vertically connected to the outer wall of the barrel. A launching pipe is fixed to the bottom of the mounting bracket, and a communication groove communicating with the launching pipe is formed inside the vertical part of the mounting bracket. The inclined pipe communicates with the communication groove. A telescopic column is also mounted on the top of the launching pipe, and the top end of the telescopic column extends into the bottom of the vertical pipe and can open or block the connection between the vertical pipe and the inclined pipe.

[0011] Preferably, the reflux part includes a firing column slidably mounted on the inner wall of one side of the launching pipe. Elastic bands are respectively connected between the outer walls on both sides of the firing column and both sides of the end of the launching pipe. A blocking strip is vertically slidably mounted on the inner wall of the communication groove, and a connecting rod is rotatably connected between the blocking strip and the firing column. The outlet of the launching pipe away from the firing column is communicated with a reflux hopper through a reflux pipe.

[0012] The reflux part further includes a driving member, and the driving member can intermittently push the firing column to move away from the launching pipe.

[0013] Preferably, the driving member includes a rotating disk rotatably mounted on the top of the workbench through a bracket. A dial rod capable of intermittently contacting the protrusion on the side of the firing column is fixed to the outer wall of the edge of the rotating disk. It further includes a driving motor mounted on the bracket and used to drive the rotating disk to rotate.

[0014] Preferably, the ball has magnetism, and the magnetic force can only make the balls adhere to each other. A sleeve is sleeved outside the reflux pipe, and a coil capable of generating a magnetic field is embedded in the sleeve.

[0015] Preferably, drain holes are formed on the outer wall of the inclined pipe, liquid leakage holes are formed on the outer wall of the launching pipe, and a liquid guiding groove for drainage is arranged on the top of the workbench below the launching pipe.

[0016] Preferably, a elastic sheet is mounted on the inner wall at the connection of the vertical pipe and the inclined pipe.

[0017] Preferably, a waterproof sleeve surrounding the telescopic column is also mounted on the top of the launching pipe.

[0018] Preferably, the reflux pipe is arranged in a spiral and obliquely conveying manner, and a section of the reflux pipe close to the reflux hopper has a downward inclination angle.

[0019] Preferably, the elastic band is an elastic fiber band or a tension spring.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. By utilizing the mutual extrusion change of the screw during the process of conveying the ball bearings, the present invention improves the cleaning effect on the screw thread groove of the screw. Moreover, by arranging the reflux hopper above, the height at which the ball bearings fall and accumulate in the screw thread groove can be equal to or greater than the radius of the screw. In this way, it can ensure that the ball bearings in the barrel are in contact with the screw in different sections, further improving the cleaning effect of the screw in different sections.

[0022] 2. The present invention sets the ball bearings as magnetic balls with a certain weak magnetism. When they are in the L section, the ball bearings will adsorb to each other and form a rolling unit with a larger volume, so as to perform rolling friction cleaning on the deeper thread grooves. And the frictional force will be greater than that of a single ball bearing. Then when they move to the L and L positions, as can be seen from the above, as the depth of the thread groove decreases, the ball bearings will be squeezed. At this time, while being squeezed, they also need to overcome the magnetic attraction force between the ball bearings. In this way, the frictional force generated by the reaction between the ball bearings and the thread groove can be made greater, further improving the cleaning effect. Under the different actions of high temperature and magnetic field, the magnetism of the ball bearings will continuously weaken and recover during the circulation process, so as to adapt to the use in different sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the left side view shaft side three-dimensional view of the present invention;

[0024] Figure 2 is the right side view isometric two-axis side three-dimensional view of the present invention;

[0025] Figure 3 is the front cross-sectional view of the present invention;

[0026] Figure 4 is of the present invention Figure 3 the enlarged view at A in;

[0027] Figure 5 is of the present invention Figure 3 the cross-sectional view along B-B in;

[0028] Figure 6 is the state diagram of the ball bearings of the present invention in different sections of the screw;

[0029] Figure 7 is the semi-sectional three-dimensional structure schematic diagram of the screw of the present invention.

[0030] In the figure: 1, workbench; 2, barrel; 3, heating part; 4, feeding trough; 5, mounting bracket; 6, emission tube; 7, return pipe; 8, sleeve; 9, return hopper; 10, screw; 11, vertical pipe; 12, inclined pipe; 13, telescopic column; 14, retaining bar; 15, communication groove; 16, firing column; 17, connecting rod; 18, liquid guide groove; 19, rotating disk; 20, shifting lever; 21, elastic band; 22, liquid discharge hole; 23, liquid leakage hole; 24, ball; 25, elastic sheet. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Please refer to Figures 1 to 7 , the present invention provides a technical solution: an injection molding machine for preparing plastic injection molded parts, including a workbench 1 and a barrel 2 installed on the top of the workbench 1. A screw 10 is installed in the barrel 2, a heating part 3 is installed on the outer wall of the barrel 2, and a feeding trough 4 is also installed on the outer wall of the barrel 2. It further includes:

[0033] A return hopper 9 installed on the outer wall of the barrel 2 away from the injection port and above. The return hopper 9 contains balls 24. An electric switch is provided at the discharge port of the return hopper 9. When the balls 24 enter the barrel 2, the height of the balls 24 accumulated in the screw grooves of the screw 10 is equal to or greater than the radius of the screw 10;

[0034] A drainage part communicatively installed on the outer wall of the barrel 2 near the injection port below, and the balls 24 can be discharged out of the barrel 2 from the drainage part;

[0035] A return part for re-returning the balls 24 discharged from the drainage part to the return hopper 9 to form a circulating loop for the balls 24.

[0036] Currently, during the use of existing injection molding machines, first, plastic particles enter the barrel 2 from the feeding trough 4, and then are rotationally conveyed by the screw 10 and gradually become molten under the heating of the heating part 3, and then are extruded into the mold from the injection port by the axial movement of the screw 10. During this process, the plastic particles need to be heated to a molten state and the air and water vapor in them need to be discharged. Therefore, the functions of different sections of the screw 10 are different, and the depths of the screw grooves of the threads in each section are also different. Refer to Figure 6 and Figure 7 ;

[0037] The screw 10 can generally be divided into three sections. The first section is the feeding section, which is the range shown as L1 in the figure. The depth of the screw groove in this section is fixed, and its main function is to be responsible for preheating, conveying, and pushing the plastic solid. And the plastic particles start to melt at the end of the feeding section. The second section is the compression section, which is the range shown as L2 in the figure. This section is a tapered screw, and the screw groove changes from deep to shallow. Its main functions are melting, kneading, shearing compression, and pressurized exhaust of the plastic raw material. In this section, the plastic particles will completely become in a molten state. And the third section is the homogenization section, which is the range shown as L3 in the figure. The depth of the screw groove in this section is fixed. Its main functions are kneading, melt conveying, metering, and it must also provide sufficient pressure to maintain the uniform temperature of the melt and the stable flow rate of the molten plastic;

[0038] From this, it can be known that the depths of the screw grooves in different sections of the screw 10 are different, which also means that the gaps between the screw and the barrel 2 are different. Therefore, after the injection molding is completed and the plastic inside is extruded, when cleaning the residual material in the screw groove of the screw 10, the electric switch of the discharge port of the reflux hopper 9 is opened, so that all the balls 24 inside can fall into the barrel 2 and first accumulate in one of the screw grooves. Then when the screw 10 rotates, the rotation of the screw 10 will convey the balls 24 forward. And since the balls 24 will not rotate together with the rotation of the screw 10, the mutual friction between the balls 24 and the inner wall of the screw groove of the screw 10 can be used to clean the screw 10. At the same time, the cleaning can also be cooperated by injecting a cleaning liquid through the feed slot 4 and heating by the heating part 3 until the balls 24 are conveyed to the drainage part and discharged out of the barrel 2, and the discharged balls will reflow into the reflux hopper 9 through the reflux part, so that the balls 24 form a circulation loop to clean the screw 10 multiple times;

[0039] It is worth noting that since the reflux hopper 9 is arranged above, in the initial state, the height at which the balls 24 fall and accumulate in the screw groove of the screw 10 can be equal to or greater than the radius of the screw 10. In this way, when the screw 10 conveys the balls 24 in the L1 section, the balls 24 can simultaneously have relative friction with the inner wall of the screw groove and the rod wall of the screw, so that the outer wall deep in the screw groove can be comprehensively cleaned, improving the cleaning effect on the screw 10 at the deep position of the screw groove. For the specific state, reference can be made to Figure 6 the state shown in

[0040] And when the balls 24 are conveyed to the L2 section, due to the gradual change in the depth of the screw groove, the balls in the screw groove will be squeezed into the screw groove spaces in front and behind while the space decreases. See Figures 6 - 7in the direction indicated by the arrow, and as can be known from the previous content, the L2 section mainly compresses and exhausts the plastic. Therefore, compared with the L1 section, the adhesion between the remaining material and the screw 10 in this section will be closer. By the mutual extrusion of the balls 24, the balls 24 can apply a more rigid frictional force to the remaining material at this position, thereby cleaning the remaining material at this section position and improving the cleaning effect;

[0041] Then when the balls 24 are conveyed to the L3 section, the number of balls 24 in the screw groove decreases, but the interval where the balls 24 are located increases, which can also improve the cleaning effect on the screw groove until the balls 24 are discharged from the drainage part out of the barrel 2, completing a cleaning process;

[0042] In summary, by utilizing the mutual extrusion change of the screw 10 during the conveying of the balls 24, the cleaning effect on the screw groove of the screw 10 is improved, and it is ensured that the balls 24 in the barrel can keep in contact with the screw in different sections, further improving the cleaning effect of the screw 10 in different sections.

[0043] In one relatively preferred embodiment, an implementation manner of the drainage part is provided. Specifically, reference can be made to Figures 3 - 4 ;

[0044] The drainage part includes a mounting frame 5 fixed on the outer wall of the lower part of the barrel 2. A drainage pipe is installed on the mounting frame 5. The drainage pipe includes a vertical pipe 11 and an inclined pipe 12 that are connected to each other. The vertical pipe 11 is vertically connected to the outer wall of the barrel 2. A launching pipe 6 is fixed at the bottom of the mounting frame 5, and a communication groove 15 communicating with the launching pipe 6 is opened inside the vertical part of the mounting frame 5. The inclined pipe 12 is communicated with the communication groove 15. A telescopic column 13 is also installed at the top of the launching pipe 6, and the top end of the telescopic column 13 extends into the vertical pipe 11 from the bottom and can open or block the connection between the vertical pipe 11 and the inclined pipe 12.

[0045] As can be known from the above content, when the balls 24 are conveyed to the position of the vertical pipe 11 along with the screw 10, the balls 24 will be discharged through the vertical pipe 11, and then enter the launching pipe 6 from the inclined pipe 12 and the communication groove 15 to prepare for the subsequent return of the balls 24;

[0046] Among them, the setting of the telescopic column 13 can make its top end extend and be sealed and flush with the inner wall of the barrel 2 during injection molding, without affecting the normal operation of injection molding. During the cleaning process, the contraction of the telescopic column 13 can open the vertical pipe 11 and make the vertical pipe 11 and the inclined pipe 12 in a communicating state to facilitate the discharge of the balls 24.

[0047] In one relatively preferred embodiment, an implementation manner of the return part is provided. Specifically, reference can be made to Figure 4 and Figure 5 ;

[0048] The return part includes a firing column 16 slidably mounted on the inner wall of one side of the launch tube 6. Elastic bands 21 are respectively connected between the outer walls on both sides of the firing column 16 and both sides of the end of the launch tube 6. A stop bar 14 is vertically slidably mounted on the inner wall of the communication groove 15, and a connecting rod 17 is rotatably connected between the stop bar 14 and the firing column 16. The outlet of the launch tube 6 far from the firing column 16 is communicated with the return hopper 9 through a return pipe 7;

[0049] The return part further includes a driving member, and the driving member can intermittently push the firing column 16 to move away from the launch tube 6.

[0050] When the balls 24 are discharged into the launch tube 6, under the action of the driving member, the firing column 16 is intermittently pushed to move, and during the movement, the elastic band 21 is stretched to accumulate elastic potential energy. When the driving member is separated from the firing column 16, the elastic potential energy of the elastic band 21 is instantaneously released, so that the firing column 16 can shoot out the balls 24 in the launch tube 6 and flow back into the return hopper 9 through the return pipe 7. In this way, through the continuous reciprocating movement of the firing column 16, the balls 24 can continuously return to the return hopper 9 to complete the return process;

[0051] Among them, in order to prevent the excessive number of balls 24 in the launch tube 6 from affecting the launch and return effect, through the arrangement of the stop bar 14 and the connecting rod 17, when the firing column 16 fires, the stop bar 14 can be driven by the connecting rod 17 to open the communication groove 15, so that the balls 24 can fall into the communication groove 15. Then, when the firing column 16 moves backward and prepares for the next firing, the stop bar 14 closes the communication groove 15 to block the continuous falling of the balls 24, and the balls 24 in the communication groove 15 will enter the launch tube 6 to prepare for launch. In this way, by controlling the feeding of the balls 24, the number of balls 24 in the launch tube 6 can be guaranteed, so as to ensure the complete return of the balls 24 and then complete the subsequent repeated cyclic cleaning.

[0052] In one relatively preferred embodiment, an implementation manner of the driving member is provided, and specific reference can be made to Figure 4 ;

[0053] The driving member includes a rotating disk 19 rotatably mounted on the top of the workbench 1 through a bracket. A dial rod 20 capable of intermittently contacting the protrusion on the side of the firing column 16 is fixed on the outer wall of the edge of the rotating disk 19. It also includes a driving motor mounted on the bracket and used to drive the rotating disk 19 to rotate.

[0054] The driving motor drives the rotating disk 19 to rotate counterclockwise, so that the dial rod 20 at the edge part can contact the protrusion part of the firing column 16 and push the firing column 16 to move until it is separated from the firing column 16, thus completing a firing process. In this way, through the continuous rotation of the rotating disk 19, the firing column 16 can be continuously fired to complete the return process of the above-mentioned balls 24.

[0055] In one relatively preferred embodiment, the ball 24 has magnetism, and the magnetic force can only make the balls 24 adhere to each other. A sleeve 8 is sleeved outside the return pipe 7, and a coil capable of generating a magnetic field is embedded in the sleeve 8.

[0056] In order to further improve the friction cleaning effect between the balls 24 and the screw grooves of the screw 10, the balls 24 are set as magnetic balls with a certain weak magnetism. In this way, when they are in the L1 section, the balls 24 will adsorb to each other and form a rolling unit with a larger volume, so as to perform rolling friction cleaning on deeper screw grooves, and the frictional force will be greater than that of a single ball 24. Then when they move to the L2 and L3 positions, as can be seen from the above, as the depth of the screw groove decreases, the balls 24 will be squeezed, and at this time, while being squeezed, it is also necessary to overcome the magnetic suction force between the balls 24, so that the frictional force generated by the reaction between the balls 24 and the screw grooves can be greater, thereby further improving the cleaning effect.

[0057] Moreover, it is worth noting that due to the heating of the heating part 3, the balls 24 will gradually enter the high-temperature area. Under the action of high temperature, the weak magnetism of the balls 24 will be further weakened, which can avoid the balls 24 directly adsorbing on the screw 10 and being relatively stationary with it, thereby ensuring relative movement between the two.

[0058] Then when the balls 24 with weakened or even disappeared magnetism flow back from the return pipe 7, they will pass through the magnetic field in the sleeve 8. Under the action of the magnetic field, the magnetism of the balls 24 can be restored. In this way, the magnetism of the balls 24 will be continuously weakened and restored during the circulation process, so as to adapt to the use in different sections.

[0059] In one relatively preferred embodiment, drain holes 22 are formed in the outer wall of the inclined pipe 12, leakage holes 23 are formed in the outer wall of the emission pipe 6, and a liquid guide groove 18 for drainage is provided at the top of the workbench 1 below the emission pipe 6.

[0060] When the cleaning liquid is introduced from the feed tank 4, a part of the cleaning liquid will also enter the vertical pipe 11 along with the balls 24. Therefore, by providing the drain holes 22 on the outer wall of the inclined pipe 12 and the leakage holes 23 on the outer wall of the emission pipe 6, the cleaning liquid can be filtered out, and at the same time, some material residues can also be filtered out and then drained away through the liquid guide groove below.

[0061] In one relatively preferred embodiment, a spring piece 25 is installed on the inner wall at the connection of the vertical pipe 11 and the inclined pipe 12.

[0062] See Figure 4, in order to avoid an included angle at the connection between the vertical pipe 11 and the inclined pipe 12 after the telescopic column 13 connects them, which may cause the ball 24 to remain at that position. Therefore, by providing the elastic piece 25, it can play a certain guiding role in the falling of the ball 24 to prevent it from staying at the corner position and affecting the subsequent closing of the vertical pipe 11 by the telescopic column 13;

[0063] Moreover, when the telescopic column 13 closes the vertical pipe 11, its upward movement can press the elastic piece 25 back, without affecting the closing of the vertical pipe 11.

[0064] In one relatively preferred embodiment, a waterproof sleeve enclosing the telescopic column 13 is further installed at the top of the emission pipe 6. The waterproof sleeve can prevent the cleaning liquid from affecting the telescopic column 13.

[0065] In one relatively preferred embodiment, the return pipe 7 is arranged in a spiral and oblique conveying manner, and a section of the return pipe 7 close to the return hopper 9 has a downward inclination angle.

[0066] See Figure 2 , the spiral and oblique conveying method can prevent the ball 24 from getting stuck in the return pipe 7. At the same time, a slightly downward inclination angle can ensure that the ball 24 can flow back into the return hopper 9 to prevent it from accumulating in the return pipe 7.

[0067] In one relatively preferred embodiment, the elastic band 21 is an elastic fiber band or a tension spring. Preferably, the elastic band 21 is a tension spring. Since the elastic band 21 is closer to the high-temperature environment, the influence of temperature on the tension spring is smaller, so its service life is longer.

[0068] The standard parts used in this embodiment can be directly purchased from the market. For the non-standard structural components described in the specification and drawings, they can also be directly processed according to the existing common technical knowledge without any doubt. At the same time, the connection methods of each component adopt the mature conventional means in the existing technology, and the machines, parts and equipment all adopt the conventional models in the existing technology. Therefore, no specific description will be made here.

[0069] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An injection molding machine for preparing plastic injection molded parts, comprising a workbench (1) and a barrel (2) mounted on the top of the workbench (1), a screw (10) being mounted in the barrel (2), a heating portion (3) being mounted on the outer wall of the barrel (2), and a feed trough (4) being mounted on the outer wall of the barrel (2), characterized in that: It also includes: a reflux hopper (9) installed on the upper outer wall of the barrel (2) away from the injection port, wherein the reflux hopper (9) contains balls (24), and an electric switch is provided at the discharge port of the reflux hopper (9). When the balls (24) enter the barrel (2), the height of the balls (24) accumulated in the screw groove of the screw (10) is equal to or greater than the radius of the screw (10); a drainage portion connected to the outer wall of the barrel (2) near the injection port, and the balls (24) can be discharged from the drainage portion to the outside of the barrel (2); and a reflux portion, used to return the balls (24) discharged from the drainage portion to the reflux hopper (9), so that the balls (24) form a circulation loop; The drainage portion comprises a mounting frame (5) fixed to the outer wall below the barrel (2), a drainage pipe is mounted on the mounting frame (5), the drainage pipe comprises a vertical pipe (11) and an inclined pipe (12) which are connected to each other, the vertical pipe (11) is vertically connected to the outer wall of the barrel (2), a launching tube (6) is fixed to the bottom of the mounting frame (5), and a connecting groove (15) connected to the launching tube (6) is provided inside the vertical portion of the mounting frame (5), the inclined pipe (12) is connected to the connecting groove (15), a telescopic column (13) is also mounted on the top of the launching tube (6), and the top end of the telescopic column (13) extends from the bottom of the vertical pipe (11) and can open or block the connection between the vertical pipe (11) and the inclined pipe (12); The reflux section comprises a firing column (16) slidably mounted on the inner wall of one side of the launch tube (6), the outer walls on both sides of the firing column (16) and the two sides of the end of the launch tube (6) are respectively connected with elastic bands (21), the inner wall of the connecting groove (15) is vertically slidably mounted with a baffle (14), and a connecting rod (17) is rotatably connected between the baffle (14) and the firing column (16), and the outlet of the launch tube (6) away from the firing column (16) is connected to the reflux bucket (9) through the reflux pipe (7); the reflux section also comprises a driving member, and the driving member can intermittently move the firing column (16) in a direction away from the launch tube (6); The screw (10) is divided into three sections, the first section is a feeding section, the screw groove depth of this section is fixed; the second section is a compression section, this section is a tapered screw, and the screw groove changes from deep to shallow; the third section is a homogenizing section, the screw groove depth of this section is fixed; The depths of the screw grooves of different sections of the screw (10) are different, resulting in different gaps between the screw (10) and the barrel (2). Therefore, after the injection molding is completed and the plastic inside is extruded, when the residual material in the screw groove of the screw (10) is cleaned, the electric switch of the discharge port of the reflux hopper (9) is turned on so that all the balls (24) inside can fall into the barrel (2) and accumulate in one of the screw grooves first. Then, when the screw (10) rotates, the rotation of the screw (10) will convey the balls (24) forward. Since the balls (24) will not rotate with the rotation of the screw (10), the mutual friction between the balls (24) and the inner wall of the screw groove of the screw (10) can be used to clean the screw (10). At the same time, the cleaning liquid can be injected through the feed trough (4). The cleaning is carried out in a manner of heating the cleaning liquid and the heating part (3) until the balls (24) are transported to the drainage part and discharged from the barrel (2), and the discharged balls are returned to the reflux bucket (9) through the reflux part, so that the balls (24) form a circulation loop to clean the screw (10) multiple times; because the reflux bucket (9) is arranged at the top, in the initial state, the height of the balls (24) falling and accumulating in the spiral groove of the screw (10) can be equal to or greater than the radius of the screw (10), and when the screw (10) transports the balls (24) in the feeding section, the balls (24) can simultaneously rub against the inner wall of the spiral groove and the rod wall of the screw, so that the outer wall deep in the spiral groove can be fully cleaned, thereby improving the cleaning effect of the screw (10) at the deep position of the spiral groove.

2. The injection molding machine for preparing plastic injection molded parts according to claim 1, characterized in that: The driving member comprises a rotating disk (19) rotatably mounted on the top of the workbench (1) via a bracket, a lever (20) being fixed to the outer edge wall of the rotating disk (19) and being capable of intermittently contacting a protrusion on the edge of a firing column (16), and a driving motor mounted on the bracket and used for driving the rotating disk (19) to rotate.

3. The injection molding machine for preparing plastic injection molded parts according to claim 1, characterized in that: The balls (24) are magnetic, and the magnetic force can only allow the balls (24) to adhere to each other. The outer part of the return pipe (7) is provided with a sleeve (8), and a coil capable of generating a magnetic field is buried in the sleeve (8).

4. The injection molding machine for preparing plastic injection molded parts according to claim 1, characterized in that: The outer wall of the inclined tube (12) is provided with a liquid discharge hole (22), the outer wall of the launching tube (6) is provided with a liquid leakage hole (23), and the top of the workbench (1) below the launching tube (6) is provided with a liquid guide groove (18) for drainage.

5. The injection molding machine for preparing plastic injection molded parts according to claim 1, characterized in that: A spring piece (25) is installed on the inner wall of the connection between the vertical tube (11) and the inclined tube (12).

6. The injection molding machine for preparing plastic injection molded parts according to claim 4, characterized in that: A waterproof casing surrounding the telescopic column (13) is also installed on the top of the launch tube (6).

7. The injection molding machine for preparing plastic injection molded parts according to claim 1, characterized in that: The reflux pipe (7) is arranged in a spiral oblique conveying manner, and a section of the reflux pipe (7) close to the reflux bucket (9) has a downward inclination angle.

8. The injection molding machine for preparing plastic injection molded parts according to claim 1, characterized in that: The elastic band (21) is an elastic fiber band or a tension spring.

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