Thin-wall injection molding process adopting variable mold temperature technology and mold structure

Abstract

The invention discloses a thin-wall injection molding process adopting a variable mold temperature technology and a mold structure, and belongs to the technical field of molds, the mold structure adopting the variable mold temperature technology comprises a female mold, a movable mold, a male mold, a fixed mold, a lower base plate, a runner structure and an adjusting part, and the adjusting part is in sliding fit with a containing cavity; the cylindrical part is clamped in a sliding cavity formed in the surface of the fixed mold, and the cylindrical part is matched with the runner structure; and the communicating mechanism is arranged in the cylindrical part and is used for enabling the runner structure and the mold cavity to be in a communicating state. According to the plastic injection mold, the adjusting part slides downwards in the containing cavity, so that the internal volume of the mold cavity is increased, the amount of molten plastic injected into the mold cavity is large, after injection is completed, the molten plastic can extrude internal air through reverse movement of the adjusting part and extrusion of the molten plastic, and therefore the air in the mold cavity can be extruded; therefore, the air is extruded to the flow channel structure, so that the surface of the injection-molded shell does not have poor appearance.

Description

Technical Field

[0001] The invention belongs to the technical field of molds, and in particular relates to a thin-wall injection molding process and a mold structure using a variable mold temperature technology. Background Art

[0002] The shell of a sweeping robot is generally made by injection molding. Injection molding is a commonly used plastic processing technology. After heating and melting plastic particles, the melt is injected into the mold under high pressure. After cooling and shaping, the plastic product of the desired shape is obtained. Variable mold temperature injection molding technology is an innovative injection molding process. By dynamically adjusting the mold temperature during the injection cycle, it can significantly improve the quality and production efficiency of plastic products.

[0003] Dynamic temperature control in variable temperature injection molding technology involves heating and cooling stages. During the heating stage, a heating medium (such as saturated steam or hot oil) is used to heat the mold surface to a temperature close to or exceeding the softening point of the plastic material before injection. During the cooling stage, a cooling medium (such as cooling water) is used to rapidly cool the mold to the demolding temperature after injection. This process can utilize two media for temperature control: a steam / water circuit (using saturated steam for heating and cooling water for cooling); and an oil / oil circuit (using high-temperature oil for heating and low-temperature oil for cooling). Furthermore, combinations of induction heating with liquid cooling, infrared heating with liquid cooling, and electric heating with liquid cooling are also possible.

[0004] The process of variable mold temperature injection molding technology is roughly as follows: Heating the mold: Saturated steam or hot oil is introduced into the heating / cooling channels of the mold to heat the mold surface to a predetermined temperature; Injection and pressure holding: Injection and pressure holding are performed at high temperature to ensure that the material fully fills the mold; Cooling the mold: After the injection is completed, switch to the cooling medium to quickly reduce the mold temperature; Open the mold and take out the product: After the mold cools down to the demoulding temperature, open the mold and take out the product. Repeat the above steps to achieve continuous automatic cycle production.

[0005] After searching, Chinese utility model patent publication number CN205255413U discloses a mold using a rapid temperature change injection molding process, including a mounting base and a movable mold core. The mounting base is provided with a mounting cavity, and the movable mold core is provided with a mold cavity and a pouring channel connected to the mold cavity. The movable mold core is installed in the mounting cavity and slides horizontally with the mounting base; the mounting cavity is divided into a heating cavity and a cooling cavity by a vertically arranged heat insulation baffle, and the heat insulation baffle is detachably mounted on the mounting base. The heating cavity is provided with a heating device, and the cooling cavity is provided with a cooling device; the mounting base is provided with a power device for pushing the movable mold core into the heating cavity or the cooling cavity. In this way, heating and cooling are carried out separately without affecting each other, improving heating or cooling efficiency, avoiding energy waste, and improving the casting quality of parts.

[0006] In the above-mentioned prior art, after the movable mold and the fixed mold are closed, the volume of the mold cavity enclosed by the female mold and the male mold is fixed, and when the mold is closed, air is generally retained in the mold cavity. This causes the material injected into the mold cavity to be affected by the air, which easily causes air gaps to be generated inside the material. If the air cannot be discharged, it will cause the outer shell surface of the injection-molded sweeping robot to have a poor appearance. Therefore, it is necessary to improve the mold in the prior art. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the disadvantages of the above-mentioned prior art and provide a thin-wall injection molding process and mold structure using variable mold temperature technology.

[0008] The technical solution adopted to solve the above technical problems is: a mold structure using variable mold temperature technology, including a movable mold with a female mold and a fixed mold with a male mold, the female mold and the male mold are used in conjunction with each other to form a mold cavity when the mold is closed, and the fixed mold is installed on the lower plate through a pad, and further includes: A flow channel structure provided on the movable mold, the flow channel structure being used in conjunction with the female mold; An adjusting portion engaged with the accommodating cavity formed on the top surface of the male mold, wherein the adjusting portion and the accommodating cavity form a sliding fit; A cylindrical portion engaged with the sliding cavity provided on the surface of the fixed mold, wherein the cylindrical portion cooperates with the flow channel structure; A communication mechanism is provided in the columnar portion, and is used to connect the flow channel structure and the mold cavity.

[0009] Through the above technical solution, the regulating part slides downward in the accommodating cavity, so that the internal volume of the mold cavity increases, so that the amount of molten plastic injected into the mold cavity is larger. After the injection is completed, the regulating part moves in the opposite direction and squeezes the molten plastic, so that the molten plastic can squeeze the air inside, so that the air is squeezed into the runner structure, thereby preventing the surface of the shell after injection molding from having a poor appearance.

[0010] Furthermore, a plurality of fluid channels are provided in the movable mold, and the openings of two adjacent fluid channels on the same side are connected by a pipeline.

[0011] Through the above technical solution, the external heat-conducting oil delivery system delivers heat-conducting oil into the fluid channel, thereby heating the molten plastic in the mold cavity.

[0012] Furthermore, the flow channel structure includes an injection hole opened on the surface of the movable mold, the cylindrical portion is in sliding fit with the injection hole, an injection nozzle is installed in the injection hole, and a through cavity that penetrates the injection hole is opened on the side of the movable mold facing the fixed mold, and the surface of the movable mold is also provided with a material flow hole that penetrates the through cavity and the female mold.

[0013] Through the above technical solution, the injection system of the injection molding machine injects the molten plastic from the injection nozzle to the injection hole, and then transports it to the mold cavity through the injection hole, the through cavity and the material flow hole.

[0014] Furthermore, a first cylinder is installed on a side of the fixed mold facing away from the movable mold, and a cylinder rod of the first cylinder is fixedly connected to the end surface of the columnar portion.

[0015] Through the above technical solution, the first cylinder drives the cylindrical portion to move, so that after the injection is completed, the cylindrical portion can be inserted into the injection hole.

[0016] Furthermore, the connecting mechanism includes a floating column slidingly inserted into the cylindrical portion, and the floating column is coaxially fixed with a tapered portion toward one end of the movable mold. The outer diameter of the tapered portion decreases from top to bottom. A tapered hole for the tapered portion to engage is provided on the upper end surface of the cylindrical portion, and a reflux hole is provided on the upper side of the periphery of the cylindrical portion. A connecting cavity that is connected to the reflux hole and the tapered hole is also provided in the cylindrical portion. When the cylindrical portion is inserted into the injection hole, the reflux hole and the through cavity are in a through state.

[0017] Through the above technical solution, when the excess molten plastic in the mold cavity is squeezed by the regulating part, the plastic is melted into the connecting cavity through the reflux hole and generates an extrusion force on the outer wall of the tapered part. Since the tapered part has a conical shape, the molten plastic can generate a thrust on the tapered part toward the movable mold, causing the tapered part to move toward the movable mold, thereby allowing the molten plastic in the connecting cavity to flow back to the injection hole through the tapered hole. After the squeezing force of the regulating part on the molten plastic in the mold cavity disappears, the tapered part is re-engaged in the tapered hole to prevent the air in the molten plastic flowing back into the injection hole from entering the mold cavity.

[0018] Furthermore, a floating ring is fixedly mounted on one end of the floating column away from the conical portion, and a mounting cavity for the floating ring to engage is opened in the cylindrical portion. The floating ring slides freely in the mounting cavity, and a first spring is wrapped around the periphery of the floating column. The two ends of the first spring in the direction of elastic force elastically press against the floating ring and the top wall of the mounting cavity respectively.

[0019] Through the above technical solution, when the conical part moves toward the movable mold, the floating ring will compress the first spring, thereby causing the first spring to accumulate elastic potential energy. When the extrusion force of the regulating part on the molten plastic in the mold cavity disappears, the elastic potential energy accumulated in the first spring is released, causing the conical part to re-engage with the conical hole and block the air in the injection hole from flowing back to the channel in the mold cavity.

[0020] Furthermore, a tubular column is coaxially fixed to the end of the adjusting portion facing away from the movable mold, and the end of the tubular column away from the adjusting portion slides out of the bottom of the fixed mold, and the end of the tubular column passing through the fixed mold is connected to a floating frame, and a second cylinder is installed on the top of the lower plate, and the cylinder rod of the second cylinder is connected to the floating frame.

[0021] Through the above technical solution, the cylinder rod of the second cylinder is extended, thereby driving the floating frame to move toward the fixed mold, so that the adjustment part can slide in the accommodating cavity, thereby adjusting the internal volume of the mold cavity.

[0022] Furthermore, a trapezoidal groove is provided on the top surface of the adjusting portion, the trapezoidal groove is wide at the top and narrow at the bottom and is engaged with a scraper rod, the scraper rod is used in conjunction with the trapezoidal groove, a floating sleeve is slidably engaged and installed in the tubular column, a spline column is slidably passed through the middle hole of the floating sleeve, the spline column is key-connected to the middle hole of the floating sleeve, the upper end of the spline column is fixed to the scraper rod, the circumference of the floating sleeve is rotatably covered with a rotating ring, the circumference of the rotating ring is vertically fixed with a tightening rod through a short pin, the circumference of the tubular column is provided with a waist-shaped hole for the short pin to pass freely, the circumference of the floating sleeve is rotatably embedded with a ball, the inner wall of the tubular column is provided with a spiral groove for the ball to engage, and the ball rolls freely in the spiral groove.

[0023] Through the above technical solution, when the adjusting part slides downward to a fixed position in the accommodating cavity, the clamping rod will come into contact with the inner bottom wall of the accommodating cavity, and as the adjusting part continues to move downward, the ball will roll in the spiral groove, and then the spline column will drive the scraper rod to rotate. The side wall of the scraper rod and the inner side wall of the trapezoidal groove slide relative to each other, and the scraper rod slides to the top surface of the adjusting part and rotates. During rotation, the plastic adhering to the surface of the adjusting part can be scraped off.

[0024] Furthermore, a nut is fixedly sleeved on the lower end of the spline column, and a second spring is also sleeved around the periphery of the spline column. The two ends of the second spring in the elastic force direction elastically press against the nut and the lower end surface of the floating sleeve respectively.

[0025] Through the above technical solution, the second spring generates an elastic resisting force on the nut, thereby enabling the spline column to slide in the center hole of the floating sleeve. That is, when the spline column moves upward, the nut will compress the second spring, and the second spring will accumulate elastic potential energy. When the scraper rod rotates into the trapezoidal groove, the elastic potential energy accumulated in the second spring is released, so that the scraper rod can quickly engage with the trapezoidal groove.

[0026] A thin-wall injection molding process using variable mold temperature technology, applied to the mold structure described above, comprises: The movable mold and the fixed mold are closed. After closing, the male mold and the female mold are engaged, and a mold cavity is formed between them. The adjustment part moves downward in the accommodating cavity to increase the internal volume of the mold cavity, and the runner structure injects the molten plastic into the mold cavity. After the injection is completed, the cylindrical portion is first moved toward the runner structure so that the upper end of the cylindrical portion is engaged with the runner structure, and then the regulating portion moves upward to restore the internal volume of the mold cavity. During this process, the regulating part will generate an extrusion force on the molten plastic in the mold cavity, causing the excess molten plastic to generate an extrusion force on the connecting mechanism and triggering the connecting mechanism to connect the runner structure and the mold cavity. This allows the excess molten plastic in the mold cavity to flow back to the runner structure, thus fixing the total amount of molten plastic in the mold cavity. At the same time, during the extrusion process, the molten plastic will squeeze out the air inside it, thereby expelling the air in the mold cavity. After the molding is completed, the movable mold and the fixed mold are separated, and the cylindrical part also retracts into the sliding cavity, and the top surface of the cylindrical part is flush with the top surface of the fixed mold.

[0027] Through the above technical solution, the regulating part slides downward in the accommodating cavity, so that the internal volume of the mold cavity increases, so that the amount of molten plastic injected into the mold cavity is larger. After the injection is completed, the regulating part moves in the opposite direction and squeezes the molten plastic, so that the molten plastic can squeeze the air inside, so that the air is squeezed into the runner structure, thereby preventing the surface of the shell after injection molding from having a poor appearance.

[0028] The beneficial effects of the present invention are as follows: 1. In the present invention, the adjusting portion slides downward within the accommodating cavity, thereby increasing the internal volume of the mold cavity. This increases the amount of molten plastic injected into the mold cavity. After injection, the adjusting portion reversely moves to squeeze the molten plastic, causing the molten plastic to squeeze the air inside. This squeezes the air into the runner structure, thereby preventing the surface of the shell from having a poor appearance after injection molding. 2. In the present invention, when the excess molten plastic in the mold cavity is squeezed by the regulating portion, the melted plastic flows into the communicating cavity through the reflux hole and generates a squeezing force on the outer wall of the tapered portion. Due to the tapered shape of the tapered portion, the molten plastic can generate a thrust on the tapered portion toward the movable mold, causing the tapered portion to move toward the movable mold. This allows the molten plastic in the communicating cavity to flow back to the injection hole through the tapered hole. After the squeezing force of the regulating portion on the molten plastic in the mold cavity disappears, the tapered portion re-engages with the tapered hole, preventing air in the molten plastic that has flowed back into the injection hole from entering the mold cavity. 3. In the present invention, when the adjusting part slides downward to a fixed position in the accommodating cavity, the clamping rod will come into contact with the inner bottom wall of the accommodating cavity, and as the adjusting part continues to move downward, the ball will roll in the spiral groove, and then the spline column will drive the scraper rod to rotate. The side wall of the scraper rod and the inner wall of the trapezoidal groove slide relative to each other, and the scraper rod slides to the top surface of the adjusting part and rotates. During the rotation, the plastic adhering to the surface of the adjusting part can be scraped off. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the overall structure of a mold structure using a variable mold temperature technology in an embodiment of the present invention; Figure 2 yes Figure 1 Schematic diagram of the position relationship of the first perspective; Figure 3 yes Figure 1 Schematic diagram of the positional relationship of the second perspective; Figure 4 yes Figure 1 Schematic diagram of the positional relationship of the middle part structure after it is cut open; Figure 5 This is a schematic diagram of the positional relationship between the tubular column and the adjustment portion after assembly in the present invention; Figure 6 yes Figure 5 A schematic diagram of the positional relationship from another perspective; Figure 7 yes Figure 5 Schematic diagram of the positional relationship of the middle part structure after it is cut open; Figure 8 yes Figure 5 Schematic diagram of the exploded structure; Figure 9 This is a schematic diagram of the positional relationship between the first cylinder and the cylindrical portion after assembly in the present invention; Figure 10 yes Figure 9 Schematic diagram of the positional relationship of the middle part structure after it is cut open; Figure 11 It is a structural schematic diagram of the tubular column in the present invention.

[0030] Reference numerals: 1, lower plate; 2, spacer; 3, fixed mold; 4, guide column; 5, bushing; 6, movable mold; 7, injection nozzle; 8, adjustment portion; 9, trapezoidal groove; 10, male mold; 11, cylindrical portion; 12, tapered hole; 13, second cylinder; 14, floating frame; 15, first cylinder; 16, female mold; 17, pipeline; 18, through cavity; 19, injection hole; 20, stopper; 21, material flow hole; 22. Accommodating chamber; 23. Tubular column; 24. Clamping rod; 25. Waist-shaped hole; 26. Scraper rod; 27. Spiral groove; 28. Short pin; 29. ​​Second spring; 30. Nut; 31. Floating sleeve; 32. Ball; 33. Rotating ring; 34. Spline column; 35. Return hole; 36. Conical portion; 37. Connecting chamber; 38. Floating column; 39. First spring; 40. Floating ring; 41. Mounting chamber. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] like Figures 1-11As shown, this embodiment provides a mold structure using a variable mold temperature technology, including a lower plate 1 installed on an injection molding machine, a fixed mold 3 is installed on the lower plate 1 through a pad 2, and a movable mold 6 is also installed on the injection molding machine. The movable mold 6 is used in conjunction with the fixed mold 3. In addition, a female mold 16 is provided on the side of the movable mold 6 facing the fixed mold 3, and a male mold 10 is fixedly connected to the side of the fixed mold 3 facing the movable mold 6. The male mold 10 and the female mold 16 are in a coordinated use state, that is, the female mold 16 can be snapped into the male mold 10, so that when the movable mold 6 and the fixed mold 3 are closed, the female mold 16 and the male mold 10 cooperate to form a mold cavity. A plurality of fluid channels are provided in the movable mold 6, and the fluid channels are relatively close to each other. The openings of the two adjacent fluid channels on the same side are connected by a pipe 17. The external heat-conducting oil delivery system delivers the heat-conducting oil to the opening on one side of the fluid channel, then enters the other fluid channel through the pipe 17, and then flows back to the heat-conducting oil delivery system. In this way, the heat-conducting oil can continuously heat the plastic in the mold cavity during circulation. A plurality of guide pillars 4 are vertically fixed to the surface of the fixed mold 3, and a bushing 5 is embedded in the surface of the movable mold 6. The bushing 5 and the guide pillars 4 are in a cooperative use state. That is, during the clamping process of the movable mold 6 and the fixed mold 3, the guide pillars 4 will slide in the bushing 5 and guide the clamping process of the fixed mold 3 and the movable mold 6; The movable mold 6 is provided with a flow channel structure, which includes an injection hole 19 in the form of a through hole opened on the surface of the movable mold 6. An injection nozzle 7 is installed in the injection hole 19. A through cavity 18 is opened on the side of the movable mold 6 facing the fixed mold 3 and connected with the injection hole 19. The surface of the movable mold 6 is also provided with a material flow hole 21 that is connected with the through cavity 18 and the female mold 16. The injection system injects the molten plastic from the injection nozzle 7 into the injection hole 19, and then enters the mold cavity through the through cavity 18 and the material flow hole 21, thereby achieving the desired effect. Molten plastic is now injected into the mold cavity. A sliding cavity in the form of a through hole is opened on the surface of the fixed mold 3 facing the movable mold 6. A cylindrical portion 11 is engaged in the sliding cavity. A first cylinder 15 is vertically mounted on the other surface of the fixed mold 3. The first cylinder 15 is fixedly connected to the end face of the cylindrical portion 11, so that when the cylinder rod of the first cylinder 15 is extended or retracted, the cylindrical portion 11 is synchronously driven to move in the sliding cavity. In addition, after the mold is closed, when the cylinder rod of the first cylinder 15 is extended, the upper end of the cylindrical portion 11 is driven to engage with the injection hole 19. A connecting mechanism is provided in the cylindrical portion 11. The connecting mechanism includes a floating column 38 coaxially slidably provided in the cylindrical portion 11. A conical portion 36 is coaxially fixed to one end of the floating column 38 facing the movable mold 6. The outer diameter of the conical portion 36 decreases from top to bottom. A conical hole 12 for engagement with the conical portion 36 is provided on the upper end surface of the cylindrical portion 11. A reflux hole 35 is provided on the upper side of the periphery of the cylindrical portion 11. A connecting cavity 37 is also provided in the cylindrical portion 11, which is in communication with the reflux hole 35 and the conical hole 12. When the cylindrical portion 11 is inserted into the injection hole 19, the reflux hole 35 and the through cavity 18 are in a through state. In addition, the floating column 38 is fixedly sleeved with a floating ring 40 at one end away from the conical portion 36. A mounting cavity 41 for the floating ring 40 to engage is provided in the cylindrical portion 11. The floating ring 40 slides freely in the mounting cavity 41. A first spring 39 is wrapped around the periphery of the floating column 38. The two ends of the first spring 39 in the direction of elastic force elastically press against the floating ring 40 and the top wall of the mounting cavity 41 respectively.

[0033] The top surface of the male mold 10 is provided with an accommodating cavity 22, in which an adjusting portion 8 is slidably engaged and installed. The end of the adjusting portion 8 facing away from the movable mold 6 is coaxially fixed with a tubular column 23, and the end of the tubular column 23 away from the adjusting portion 8 slides out of the bottom of the fixed mold 3. The end of the tubular column 23 that passes through the fixed mold 3 is connected to a floating frame 14, and a second cylinder 13 is installed on the top of the lower plate 1. The cylinder rod of the second cylinder 13 is connected to the floating frame 14. A trapezoidal groove 9 is provided on the top surface of the adjusting portion 8. The trapezoidal groove 9 is wide at the top and narrow at the bottom and is engaged with a scraper rod 26. The scraper rod 26 is used in conjunction with the trapezoidal groove 9 to slide in the tubular column 23. A floating sleeve 31 is mounted on the floating sleeve 31, and a spline column 34 is slidably inserted into the center hole of the floating sleeve 31. The spline column 34 is key-connected to the center hole of the floating sleeve 31, and the upper end of the spline column 34 is fixed to the scraper rod 26. A rotating ring 33 is rotatably mounted on the periphery of the floating sleeve 31. The periphery of the rotating ring 33 is vertically fixed to the tightening rod 24 through a short pin 28. A waist-shaped hole 25 is provided on the periphery of the tubular column 23 for the short pin 28 to pass freely. A ball 32 is rotatably embedded in the periphery of the floating sleeve 31, and a spiral groove 27 for the ball 32 to engage is provided on the inner wall of the tubular column 23. The ball 32 rolls freely in the spiral groove 27. The lower end of the spline column 34 is fixedly sleeved with a nut 30, and the periphery of the spline column 34 is also sleeved with a second spring 29. The two ends of the elastic force direction of the second spring 29 elastically press against the nut 30 and the lower end of the floating sleeve 31 respectively. In addition, the floating frame 14 is fixedly connected to the side facing the fixed mold 3 with a stop portion 20. The stop portion 20 is used to limit the floating frame 14 when the floating frame 14 moves toward the fixed mold 3, so that when the floating frame 14 moves into place, the top surface of the adjusting portion 8 is flush with the top surface of the male mold 10. When the adjusting portion 8 slides downward in the accommodating cavity 22 to a fixed position, the tightening rod 24 will produce a pressure against the inner bottom wall of the accommodating cavity 22. When the adjusting portion 8 is rotated, the scraper rod 26 is in contact with the adjusting portion 8, and as the adjusting portion 8 continues to move downward, the ball 32 is caused to roll in the spiral groove 27, and the spline column 34 drives the scraper rod 26 to rotate. The side wall of the scraper rod 26 slides relative to the inner wall of the trapezoidal groove 9, and the scraper rod 26 slides to the top surface of the adjusting portion 8 and rotates. When rotating, the plastic adhering to the surface of the adjusting portion 8 can be scraped off. In this embodiment, the material of the scraper rod 26 and the adjusting portion 8 can be selected from stainless steel, so that the friction coefficient between the two is small, it is not easy to produce large wear, and when the plastic adheres to the surface of the adjusting portion 8, it is also easier to be scraped off.

[0034] The working principle of this embodiment is as follows: In the initial state, the top surfaces of the cylindrical portion 11 and the tapered portion 36 are flush with the top surface of the fixed mold 3, and the top surfaces of the adjusting portion 8 and the scraper rod 26 are flush with the top surface of the male mold 10. The hydraulic system of the injection molding machine drives the movable mold 6 to move toward the fixed mold 3, so that the fixed mold 3 and the movable mold 6 begin to close the mold. After the molds are closed in place, a mold cavity is formed between the male mold 10 and the female mold 16. The second cylinder 13 drives the adjusting portion 8 to move toward the inner side of the accommodating cavity 22, thereby increasing the internal volume of the mold cavity. It should be noted that at this time, the movement stroke of the adjusting portion 8 does not reach the inner bottom wall of the accommodating cavity 22 by pressing the rod 24. At this time, the internal volume of the mold cavity is larger. Then, the injection system of the injection molding machine injects the molten plastic into the injection nozzle 7, and then enters the mold cavity through the through cavity 18 and the material flow hole 21, so that the mold cavity is filled with molten plastic. The first cylinder 15 is activated, and the cylinder rod of the first cylinder 15 extends and drives the cylindrical portion 11 to move upward, so that the upper end of the cylindrical portion 11 is engaged with the injection hole 19. At this time, the two reflux holes 35 on the cylindrical portion 11 are respectively connected to the two through cavities 18. The cylinder rod of the second cylinder 13 extends, thereby driving the floating frame 14 to move toward the fixed mold 3, so that the tubular column 23 drives the adjustment portion 8 to move upward, thereby causing the internal volume of the mold cavity to begin to decrease. During the reduction process, the adjustment portion 8 generates an extrusion force on the molten plastic in the mold cavity, thereby causing the excess molten plastic in the mold cavity to enter the through cavity 18 through the material flow hole 21, and then enter the reflux hole 35 from the through cavity 18, and then enter the connecting cavity 37. After the melted plastic enters the communication cavity 37 through the reflux hole 35, it exerts an extrusion force on the outer wall of the tapered portion 36. Due to the tapered shape of the tapered portion 36, the melted plastic can exert a thrust on the tapered portion 36 toward the movable mold 6, causing the tapered portion 36 to move toward the movable mold 6. This creates a gap between the periphery of the tapered portion 36 and the wall of the tapered hole 12, allowing the melted plastic in the communication cavity 37 to flow back to the injection hole 19 through the gap. After the extrusion force exerted by the regulating portion 8 on the melted plastic in the mold cavity disappears, the tapered portion 36 reengages with the tapered hole 12, preventing air in the melted plastic that has flowed back into the injection hole 19 from entering the mold cavity. After the molten plastic in the mold cavity solidifies, a semi-finished shell of the sweeping robot is formed. Then, the first cylinder 15 is started, causing the cylindrical portion 11 to retract into the sliding cavity, and causing the top surface of the cylindrical portion 11 to be flush with the top surface of the fixed mold 3. In addition, the cylinder rod of the second cylinder 13 contracts, driving the floating frame 14 to move in the direction away from the fixed mold 3, and causing the adjusting portion 8 to move downward in the accommodating cavity 22. Note that the moving stroke of the adjusting portion 8 at this time is large, so that the clamping rod 24 can contact the inner bottom wall of the accommodating cavity 22, and as the adjusting portion 8 continues to move downward, the clamping rod 24 and the adjusting portion 8 form a relative movement, thereby causing the ball 32 to roll in the spiral groove 27, causing the spline column 34 to drive the scraper rod 26 to rotate, and the side wall of the scraper rod 26 slides relative to the inner side wall of the trapezoidal groove 9, and causes the scraper rod 26 to slide to the top surface of the adjusting portion 8 and rotate. During the rotation, the plastic adhering to the surface of the adjusting portion 8 can be scraped off; When the scraper rod 26 slides relative to the inner wall of the trapezoidal groove 9, the scraper rod 26 will drive the spline column 34 to move axially along the floating sleeve 31, so that the nut 30 compresses the second spring 29 and the second spring 29 accumulates elastic potential energy. In this way, when the adjusting part 8 moves upward, the ball 32 rolls in the spiral groove 27 in the opposite direction. When the scraper rod 26 rotates into the trapezoidal groove 9, the elastic potential energy accumulated by the second spring 29 is released, so that the scraper rod 26 can be quickly engaged into the trapezoidal groove 9, so that the scraper rod 26 can be re-engaged in the trapezoidal groove 9 and move synchronously with the adjusting part 8.

[0035] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

Claims

1. A mold structure using a variable mold temperature technology, comprising a movable mold (6) provided with a female mold (16) and a fixed mold (3) provided with a male mold (10), wherein the female mold (16) and the male mold (10) are used in conjunction with each other and form a mold cavity when the molds are closed, and the fixed mold (3) is mounted on a lower plate (1) via a pad (2), characterized in that: Also includes: A flow channel structure provided on the movable mold (6), the flow channel structure being used in conjunction with the female mold (16); An adjusting portion (8) engaged with a receiving cavity (22) provided on the top surface of the male mold (10), wherein the adjusting portion (8) and the receiving cavity (22) form a sliding fit; A columnar portion (11) engaged in a sliding cavity provided on the surface of the fixed mold (3), wherein the columnar portion (11) cooperates with the flow channel structure; A communication mechanism is provided in the columnar portion (11), and the communication mechanism is used to connect the flow channel structure and the mold cavity.

2. The mold structure using the variable mold temperature technology according to claim 1, characterized in that: A plurality of fluid channels are provided in the movable mold (6), and the openings of two adjacent fluid channels on the same side are connected via a pipeline (17).

3. The mold structure using the variable mold temperature technology according to claim 1, characterized in that: The flow channel structure includes an injection hole (19) opened on the surface of the movable mold (6), the columnar portion (11) is in sliding cooperation with the injection hole (19), an injection nozzle (7) is installed in the injection hole (19), and a through cavity (18) is opened on the side of the movable mold (6) facing the fixed mold (3) and connected to the injection hole (19), and a material flow hole (21) is also opened on the surface of the movable mold (6) and connected to the through cavity (18) and the female mold (16).

4. The mold structure using the variable mold temperature technology according to claim 3, characterized in that: A first cylinder (15) is installed on a side of the fixed mold (3) facing away from the movable mold (6), and a cylinder rod of the first cylinder (15) is fixedly connected to the end face of the columnar portion (11).

5. The mold structure using the variable mold temperature technology according to claim 3, characterized in that: The connecting mechanism includes a floating column (38) slidingly inserted into the cylindrical portion (11), and the floating column (38) is coaxially fixed with a tapered portion (36) at one end facing the movable mold (6). The outer diameter of the tapered portion (36) decreases from top to bottom. The upper end surface of the cylindrical portion (11) is provided with a tapered hole (12) for engaging with the tapered portion (36). The upper side of the periphery of the cylindrical portion (11) is provided with a reflux hole (35). The cylindrical portion (11) is further provided with a connecting cavity (37) that is connected with the reflux hole (35) and the tapered hole (12). When the cylindrical portion (11) is inserted into the injection hole (19), the reflux hole (35) and the through cavity (18) are in a connected state.

6. The mold structure using the variable mold temperature technology according to claim 5, characterized in that: A floating ring (40) is fixedly sleeved on one end of the floating column (38) away from the conical portion (36); a mounting cavity (41) for the floating ring (40) to engage is provided in the columnar portion (11); the floating ring (40) slides freely in the mounting cavity (41); a first spring (39) is sleeved around the periphery of the floating column (38); and the two ends of the first spring (39) in the direction of elastic force elastically press against the floating ring (40) and the top wall of the mounting cavity (41) respectively.

7. The mold structure using the variable mold temperature technology according to claim 1, characterized in that: The end of the adjusting portion (8) facing away from the movable mold (6) is coaxially fixed with a tubular column (23), and the end of the tubular column (23) away from the adjusting portion (8) slides out of the bottom of the fixed mold (3), and the end of the tubular column (23) passing through the fixed mold (3) is connected to a floating frame (14), and a second cylinder (13) is installed on the top of the lower plate (1), and the cylinder rod of the second cylinder (13) is connected to the floating frame (14).

8. The mold structure using the variable mold temperature technology according to claim 7, characterized in that: The top surface of the adjusting portion (8) is provided with a trapezoidal groove (9), the trapezoidal groove (9) is wide at the top and narrow at the bottom and is engaged with a scraper rod (26), the scraper rod (26) is used in conjunction with the trapezoidal groove (9), a floating sleeve (31) is slidably engaged and installed in the tubular column (23), a spline column (34) is slidably penetrated in the middle hole of the floating sleeve (31), the spline column (34) is key-connected to the middle hole of the floating sleeve (31), the upper end of the spline column (34) is fixedly connected to the scraper rod (26), the The floating sleeve (31) is rotatably fitted with a rotating ring (33) on its periphery. The rotating ring (33) is vertically fixed to a tightening rod (24) on its periphery via a short pin (28). A waist-shaped hole (25) is provided on the periphery of the tubular column (23) for the short pin (28) to pass freely. A ball (32) is rotatably embedded in the periphery of the floating sleeve (31). A spiral groove (27) for the ball (32) to engage is provided on the inner wall of the tubular column (23). The ball (32) rolls freely in the spiral groove (27).

9. The mold structure using the variable mold temperature technology according to claim 8, characterized in that: The lower end of the spline column (34) is fixedly sleeved with a nut (30), and the periphery of the spline column (34) is also sleeved with a second spring (29), and the two ends of the second spring (29) in the elastic direction elastically press against the nut (30) and the lower end surface of the floating sleeve (31).

10. A thin-wall injection molding process using variable mold temperature technology, applied to the mold structure according to any one of claims 1 to 9, characterized in that: include: The movable mold (6) and the fixed mold (3) are closed. After closing, the male mold (10) and the female mold (16) are engaged with each other, and a mold cavity is formed between the two. The adjusting portion (8) moves downward in the accommodating cavity (22), thereby increasing the internal volume of the mold cavity, and the runner structure injects the molten plastic into the mold cavity. After the injection is completed, the columnar portion (11) is first moved toward the flow channel structure so that the upper end of the columnar portion (11) is engaged with the flow channel structure, and then the regulating portion (8) is moved upward again so that the internal volume of the mold cavity is restored; After the molding is completed, the movable mold (6) and the fixed mold (3) are separated, and the columnar portion (11) is also retracted into the sliding cavity, and the top surface of the columnar portion (11) is flush with the top surface of the fixed mold (3).

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