8) It has a long molding cycle 1. sprue bush: 2. guide pin: 3. clamping plate of the fixed half; 4. cavity-retainer plate: 5.spring 6. top pin: 7.core: 8. core-retainer plate: 9.suport plate: 10. spacer block: 11.screw: 12. return pin: 13ejector pin: 14 clamping plate of the moving half: 15. ejector-retainer plate: 16. ejector-support plate Fig 1-24: three-plate injection mold Fig. 1-25 is the photos of three-plate injection mold with two cavities for a plastic cover of Bluetooth product which has been installed on a plastic injection molding machine a) fixed half mold b)moving half mold Fig. 1-25 three-plate injection mold with two cavities for a plastic cover of Bluetooth product 1.3.2 Types of Mold 1. Angle Pin Side Core-pulling Mold Structure Fig. 1-26 illustrates a mold structure adopting angle pin side core-pulling mechanism, which shows how to demold the side concave structure on the molding product to be used as shell of a kitchenware While the mold is being clamped, slide 23 is retained by wedge plate 26, and therefore angle pin 24 essentially bears no force during injection. As the mold gradually opens, angle pin 24 pushes slide 23 to move outward until the side concave structure on the product is completely ejected. The molded product When the mold closes, the ejection system and slide 23 will return to their original position by means of return pin 12 and angle pin 24. The same method is employed for the ejection of shells for beverage cartons, wind wheel of hair driers as well as winding bushes. The possible number of cavities and their arrangement in the mold are mainly determined by the number and position of slides
8) It has a long molding cycle. 1. sprue bush；2. guide pin；3. clamping plate of the fixed half；4. cavity-retainer plate；5.spring； 6.stop pin；7.core；8. core-retainer plate；9.suport plate；10. spacer block；11.screw； 12. return pin；13.ejector pin；14. clamping plate of the moving half；15. ejector-retainer plate；16. ejector-support plate Fig.1-24: three-plate injection mold Fig. 1-25 is the photos of three-plate injection mold with two cavities for a plastic cover of Bluetooth product which has been installed on a plastic injection molding machine. a) fixed half mold b) moving half mold Fig. 1-25: three-plate injection mold with two cavities for a plastic cover of Bluetooth product 1.3.2 Types of Mold 1. Angle Pin Side Core-pulling Mold Structure Fig. 1-26 illustrates a mold structure adopting angle pin side core-pulling mechanism, which shows how to demold the side concave structure on the molding product to be used as shell of a kitchenware. While the mold is being clamped, slide 23 is retained by wedge plate 26, and therefore angle pin 24 essentially bears no force during injection. As the mold gradually opens, angle pin 24 pushes slide 23 to move outward until the side concave structure on the product is completely ejected. The molded product is then left in the moving half and will be further ejected there out by ejector pin 4 and ejector bush 9. When the mold closes, the ejection system and slide 23 will return to their original position by means of return pin 12 and angle pin 24. The same method is employed for the ejection of shells for beverage cartons, wind wheel of hair driers as well as winding bushes. The possible number of cavities and their arrangement in the mold are mainly determined by the number and position of slides
One single cavity is allowed for a mold with a multiplicity of radial slides, such as the mold for steam turbine blades. The parting of a slide or a cavity can also be made by means of compressed air or a hydraulic cylinder. A mechanical clamping mechanism is usually used to avoid unnecessary displacement of the mold 1. ejector-retainer plate: 2. ejector-support plate: 3 straight pin: 4.ejector pin: 5 back locating ring: 6. back ejector-support plate: 7-pillar le puller pin: 9.ejector bush: 10. location pin 11. screw: 12 return pin: 13guide pin 14.guide bush: 15. core-support plate: 16. return pin: 17.core insert: 18 cavity insert: 19. locating ring: 20.sprue bush: 21 cavity insert: 22. cavity-support plate: 23 slanted slide 24 angle pin: 25. wear plate: 26. wedge plate: 27. cavity-retainer plate; 28.slide insert: 29. cooling pipe: 30. core-retainer plate; 31. wear plate: 47 spacer block: 48 clamping plate of moving half Fig 1-26: angle pin side core-pulling mold 2. Slanted Lifter Side Core-pulling Mold Structure A lifter mold is shown in Fig. 1-27. It consists of slide 2 and lifter 5, core-retainer plate 4 and main core 3. The lifter 5 is guided by the side hole on the moving half. After opening the mold, ejector-retainer plate 8 pushes the lifter 5 and ejector pin 1, making the slide 2 and the ejector pin I to eject the plastic part while pulling out the internal side core-slide While locking the mold, the ejector plate on the moving half retracts backward by spring 6 for rough return. The moving half continues moving backward to push the slide for precision return. As the lifter is pushed back, friction is created between the ejector-retainer plate and the bottom of the lifter. To reduce the friction and prolong the mold life, the
One single cavity is allowed for a mold with a multiplicity of radial slides, such as the mold for steam turbine blades. The parting of a slide or a cavity can also be made by means of compressed air or a hydraulic cylinder. A mechanical clamping mechanism is usually used to avoid unnecessary displacement of the mold. 1.ejector-retainer plate；2. ejector-support plate；3. straight pin；4.ejector pin；5.back locating ring； 6.back ejector-support plate；7.pillar；8.sprue puller pin；9.ejector bush；10.location pin； 11.screw；12.return pin；13.guide pin； 14.guide bush；15.core-support plate；16.return pin；17.core insert；18.cavity insert； 19. locating ring；20.sprue bush；21.cavity insert；22. cavity-support plate；23. slanted slide； 24 angle pin；25.wear plate；26. wedge plate；27. cavity-retainer plate；28.slide insert； 29.cooling pipe；30. core-retainer plate；31. wear plate；47.spacer block；48. clamping plate of moving half Fig.1-26: angle pin side core-pulling mold 2. Slanted Lifter Side Core-pulling Mold Structure A lifter mold is shown in Fig.1-27. It consists of slide 2 and lifter 5, core-retainer plate 4 and main core 3. The lifter 5 is guided by the side hole on the moving half. After opening the mold, ejector-retainer plate 8 pushes the lifter 5 and ejector pin 1, making the slide 2 and the ejector pin 1 to eject the plastic part while pulling out the internal side core-slide. While locking the mold, the ejector plate on the moving half retracts backward by spring 6 for rough return. The moving half continues moving backward to push the slide for precision return. As the lifter is pushed back, friction is created between the ejector-retainer plate and the bottom of the lifter. To reduce the friction and prolong the mold life, the
lifter's bottom is usually made in a ball shape hardened with local quenching process. The insert 9 on the ejector-retainer plate which comes in touch with the lifter also requires the hardening process I ejector pin: 2. slanted slide: 3. main core; 4. core-retainer plate 5. slanted lifter: 6.spring: 7.return pin: 8. ejector-retainer plate: 9. insert: Fig 1-27: internal side core-pulling mechanism with a slanted lifter Fig 1-28 illustrates the roller-type slanted lifter for external side core-pulling mechanism. Roller 9 is connected onto slanted lifter 7 with axle 8. which means that the slanted lifter is in rolling contact with ejector-retainer plate 10 through the roller, and the sliding friction is replaced with rolling friction, thereby enormously reducing relative friction force As indicated in Fig. 1-29, slanted lifter 7 is secured on channel frame 2 by rolling axis 3, which reduces moving friction and meanwhile can drive slanted lifter to return during mold clamping Fig 1-30 illustrates the translational slanted lifter inner core-pulling mechanism. During the ejection, slanted lifter 3 and ejector pin 4 act together to prop up the plastic part from main core 1, and when it moved to distance L, point a on the lifter 3 breaks away from the restriction of major core, while point B bumps with Bo on the moving half, and the bevel forces the lifter to move horizontally inward, thereby making inner core-pulling action. It should be noted that when the inner core-pulling action starts, the plastic part should be partially retained in the major core so as to avoid horizontal moving of the part, which can influence core-pulling. The uniform bevel at the end of the lifter is designed to prevent damage caused by the collision of the lifter with straight end angle of the major core during the returning of the lifter. Therefore, when designing make sure a>B, wherein during mold clamping, point D on the lifter first bumps with Do on the major core and moves outward so that the lifter all along does not collide with end face of the major core As indicated in Fig. 1-31 is a swing slanted lifter inner core-pulling mechanism. The slanted lifter 5 is connected through a spindle with swing rod seat 7 that is mounted on the ejector plate. When the ejection starts, swing rod 5 acts together with ejector pin 4 to prop up the plastic part from major core 2 When it is moved to a pre-set distance, the convex block b of the swing rod touches the bevel on core-retainer plate 1, forcing the swing rod to swing anticlockwise inward around core shaft 6, thereby aking core-pulling while ejecting
lifter’s bottom is usually made in a ball shape hardened with local quenching process. The insert 9 on the ejector-retainer plate which comes in touch with the lifter also requires the hardening process. 1. ejector pin；2. slanted slide；3.main core；4. core-retainer plate； 5. slanted lifter；6.spring；7.return pin；8.ejector-retainer plate；9. insert； Fig.1-27: internal side core-pulling mechanism with a slanted lifter Fig.1-28 illustrates the roller-type slanted lifter for external side core-pulling mechanism. Roller 9 is connected onto slanted lifter 7 with axle 8, which means that the slanted lifter is in rolling contact with ejector-retainer plate 10 through the roller, and the sliding friction is replaced with rolling friction, thereby enormously reducing relative friction force. As indicated in Fig.1-29, slanted lifter 7 is secured on channel frame 2 by rolling axis 3, which reduces moving friction and meanwhile can drive slanted lifter to return during mold clamping. Fig.1-30 illustrates the translational slanted lifter inner core-pulling mechanism. During the ejection, slanted lifter 3 and ejector pin 4 act together to prop up the plastic part from main core 1, and when it is moved to distance L, point A on the lifter 3 breaks away from the restriction of major core, while point B bumps with B0 on the moving half, and the bevel forces the lifter to move horizontally inward, thereby making inner core-pulling action. It should be noted that when the inner core-pulling action starts, the plastic part should be partially retained in the major core so as to avoid horizontal moving of the part, which can influence core-pulling. The uniform bevel at the end of the lifter is designed to prevent damage caused by the collision of the lifter with straight end angle of the major core during the returning of the lifter. Therefore, when designing make sureα > β , wherein during mold clamping, point D on the lifter first bumps with D0 on the major core and moves outward so that the lifter all along does not collide with end face of the major core. As indicated in Fig. 1-31 is a swing slanted lifter inner core-pulling mechanism. The slanted lifter 5 is connected through a spindle with swing rod seat 7 that is mounted on the ejector plate. When the ejection starts, swing rod 5 acts together with ejector pin 4 to prop up the plastic part from major core 2. When it is moved to a pre-set distance, the convex block b of the swing rod touches the bevel on core-retainer plate 1, forcing the swing rod to swing anticlockwise inward around core shaft 6, thereby making core-pulling while ejecting
1. side core insert: 2.core pin: 3. main core: 4. core-retainer plate: 5. ejector pin 6. return pin: 7. slanted lifter: 8. axle: 9. roller: 10. ejector-retainer plate Fig 1-28: external side core-pulling mechanism with a roller-type slanted lifter 1. ejector-support plate: 2. channel frame: 3. rolling axis: 4. ejector pin: 5. core-retainer plate 6.core: 7. slanted lifter: 8. cavity-retainer plate Fig 1-29: internal core-pulling mechanism with a slanted lifter main core: 2, core-retainer plate: 3. slanted lifter: 4. ejector pin: 5. return pin; 6. ejector-retainer plate Fig 1-30: translational slanted lifter inner core-pulling mechanism
1. side core insert；2.core pin；3.main core；4. core-retainer plate；5. ejector pin； 6.return pin；7. slanted lifter；8. axle；9.roller；10. ejector-retainer plate Fig.1-28: external side core-pulling mechanism with a roller-type slanted lifter 1. ejector-support plate；2. channel frame；3. rolling axis；4. ejector pin；5. core-retainer plate； 6.core；7. slanted lifter；8. cavity-retainer plate Fig.1-29: internal core-pulling mechanism with a slanted lifter 1. main core；2. core-retainer plate；3. slanted lifter；4. ejector pin；5. return pin；6. ejector-retainer plate Fig.1-30: translational slanted lifter inner core-pulling mechanism
I core-retainer plate: 2. main core: 3. return pin: 4. ejector pin 5. slanted lifter: 6core shaft: 7. swing rod seat; 8.ejector-retainer plate Fig 1-31: swing slanted lifter inner core-pulling mechanism 3. Mold with Unscrewing Equipment High quality threads can only be molded economically and in large quantities by using an unscrewing device. The mold components which form the threads, generally cores for internal and sleeves for external threads, can be rotated in the mold During demolding they are either screwed off or out of the part while the mold is either open or closed. The part has to be designed in such a way that it can be protected against rotation In all such molds attention has to be paid to an exact mounting and alignment of cores and drive units. Insufficiently supported cores, particularly slender ones, can be shifted from their center position by the entering plastic material more easily than rigidly mounted cores. This would impede or even prevent the unscrewing process because the driving torque becomes insufficient for the deformed molding part The drive force for these molds is transmitted from the opening movement by a lead screw with coarse threads or a rack. Separate drives such as electric, pneumatic, or hydraulic drives are common, too. The latter are often actuated by separate controls a) Unscrewing mold with racks The number of threads that can be molded in these molds is limited by the diameter of the part, the force of the machine or the rack drive, and the stroke of the rack. The stroke is actuated by the opening movement of the machine or by a separate hydraulic or pneumatic actuator
1. core-retainer plate；2.main core；3. return pin；4. ejector pin； 5. slanted lifter；6.core shaft；7.swing rod seat ; 8.ejector-retainer plate Fig.1-31: swing slanted lifter inner core-pulling mechanism 3. Mold with Unscrewing Equipment High quality threads can only be molded economically and in large quantities by using an unscrewing device. The mold components which form the threads, generally cores for internal and sleeves for external threads, can be rotated in the mold. During demolding they are either screwed off or out of the part while the mold is either open or closed. The part has to be designed in such a way that it can be protected against rotation. In all such molds attention has to be paid to an exact mounting and alignment of cores and drive units. Insufficiently supported cores, particularly slender ones, can be shifted from their center position by the entering plastic material more easily than rigidly mounted cores. This would impede or even prevent the unscrewing process because the driving torque becomes insufficient for the deformed molding part. The drive force for these molds is transmitted from the opening movement by a lead screw with coarse threads or a rack. Separate drives such as electric, pneumatic, or hydraulic drives are common, too. The latter are often actuated by separate controls. a) Unscrewing mold with racks The number of threads that can be molded in these molds is limited by the diameter of the part, the force of the machine or the rack drive, and the stroke of the rack. The stroke is actuated by the opening movement of the machine or by a separate hydraulic or pneumatic actuator