Ejector pin structure, injection molding machine using ejector pin, and ejector method

Abstract

This application relates to a ejector pin structure, an injection molding machine using ejector pins, and an ejector pin method, belonging to the field of packaging equipment technology. It includes a pin plate with multiple ejector pins. The ejector pins are used to abut against the surface of the chip facing away from the heat sink. The pin plate drives the ejector pins to slide towards the contact surface facing the heat sink, ensuring seamless contact between the surface of the heat sink facing away from the chip and the contact surface. This application has the effect of extending the lifespan of the chip.

Description

Technical Field

[0001] This application relates to the field of packaging equipment technology, and in particular to an ejector pin structure, an injection molding machine using ejector pins, and an ejector pin extraction method. Background Technology

[0002] In the field of integrated circuit technology, chip packaging is one of the most fundamental processes. Chip packaging is further divided into many types, often including plastic packaging, ceramic packaging, and metal packaging based on the properties of the packaging materials. Among these, plastic packaging is a low-cost, simple, and highly reliable packaging structure, commonly used in consumer electronics and holding the largest market share.

[0003] The general process flow for plastic encapsulation is as follows: the lead frame, substrate or chip is placed on the frame preheating stage, the frame is then placed in the encapsulation mold of the injection molding machine, the encapsulation mold is closed, molten resin is squeezed into the mold, the resin is filled and hardened, the mold is opened and the encapsulation process is completed.

[0004] Regarding the aforementioned technologies, the inventors believe that the following defects exist: As a high-energy-consuming device, the chip needs to accelerate heat dissipation to ensure its normal operation. Therefore, a heat sink needs to be added to the chip surface. However, during the chip packaging process, the molten liquid plastic is prone to covering the heat sink, which makes the chip easily damaged during subsequent use. Summary of the Invention

[0005] To extend the lifespan of chips, this application provides an ejector pin structure, an injection molding machine using ejector pins, and an ejector pin method.

[0006] Firstly, this application provides a pull-out pin structure, which adopts the following technical solution:

[0007] A pin-pulling structure includes a pin plate on which pins are provided. The pins are used to abut against the surface of a chip away from a heat sink. The pin plate drives the pins to slide toward the contact surface facing the heat sink, so that the surface of the heat sink away from the chip abuts against the contact surface without gap.

[0008] By adopting the above technical solution, when encapsulating the chip in plastic, the end of the ejector pin abuts against the surface of the chip away from the heat sink, so that the heat sink is pressed tightly against the contact surface. When the hot-melt plastic surrounds and encapsulates the chip, the gap between the heat sink and the contact surface is small, making it difficult for the hot-melt plastic to enter the gap between the heat sink and the contact surface. This keeps the surface of the heat sink away from the chip in an open state, which facilitates the heat sink's heat dissipation operation and extends the chip's lifespan. Furthermore, the ejector pin is needle-shaped, making it easy to pull out from the gradually solidifying plastic. At the same time, in the above process, the impact of the ejector pin on the initially solidified plastic is reduced, ensuring the chip encapsulation effect.

[0009] Optionally, the ejector pin is cylindrical and hollow. A receiving plate is slidably disposed inside the ejector pin. A notch is provided on the side wall of the ejector pin for the receiving plate to slide out. The surface of the receiving plate away from the pin plate is on the same plane as the end face of the ejector pin, and the end face of the ejector pin away from the pin plate is closed. The ejector pin structure also includes a first driving member for driving the receiving plate to slide, so that the receiving plate slides out of the ejector pin or is retracted into the area inside the ejector pin.

[0010] By adopting the above technical solution, when the ejector pin contacts the chip and compresses the heat sink, the contact area between the ejector pin and the chip is small, which can easily lead to chip damage. Before the ejector pin contacts the chip, the first driving component drives the receiving plate to slide out of the ejector pin. The receiving plate and the ejector pin work together to press the chip, increasing the pressure point on the chip and thus reducing the possibility of chip damage. At the same time, the first driving component drives the receiving plate to slide back into the ejector pin, making it easier for the ejector pin to be pulled out of the pre-cured plastic, thereby ensuring the chip packaging effect.

[0011] Optionally, the first driving component includes an airbag disposed inside the ejector pin, and the end of the receiving plate located inside the ejector pin is fixedly disposed on the airbag, and the airbag is connected to an external air supply system.

[0012] By adopting the above technical solution, when the receiving plate is driven to slide, the airbag is connected to the external air supply system. During the inflation process, the volume of the airbag gradually increases, and the airbag drives the receiving plate to slide as the volume increases. The operation is simple and convenient. At the same time, the airbag has the advantages of simple structure and long service life.

[0013] Optionally, multiple receiving plates are provided, and the multiple receiving plates are arranged around the circumference of the ejector pin and are all fixedly connected to the airbag. The end of the receiving plate away from the airbag is arc-shaped and has the same curvature as the side wall of the ejector pin.

[0014] By adopting the above technical solution, multiple receiving plates are provided, which further increases the force-bearing area of ​​the chip and further reduces the possibility of chip damage. The end of the receiving plate away from the airbag is arc-shaped, which makes it easy for the receiving plate to be retracted into the ejector pin. The end face of the receiving plate and the peripheral wall of the ejector pin are located on the same arc surface, which makes it easier for the ejector pin to be removed from the initially cured plastic.

[0015] Optionally, multiple ejector pins are provided, and the multiple ejector pins are arranged in a circle on the pin plate.

[0016] By adopting the above technical solution, multiple ejector pins are provided, which further increases the force-bearing area of ​​the chip and reduces the possibility of chip damage. The ejector pins are arranged in a circular pattern. Under the same conditions, the circular arrangement of ejector pins is more compact, which ensures the force-bearing range of the chip when pressing it, thereby reducing the gap between the chip heat sink and the contact surface and reducing the possibility of the heat sink being encapsulated.

[0017] Secondly, this application provides an injection molding machine using an ejector pin, which adopts the following technical solution:

[0018] Optionally, an injection molding machine using an ejector pin structure further includes an upper mold and a lower mold, the upper mold and the lower mold being fastened together to form an encapsulation cavity, the chip being placed in the lower mold with the heat sink facing the lower mold, the pin plate being disposed in the upper mold and located on the surface opposite to the lower mold, the upper mold having a first through hole for the ejector pin to pass through, the pin plate being slidably disposed in the upper mold, the sliding direction of the pin plate being perpendicular to the plane of the upper mold, and the upper mold also having a second driving member for driving the pin plate to slide.

[0019] By adopting the above technical solution, during chip packaging, the chip is first placed in the lower mold, and the heat sink is placed flat on the contact surface of the lower mold. Then, the upper mold slides and snaps onto the lower mold. The second driving component drives the pin plate to slide, and the sliding of the pin plate drives the ejector pin to slide. The ejector pin slides and abuts against the chip, compressing the chip and making the heat sink press tightly against the contact surface of the lower mold. Then, hot melt plastic is injected into the mold cavity through the pouring port of the upper mold. After the plastic has initially solidified, the second driving component drives the pin plate to slide, and the sliding of the pin plate drives the ejector pin to slide out and separate from the solidified plastic, completing the chip packaging. The operation is simple and convenient.

[0020] Optionally, the second driving component includes an electric push rod disposed on the upper mold. The body of the electric push rod is fixedly disposed on the upper mold, the length direction of the output shaft of the electric push rod is perpendicular to the plane where the upper mold is located, and the needle plate is fixedly disposed on the output shaft of the electric push rod.

[0021] By adopting the above technical solution, when the ejector pin is extracted from the pre-cured plastic, the electric push rod is activated. The electric push rod drives the needle plate to slide, and the sliding of the needle plate causes the ejector pin to slide away from the upper mold, so that the ejector pin is separated from the pre-cured plastic. The operation is simple and convenient. The electric push rod has the advantages of simple structure and easy use.

[0022] Optionally, the upper mold includes an upper mold body and an extrusion plate disposed on the upper mold body. The extrusion plate has a cavity and a flow channel for the flow of plastic solution. The extrusion plate is located on the surface of the upper mold body facing the lower mold. The upper mold body is fixedly disposed on the output shaft of the electric push rod. The extrusion plate has a second through hole for the ejector pin to pass through. The extrusion plate is slidably disposed on the upper mold body. The sliding direction of the extrusion plate is parallel to the length direction of the output shaft of the electric push rod. The injection molding machine also includes a third driving member for driving the extrusion plate to slide and compress the void formed by the ejector pin in the plastic solution.

[0023] By adopting the above technical solution, after the ejector pin is extracted from the pre-cured plastic, a cylindrical channel is formed within the pre-cured plastic, resulting in a relatively poor chip packaging effect. After the ejector pin is removed from the pre-cured plastic, the extrusion plate is driven to slide towards the lower die via a third driving component. During this process, the extrusion plate compresses the pre-cured plastic, compressing the cylindrical channel formed earlier. This causes the less fluid plastic to flow towards the cylindrical channel, thereby eliminating the cylindrical channel and improving the chip packaging effect.

[0024] Optionally, the third driving component includes a snap-fit ​​groove formed on the extrusion plate. The snap-fit ​​groove is formed on the side wall of the second through hole. The snap-fit ​​groove allows the receiving plate to slide into it. The sliding of the needle plate drives the extrusion plate to slide and compress the initially cured plastic.

[0025] By adopting the above technical solution, before the extrusion plate slides, the needle plate is first driven to slide by the electric push rod. The needle plate drives the ejector pin to slide into the second through hole and align the receiving plate with the snap-fit ​​groove. Then, air is supplied to the airbag through the external air supply system. The volume of the airbag gradually increases, causing the receiving plate to slide out and enter the snap-fit ​​groove. Then, the electric push rod is activated. The output shaft of the electric push rod drives the extrusion plate to slide. The extrusion plate compresses the initially cured plastic and then compresses the cylindrical channel. The operation is convenient. At the same time, the third driving component and the second driving component share the electric push rod, which reduces the investment in the driving source and reduces the investment cost. It also reduces the space occupied.

[0026] Thirdly, this application provides a method for removing ejector pins, which adopts the following technical solution:

[0027] Optionally, an ejection method using ejector pins, using an injection molding machine employing ejector pins, further includes;

[0028] S1: Place the chip mounting frame on the lower mold and make the heat sink on the chip abut against the flat contact surface of the lower mold. Then the upper mold slides and snaps onto the lower mold.

[0029] S2: Start the electric push rod. The output shaft of the electric push rod drives the needle plate to slide. The sliding of the needle plate drives the ejector pin to slide and approach the chip. Then, the air bag is inflated through the external air supply system. The volume of the air bag increases. The increased volume of the air bag drives the receiving plate to slide. The receiving plate slides out of the ejector pin. The side of the receiving plate that is close to the chip abuts against the chip. Then start the electric push rod again. The electric push rod drives the ejector pin to slide and abut against the chip, so that the heat sink on the chip is pressed against the lower mold.

[0030] S3: The hot-melt plastic enters the mold cavity through the sprue of the upper mold. As the temperature of the molten plastic gradually decreases to the initial solidification stage, the gas in the airbag is discharged through the air supply system, and the volume of the airbag gradually decreases. The airbag drives the receiving plate to retract into the ejector pin. Then, the electric push rod is activated to pull the ejector pin out of the plastic and position the end of the ejector pin in the second through hole. The airbag is then inflated through the air supply system, and the airbag drives the receiving plate to slide into the snap-fit ​​groove.

[0031] S4: Start the electric push rod. The electric push rod drives the extrusion plate to slide towards the lower mold. The extrusion plate slides and compresses the initially solidified plastic. During the compression process, the plastic fills the gaps formed by the ejector pins in the solidified plastic.

[0032] S5: After the plastic has fully cured, the upper mold slides open and the packaged chip is removed.

[0033] In summary, this application includes at least one of the following beneficial technical effects:

[0034] 1. When encapsulating a chip in plastic, the end of the ejector pin abuts against the chip's surface away from the heatsink, ensuring the heatsink is firmly pressed against the contact surface. When the hot-melt plastic surrounds and encapsulates the chip, the small gap between the heatsink and the contact surface makes it difficult for the hot-melt plastic to enter the gap, leaving the heatsink's surface away from the chip open. This facilitates heat dissipation from the chip, extending its lifespan. Furthermore, the ejector pin's needle-like shape allows it to be easily pulled out of the gradually solidifying plastic. Simultaneously, this process reduces the impact of the ejector pin on the initially solidified plastic, ensuring the chip encapsulation effect.

[0035] 2. During chip packaging, the chip is first placed in the lower mold, and the heat sink is placed flat on the contact surface of the lower mold. Then, the upper mold slides and snaps onto the lower mold. The second driving component drives the pin plate to slide, which in turn drives the ejector pin to slide. The ejector pin slides and abuts against the chip, compressing the chip and pressing the heat sink tightly against the contact surface of the lower mold. Then, hot melt plastic is injected into the mold cavity through the pouring port of the upper mold. After the plastic has initially solidified, the second driving component drives the pin plate to slide, which causes the ejector pin to slide out and separate from the solidified plastic, completing the chip packaging. The operation is simple and convenient. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall structure of a pull-out pin structure according to an embodiment of this application;

[0037] Figure 2 This is a bottom view of the needle plate in a needle-pulling structure according to an embodiment of this application;

[0038] Figure 3 This is a cross-sectional view of the ejector pin in an embodiment of the present application.

[0039] Figure 4 yes Figure 3 An enlarged schematic diagram of part A in the middle;

[0040] Figure 5 This is a schematic diagram of the upper and lower molds in an injection molding machine using ejector pins, according to an embodiment of this application.

[0041] Figure 6 This is a cross-sectional view of the upper and lower molds in an injection molding machine using ejector pins, according to an embodiment of this application.

[0042] Figure 7 yes Figure 6 Enlarged diagram of part B.

[0043] Explanation of reference numerals in the attached diagram: 1. Needle plate; 2. Ejector pin; 3. Chip; 4. Heat sink; 5. Receiving plate; 6. Notch; 7. Airbag; 8. Connecting air pipe; 9. Upper mold; 91. Upper mold body; 92. Extrusion plate; 10. Lower mold; 11. First through hole; 12. Electric push rod; 13. Second through hole; 14. Snap-fit ​​groove. Detailed Implementation

[0044] The following is in conjunction with the appendix Figure 1-7 This application is described in further detail.

[0045] This application discloses a pull-out pin structure. (Refer to...) Figure 1 and Figure 2The ejector pin structure includes a pin plate 1, on which ejector pins 2 are fixedly mounted. In this embodiment, the ejector pins 2 are cylindrical, with their length direction perpendicular to the plane of the pin plate 1. The ejector pins 2 abut against the surface of the chip 3 facing away from the heat sink 4. The pin plate 1 drives the ejector pins 2 to slide towards the contact surface facing the heat sink 4, ensuring seamless contact between the surface of the heat sink 4 facing away from the chip 3 and the contact surface. Before injection molding, the chip 3 is placed flat on the contact surface, and the heat sink 4 is also placed flat on the contact surface. Then, the ejector pins 2 are pressed onto the chip 3, and the pin plate 1 is pressed down. The pin plate 1 drives the ejector pins 2 to eliminate the gap between the heat sink 4 and the contact surface, thereby reducing the possibility of hot-melt plastic covering the surface of the heat sink 4, facilitating heat dissipation during subsequent chip 3 operation, and extending the service life of the chip 3.

[0046] Reference Figure 3 and Figure 4 In this embodiment, the ejector pin 2 is hollow, and a receiving plate 5 is slidably disposed inside the ejector pin 2. A notch 6 is provided on the side wall of the ejector pin 2 for the receiving plate 5 to slide out. The surface of the receiving plate 5 facing away from the pin plate 1 is on the same plane as the end face of the ejector pin 2, and the end face of the ejector pin 2 facing away from the pin plate 1 is closed. In this embodiment, the receiving plate 5 is T-shaped and is slidably engaged in the notch 6 to reduce the possibility of the receiving plate 5 falling off. When pressing the chip 3, the receiving plate 5 slides out. Under the action of the receiving plate 5 and the end of the ejector pin 2, the force-bearing area of ​​the chip 3 is increased, thereby reducing the possibility of damage to the chip 3 and extending the service life of the chip 3.

[0047] Reference Figure 3 and Figure 4 To facilitate the sliding of the receiving plate 5, the ejector pin structure also includes a first driving member for driving the receiving plate 5 to slide out of the ejector pin 2 or retract into the area within the ejector pin 2. In this embodiment, the first driving member includes an airbag 7 disposed within the ejector pin 2. In this embodiment, the end of the receiving plate 5 located within the ejector pin 2 is fixedly disposed on the airbag 7. The airbag 7 is connected to an external air supply system. Furthermore, the airbag 7 is provided with a connecting air pipe 8, which is connected to an external air supply system. When the receiving plate 5 is driven to slide, the air supply system supplies air to the airbag 7. When the airbag 7 is inflated, the volume of the airbag 7 gradually increases. As the volume of the airbag 7 increases, it drives the receiving plate 5 to slide. The operation is simple and convenient.

[0048] Reference Figure 3 and Figure 4In other embodiments, the external air supply system can be replaced by a water supply system, which is connected to the connecting air pipe 8. The water supply system adds liquid water into the airbag 7. The boiling point of the liquid water is about 100°, so that the maximum temperature of the airbag 7 is 100°, reducing the possibility of damage to the airbag 7. The volume of the airbag 7 gradually increases, thereby driving the receiving plate 5 to slide. The operation is simple and convenient. When the receiving plate 5 is retracted, the liquid in the airbag 7 is extracted through the water supply system. The volume of the airbag 7 gradually decreases, thereby driving the receiving plate 5 to be retracted into the ejector pin 2.

[0049] Reference Figure 3 and Figure 4 To further increase the contact area between the chip 3 and the ejector pin 2, multiple receiving plates 5 are provided. The multiple receiving plates 5 are arranged along the circumference of the ejector pin 2 and are all fixedly connected to the airbag 7. The end of the receiving plate 5 away from the airbag 7 is arc-shaped and has the same curvature as the side wall of the ejector pin 2. In this embodiment, four receiving plates 5 are provided on the ejector pin 2 and are evenly distributed along the circumference of the ejector pin 2.

[0050] Reference Figure 1 and Figure 2 Furthermore, multiple ejector pins 2 are provided, and the multiple ejector pins 2 are arranged in a circle on the needle plate 1. In this embodiment, four ejector pins 2 correspond to one chip 3, and the four ejector pins 2 are arranged in a circle on the needle plate 1.

[0051] The implementation principle of a pull-out pin structure in this application embodiment is as follows:

[0052] Before the ejector pin 2 presses the chip 3, the external air supply system is connected to the connecting air pipe 8. The air supply system adds gas into the air bag 7, and the volume of the air bag 7 gradually increases. As the volume of the air bag 7 increases, the receiving plate 5 slides out from the ejector pin 2. Then, the pin plate 1 is pressed, and the pin plate 1 moves the ejector pin 2 toward the chip 3, so that the end of the ejector pin 2 and the receiving plate 5 abut against the chip 3 and press the chip 3, so that the heat sink 4 of the chip 3 is tightly attached to the contact surface, thereby reducing the possibility that the surface of the heat sink 4 is encapsulated, thus extending the service life of the chip 3.

[0053] This application discloses an injection molding machine using an ejector pin, referring to... Figure 5 and Figure 6 The injection molding machine using ejector pins uses an ejector pin structure and also includes an upper mold 9 and a lower mold 10. The upper mold 9 and the lower mold 10 are fastened together to form an encapsulation cavity. The chip 3 is placed in the lower mold 10 with the heat sink 4 facing the lower mold 10. The heat sink 4 is placed on the upper surface of the lower mold 10. The pin plate 1 is set in the upper mold 9 and is located on the surface away from the lower mold 10. The upper mold 9 has a first through hole 11 for the ejector pin 2 to pass through. The pin plate 1 is slidably set in the upper mold 9, and the sliding direction of the pin plate 1 is perpendicular to the plane where the upper mold 9 is located.

[0054] Reference Figure 5 and Figure 6 The upper mold 9 is also provided with a second driving member for driving the needle plate 1 to slide. In this embodiment, the second driving member includes an electric push rod 12 disposed on the upper mold 9. The body of the electric push rod 12 is fixedly disposed on the upper mold 9. The length direction of the output shaft of the electric push rod 12 is perpendicular to the plane where the upper mold 9 is located. The needle plate 1 is fixedly disposed on the output shaft of the electric push rod 12.

[0055] Before encapsulating chip 3, chip 3 is first moved onto lower mold 10 and its position is adjusted so that heat sink 4 rests on the flat contact surface of lower mold 10. Then, upper mold 9 slides and engages with lower mold 10. Then, electric push rod 12 is activated, which drives pin plate 1 to slide toward upper mold 9. During this process, ejector pin 2 moves toward chip 3 and presses against chip 3. Then, external air supply system is connected to connecting air pipe 8, and air supply system adds gas into air bag 7. The volume of air bag 7 gradually increases, and the increase in volume of air bag 7 causes the receiving plate 5 to slide out from ejector pin 2, so that ejector pin 2 and receiving plate 5 are both pressed against the surface of chip 3. Then, hot melt plastic is poured into the mold cavity through the pouring port of upper mold 9 to complete the encapsulation of chip 3.

[0056] Reference Figure 6 and Figure 7 To improve the packaging effect of chip 3, the upper mold 9 includes an upper mold body 91 and an extrusion plate 92 disposed on the upper mold body 91. The extrusion plate 92 has a cavity and a flow channel for the flow of plastic solution. The extrusion plate 92 is located on the surface of the upper mold body 91 facing the lower mold 10. The upper mold body 91 is fixedly disposed on the output shaft of the electric push rod 12. The extrusion plate 92 has a second through hole 13 for the ejector pin 2 to pass through.

[0057] Reference Figure 6 and Figure 7 The extrusion plate 92 is slidably disposed on the upper mold body 91. The sliding direction of the extrusion plate 92 is parallel to the length direction of the output shaft of the electric push rod 12. Furthermore, a magnet is disposed on the surface of the upper mold body 91 near the extrusion plate 92. The extrusion plate 92 is attracted to the magnet, so that the upper mold body 91 and the extrusion plate 92 are connected as a whole. The injection molding machine also includes a third driving member for driving the extrusion plate 92 to slide and compress the gap formed by the ejector pin 2 in the plastic solution. In this embodiment, the third driving member includes a snap-fit ​​groove 14 opened on the extrusion plate 92. The snap-fit ​​groove 14 is opened on the side wall of the second through hole 13. The snap-fit ​​groove 14 allows the receiving plate 5 to slide into it. The sliding of the needle plate 1 drives the extrusion plate 92 to slide and compress the initially cured plastic.

[0058] After the plastic has initially cured, the electric push rod 12 is activated. The electric push rod 12 drives the needle plate 1 to slide away from the lower mold 10, so that the ejector pin 2 is extracted from the plastic. Then, the receiving plate 5 is positioned in the second through hole 13 and aligned with the snap-fit ​​groove 14. The air supply system is then connected to the connecting air pipe 8. The airbag 7 drives the receiving plate 5 to slide out and snap into the snap-fit ​​groove 14. The electric push rod 12 is activated again, and the electric push rod 12 drives the needle plate 1 to slide. The sliding of the needle plate 1 drives the extrusion plate 92 to slide towards the lower mold 10. The sliding of the extrusion plate 92 compresses the plastic. During the compression process, the channels in the plastic are eliminated, thereby improving the encapsulation effect of the chip 3.

[0059] The implementation principle of an injection molding machine using an ejector pin according to an embodiment of this application is as follows:

[0060] When packaging chip 3, chip 3 is first moved onto lower mold 10 and its position is adjusted so that heat sink 4 is supported on the flat contact surface of lower mold 10. Then upper mold 9 is slid to engage with lower mold 10. Then electric push rod 12 is activated, which drives pin plate 1 to slide toward upper mold 9. During this process, ejector pin 2 moves toward chip 3 and presses against chip 3. Then external air supply system is connected to connecting air pipe 8. Air supply system adds gas into air bag 7. The volume of air bag 7 gradually increases. The increase in volume of air bag 7 causes support plate 5 to slide out from ejector pin 2, so that ejector pin 2 and support plate 5 are both pressed against the surface of chip 3.

[0061] After the plastic has initially cured, the electric push rod 12 is activated. The electric push rod 12 drives the needle plate 1 to slide away from the lower mold 10, so that the ejector pin 2 is extracted from the plastic. Then, the receiving plate 5 is positioned in the second through hole 13 and aligned with the snap-fit ​​groove 14. The air supply system is then connected to the connecting air pipe 8. The airbag 7 drives the receiving plate 5 to slide out and snap into the snap-fit ​​groove 14. The electric push rod 12 is activated again, and the electric push rod 12 drives the needle plate 1 to slide. The sliding of the needle plate 1 drives the extrusion plate 92 to slide towards the lower mold 10. The sliding of the extrusion plate 92 compresses the plastic. During the compression process, the channels in the plastic are eliminated, thereby improving the encapsulation effect of the chip 3.

[0062] This application discloses a method for removing ejector pins, which uses an injection molding machine that employs ejector pins, and further includes:

[0063] S1: Place the frame for mounting chip 3 on the lower mold 10, and make the heat sink 4 on chip 3 abut against the flat contact surface of the lower mold 10. Then the upper mold 9 slides and snaps onto the lower mold 10.

[0064] S2: Start the electric push rod 12. The output shaft of the electric push rod 12 drives the needle plate 1 to slide. The sliding of the needle plate 1 drives the ejector pin 2 to slide and approach the chip 3. Then, the air bag 7 is inflated through the external air supply system. The volume of the air bag 7 increases. The increased volume of the air bag 7 drives the receiving plate 5 to slide. The receiving plate 5 slides out of the ejector pin 2. The surface of the receiving plate 5 that is close to the chip 3 abuts against the chip 3. Then start the electric push rod 12 again. The electric push rod 12 drives the ejector pin 2 to slide and abut against the chip 3, so that the heat sink 4 on the chip 3 is pressed against the lower mold 10.

[0065] S3: The hot-melt plastic enters the mold cavity through the sprue of the upper mold 9. As the temperature of the molten plastic gradually decreases to the initial solidification stage, the gas in the airbag 7 is discharged through the air supply system, and the volume of the airbag 7 gradually decreases. The airbag 7 drives the receiving plate 5 to retract into the ejector pin 2. Then, the electric push rod 12 is activated to pull the ejector pin 2 out of the plastic and position the end of the ejector pin 2 in the second through hole 13. Then, the airbag 7 is inflated through the air supply system, and the airbag 7 drives the receiving plate 5 to slide into the snap-fit ​​groove 14.

[0066] S4: Start the electric push rod 12. The electric push rod 12 drives the extrusion plate 92 to slide towards the lower mold 10. The extrusion plate 92 slides to compress the initially solidified plastic. During the compression process, the plastic fills the gaps formed by the ejector pin 2 in the solidified plastic.

[0067] S5: After the plastic is completely cured, the upper mold 9 slides open and the packaged chip 3 is removed.

[0068] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A ejector pin structure, characterized in that: Includes a pin plate (1), on which a pull pin (2) is provided. The pull pin (2) is used to abut against the surface of the chip (3) away from the heat sink (4). The pin plate (1) drives the pull pin (2) to slide toward the contact surface facing the heat sink (4), so that the surface of the heat sink (4) away from the chip (3) abuts against the contact surface without gap. The ejector pin (2) is cylindrical and hollow. A receiving plate (5) is slidably disposed inside the ejector pin (2). A notch (6) is opened on the side wall of the ejector pin (2) for the receiving plate (5) to slide out. The surface of the receiving plate (5) away from the needle plate (1) is on the same plane as the end face of the ejector pin (2) and the end face of the ejector pin (2) away from the needle plate (1) is closed. The ejector pin structure also includes a first driving member for driving the receiving plate (5) to slide out of the ejector pin (2) or retract into the area inside the ejector pin (2). The first driving component includes an airbag (7) disposed inside the ejector pin (2), and the end of the receiving plate (5) located inside the ejector pin (2) is fixedly disposed on the airbag (7), and the airbag (7) is connected to an external air supply system.

2. The ejector pin structure according to claim 1, characterized in that: Multiple receiving plates (5) are provided. The multiple receiving plates (5) are arranged along the circumference of the ejector pin (2) and are all fixedly connected to the airbag (7). The end of the receiving plate (5) away from the airbag (7) is arc-shaped and has the same arc as the side wall of the ejector pin (2).

3. The ejector pin structure according to claim 1, characterized in that: Multiple ejector pins (2) are provided, and the multiple ejector pins (2) are arranged in a circle on the pin plate (1).

4. An injection molding machine using an ejector pin, characterized in that: The ejector pin structure as described in any one of claims 1-3 further includes an upper mold (9) and a lower mold (10), the upper mold (9) and the lower mold (10) being fastened together to form an encapsulation cavity, the chip (3) being placed in the lower mold (10) with the heat sink (4) facing the lower mold (10), the pin plate (1) being disposed on the upper mold (9) and located on the surface away from the lower mold (10), the upper mold (9) having a first through hole (11) through which the ejector pin (2) passes, the pin plate (1) being slidably disposed on the upper mold (9), the sliding direction of the pin plate (1) being perpendicular to the plane of the upper mold (9), and the upper mold (9) also having a second driving member for driving the pin plate (1) to slide.

5. An injection molding machine using an ejector pin according to claim 4, characterized in that: The second driving component includes an electric push rod (12) disposed on the upper mold (9). The body of the electric push rod (12) is fixedly disposed on the upper mold (9). The length direction of the output shaft of the electric push rod (12) is perpendicular to the plane where the upper mold (9) is located. The needle plate (1) is fixedly disposed on the output shaft of the electric push rod (12).

6. An injection molding machine using an ejector pin according to claim 4, characterized in that: The upper mold (9) includes an upper mold body (91) and an extrusion plate (92) disposed on the upper mold body (91). The extrusion plate (92) has a cavity and a flow channel for the flow of plastic solution. The extrusion plate (92) is located on the surface of the upper mold body (91) facing the lower mold (10). The upper mold body (91) is fixedly disposed on the output shaft of the electric push rod (12). The extrusion plate (92) has a second through hole (13) for the ejector pin (2) to pass through. The extrusion plate (92) is slidably disposed on the upper mold body (91). The sliding direction of the extrusion plate (92) is parallel to the length direction of the output shaft of the electric push rod (12). The injection molding machine also includes a third driving member for driving the extrusion plate (92) to slide and compress the gap formed by the ejector pin (2) in the plastic solution.

7. An injection molding machine using an ejector pin according to claim 6, characterized in that: The third driving component includes a snap-fit ​​groove (14) formed on the extrusion plate (92). The snap-fit ​​groove (14) is formed on the side wall of the second through hole (13). The snap-fit ​​groove (14) allows the receiving plate (5) to slide into it. The needle plate (1) slides to drive the extrusion plate (92) to slide and compress the initially cured plastic.

8. A method for removing ejector pins, characterized in that: The injection molding machine using the ejector pin as described in claim 7 further includes: S1: Place the frame for mounting the chip (3) on the lower mold (10) and make the heat sink (4) on the chip (3) abut against the flat contact surface of the lower mold (10), and then the upper mold (9) slides and snaps onto the lower mold (10); S2: Start the electric push rod (12), the output shaft of the electric push rod (12) drives the needle plate (1) to slide, the needle plate (1) slides and drives the ejector pin (2) to slide and approach the chip (3), then inflate the air bag (7) through the external air supply system, the volume of the air bag (7) increases, the volume of the air bag (7) drives the receiving plate (5) to slide, the receiving plate (5) slides out of the ejector pin (2), the receiving plate (5) near the chip (3) abuts against the chip (3); start the electric push rod (12) again, the electric push rod (12) drives the ejector pin (2) to slide and abut against the chip (3), so that the heat sink (4) on the chip (3) abuts against the lower mold (10); S3: The hot-melt plastic enters the mold cavity through the pouring port of the upper mold (9). When the temperature of the molten plastic gradually decreases to the initial solidification, the gas in the air bag (7) is discharged through the air supply system. The volume of the air bag (7) gradually decreases. The air bag (7) drives the receiving plate (5) to retract into the ejector pin (2). Then, the electric push rod (12) is activated to pull the ejector pin (2) out of the plastic and make the end of the ejector pin (2) located in the second through hole (13). Then, the air bag (7) is inflated through the air supply system. The air bag (7) drives the receiving plate (5) to slide into the snap-fit ​​groove (14). S4: Start the electric push rod (12), the electric push rod (12) drives the extrusion plate (92) to slide toward the lower mold (10), the extrusion plate (92) slides to compress the initially solidified plastic, and the plastic fills the gap formed by the ejector pin (2) in the solidified plastic during the compression process; S5: After the plastic is completely cured, the upper mold (9) slides open and the packaged chip (3) is removed.

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