CN212920237U

CN212920237U - Injection mold adopting withdrawal ejector rod technology

Info

Publication number: CN212920237U
Application number: CN202021266129.4U
Authority: CN
Inventors: 徐洋; 吴春健; 施嘉颖
Original assignee: JIANGSU JIEJIE MICROELECTRONICS CO Ltd
Current assignee: JIANGSU JIEJIE MICROELECTRONICS CO Ltd
Priority date: 2020-07-02
Filing date: 2020-07-02
Publication date: 2021-04-09
Anticipated expiration: 2030-07-02

Abstract

The utility model discloses an adopt injection mold of pumpback technique, including upper die base and die holder, the upper die base upside is equipped with pumpback and goes up the ejector pin base, and the die holder downside is equipped with pumpback and lower ejector pin base down, and the upper die base is equipped with and goes up pumpback assorted through-hole, and the die holder all is equipped with and takes back ejector pin assorted through-hole down, and the through-hole is linked together with the die cavity of constituteing behind upper die base and the die holder compound die, goes up ejector pin base and last pumpback fixed connection, lower ejector pin base and lower pumpback fixed connection. The utility model discloses simple structure, simple operation. Through adopting the utility model discloses an injection mold moulds plastics and can make to the most genuine integration and encapsulate the product entirely. The problem of copper exposure left in the traditional production mode is solved, and the subsequent glue filling step is omitted. The production mode is simplified, and the raw material investment is reduced. The hidden danger that the radiating fins are layered when the product is used at the client is avoided, and the service life of the product is prolonged.

Description

Injection mold adopting withdrawal ejector rod technology

Technical Field

The utility model relates to a semiconductor injection mold technical field especially relates to an adopt injection mold of pumpback ejector pin technique.

Background

A TO-220FP device which is popular in the market is designed TO be a full-encapsulation structure as a certain insulation resistant requirement is required. In the plastic packaging process, the common practice is as follows:

after the lead frame enters the die cavity, the whole heat sink frame area is in a suspended state in the die cavity due to the special frame structure and the requirement of full encapsulation if no supporting point is fixed. After the molding compound enters, the whole frame is displaced under the pushing of the injection pressure, the thickness of the molding compound wrapped around the radiating fin deviates from the designed size, and the insulation and pressure resistance are seriously affected. Therefore, as shown in fig. 1-4, most manufacturers set a fixed ejector rod in a mold cavity, perform pre-forming before placing the frame in the mold cavity, pre-bend the frame by a certain angle toward the fixed ejector rod, and after entering the mold cavity, the fixed ejector rod will gradually push against the frame along with the pressing of the mold, so as to fix the lead frame. After a series of processes of injection molding, pressure maintaining and cooling, the ejector rods are separated along with the opening of the mold in the mold opening stage, and then the product is ejected out of the mold cavity under the pushing of the mold ejection pin, so that the whole plastic packaging process is completed.

However, the plastic packaging process still has certain defects. Due to the action of the fixed ejector rod, after plastic package is completed, the action point of the ejector rod becomes a copper exposing point which is not insulated, and in order to achieve the insulating effect, epoxy glue is poured into the copper exposing point so as to achieve the purpose that the insulating voltage resistance can bear AC 2500V @1 s. However, in the actual working environment of the device, with the erosion of water vapor and the change of high and low temperature environments, the injected epoxy glue and the molding compound are layered, so that the insulating property is lost, and serious electric leakage accidents are caused.

SUMMERY OF THE UTILITY MODEL

In order to solve the defects, the utility model aims to provide an injection mold of the adoption pumpback technique that simple structure, use convenient, be applicable to full encapsulated type semiconductor components and parts.

In order to achieve the above object, the utility model discloses a following technical scheme realizes: the utility model provides an adopt injection mold of back extraction ejector pin technique, includes upper die base and die holder, the upper die base upside is equipped with back extraction ejector pin and goes up the ejector pin base, the die holder downside is equipped with back extraction ejector pin and lower ejector pin base down, the upper die base be equipped with last back extraction ejector pin assorted through-hole, the die holder all is equipped with back extraction ejector pin assorted through-hole down, the through-hole is linked together with the die cavity of constituteing behind upper die base and the die holder compound die, go up ejector pin base and last back extraction ejector pin fixed connection, lower ejector pin base and back extraction ejector pin fixed connection down.

Preferably, an upper ejector rod sleeve base is arranged between the upper die base and the upper ejector rod base, a lower ejector rod sleeve base is arranged between the lower die base and the lower ejector rod base, through holes are formed in the upper ejector rod sleeve base and the lower ejector rod sleeve base, the through holes formed in the upper ejector rod sleeve base are matched with the upper withdrawing ejector rod, and the through holes formed in the lower ejector rod sleeve base are matched with the lower withdrawing ejector rod.

Preferably, springs are respectively arranged between the upper ejector rod base and the upper ejector rod sleeve base and between the lower ejector rod base and the lower ejector rod sleeve base.

Preferably, the upper side of the upper ejector rod base and the lower side of the lower ejector rod base are respectively and fixedly connected with an oil cylinder through a fixing rod.

The utility model has the advantages that: the utility model has the advantages of simple structure, the simple operation. During injection molding, the upper ejector rod sleeve base and the lower ejector rod sleeve base can be ejected and withdrawn under the acting force of the oil cylinder and the spring. After the lead frame is placed in place in the die cavity (one surface for mounting a chip is downward), the die cavity is pressed, and the upper ejector rod and the lower ejector rod extend out to clamp the radiating fin frame, so that the effect of guiding and fixing the lead frame is achieved. When the filling is about to be finished, the ejector rod is withdrawn and retracted in the opposite direction for a certain depth, and the molding compound which is not completely solidified is continuously filled into the mold under the thrust action of the injection molding rod until the injection molding rod reaches the set pressure. The occupied position of the drawing-back ejector rod is completely filled by the molding compound, and the integrated full encapsulation structure of the molding compound body can be obtained.

Through adopting the utility model discloses an injection mold moulds plastics and can make to the most genuine integration and encapsulate the product entirely. The problem of copper exposure left in the traditional production mode is solved, and the subsequent glue filling step is omitted. The production mode is simplified, and the raw material investment is reduced. The hidden danger that the radiating fins are layered when the product is used at the client is avoided, and the service life of the product is prolonged.

Drawings

Fig. 1 shows a state of placement of a lead frame described in the background art.

Fig. 2 shows a state in which the mold cavity is closed as described in the background art.

FIG. 3 shows the state of injection of the molding compound described in the background art.

Fig. 4 shows the mold cavity in the prior art in the open state.

Fig. 5 is a schematic view of the structure of the present invention (the lead frame is placed in the mold cavity).

Fig. 6 is a schematic structural diagram of the state of the die cavity closing die of the present invention.

Fig. 7 is a schematic view of the clamping state of the upper and lower withdrawing rods of the present invention.

Fig. 8 is a structural diagram illustrating the injection state of the molding compound in the clamping state of the withdrawing rod of the present invention.

Fig. 9 is a structural schematic diagram of the injection state of the molding compound when the retractable ejector rod is in the retracted state.

Fig. 10 is a schematic structural view of the upper and lower withdrawing rods of the present invention in a withdrawing state.

Fig. 11 is a schematic view of the mold cavity open state structure of the present invention.

Wherein: 1. the device comprises an upper die base, 2, an upper withdrawing ejector rod, 3, an upper ejector rod base, 4, an upper ejector rod sleeve base, 5, a lower die base, 6, a lower withdrawing ejector rod, 7, a lower ejector rod base, 8, a lower ejector rod sleeve base, 9, through holes I, 10, through holes II, 11, a die cavity, 12, through holes III, 13, springs, 14, fixing rods, 15, an oil cylinder, 16, a lead frame, 17, a flow channel, 18 and a plastic package material cake.

Detailed Description

The following describes embodiments of the present invention with reference to the drawings.

As shown in fig. 5, an injection mold using a back-drawing ejector pin technique includes an upper mold base 1 and a lower mold base 5. An upper withdrawing mandril 2 and an upper mandril base 3 are arranged on the upper side of the upper die base 1, and a lower withdrawing mandril 6 and a lower mandril base 7 are arranged on the lower side of the lower die base 5. The upper die base 1 is provided with a through hole I9 matched with the upper withdrawing ejector rod 2, the lower die base 5 is provided with a through hole II 10 matched with the lower withdrawing ejector rod 6, and the through hole I9 and the through hole II 10 are communicated with a die cavity 11 formed after the upper die base 1 and the lower die base 5 are assembled. The upper ejector rod base 3 is fixedly connected with the upper withdrawing ejector rod 2, and the lower ejector rod base 7 is fixedly connected with the lower withdrawing ejector rod 6.

An upper ejector rod sleeve base 4 is arranged between the upper die base 1 and the upper ejector rod base 3, a lower ejector rod sleeve base 8 is arranged between the lower die base 5 and the lower ejector rod base 7, the upper ejector rod sleeve base 4 and the lower ejector rod sleeve base 8 are both provided with through holes III 12, III 12 of the upper ejector rod sleeve base 4 is matched with the upper withdrawing ejector rod 2, and III 12 of the lower ejector rod sleeve base 8 is matched with the lower withdrawing ejector rod 6.

Springs 13 are respectively arranged between the upper ejector rod base 3 and the upper ejector rod sleeve base 4 and between the lower ejector rod base 7 and the lower ejector rod sleeve base 8.

The upper side of the upper mandril base 3 and the lower side of the lower mandril base 7 are respectively fixedly connected with an oil cylinder 15 through a fixed rod 14.

Wherein, the upper mandril base 3 and the lower mandril base 7 can realize the ejection and the retraction under the acting force of the oil cylinder 15 and the spring 13.

As shown in fig. 6-11, the use method of the injection mold of the present invention is adopted:

after the lead frame 16 is placed in place in the cavities 11 of the upper die holder 1 and the lower die holder 5 (with the surface for mounting the chip facing downwards), the upper die holder 1 and the lower die holder 5 are pressed together. The hydraulic oil enters the oil cylinder 15 through the oil filling hole, the generated power pushes the fixing rod 14 connected with the oil cylinder, the upper ejector rod base 3 and the lower ejector rod base 7 are further pushed, and the spring 13 is compressed. The upper drawing ejector rod 2 and the upper ejector rod base 3 fixed on the upper ejector rod base 3 and the lower ejector rod base 7 extend out through the upper ejector rod sleeve base 4 and the lower ejector rod sleeve base 8 under a series of acting forces, and the upper drawing ejector rod 2 and the lower drawing ejector rod 6 clamp the lead frame 16 at specific positions to achieve the effect of guiding and fixing through the through hole I9 of the upper die base 1 and the through hole II 10 of the lower die base 5.

And secondly, when the filling is to be finished, the molding compound basically fills the die cavity 11, and the injection molding rod is not in a pressure maintaining state. After the hydraulic oil flows out of the oil outlet hole, the oil cylinder 15 loses power. At this time, the spring 13 rebounds reversely to push the upper ejector rod base 3 and the lower ejector rod base 7 out, and further drives the upper withdrawing ejector rod 2 and the lower withdrawing ejector rod 6 to withdraw.

And thirdly, the upper withdrawing ejector rod 2 and the lower withdrawing ejector rod 6 are withdrawn to a certain depth, and the incompletely solidified molding compound is continuously filled into the mold under the thrust action of the injection molding rod until the injection molding rod reaches the set pressure. And the occupied positions of the upper drawing ejector rod 2 and the lower drawing ejector rod 6 are completely filled by the molding compound, so that the integrated full encapsulation structure of the molding compound body can be obtained.

The utility model has the advantages of simple structure, the simple operation. During injection molding, the upper ejector rod sleeve base and the lower ejector rod sleeve base can be ejected and withdrawn under the acting force of the oil cylinder and the spring. After the lead frame is placed in place in the die cavity (one surface for mounting the chip is downward), the die cavity is pressed, and the upper withdrawing ejector rod and the lower withdrawing ejector rod extend out to clamp the radiating fin frame, so that the lead frame is guided and fixed. When the filling is about to be finished, the upper withdrawing ejector rod and the lower withdrawing ejector rod are withdrawn in the opposite directions to a certain depth, and the incompletely solidified molding compound is continuously filled into the mold under the thrust action of the injection molding rod until the injection molding rod reaches the set pressure. And the occupied positions of the upper and lower withdrawing push rods are completely filled by the molding compound, so that the integrated full encapsulation structure of the plastic-sealed body can be obtained.

Claims

1. The utility model provides an adopt injection mold of back extraction ejector pin technique, includes upper die base and die holder, its characterized in that: the die comprises an upper die base and a lower die base, and is characterized in that an upper withdrawing ejector rod and an upper ejector rod base are arranged on the upper side of the upper die base, a lower withdrawing ejector rod and a lower ejector rod base are arranged on the lower side of the lower die base, the upper die base is provided with a through hole matched with the upper withdrawing ejector rod, the lower die base is provided with a through hole matched with the lower withdrawing ejector rod, the through hole is communicated with a die cavity formed after the upper die base and the lower die base are assembled, the upper ejector rod base is fixedly connected with the upper withdrawing ejector rod, and the lower ejector rod base is fixedly connected.

2. The injection mold adopting the pullback push rod technology as claimed in claim 1, wherein: an upper ejector rod sleeve base is arranged between the upper die base and the upper ejector rod base, a lower ejector rod sleeve base is arranged between the lower die base and the lower ejector rod base, through holes are formed in the upper ejector rod sleeve base and the lower ejector rod sleeve base, the through holes formed in the upper ejector rod sleeve base are matched with the upper withdrawing ejector rod, and the through holes formed in the lower ejector rod sleeve base are matched with the lower withdrawing ejector rod.

3. The injection mold adopting the pullback push rod technology as claimed in claim 2, wherein: and springs are respectively arranged between the upper ejector rod base and the upper ejector rod sleeve base and between the lower ejector rod base and the lower ejector rod sleeve base.

4. The injection mold adopting the pullback push rod technology as claimed in claim 2, wherein: the upper side of the upper ejector rod base and the lower side of the lower ejector rod base are fixedly connected with oil cylinders through fixing rods respectively.