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CN-122008499-A - Anti-blocking exhaust precision die for complex electronic part molding and preparation process thereof

CN122008499ACN 122008499 ACN122008499 ACN 122008499ACN-122008499-A

Abstract

The invention provides an anti-blocking exhaust precise die for forming a complex electronic part and a preparation process thereof. The insert is a standard geometrical body with a three-dimensional communicated pore network inside, and the inner wall of the pore and the end face exposed to the cavity are modified by vacuum impregnation and coated with an ultra-lyophobic fluorosilane molecular layer. The insert is fixed in the mounting hole of the die body through interference fit and coated high-temperature resistant sealant in a press fit mode, the end face of the insert is precisely flush with the surface of the cavity, and a buffer cavity communicated with the outside through a vacuum channel is formed in the bottom of the mounting hole. The invention realizes high-efficiency, long-acting and maintenance-free active exhaust, fundamentally solves the problems of trapped air and exhaust groove blockage in the forming of the precise electronic part, and remarkably improves the product yield and the production efficiency.

Inventors

  • SUN ZHENLEI
  • WU LEI
  • ZENG YINGBIN

Assignees

  • 东莞市石上精密模具有限公司

Dates

Publication Date
20260512
Application Date
20260330

Claims (10)

  1. 1. Be used for fashioned anti-blocking material exhaust precision die of complicated electronic part, including mould body and at least one exhaust unit, this internal die cavity that is equipped with of mould, its characterized in that: the exhaust unit comprises a group of porous metal exhaust inserts and a mounting structure arranged on the die body; the porous metal exhaust insert is a regular geometrical body, a three-dimensional communicated pore network is arranged in the porous metal exhaust insert, and the inner wall of the pore and the end face of the insert, which is used for being exposed to the cavity, are provided with ultra-lyophobic functional layers; The mounting structure comprises a mounting hole matched with the outline of the insert, the insert is fixed in the mounting hole through interference fit, and the exposed end face of the insert is precisely flush with the working surface of the cavity; A group of buffer cavities are defined between the bottom of the mounting hole and the insert, and the buffer cavities are communicated with an external vacuum system through vacuum channels formed in the die body.
  2. 2. The anti-plugging venting precision die of claim 1, wherein the porous metal venting insert is sintered from a metal matrix composite, the raw material composition comprising, based on the total weight of the metal matrix composite: 70% -85% of 316L stainless steel powder; 5% -7% of nickel-coated aluminum composite powder; 8% -12% of Cu-10Sn-3Ti active alloy powder; 8% -10% of polycarbonate microspheres; 0.5% -1.0% of lubricant.
  3. 3. The anti-plugging venting precision die of claim 1, wherein an H7/p6 interference fit is provided between the mounting hole and the porous metal venting insert, and a high temperature resistant sealing material is filled between the mating interfaces of the two.
  4. 4. The anti-plugging venting precision mold of claim 1, wherein the porous metal venting insert is disposed in a trapped air region of the mold body cavity, the trapped air region comprising at least one of a melt-filled tip, a blind hole bottom, a stiffener tip, and a wall thickness discontinuity.
  5. 5. The anti-plugging venting precision mold of claim 1, wherein the porous metal venting insert is a replaceable modular component.
  6. 6. A method for preparing the anti-blocking exhaust precision die according to any one of claims 1 to 5, comprising the steps of: ① Preparing a porous metal exhaust insert, namely mixing metal powder, performing compression molding, and sintering, wherein the sintering comprises degreasing at 450 ℃, decomposing a pore-forming agent at 750 ℃, performing nickel-aluminum exothermic reaction, and performing liquid-phase sintering at 1130+/-10 ℃; ② The method comprises the steps of processing a die body, namely processing a die cavity, a vacuum channel and a mounting hole in interference fit with an insert on the die body, wherein a buffer cavity is reserved at the bottom of the mounting hole and is communicated with the vacuum channel; ③ And (3) integrated assembly, namely after a sealing medium is applied to the outer surface of the insert and/or the inner surface of the mounting hole, pressing the insert into the mounting hole by adopting a temperature difference method, enabling the upper end surface of the insert to be flush with the surface of the cavity, and completing the integration of the exhaust unit after solidification.
  7. 7. The method according to claim 6, wherein the vacuum impregnation method comprises placing the cleaned sintered body in a vacuum environment, injecting a heptadecafluorodecyl trimethoxysilane ethanol solution with a concentration of 1% -3%, penetrating into pores, and taking out for curing.
  8. 8. The manufacturing process according to claim 6 or 7, wherein the temperature difference method comprises heating the mold body to 100-120 ℃ while cooling the porous metal exhaust insert, and then pressing the insert into the mounting hole.
  9. 9. The process of claim 6, wherein the mounting holes are formed at locations determined by die flow analysis at melt filling ends, blind hole bottoms, rib ends, or wall thickness discontinuities of the cavity.
  10. 10. The manufacturing process according to claim 6, wherein the precision grinding includes controlling the diameter tolerance of the outer cylindrical surface of the sintered body to be within + -0.003 mm, and controlling the flatness error of the upper end surface of the insert to be within 0.005mm with respect to the surface of the surrounding cavity.

Description

Anti-blocking exhaust precision die for complex electronic part molding and preparation process thereof Technical Field The invention relates to the technical field of complex electronic forming, in particular to an anti-blocking exhaust precise die for complex electronic part forming and a preparation process thereof. Background In the injection molding process of precision electronic devices such as microconnectors, chip package cases, and sensor housings, the exhaust performance of the mold is a central factor in determining the yield, appearance quality, and production stability of the product. The parts are generally complex in structure, ultrathin in wall thickness, dense in rib positions and numerous in deep cavities, and air in the cavities and gas generated by thermal decomposition of materials are extremely easy to wrap when the melt is filled at a high speed, so that trapped gas is formed. If the gas cannot be timely and completely discharged, a series of defects such as short shot, scorching, internal bubbles, obvious weld marks and the like of the product are caused, a large amount of waste products are generated, and the manufacturing efficiency and the reliability of the high-end electronic product are seriously restricted. In the prior art, a channel with the depth of 0.01-0.03 mm is formed in a parting surface of a die to guide gas to be discharged. But has limited air exhausting capability and has little effect on trapping air points such as the bottom of the deep cavity and the like far away from the parting surface. More seriously, the shallow groove is easily blocked by the waste edges or plastic decomposers after the front end of the melt is cooled, frequent shutdown is required for manual cleaning, the production continuity is seriously affected, and the cleaning process can damage the die. In the prior art, micron-sized fit clearances between movable parts of the mold are also utilized as exhaust passages. The method has small air displacement and extremely high requirements on machining precision. If the gap is too small, the exhaust is insufficient, and if the gap is too large, an unacceptable burr on the precision electronic part is generated. The reliability thereof rapidly decreases as the mold wears. In order to improve the exhaust efficiency, the prior art uses a die steel manufactured by a special process and integrally provided with a uniform micropore structure. Although the surface exhaust can be realized, the material is extremely expensive, and the mechanical strength, hardness and wear resistance are far lower than those of the conventional die steel, so that the die steel cannot be used as a main stress structure. Meanwhile, the whole breathable steel part is extremely difficult in the aspects of processing, polishing, rust prevention and cleaning, has high maintenance cost and is limited in application in actual mass production. Therefore, the invention provides an anti-blocking exhaust precise die for forming a complex electronic part and a preparation process thereof. According to the scheme, through the assembled porous metal exhaust insert, the high porosity of the insert is maintained to realize efficient exhaust, and meanwhile, the sufficient mechanical property is ensured through an optimized material system and a sintering process, so that the insert can bear injection pressure. More importantly, the ultra-lyophobic functional coating is attached to the inner wall of the three-dimensional communicated pore, so that infiltration of melt can be actively blocked, the pore is fundamentally prevented from being blocked, and a long-acting, stable and maintenance-free exhaust effect is realized, thereby systematically solving the exhaust problem in precision molding. Disclosure of Invention (One) solving the technical problems Aiming at the defects of the prior art, the invention provides an anti-blocking exhaust precise die for forming a complex electronic part and a preparation process thereof, so as to solve the problems in the background art. (II) technical scheme In order to achieve the above purpose, the invention is realized by the following technical scheme: A prevent stifled material exhaust precision die for complicated electronic part shaping, includes mould body and at least one exhaust unit, is equipped with the die cavity in the mould body, wherein: The exhaust unit comprises a group of porous metal exhaust inserts and a mounting structure arranged on the die body; The porous metal exhaust insert is a regular geometrical body, a three-dimensional communicated pore network is arranged in the porous metal exhaust insert, and the inner walls of the pores and the end face of the insert, which is exposed to the cavity, are provided with ultra-lyophobic functional layers; The mounting structure comprises a mounting hole matched with the outline of the insert, the insert is fixed in the mounting hole through interference fit, and the exposed end face of the in