CN111136875A - Back pressure injection mold seal structure - Google Patents
Back pressure injection mold seal structure Download PDFInfo
- Publication number
- CN111136875A CN111136875A CN201811313868.1A CN201811313868A CN111136875A CN 111136875 A CN111136875 A CN 111136875A CN 201811313868 A CN201811313868 A CN 201811313868A CN 111136875 A CN111136875 A CN 111136875A
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- China
- Prior art keywords
- plate
- sealing
- cavity
- mold
- core
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- Pending
Links
- 238000002347 injection Methods 0.000 title claims abstract description 21
- 239000007924 injection Substances 0.000 title claims abstract description 21
- 238000007789 sealing Methods 0.000 claims abstract description 80
- 238000000034 method Methods 0.000 abstract description 12
- 238000001746 injection moulding Methods 0.000 description 12
- 238000005187 foaming Methods 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 5
- 230000003068 static effect Effects 0.000 description 5
- 238000000465 moulding Methods 0.000 description 3
- 230000002035 prolonged effect Effects 0.000 description 3
- 238000011217 control strategy Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000005429 filling process Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002991 molded plastic Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/2608—Mould seals
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Abstract
The invention discloses a sealing structure of a back pressure injection mold, which comprises a positioning ring and a fixed mold plate, wherein a cavity fixing plate is fixed on the fixed mold plate, a cavity plate is installed on the cavity fixing plate, a core fixing plate and an ejector rod fixing plate are fixed on the movable mold plate, and a core plate and a core backing plate are installed on the core fixing plate; the cavity fixing plate, the cavity plate and the die parting surface are all used for processing air passages for air to enter and exit the die cavity of the die, air passage interfaces are arranged on the air passages on the cavity fixing plate, and external air pressure control equipment, a pressure sensor, a pressure gauge and the like can be connected with the die air passages through the air passage interfaces. The invention can not only meet the requirements of pressurization and pressure relief of the gas in the die cavity in the back-pressure injection process, but also effectively prolong the service life of the die and reduce the subsequent die repairing process.
Description
Technical Field
The invention relates to a sealing structure of a mold, in particular to a sealing structure of a back-pressure injection mold.
Background
The foaming injection molding technology is a novel injection molding process developed by taking raw material saving as a main purpose. The technology can reduce the consumption of raw materials, eliminate the residual stress of a molded product, reduce the shrinkage deformation of a molded plastic part and improve the size precision of the product. However, the surface of the product formed by the common foaming injection molding process has gas mark defects, which cannot meet the surface quality requirement of the appearance product, and the product can be used as the appearance product after secondary treatment by the procedures of grinding, polishing, spraying and the like.
At present, the gas back pressure technology has proved to be one of the most effective methods for eliminating the gas mark defect on the surface of the foaming injection molding product. The main difference between the back pressure foam injection molding process and the conventional foam injection molding process is the control strategy of the gas pressure in the mold cavity during the molding process. In the conventional foaming injection molding process, gas in a mold cavity is automatically discharged along with the melt filling process, and the counter-pressure foaming injection molding process adopts a dynamic mold cavity gas pressure control strategy based on rapid pressurization and rapid pressure relief technologies. In the process of back pressure foaming injection molding, the variation range of the gas pressure of the die cavity is 0MPa to 20 MPa.
From the above, the change of the gas pressure in the cavity of the mold during the back pressure foaming injection molding process puts higher requirements on the sealing performance of the mold. Qingdao Haixin molds, Inc. disclosed a patent technology entitled "a sealing structure for back-pressure injection molds" (publication number: CN 202556678U) in China in 2012. The sealing structure of the back pressure injection mold comprises a static module, a dynamic module, a static template and a dynamic template, wherein a first sealing ring is arranged on a parting surface between the static template and the dynamic template, an air sealing plate is arranged on the outer side of the static template, a third sealing ring is arranged between the air sealing plate and the static template, and an ejector rod is sealed by an axial sealing ring. Above-mentioned patent technique can solve back pressure injection mold's sealed problem betterly, however, at the in-process of moulding plastics, every shaping cycle ejector pin all carries out a reciprocating motion, and this just leads to the ejector pin sealing washer very easily to wear and tear the inefficacy, causes the decline of mould sealing ability, has greatly reduced the life of mould.
Disclosure of Invention
Aiming at the characteristics of the back pressure injection molding process, the invention provides a sealing structure of a back pressure injection mold, namely a method for combining sealing of a sealing ring and sealing of a conical surface is adopted, so that the service life of the back pressure injection mold is prolonged. The specific implementation method comprises the following steps: the ejector rod part which periodically reciprocates in the back pressure injection mold is sealed by adopting a conical surface structure, and the parting surface of the mold cavity and other structures corresponding to the mold cavity are sealed by utilizing the sealing ring.
In order to achieve the purpose, the invention adopts the following technical scheme:
a sealing structure of a back-pressure injection mold mainly comprises a positioning ring, a fixed mold plate, a mold cavity fixing plate, a mold cavity plate, a mold core base plate, a mold core fixing plate, an ejector rod fixing plate and a movable mold plate.
The cavity plate and the core plate form a mold cavity and a cavity parting surface, gas passages for gas to enter and exit the mold cavity are formed in the cavity fixing plate, the cavity plate and the mold parting surface, gas passage interfaces are mounted on the gas passages of the cavity fixing plate, and the gas passage interfaces can be connected with external gas pressure control equipment, a pressure sensor, a pressure gauge and the like in a threaded connection or flange connection mode.
A first sealing groove is formed in the core plate (or the cavity plate), the first sealing groove is located on the peripheries of the mold cavity, the mold parting surface air passage and the ejector rod, and a first sealing ring is placed in the first sealing groove to seal the mold parting surface.
The ejector rod is designed by adopting a boss structure and a double-conical surface structure, the boss structure can increase the ejection area, the ejection efficiency is improved, and the service life of the ejector rod is prolonged; the double-conical surface structure is respectively matched with the conical surface of the core plate and the conical surface of the core backing plate to realize the sealing of the ejector rod part.
The core plate is provided with a first sealing conical surface which is matched with the conical surface of the ejector rod boss to form a first sealing structure of the ejector rod.
The core backing plate is positioned between the core fixing plate and the core plate, and a second sealing conical surface is processed on the core backing plate and matched with the conical surface of the ejector rod to form a second sealing structure of the ejector rod.
And a second sealing groove is processed on the core backing plate (or the core plate), the second sealing groove is positioned at the periphery of all the ejector rods, and a second sealing ring is placed in the second sealing groove to form a third sealing structure of the ejector rods.
The minimum diameter of the ejector rod mounting through hole processed on the core plate is slightly larger than the maximum diameter of the second sealing conical surface, so that the ejector rod can be normally mounted.
The invention has the advantages that the requirements of pressurization and pressure relief of the gas in the die cavity in the back pressure injection molding process can be realized, and the sealing and gas leakage of the die in the molding process are ensured. By adopting the back-pressure injection mold sealing structure, the service life of the mold can be effectively prolonged while the sealing performance of the mold is improved, the subsequent mold repairing process is reduced, and the waste of resources and labor is reduced.
Drawings
FIG. 1 is a schematic view of a sealing structure of a back-pressure injection mold according to the present invention.
Fig. 2 is a partially enlarged schematic view of a dotted line portion of fig. 1.
The sealing structure comprises a positioning ring 1, a fixed die plate 2, a die cavity fixing plate 3, a die cavity plate 4, a die core plate 5, a die core backing plate 6, a die core fixing plate 7, a mandril 8, a mandril fixing plate 9, a movable die plate 10, an air passage interface 11, an air passage 12, a first sealing ring 13, a second sealing ring 14, a first sealing conical surface 15 and a second sealing conical surface 16.
Detailed Description
With reference to fig. 1 and 2, the sealing structure of the back-pressure injection mold comprises a positioning ring 1, a fixed mold plate 2, a fixed mold cavity fixing plate 3 fixed on the fixed mold plate 2, a mold cavity plate 4 mounted on the mold cavity fixing plate 3, a movable mold plate 10 for fixing a core fixing plate 7 and an ejector rod fixing plate 9, and a core plate 5 and a core backing plate 6 mounted on the core fixing plate 7; the cavity plate 4 and the core plate 5 form a mold cavity and a mold parting surface, air passages 12 for air to enter and exit the mold cavity are formed in the cavity fixing plate 3, the cavity plate 4 and the mold parting surface, an air passage interface 11 is arranged on the air passage on the cavity fixing plate 3, and external air pressure control equipment, a pressure sensor, a pressure gauge and the like can be connected with the mold air passage through the air passage interface 11; a sealing groove is processed on the cavity plate 4 or the core plate 5 at the parting surface of the mold, and a first sealing ring 13 is placed in the groove to seal the parting surface of the mold; the ejector rod 15 is designed by adopting a boss structure and a conical surface structure, and is respectively matched with the conical surface of the core plate 5 and the conical surface of the core backing plate 6 to form a first sealing structure and a second sealing structure of the ejector rod; and a sealing groove is processed on the contact surface of the core plate 5 and the core backing plate 6 at the periphery of all the ejector rods, and a second sealing ring 14 is arranged in the groove and used as a third sealing structure of the ejector rods.
The air flue 12 of the cavity fixing plate 3 and the cavity plate 4 is processed in a drilling mode, the cross section of the air flue is circular, and the diameter range is as follows: 1-10 mm.
The connection form of the air flue interface 11 is a threaded connection or a flange connection.
The cross section of the groove of the first sealing ring 13 and the second sealing ring 14 can be semicircular or rectangular, and the diameter range of the sealing rings is as follows: 3-10 mm.
The taper ranges of the first sealing taper surface 15 and the second sealing taper surface 16 are as follows: 30 to 60 degrees.
The technical contents not mentioned in the above modes can be realized by adopting or referring to the prior art.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.
Claims (6)
1. A back pressure injection mold sealing structure is characterized by comprising a positioning ring, a fixed mold plate, a cavity fixing plate fixed on the fixed mold plate, a cavity plate installed on the cavity fixing plate, a core fixing plate and an ejector rod fixing plate fixed on the movable mold plate, and a core plate and a core backing plate installed on the core fixing plate; the cavity plate and the cavity plate form a mold cavity and a mold parting surface, and the cavity fixing plate, the cavity plate and the mold parting surface are all provided with air passages for processing air to enter and exit the mold cavity; processing a sealing groove on a core plate or a cavity plate at the parting surface of the mold, and placing a first sealing ring in the groove to realize sealing of the parting surface of the mold; the ejector rod adopts a boss structure and a conical surface structure design, and the sealing of the ejector rod is realized by utilizing the mode of combining conical surface sealing and sealing ring sealing.
2. The sealing structure of back-pressure injection mold according to claim 1, wherein the air passage of the cavity fixing plate is provided with an air passage port, and the external air pressure control device, the pressure sensor and the pressure gauge can be connected with the air passage of the mold through the air passage port.
3. The sealing structure of back-pressure injection mold according to claim 1, wherein the core plate (or cavity plate) is formed with a first sealing groove, the first sealing groove is located at the periphery of the mold cavity, the mold parting surface air passage and the ejector pin, and the first sealing ring is placed in the first sealing groove to realize the sealing of the mold parting surface.
4. The back-pressure injection mold sealing structure according to claim 1, wherein the core plate is formed with a ram mounting through hole having a minimum diameter slightly larger than a maximum diameter of the second sealing tapered surface.
5. The back-pressure injection mold sealing structure according to claim 1, wherein the two conical surfaces of the ejector pin cooperate with the conical surfaces of the core plate and the core plate, respectively, to form a first sealing structure and a second sealing structure of the ejector pin.
6. The back pressure injection mold sealing structure according to claim 1, wherein a sealing groove is formed on the contact surface of the core plate and the core plate, and a second sealing ring is disposed in the groove to serve as a third sealing structure for the ejector pin.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811313868.1A CN111136875A (en) | 2018-11-06 | 2018-11-06 | Back pressure injection mold seal structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811313868.1A CN111136875A (en) | 2018-11-06 | 2018-11-06 | Back pressure injection mold seal structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111136875A true CN111136875A (en) | 2020-05-12 |
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ID=70515889
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811313868.1A Pending CN111136875A (en) | 2018-11-06 | 2018-11-06 | Back pressure injection mold seal structure |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111136875A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202556678U (en) * | 2012-05-07 | 2012-11-28 | 青岛海信模具有限公司 | Sealing structure for back-pressure injection mold |
| CN105313274A (en) * | 2014-07-31 | 2016-02-10 | 天津联欣盈塑胶科技有限公司 | Highlight television screen framework steam injection mold |
| CN205969711U (en) * | 2016-08-19 | 2017-02-22 | 重庆长安汽车股份有限公司 | Chemistry foaming mold utensil |
| CN106881827A (en) * | 2017-04-05 | 2017-06-23 | 青岛海信模具有限公司 | A kind of encapsulating method and mould of extraneous gas aided injection mould mould |
| CN208992991U (en) * | 2018-11-06 | 2019-06-18 | 临沂大学 | A kind of back-pressure injection mold sealing structure |
-
2018
- 2018-11-06 CN CN201811313868.1A patent/CN111136875A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202556678U (en) * | 2012-05-07 | 2012-11-28 | 青岛海信模具有限公司 | Sealing structure for back-pressure injection mold |
| CN105313274A (en) * | 2014-07-31 | 2016-02-10 | 天津联欣盈塑胶科技有限公司 | Highlight television screen framework steam injection mold |
| CN205969711U (en) * | 2016-08-19 | 2017-02-22 | 重庆长安汽车股份有限公司 | Chemistry foaming mold utensil |
| CN106881827A (en) * | 2017-04-05 | 2017-06-23 | 青岛海信模具有限公司 | A kind of encapsulating method and mould of extraneous gas aided injection mould mould |
| CN208992991U (en) * | 2018-11-06 | 2019-06-18 | 临沂大学 | A kind of back-pressure injection mold sealing structure |
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