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
  • B29C45/36—Moulds having means for locating or centering cores
• • 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
  • B29C45/40—Removing or ejecting moulded articles
  • B29C45/44—Removing or ejecting moulded articles for undercut articles
• • 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
  • B29C45/36—Moulds having means for locating or centering cores
  • B29C2045/363—Moulds having means for locating or centering cores using a movable core or core part
• • 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
  • B29C45/36—Moulds having means for locating or centering cores
  • B29C2045/366—Moulds having means for locating or centering cores using retractable pins
• • 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
  • B29C45/261—Moulds having tubular mould cavities
• • 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
  • B29C45/33—Moulds having transversely, e.g. radially, movable mould parts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2023/00—Tubular articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2023/00—Tubular articles
  • B29L2023/22—Tubes or pipes, i.e. rigid

Definitions

• This invention relates to an injection molding tool and to a method of manufacturing injection molded products having long, thin channels.
• Injection molding tools for manufacturing injection molded products typically comprise a die holding plate having at least one cavity-forming die and a core holding plate having at least one core-forming core-forming core unit.
• the die typically defines an outer surface of the injection molded article.
• the core typically defines an inner surface of the injection molded article.
• a correspondingly long, thin core pin is required.
• the minimum diameter of the core pin - and thus the minimum diameter of the channel - is limited because too thin a core pin is not sufficiently rigid and is pushed away during injection of the plastic melt from the central location in the die. This pushing away leads to uneven wall thicknesses of the channel up to breakthroughs in the channel wall when the core pin is pressed against the die wall.
• An object of the invention is to provide an injection molding tool and a method, with which injection molded products with elongated, thin channels can be produced.
• the injection molding tool having a cavity-forming die and a cavity-forming core pin, which together form at least a part of a cavity, comprises at least one core centering device for centering and supporting the core pin.
• the core centering device comprises at least one retaining pin guided in a bore of the cavity-forming die, which in a retracted position contacts the core pin with an end face and retracts in an extended position such that the end face does not protrude beyond an inner surface of the cavity-forming die in which the Bore ends.
• a pushing away of the core pin can be prevented by the retaining pin abuts against the core pin and so supports them in a centered position within the die.
• the production of injection molded products having long, thin channels is made possible by placing the retaining pins in the extended position or a partially extended position shortly before the injection process is completed, in which the end face is spaced from the core pin and completely protrudes beyond the inner surface of the cavity forming die , to be pulled. At this point, the cavity is almost completely filled around the core pin. The still liquid melt fills the gaps created by the extension of the retaining pins and the spraying process is completed. Subsequently, the fuel product can be removed from the mold. If the retaining pin is in the partially extended position, this is pulled before demolding in the fully extended position.
• the cavity-forming die in the region of the bore can be designed such that the end face of the retaining pin terminates flush with the cavity-forming surface of the die in an extended position so that no undercut is formed on the injection molded article or cavity-forming die in the demolding direction of the injection molded article.
• the end surface may be shaped complementarily to a contact surface of the core pin and the shape of the border of the contact surface of the retaining pin may correspond to the shape of the border of the bore on the cavity-forming surface of the die.
• the retaining pin may have a front end with a concave recess for forming the end face and an inner radius of the end face of the retaining pin may be complementary to the outer radius of the core pin in the region of the contact surface. That the end face has an inner radius, which corresponds to the outer radius of the core pin and so can contact the core pin over the entire surface.
• the cavity-forming die can have a depression, preferably a groove aligned parallel to the core pin, whose inner radius in the region of the bore corresponds to the outer radius of the core pin in the region of the contact surface.
• the injection molding tool may include two core centering devices each having a retaining pin.
• the retaining pins are coaxially aligned and arranged diametrically with respect to the longitudinal axis of the core pin, so that the core pin is held by two opposite sides. Pushing away is hardly possible anymore.
• the core pin is very long or very thin, several core centering devices may be arranged one after the other in the longitudinal direction of the core pin, or the core centering device has two retaining pins arranged one after the other in the longitudinal direction of the core pin.
• the retaining pin may be slidably disposed at right angles to the core pin.
• the core centering device may include a front stop for limiting the retracted position of the retaining pin and / or a rear stop for limiting the extended position of the retaining pin.
• the core centering device may include a sensor, preferably a contact sensor, which detects the extended position of the retaining pin. This can ensure that the tool is opened only after complete extension of all retaining pins.
• the core pin is slightly conical in shape so that it can easily be pulled out of the injection molded product.
• the core pin may be held at one or both ends when the tool is closed.
• the invention further relates to an injection molded product having a channel formed by a core pin made with the above-described injection molding tool.
• the injection-molded product may have an elongated, preferably tubular, channel portion, on the outside of which a projection extending in the axial direction of the channel portion, for. B. in the form of a rib, wherein the outer radius of the projection corresponds to the inner radius of the channel portion perpendicular to the longitudinal axis of the channel.
• the ribs may vary in length.
• the ribs / projections may be arranged offset laterally relative to the longitudinal axis.
• the channel of the injection-molded product can be formed continuously with axial through openings on both sides or it can have a lateral passage opening on one side.
• the invention further relates to a method of manufacturing an injection molded product having an elongated channel.
• the method comprises the steps of: (a) inserting a cavity-forming core pin into a cavity-forming die; (b) moving at least one retainer pin to a retracted position to contact a contact surface of the core pin with a complementary end surface of the retainer pin; (c) injecting at least one plastic melt until at least a portion of a cavity formed by the core pin and the die is approximately completely filled; (d) displacing the at least one retaining post into an extended position in which the end surface terminates flush with an interior surface of the cavity forming die or a partially extended position wherein the end surface is spaced from the core post and extends completely beyond the interior surface of the cavity forming die; (e) completing the injection of the at least one plastic melt until the cavity is completely filled; (f) optionally displacing the at least one retaining pin to a fully extended position in which the retaining pin is retracted such that the end surface does not
• FIG. 1 a partial perspective view of the injection molded product of FIG. 1 and two retaining pins;
• FIG. 1 shows a partial perspective view of an injection molded product with an elongate channel portion 1.
• FIG. 2 shows a sectional view along I-I through the channel section of FIG. 1.
• FIG. 3 shows a partial perspective view of the injection molded article of FIG. 1 and two retaining pins 31 as they are arranged in the injection molding tool relative to the injection molded product.
• 4 shows a sectional view along II-II of FIG. Second
• the channel section 1 forms an axially continuous channel 4 with through-openings on both sides.
• On the outside 2 of the channel section is an elongated, in the axial direction formed the channel 4 extending rib 3, whose function will be explained below.
• the channel 4 usually has a slightly conical shape with an inclination of approximately 2 degrees, so that a cavity-forming core pin 11 (cf., for example, FIG. 6) necessary for the formation of the channel 4 can simply be pulled out into a demoulding direction A after the injection molding process ,
• the core pin 11 is held on both sides in the closed tool if possible. If a channel, which can be several inches long, with a small diameter of z. B. be made about 1 mm, the core pin 11 is usually not sufficiently rigid and during the injection process, it may happen that this is pushed away from a central location. In order to prevent such pushing away, the injection molding tool has two core centering devices 30 (see, for example, FIG.
• the retaining pins 31 are shown in such as are disposed in the injection molding tool relative to the injection molded product.
• the two retaining pins 31 are arranged in the region of the molded-in ribs 3. These ribs 3 are shaped so that they do not form undercuts and the plastic product can be easily removed from the mold. Depending on the positioning of the retaining pins, they can be longer or shorter.
• the two retaining pins 31 are applied to the core pin in a retracted position prior to injection of the plastic melt. Only when the cavity 12 (cf., for example, FIG. 6), which forms the channel section 1, is almost completely filled are the two holding pins 31 moved to an extended position and the resulting gap in the injection-molded product becomes with the still liquid plastic melt filled. In Fig. 4, this process is shown schematically. On the left side of the core pin 11 is shown in the retracted position. On the right side of the core pin 11 is shown in the extended position.
• the two retaining pins 31 in the retracted position with the core pin 11 satiate complete, they have at the front end 33 has a concave shape End face 32, which has an inner radius corresponding to the outer radius of the core pin 11, respectively. the inner radius 5 of the channel 4 corresponds.
• the molded rib 3 has an outer radius 6, which also the inner radius 5 of the channel 4, respectively.
• the outer radius of the core pin 11 resp. the inner radius of the end face 32 corresponds to.
• the end face 32 of the retaining pin 31 terminates flush with the cavity-forming die. An immersion of the retaining pins 31 or a depression resp. an undercut in the cavity wall is prevented.
• Fig. 5 shows a sectional view through a channel section 1 with two channels.
• the channel 4 is also formed by a thin core pin, which is supported on both sides with retaining pins.
• the channel section has two integrally formed projections 3, the outer radius 6 of which also corresponds to the inner radius 5 of the channel 4.
• the two projections or ribs 3 are arranged offset in accordance with the displacement direction of the retaining pins to the center of the channel section.
• Fig. 6 shows under (a) is a sectional view of a detail respectively. of parts of an injection molding tool with two core centering devices 30 and under (b) a detail view A of Fig. 6 (a).
• a cavity-forming die 11 and the cavity-forming core pin 11 form the cavity 12 for the channel portion 1 of the injection-molded product.
• a depression or groove 16 is formed, which forms the projection or the rib 3 of the channel portion 1.
• the retaining pin 31 is guided.
• the retaining pin 31 is in the extended position and closes flush with the bore 13th surrounding cavity-forming surface 15 of the die 10 from.
• the core centering device 30 further includes a contact sensor 36 which detects whether the retaining pin 31 is in the extended position. Only when the retaining pins 31 are in the extended position, the injection mold can be opened and the injection molded product can be removed from the mold.
• FIG. 7 shows under (a) a sectional view along III-III of the injection molding tool of FIG. 6 and at (b) a detailed view B from FIG. 7 (a).
• a front stop 34 and a rear stop 35 recognizable. These limit the maximum displacement of the retaining pins 31, so that they rest in the retracted position with the end face 32 exactly to the core pin 11 and in the extended position, the end face 32 flush with the surface of the cavity-forming die 10.
• Fig. 7 is the retaining pin 31 shown in the retracted position and the retaining pin 31 shown below in the extended position.
• FIG. 8 shows under (a) a partially cutaway perspective view of the injection molding tool of FIG. 6 and at (b) a detailed view C of FIG. 8 (a).
• the retaining pin 31 shown on the right is in the extended position and the retaining pin 31 shown on the left in the retracted position.
• the end face 32 is flush with the surface 15 surrounding the bore 13 of the cavity-forming die 10.
• the retracted holding pin 31 rests with the end face 32 on the contact surface 14 of the core pin 11. 1 channel section

Applications Claiming Priority (2)

Publications (1)

Family

ID=59362854

Family Applications (1)

Country Status (6)

Families Citing this family (4)

Family Cites Families (8)

• 2017
  • 2017-04-07 CH CH00470/17A patent/CH713679A1/de not_active Application Discontinuation
• 2018
  • 2018-04-04 WO PCT/EP2018/058546 patent/WO2018185129A1/de active Application Filing
  • 2018-04-04 US US16/603,367 patent/US20210086417A1/en not_active Abandoned
  • 2018-04-04 JP JP2019554910A patent/JP2020512945A/ja active Pending
  • 2018-04-04 EP EP18713983.7A patent/EP3606719A1/de not_active Withdrawn
  • 2018-04-04 CN CN201880023808.8A patent/CN110769998A/zh active Pending

Also Published As

Similar Documents

Legal Events