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Title:
METHODS AND MOLDING APPARATUS FOR FORMING A FLASHLESS ARTICLE WITH TABS
Document Type and Number:
WIPO Patent Application WO/2019/134041
Kind Code:
A1
Abstract:
A molding system for blow molding a hollow article. The molding system comprises a mold tool having a first mold half and second mold half, the first and second mold halves together defining a cavity for blow molding a hollow article. The molding system includes a suction device to draw a parison through the mold cavity of the closed mold tool, and at least one tab-forming assembly operationally arranged on the mold tool. Each tab-forming assembly serves to pinch the parison at defined locations to form an integral tab with minimal flash formation.

Inventors:
CACCIACARRO, Danny (2206 Robinwood Court, Mississauga, Ontario L5M 5B9, L5M 5B9, CA)
Application Number:
CA2019/050006
Publication Date:
July 11, 2019
Filing Date:
January 04, 2019
Export Citation:
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Assignee:
ABC GROUP INC. (2 Norelco Drive, Toronto, Ontario M9L2X6, M9L2X6, CA)
International Classes:
B29C49/04; B29C49/56; B29C49/58
Attorney, Agent or Firm:
COLUCCI, Michael (2 Norelco Drive, Toronto, Ontario M9L2X6, M9L2X6, CA)
Download PDF:
Claims:
CLAIMS

1. A molding system for blow molding a hollow article, the molding system comprising: a mold tool having a first mold half and second mold half, the first and second mold halves together defining a cavity for blow molding a hollow article; a suction device to draw a parison through the mold cavity of a closed mold tool; at least one tab-forming assembly operationally arranged on the mold tool;

wherein each tab-forming assembly serves to pinch the parison at defined locations to form an integral tab with minimal flash formation.

2. The molding system according to claim 1 , wherein the tab-forming assembly includes a first tab slide that presents a first molding face, and a second tab slide that presents a second molding face.

3. The molding system according to claim 2, wherein the first and second molding faces meet at a tab-parting line.

4. The molding system according to claim 2, wherein the first tab slide is operationally arranged in a first mold half, and the second tab slide is operationally arranged in a second mold half.

5. The molding system according to claim 2, wherein the first and second tab slides are operationally arranged in the same mold half.

6. A method for molding a hollow article, comprising

extruding a hollow parison into a mold tool defining a cavity; closing a first set of seal plates at an inlet end of the mold tool, and closing a second set of sea] plates at an outlet end of the mold tool;

introducing a blowing gas into the interior or the parison to urge the parison against the cavity to form the primary shape of the desired hollow article;

venting the blowing gas;

activating one or more tab-forming assemblies to pinch select portions of the parison to form one or more tabs with minimal flash formation.

7. The method according to claim 6, further comprising a second cycle of blowing gas to form the final configuration of the desired hollow article.

Description:
METHODS AND MOLDING APPARATUS FOR FORMING A FLASHLESS ARTICLE

WITH TABS

FIELD

[0001] The present disclosure relates to the field of automotive HVAC ducts, and in particular to a method of manufacture that provides a flashless HVAC duct with one or more integrally formed tabs.

BACKGROUND

[0002] Hollow articles for use in automotive applications often use conventional blow molding during the manufacturing process. Following the blow molding operation, post mold processing is performed to trim the article to the finished dimensions. Post-molding processing increases overall cycle time for unit production, having the effect of increased overall cost. Post-mold processing also has the potential to introduce into the finished article debris which could have detrimental effect to the larger operating system (e.g. engine) during use.

SUMMARY

[0003] According to an embodiment of the invention, provided is a molding system for blow molding a hollow article. The molding system comprises a mold tool having a first mold half and second mold half, the first and second mold halves together defining a cavity for blow molding a hollow article. The molding system includes a suction device to draw a parison through the mold cavity of the closed mold tool, and at least one tab-forming assembly operationally arranged on the mold tool. Each tab-forming assembly serves to pinch the parison at defined locations to form an integral tab with minimal flash formation.

[0004] According to another embodiment of the invention provided is a method for molding a hollow article. The method comprises extruding a hollow parison into a mold tool defining a cavity, closing a first set of seal plates at an inlet end of the mold tool, and closing a second set of seal plates at an outlet end of the mold tool. A blowing gas is then introduced into the interior of the parison to urge the parison against the cavity to form the primary shape of the desired hollow article. The blowing gas is then vented, after which one or more tab-forming assemblies are activated to pinch select portions of the parison to form one or more tabs with minimal flash formation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The foregoing and other features and advantage of the disclosure will be apparent from the following description of the disclosure as illustrated in the accompanying drawings. The accompanying drawings, which are incorporated herein and form a part of the specification, further serve to explain the principles of the disclosure and to enable a person skilled in the pertinent art to make and use the disclosure. The drawings are not to scale.

[0006] Fig. 1 is a schematic representation of a mold tool according to an embodiment of the invention.

[0007] Fig. 2 is a schematic representation of the mold tool according to the embodiment of Fig. 1 , showing each plate of the molding tool rotated to illustrate the molding surfaces.

[0008] Fig. 3 presents an automotive HVAC duct formed using the mold tool according to the embodiment of Fig. 1.

[0009] Figs. 4a and 4b present a tab-forming assembly in isolation, shown in an opened configuration in Fig. 4a, and in a closed configuration in Fig. 4b.

[0010] Fig. 5a is a schematic representation of the mold tool according to the embodiment of Fig. 1, showing the mold tool in the open position.

[001 1] Fig. 5b is a schematic representation of the mold tool according to the embodiment of Fig. 1, showing the mold tool in the closed and ready position to begin a molding cycle.

[0012] Fig. 6 is a schematic representation of the mold tool according to the embodiment of Fig. 1, showing the mold tool in the closed position and receiving a parison from an extruder.

[0013] Fig. 7 is a schematic representation of the mold tool according to the embodiment of Fig. 1, showing the mold tool with the first and second set of seal plates closed to seal the upper and lower ends of the parison.

[0014] Fig. 8 is a schematic representation of the mold tool according to the embodiment of Fig. 1, showing the parison in a blown state to engage the outside surfaces of the parison with the molding surfaces of the mold tool.

[0015] Fig. 9 is a schematic representation of the mold tool according to the embodiment of Fig. 1, showing the tab-forming assemblies in the closed configuration, so as to locally pinch the parison to form the tab formations.

[0016] Fig. 10 is a schematic representation of the mold tool according to the embodiment of Fig. 1, showing the mold tool opened to release the formed HVAC duct.

DETAILED DESCRIPTION

[0017] Specific embodiments of the present disclosure will now be described with reference to the Figures, wherein like reference numbers indicate identical or functionally similar elements. The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or the application and uses of the disclosure. A person skilled in the relevant art will recognize that other configurations and arrangements can be used without departing from the scope of the disclosure. Although the description and drawings of the embodiments hereof exemplify the technology as applied to automotive HVAC ducts, the disclosure may be applied in the manufacture of other automotive/non- automotive molded plastic structures. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, brief summary or the following detailed description.

[0018] Generally, the present invention is a blow-molding system designed for manufacturing automotive HVAC ducts. The system is configured to be generally flashless, that is operable in a manner that eliminates or substantially reduces the formation of flash around the pinch-line of the article being formed. In addition, the flashless system as described herein forms the HVAC duct with one or more integral tabs. Achieving a flashless product with integral fixtures (i.e. tabs) serves to reduce and/or eliminate the need for post mold processing, thereby reducing labour costs and production time.

[0019] A flashless blow molding process generally requires the parison to arrange within the mold cavity, with minimal material being subject to pinching. This is best achieved by supplying a parison to a closed mold tool, but this form of parison delivery is fraught with challenges. Of particular note is the tendency of the parison to stick to the sides of the mold cavity, therein preventing the parison from arranging correctly therein.

[0020] Parison delivery to a closed mold tool can be facilitated through the use of air and/or vacuum. One such method of parison delivery using air is described in US 4,865,799 (the contents of which are incorporated herein by reference). US 4,865,799 provides one or more orifices that direct air under pressure onto the parison during mold loading. The jets of air serve to maintain the parison centered in the mold cavity and help drive the parison towards the bottom end. US 4,865,799 also suggests that vacuum may be applied to the bottom end of the mold cavity to further facilitate the loading of the parison into the mold tool.

[0021] Turning now to Figs. 1 and 2, shown is a molding system comprising a mold tool 10 for use in a blow molding machine. The mold tool 10 is split along a parting line P (see Fig. 1) to provide at least two mold members. As shown, the mold tool 10 includes a first mold half 20, and a second mold half 22, the first and second mold halves 20, 22 jointly defining a mold cavity 24 in which to blow mold and shape a desired plastic product. For example, the molded plastic product may be an automotive HVAC duct. The first mold half 20 is shown to include a first mold plate 26, while the second mold half 22 is shown to include a second mold plate 28. It will be appreciated that the mold tool 10 may be constructed in various ways, for example where the mold tool is comprised of more than two members.

[0022] The mold tool 10 is provided with a first set of seal plates 30a, 30b (collectively seal plates 30) located adjacent an inlet end 32 of the mold cavity 24. A second set of seal plates 34a, 34b (collectively seal plates 34) are provided adjacent an outlet end 36 of the mold cavity 24. The first and second set of seal plates 30, 34 serve to seal the parison 42 prior to the application of air pressure during the blow-molding cycle. Each plate of the first and second set of seal plates 30, 34 are respectively attached to an actuation rod 44. Each actuation rod 44 is in turn fixed to an actuator illustrated diagrammatically as actuator block 46. Movement within the actuator block 46 moves the respective plate of the first and second set of seal plates 30, 34 laterally as required to seal the parison 42. The actuator represented at the actuator block 46 may be any actuator suitable for use in a molding environment. For example the actuator may be a hydraulic actuator, although electric and pneumatic actuators may also be possible. Also shown proximal the outlet end 36 is a suction device 38 that facilitates the loading of the parison in accordance with suction blow-molding, as generally known in the art.

[0023] The molding system also includes an extruder 40 designed to provide the parison 42 to the mold tool 10. As shown, the extruder 40 is positioned directly in line with the mold tool 10 so as to extrude the parison 42 directly into the inlet end 32 of the mold cavity 24. As will be appreciated, the molding system 10 may implement an alternate arrangement for parison delivery. For example, the molding system may be configured with a suitable conveying device (not shown) to deliver an extruded parison from a separately located extruder. An exemplary conveying device would be a robotic assembly system fitted with end-of-arm tooling suitable for handling a parison, such as a gripper assembly. A variety of configurations are possible for the gripper assembly, as known in the art. In general, the gripper assembly would be configured to grasp and release the top end of the parison to permit for parison transport and control.

[0024] The molding system is configured to permit for the molding of a hollow article including one or more integral tabs. Accordingly, Fig. 3 provides an exemplary HVAC duct 50 molded in accordance with the molding system described herein. As shown, the HVAC duct 50 provides a first tab 52a and a second tab 52b (collectively tabs 52), both positioned at an intermediate location between a first duct end 54 and a second duct end 56. The tabs 52 serve to attach the article to a frame, body component, engine mount feature or other supporting structure. One or more tabs 52 may be molded, depending on the number required to achieve the intended function. The tab 52 comprises a central web 58a and a peripheral edge 58b. [0025] The tab 52 is formed during the blow molding process. Referring back to Figs. 1 and 2, each mold half is cut away in the desired vicinity of the tab, to facilitate the mounting of a tab-forming assembly 60. With reference to Fig. 4a showing the tab-forming assembly 60 in isolation, the tab-forming assembly 60 will generally include a first tab slide 62a and a second tab slide 62b. The first tab slide 62a presents a first molding face 64a, while the second tab slide 62b presents a second molding face 64b. The first and second molding faces 64a, 64b meet at a tab-parting line P2, and therein define a local tab-forming interface. The tab-forming interface serves to form the central web 58a and peripheral edge 58b of the tab 52.

[0026] The first and second tab slides 62a, 62b are displaceable from a first closed position as shown in Fig. 4b, to a second open position as shown in Fig. 4a. The first and second tab slides 62a, 62b are respectively attached to actuation rods 66a, 66b. The actuation rods 66a, 66b are in turn fixed to an actuator illustrated diagrammatically as actuator blocks 68a and 68b (collectively actuator blocks 68), respectively. Movement within the actuator blocks 68a, 68b move the first and second tab slides 62a, 62b laterally as shown in Figs. 4a and 4b. Depending on the location of the tab to be formed on the hollow article, the tab forming assembly 60 may be operationally arranged to present the tab slides 62a, 62b on opposing mold halves, as shown for example in Fig. 2, or on the same mold half (not shown). The actuator represented at the actuator block 68 may be any actuator suitable for use in a molding environment. For example the actuator may be a hydraulic actuator, although electric and pneumatic actuators may also be possible.

[0027] Reference is now made to Figs. 5a through 10 showing the molding system in operation. Starting with Fig. 5a, the mold tool 10 is opened, all surfaces are cleared and the mold tool 10 is readied for the molding cycle. The first and second set of seal plates 30, 34 are opened, that is the components comprising each of the seal plates are retracted so as to permit for passage of the parison therethrough. The tab-forming assemblies 60 present in the mold tool 10 are opened, that is the first and second tab slides 62 are retracted so as to separate the first and second tab-forming faces 64. In Fig. 5b, the mold tool 10 is closed by moving the mold halves 20, 22 together to define the mold cavity 24. In Fig. 6, the extruded parison 42 is introduced into the mold cavity 24 through the inlet end 32. Vacuum/suction from the suction device 38 helps to draw the parison 42 towards the outlet end 36 of the mold cavity 24. Referring now to Fig. 7, on arrival of the parison 42 at the outlet end 36, the first and second seal plates 30, 34 are closed, and blowing gas is then admitted to the interior of the parison in typical blow molding fashion, as shown in Fig. 8. This will expand the parison 42 against the mold cavity 24, and against the molding surface of the first and second tab slides 62. Thus, all of the parison material will be expanded so that the exterior of the parison touches the molding surface of the mold cavity 24 and the molding surfaces of the tabforming assemblies 60. At that time, the pressure of the blowing gas is then vented. With the parison 42 engaging the aforementioned molding surfaces, the one or more tab-forming assemblies 60 are activated to displace the first and second tab slides 62 towards each other, therein pinching the parison between the first and second tab-forming faces 64, as shown in Fig. 9. This effectively pinches the portion of the parison 42 creating the final configuration of the molded article, including the one or more tabs 52 with minimal flash formation. It will be appreciated that the pinch formed by the tab-forming assemblies 60 leaves two interior surfaces of the parison 42 in substantial contact with one another. After the first and second tab slides 62 are closed, the interior of the parison may be subject to a second cycle of blowing gas, to form the final configuration of the blow-molded article. On sufficient cooling, the mold tool 10 is opened, and the formed article is removed, as shown in Fig. 10. Flash that may form around the tab is removed, to arrive at the HVAC duct shown in Fig. 3. [0028] The flashless blow molding process described herein may be practiced with any suitable blow moldable thermoplastic material. Such materials include, but are not limited to, polyethylene, polypropylene, polyvinyl chloride and elastomeric polyolefins.

[0029] While various embodiments according to the present disclosure have been described above, it should be understood that they have been presented by way of illustration and example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the scope of the disclosure. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the appended claims and their equivalents. It will also be understood that each feature of each embodiment discussed herein, and of each reference cited herein, can be used in combination with the features of any other combination. All patents and publications discussed herein are incorporated by reference herein in their entirety.