WO2008112098A1

WO2008112098A1 - Method and apparatus for forming a mold-in-place gasket

Info

Publication number: WO2008112098A1
Application number: PCT/US2008/002856
Authority: WO
Inventors: Robert P. Cross; Debora E. Duch; Anthony R. Horelik; Gregory A. Krueger
Original assignee: Henkel Corp
Current assignee: Henkel Corp
Priority date: 2007-03-09
Filing date: 2008-03-04
Publication date: 2008-09-18
Anticipated expiration: 2009-09-09

Abstract

A method and apparatus forms a mold-in-place gasket on a work piece. A loading station is provided for loading the work piece in a mold. An injection station injects UV-curable gasket material onto the work piece. A UV curing station applies UV energy to the gasket material to cure the material. An ejection station is provided for ejecting the work piece, including the gasket formed thereon from the mold. A transfer system provides for transferring the work piece among the loading station, the injection station, the UV curing station and the ejection station.

Description

METHOD AND APPARATUS FOR FORMING A MOLD-IN-PLACE GASKET

FIELD OF THE INVENTION:

[0001] The present invention relates generally to a method an apparatus for forming a mold-in-place gasket by liquid injection molding. More particularly, the present invention relates to a method and apparatus for forming a cured gasket directly on a work piece.

BRIEF DESCRIPTION OF RELATED TECHNOLOGY:

[0002] Mold-in-place gaskets are generally formed by liquid injection molding where the gasket forming material is dispensed directly into a mold and onto a work piece. The gasket material is then cured in place for use.

[0003] Typical processes for forming such gaskets include the use of upper and lower mold halves which are mated to define a mold cavity therebetween which supports the work piece. Liquid gasketing material such as UV curable material is injected into the mold cavity. Once injected, the gasketing material is subjected to radiation, such as UV radiation to cure the gasket material in place.

[0004] As may be appreciated, several distinct steps are required in order to directly form the gasket on a desired work piece. This requires transference of the work piece among various distinct and separate work stations. [0005] Therefore, there is a need for a method and apparatus which allows for the efficient and cost effective forming of the gasket in place as well as the transfer of the work piece through the process of forming the mold-in-place gasket.

SUMMARY OF THE INVENTION:

[0006] In one aspect of the present invention, an apparatus is provided for forming the mold-in-place gasket on a work piece. The apparatus including a loading station for placing the work piece in the mold. An injection station is provided for injecting a curable gasket composition onto the work piece. A curing station applies curing energy to the gasket composition on the work piece. An ejection station ejects the work piece from the mold with the gasket material thereon. A transfer system provides for the transference of the mold among the loading station, the injection station, the curing station and the ejection station.

[0007] The method aspect of the present invention provides a method of forming a mold- in-place gasket on a work piece. The method includes loading the work piece into a mold. The curable gasket material is then injected onto the work piece. The curable gasket composition is then cured with curing energy. The work piece including the gasket formed thereon is ejected from the mold.

[0008] Preferably, the gasketing material is a UV-curable composition which is cured with UV energy. DETAILED DESCRIPTION AND PREFERRED EMBODIMENT:

[0009] The present invention provides a method and apparatus for forming a mold-in- place gasket directly onto a work piece. With reference to Figures 1-3, as will described in further detail hereinbelow, the apparatus 10 of the present invention includes a load/ejection station 20, an injection station 30 and a UV-curing station 40. A transfer system 50 connects each of the stations.

[0010] More particularly, the present invention provides a load station 20 where a work piece 21, which is the part on which the gasket material is to be placed, is loaded into a mold 22 between upper and lower mold halves 23, 24. The load station 20 provides for the clamping of the work piece 21 between the mold halves. The transfer system 50 then transfers the clamped mold 22 to an injection station 30 where the UV curable gasketing material is injected into the mold halves and is deposited onto the work piece. The transfer system 50 then transfers the mold 22, including the work piece 21 having the UV material formed thereon, to a curing station 40 where the gasketing material is cured in place preferably with ultra violet (UV) energy. Thereafter, the work piece 21 including the cured gasket 25 in the mold 22 is transferred to the ejection station which opens the mold 22 and ejects the work piece 21 therefrom. Each of the stations as well as the transfer system is computer controlled using a central controller. The system controls include various components which operate the system. The system control components include a solenoid valve, machine function sensors, safety sensors, ASI in-put output modules, monitor centers, power distribution to on/off line control, light touch screen, alarm light as well as an improved electrical enclosure capable of housing all electrical drives, controls and wires. [0011] The mold 22, shown in the more detail in Figure 7, which is employed to support the work piece is a modular pallet transfer style mold. The mold includes, a mold base and a flexible mold sub-frame assembly (not shown). The mold supports the sub-frame for quick removal therefrom. The mold sub-frame supports the work piece 21 and allows for quick change thereof. A removable UV transmissive glass plate 26 (Figure 3) is used to support the mold sub- frame in the mold base. The glass plate 26 overlies the work piece 21. Rubber cushions seal the glass piece over the mold base. Various clamps are used to lock and unlock the mold components.

[0012] The load station 20, shown in more detail in Figure 4, provides for positioning of the mold. The load station 20 also delivers the bottom mold half up to the top mold half to secure the work piece 21 therebetween. The load station provides for clamping of the mold components. As will be described below, the load station 20 may be coextensive with and serve as the ejection station once the mold-in-place process is complete.

[0013] The injection station 30, shown in more detail in Figure 5, includes a custom fabricated injection cylinder as well as nozzles coupled to a pump for injecting a UV curable material onto the work piece. The material employed in the present invention may be selected from a wide variety of gasketing materials which are subject to UV curing. More specifically, the UV curable material may be such material disclosed in WO2006/086324 which is incorporated by reference herein for all purposes. [0014] In addition to the pump, the injection station includes components such as a pressure regulator, pressure transducers, stainless steel valve pin injection and gate nozzles, stainless steel braided hosing for the material and pneumatic connections, stainless steel flow control valves, pneumatic slide assemblies, actuation centers, a vacuum generator, a vacuum charge port, a vacuum circuit regulator, a pallet lock device, heated hoses, thermal couples, digital temperature controllers, transformer units for power supply to the heaters, piping for the material and stainless steel connections.

[0015] The UV-curing station 40, shown in more detail in Figure 5, includes an elongate curing chamber or enclosure 41 that is integrated with the powered section of the transfer system. The UV curing station 40 includes a UV curing light with power supplies and mounting structure. An adjustable hand crank allows for height adjustment of the work piece. The curing chamber includes light curtains at either end thereof and a sensor for monitoring chamber temperature. Remote RF sensors monitor microwave leakage in the chamber. Various other sensors such as pallet sensors and air filter sensors are also employed. Input/output connections allow remote control from the computer controller.

[0016] Each of the stations are connected by a conveyor/transfer system 50 which is arranged in a closed loop preferably rectangular in configuration. The conveyor based transfer system includes features mounted thereon such as anti rebound components, control interfaces, switches, connector cables, conduit, routing wire trays and protectors. [0017] Having described the components of the apparatus of the present invention, the operation of the system may now be described. The present mold-in-place gasket process is based on injecting a flowable UV curable gasketing material and curing the material with UV energy.

[0018] At the load station 20, a vacuum pump is attached to retain the work piece21 in an upper platen. A load station actuation button is pushed to start the automated sequence. Pneumatic mold clamp locks are charge in the open position. A ram delivers mold to the upper platen. The pneumatic mold clamp locks are then charged in the closed position. An upper mold plate gripper retainer is actuated to the open position. A pneumatic charge in the mold clamps is turned off. The ram reacts with the clamp mold. This effectively locks the mold for transfer.

[0019] The mold 22 is then transferred to the injection station 30. The mold is sent to a position sensor in the injection station. A lift, lifts the mold off of the transfer rails of the transfer station. An injection ram cylinder delivers the nozzle to the gate location on the mold. The nozzle valve pin opens. The UV curable material is then dispensed onto the work piece using a robocylinder. The vent ram cylinder operates the vent nozzle to vent the mold during injection. The vent nozzle valve pin opens and the vent vacuum is initiated. The injection stops when an adjustable preset condition is achieved, thereby closing the vent valve pin after an adjustable dwell time. The injection ram cylinder retracts the vent nozzle. The mold is then delivered back to the transfer rail. The cylinder is refilled for the next cycle. [0020] The mold 22 is next transferred to the UV curing station 40. A transfer belt carries the mold through the UV chamber 41 at an adjustable speed. UV energy is turned on when the mold passes over a proximity switch. UV energy is turned off when the mold passes over a second proximity switch. UV energy is delivered to the gasketing material through the glass piece in the mold. The energy is applied for a time sufficient to cure the gasketing metal.

[0021] Thereafter, the mold 22 is delivered to the load station 20 which now serves as an ejection station for ejection of the part. The actuation button is pushed to start the automatic sequence for part removal. A ram delivers the mold to the upper platen. A ram then actuates downward to deliver the bottom half of the mold to an un-load position. The work piece can then be removed from the bottom half of the mold.

[0022] The mold-in-place system described above, maybe operated in an auto cycle mode. However, all integrated actuation can also be run independently in a manual mode.

[0023] Various changes to the foregoing described and shown structures would now be evident to those skilled in the art. Accordingly, the particularly disclosed scope of the invention is set forth in the following claims.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for forming a mold-in-place gasket onto a work piece comprising: a loading station for placing the work piece in a mold; an injection station for injecting a curable gasket composition on said work piece; a curing station for applying curing energy to said gasket composition; an ejection station for ejecting said work piece, including said gasket formed thereon, from said mold; and a transfer system for transferring said work piece among said loading station, said injection station, said curing station and said ejection station.

2. An apparatus of claim 1 wherein said gasket composition is UV-curable and wherein said curing station applies UV energy to said gasket composition.

3. An apparatus of claim 2 wherein said load station and said ejection station are coextensive.

4. An apparatus of claim 2 wherein said mold includes a mold housing for supporting said work piece and UV-transmissive plate overlying said work piece.

5. An apparatus of claim 2 wherein said transfer system is a conveyer-based system for transferring said work piece.

6. An apparatus of claim 2 wherein said UV-curing station includes a curing chamber and a UV-light supported therein.

7. A method of forming a mold-in-place gasket on a work piece comprising the steps of: loading said work piece into a mold; injecting a curable gasket composition onto said work piece; curing said gasket composition with curing energy; and ejecting said work piece with said gasket thereon from said mold.

8. A method of claim 7 wherein said injecting step includes injecting a UV-curable composition onto said work piece.

9. A method of claim 7 wherein said curing step includes curing said UV-curable composition with UV-energy.

10. A method of claim 9 wherein said loading step includes placing a UV-transmissive plate over said work piece.