Ambient UVL-curable elastomer mold apparatus

• US 5,885,514 A
• Filed: 12/09/1996
• Issued: 03/23/1999
• Est. Priority Date: 12/09/1996
• Status: Expired due to Fees

• Current Assignee: Dana Corporation (Dana, Inc.)
• Original Assignee: Dana Corporation (Dana, Inc.)
• Inventors: Tensor, Paul M.
• Primary Examiner(s): Silbaugh, Jan H.
• Assistant Examiner(s): MCDOWELL, SUZANNE E
• Application Number:
  US08/761,516
• Time in Patent Office: 834 Days
• Field of Search: 264/478, 264/496, 264/494, 264/266, 264/259, 425/174.4, 425/121, 425/116
• US Class Current: 264/478
• CPC Class Codes: B29C 2035/0827 using UV radiation
• CPC Class Codes: B29C 35/0888 using transparant moulds
• CPC Class Codes: B29C 35/0894 provided with masks or diaphragms
• CPC Class Codes: B29C 39/02 for making articles of definite length, i.e. discrete articles
• CPC Class Codes: B29K 2083/00 Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as moulding material
• CPC Class Codes: B29L 2031/26 Sealing devices, e.g. packaging for pistons or pipe joints
• CPC Class Codes: F16J 15/122 generally parallel to the surfaces

Abstract

An improved process for molding parts such as gaskets using an injection molding machine including upper and lower mold plates which are transparent to UV light and have pattern recesses of differing sizes and spaced apart locations, a UV light source, and a low pressure injection system for delivering elastomers to the mold plates. The elastomers are cured by exposure to UV light. An optional carrier plate may be inserted between the mold plates and provides a rigid surface for attachment of the elastomer. The carrier plate selectively covers the pattern recesses located in the mold plates.

Claims

1. A method of forming a gasket comprising the steps of:

providing at least one upper gasket mold plate that is transparent to ultraviolet radiation;

providing at least one lower gasket mold plate in opposing relation to said upper mold plate wherein said lower mold plate is transparent to ultraviolet radiation;

providing at least one injection channel in one of said upper and lower mold plates, said injection channel being opaque to ultraviolet radiation;

providing at least one UV radiation source for directing UV radiation toward said mold plates;

injecting elastomeric material between said upper and said lower mold plates to form a gasket element; and

irradiating said elastomeric material by activating said UV radiation source,

wherein said UV radiation passes through said upper and lower mold plates where said upper and lower mold plates are transparent and does not pass through said opaque injection channel, thereby effecting curing of said elastomeric material where said upper and lower mold plates are transparent.

2. The method of claim 1 further comprising the step of:

positioning a gasket carrier plate between the upper and lower mold plates for attachment to said elastomeric material.

3. The method of claim 1 further comprising the step of:

providing predetermined, spaced apart recesses in at least one of said mold plates, said recesses having different sizes.

4. The method of claim 1 further comprising the step of:

providing two radiation sources, located on opposing sides of said mold plates.

5. The method of claim 1 further comprising the step of:

selecting ambient temperature as an operating temperature for the elastomeric material, the upper mold plate and the lower mold plate.

6. The method of claim 1 further comprising the steps of:

selecting an injection pressure of approximately 5-10 atmospheres; and

selecting a curing time of approximately 10-20 seconds.

13. The method of claim 3 wherein the step of providing at least one injection channel is providing a plurality of injection channels leading to said recesses such that said injection channels are opaque to ultraviolet radiation.

14. The method of claim 2 further comprising the step of:

forming a separate sealing element by positioning said carrier plate to cover less than all of said recesses.

15. The method of claim 1 further comprising the step of:

providing a plurality of spaced apart recesses on both said upper and lower mold plates such that each recess in said upper mold plate is aligned with a corresponding, opposing recess, in said lower mold plate.

16. The method of claim 1 wherein the step of providing at least one upper mold plate further comprises providing a generally transparent layer connected to a generally opaque layer, said opaque layer having a pattern cut-out that allows passage of ultraviolet light through said transparent layer.

7. A method of forming a gasket comprising the steps of:

providing at least one gasket mold plate that is transparent to UV radiation at preselected locations and opaque to UV radiation at other locations;

forming a plurality of recesses having predetermined sizes at spaced apart locations in said mold plate that correspond with said preselected locations;

positioning a gasket carrier plate over said mold plate so as to selectively cover a predetermined number of said recesses;

injecting an elastomer between said gasket carrier plate and said mold plate to form gasket elements on said gasket carrier plate; and

irradiating said elastomer by activating a UV radiation source, wherein said UV radiation passes through said preselected locations and does not pass through said opaque locations, thereby effecting curing of said elastomer in said preselected locations.

8. The method of claim 7 further comprising the step of:

providing a second gasket mold plate located opposite to said at least one mold plate, said second mold plate being transparent to UV radiation at preselected locations.

9. The method of claim 7 wherein said carrier plate covers all of said recesses.

10. The method of claim 7 wherein said elastomer is injected at ambient temperature.

11. The method of claim 8 further comprising the step of:

selecting an injection pressure of approximately 5-10 atmospheres.

12. The method of claim 8 further comprising the step of:

selecting a curing time of approximately 10-20 seconds.

17. The method of claim 7 further comprising the step of:

forming a separate sealing element by positioning said carrier plate to cover less than all of said recesses.

18. The method of claim 7 further comprising forming injection channels leading to said recesses such that said injection channels are opaque to ultraviolet radiation.

19. A method of forming a gasket comprising the steps of:

providing at least one upper gasket mold plate having a transparent layer connected to a opaque layer, said opaque layer having a first pattern cut-out to allow passage of ultraviolet radiation through said upper mold plate;

providing at least one lower gasket mold plate in opposing relation to said upper mold plate wherein said lower mold plate has a transparent layer and a opaque layer, said opaque layer having a second pattern cut-out to permit passage of ultraviolet light through said lower mold plate;

providing at least one injection channel in said lower mold plate by forming channels in said opaque layer that are shallower than an overall thickness of said opaque layer to prevent passage of ultraviolet radiation;

providing a least one UV radiation source for directing UV radiation toward said mold plate;

injecting elastomeric material between said upper and said lower mold plates to form a gasket element; and

irradiating said elastomeric material by activating said UV radiation source wherein said UV radiation passes through said first pattern cut-out of said upper mold plate and does not pass through said opaque layer of said upper mold plate, thereby effecting curing of said elastomeric material in said first pattern cut-out.