Apparatus for a mold vacuum system and method of forming a sheet metal utilizing the system

• US 20070262494A1
• Filed: 05/12/2006
• Published: 11/15/2007
• Est. Priority Date: 05/12/2006
• Status: Active Grant

• Current Assignee: Clear Armor, LLC, PH Realty, LLC
• Original Assignee: PH Realty, LLC
• Inventors: Oakey, Edwin
• Granted Patent: US 8,251,688 B2
• Time in Patent Office: Days
• US Class Current: 264/571
• CPC Class Codes: B29C 2791/006 Using vacuum
• CPC Class Codes: B29C 51/008 without using a mould, e.g. ballooning as prestretching step B29C51/06
• CPC Class Codes: B29C 51/10 Forming by pressure difference, e.g. vacuum
• CPC Class Codes: B29C 51/262 Clamping means for the sheets, e.g. clamping frames
• CPC Class Codes: B29C 51/46 Measuring, controlling or regulating
• CPC Class Codes: B29K 2069/00 Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• CPC Class Codes: B29L 2031/3076 Aircrafts blades, propellers B29L2031/08
• CPC Class Codes: B29L 2031/778 Windows profiled elements for making window frames B29L2031/005, windscreens B29L2031/3052

Abstract

A method and an apparatus to form a sheet of polymeric material have first and second mold halves which clamp together on a polymeric sheet. A vacuum mechanism draws the sheet into an interior space. The vacuum mechanism has a plurality of controllable vacuum ports positioned about the interior space to direct the vacuum at specific portions of the sheet. Also, the sensing mechanism determines the draw depth of the sheet.

Claims

1. An apparatus for forming a sheet of polymeric material comprising:

a first mold half having a bottom wall and a first sidewall defining a first interior space, said first sidewall having a first edge;

a second mold half having a top wall and a second sidewall defining a second interior space, said second wall having a second edge;

said first and second halves clamping the sheet between said first and second edges, a vacuum mechanism for drawing the sheet into one of said first and second interior spaces, said vacuum mechanism including a plurality of controllable vacuum ports, said plurality of controllable vacuum ports positioned about said mold halves for directing a vacuum source at specific portions of the sheet; and

a mechanism for sensing a draw depth of the sheet within one of said first and second interior surfaces.

2. The apparatus according to claim 1 further comprising said plurality of ports having a mechanism for varying the vacuum source at the plurality of ports for directing the vacuum at specific portions of the sheet.

3. The apparatus according to claim 2 wherein said mechanism includes a valve at each port of said plurality of ports.

4. The apparatus according to claim 1 wherein said plurality of ports are positioned adjacent a periphery of one of said first and second interior spaces.

5. The apparatus according to claim 4 wherein a number of said plurality of ports positioned near a center of one of said first and second interior spaces.

6. An apparatus for forming a sheet of polymeric material comprising:

a first mold half having a bottom wall and a first sidewall defining a first interior space, said first sidewall having a first edge;

a second mold half having a top wall and a second sidewall defining a second interior space, said second wall having a second edge;

said first and second halves clamping the sheet between said first and second edges, a vacuum mechanism for drawing the sheet into one of said first and second interior spaces, said vacuum mechanism including one or more manifolds, said one or more manifolds including a plurality of ports, each port having an independently controlled vacuum source for directing the vacuum source at a specific portion of the sheet for drawing the specific portion of the sheet into one of said first and second interior surfaces; and

a mechanism for sensing a draw depth of the sheet within one of said first and second interior spaces.

7. The apparatus according to claim 6 further comprising at least two manifolds.

8. The apparatus according to claim 7 wherein one of said manifolds being positioned adjacent a periphery of one of said first and second interior spaces.

9. The apparatus according to claim 7 wherein one of said manifolds being positioned adjacent a center of one of said first and second interior spaces.

10. The apparatus according to claim 6 wherein each port includes a valve for independently controlling its vacuum source for directing the vacuum source at a specific portion of the sheet.

11. A method for forming a sheet of polymeric material, comprising the steps of:

heating the sheet to a first temperature;

retaining the sheet between first and second mold halves of a forming mold with the sheet supported along a peripheral edge;

generating a vacuum on one side of the sheet thereby drawing the sheet into an interior space of one of said first and second mold halves;

controlling said vacuum at specific locations in said interior space of one of said first and second mold halves such that different vacuum pressure may be created at said specific locations for enhancing drawing of the sheet into the interior space at the specific location; and

cooling the sheet from said first temperature to a second temperature upon achieving a specified draw depth of the sheet within one of said first and second mold halves.

12. The method of claim 11 further comprising drawing a first vacuum adjacent at least a portion of the peripheral edge of said mold halves.

13. The method of claim 12 further comprising drawing a second vacuum adjacent a center of the interior space.

14. The method of claim 13 wherein said first vacuum is greater than said second vacuum.

15. The method of claim 11 further comprising generating a plurality of independent vacuums at said specific locations.

16. The method of claim 15 further comprising controlling the vacuum pressure at said specific locations.

17. The method of claim 11 further comprising positioning one or more manifolds in said interior space and drawing the vacuum through said one or more manifolds.