Multi air-knife box and method of use

• US 6,282,812 B1
• Filed: 12/20/1999
• Issued: 09/04/2001
• Est. Priority Date: 12/20/1999
• Status: Expired due to Fees

• Current Assignee: ST Assembly Test Services Inc.
• Original Assignee: ST Assembly Test Services Inc.
• Inventors: Chong, Sean Shiao Shiong, Wee, Hwee Nam, Ng, Peter Hock Ming
• Primary Examiner(s): WILSON, PAMELA ANNE
• Application Number:
  US09/467,112
• Time in Patent Office: 624 Days
• Field of Search: 344/19, 344/51, 344/64, 345/08, 342/07, 342/10, 342/15, 342/16, 342/17, 342/18, 342/32, 342/36, 342/41, 228/223, 228/19, 228/20.1
• US Class Current: 34/464
• CPC Class Codes: F26B 15/18 the objects or batches of materials being carried by endless belts
• CPC Class Codes: F26B 21/004 Nozzle assemblies; Air knives; Air distributors; Blow boxes F26B3/082, F26B13/104, F26B13/108, F26B21/006 take precedence
• CPC Class Codes: F26B 5/14 by applying pressure, e.g. wringing; by brushing; by wiping

Abstract

An apparatus is provided for the drying of electronic components. The invention provides multiple holes through which air is passed before striking the components. This provides the apparatus of the invention with multiple air knives, thereby breaking major air flow into multiple eddy currents whereby these eddy currents have a low enough air pressure gradient such that the electronic components are not damaged or lifted from the conveyer belt on which they are transported.

Claims

1. An apparatus for removing moisture from a water-based flux on the surface of assemblies that are moving through a drying station, said apparatus to comprise:

a high-pressured gas delivery apparatus;

a heating apparatus for heating the high-pressured gas; and

a multi air-knife box comprising a hollow cylindrical member having a first end in addition to having a second end, said multi air knife box further comprising an air distribution nozzle, said first end of said hollow cylindrical member being connected to said high-pressured gas delivery apparatus, said second end of said hollow cylindrical member being connected to said air distribution nozzle, said air distribution nozzle directing said heated and pressurized gas at said water based flux, said air distribution nozzle comprising air distribution slots having a first end in addition to having a second end, said air distribution nozzle further comprising a multiplicity of narrow openings, said first end of said air distribution slots being connected said second end of said hollow cylindrical member, said second end of said air distribution slots being connected to said multiplicity of narrow openings that function as multiple air-knives.

2. The apparatus of claim 1 wherein said high-pressured gas is a gaseous substance used to dry electronic assemblies.

3. The apparatus of claim 1, said assembly of said multi air-knife box containing said hollow cylindrical member being a first sub-assembly of said multi air-knife box, said air distribution nozzle being a second sub-assembly of said multi air-knife box, said bottom surface of said first sub-assembly being mechanically connected to the surface of said second sub-assembly, said connection forcing a gas from said first sub-assembly into said second sub-assembly, assuring that no gas escapes from an interface between said first and said sub-assembly other than through said openings in said second sub-assembly.

4. The apparatus of claim 1 wherein said air distribution slots are provided in the surface of said air distribution nozzle, a direction under which said air distribution slots are provided in said surface of said air distribution nozzle being a direction in which said assemblies move through said drying station, said air distribution slots being provided in at least two groupings of air distribution slots, each grouping comprising between 3 and 5 air distribution slots, said air distribution slots having a depth of between about 0.3 and 0.7 mm and a pitch of between about 3 and 7 mm.

5. The apparatus of claim 1, said multiplicity of narrow openings that function as multiple air-knives comprising openings essentially perpendicular to a direction in which said assemblies move through said drying station, each of said openings having a diameter of between about 1.0 and 1.4 mm and a pitch of between about 4 and 5 mm and a depth through said air distribution nozzle of between about 9 and 11 mm.

6. The apparatus of claim 1, said air distribution nozzle having a height in a direction perpendicular to a direction in which said assemblies move through said drying station of between about 9 and 11 mm and a width across a means of transportation that is used to move said assemblies through said drying station about equal to a width of said means of transportation and a length in a direction in which said assemblies move through said drying station of between about 3 to 15 times its width.

7. A method for removing moisture from a water-based flux on the surface of assemblies that are moving through a drying station, said method to comprise the steps of:

providing a high-pressured gas delivery apparatus;

providing a heating apparatus for heating the high-pressured gas; and

providing a multi air-knife box, comprising a hollow cylindrical member having a first end in addition to having a second end, said multi-air knife box further comprising an air distribution nozzle, said air distribution nozzle having a first surface in addition to having a second surface, said first end of said hollow cylindrical member being connected to said high-pressured gas delivery apparatus, said second end of said hollow cylindrical member being connected to said air distribution nozzle, said air distribution nozzle directing said heated and pressurized gas at said water based flux, said air distribution nozzle comprising air distribution slots having a first end in addition to having a second end, said air distribution nozzle further comprising a multiplicity of narrow openings, said first end of said air distribution slots being connected to said second end of said hollow cylindrical member, said second end of said air distribution slots being connected to said multiplicity of narrow openings functioning as multiple air-knives.

8. The method of claim 7, said high-pressured gas being a gaseous substance used to dry electronic assemblies.

9. The method of claim 7, said assembly of said multi air-knife box comprising said hollow cylindrical member being a first sub-assembly of said multi air-knife box, said first sub-assembly having a first end in addition to having a second end, said air distribution nozzle being a second sub-assembly of said multi air-knife box, said second sub-assembly having a first surface in addition to having a second surface, said second end of said first sub-assembly being mechanically connected to said second surface of said second sub-assembly, said connection forcing a gas from said first sub-assembly into said second sub-assembly, assuring that no gas escapes from an interface between said first and said sub-assembly other than through openings in said second sub-assembly.

10. The method of claim 7, said air distribution slots being provided in the second surface of said air distribution nozzle, a direction under which said air distribution slots are provided in said second surface of said air distribution nozzle being a direction in which said assemblies move through said drying station, said air distribution slots being provided in at least two groupings of air distribution slots, each grouping comprising between 3 and 5 air distribution slots, said air distribution slots having a depth of between about 0.3 and 0.7 mm and a pitch of between about 3 and 7 mm.

11. The method of claim 7, said multiplicity of narrow openings functioning as multiple air-knives comprising openings being essentially perpendicular to a direction in which said assemblies move through said drying station, each of said openings having a diameter of between about 1.0 and 1.4 mm and a pitch of between about 4 and 5 mm and a depth through said air distribution nozzle of between about 9 and 11 mm.

12. The method of claim 7, said air distribution nozzle having a height in a direction perpendicular to a direction in which said assemblies move through said drying station of between about 9 and 11 mm and a width across a means of transportation used to move said assemblies move through said drying station being about equal to a width of said means of transportation and a length in a direction in which said assemblies move through said drying station of between about 3 to 15 times its width.