Dual track stenciling system with solder gathering head

• US 6,066,206 A
• Filed: 08/26/1997
• Issued: 05/23/2000
• Est. Priority Date: 02/21/1997
• Status: Expired due to Term

• Current Assignee: KPS Special Situations Fund II, L.P.
• Original Assignee: Speedline Technologies Incorporated (Illinois Tool Works Inc.)
• Inventors: Doyle, Dennis G., Freeman, Gary T., Hall, Steven W.
• Primary Examiner(s): Mayes, Curtis
• Assistant Examiner(s): LORENGO, JERRY A
• Application Number:
  US08/920,121
• Time in Patent Office: 1,001 Days
• Field of Search: 118/213, 118/301, 118/406, 118/410, 118/413, 118/DIG. 4, 101/118, 101/123, 101/44, 101/124, 101/125, 101/126, 101/127, 101/129, 101/115, 427/282, 427/96
• US Class Current: 427/98.5
• CPC Class Codes: H05K 3/1216 by screen printing or stencil printing

Abstract

A dual track stencil system includes a first set of rails and a second set of rails, each of the rails being independently controlled for allowing for independent movement of circuit boards through the stencil system for processing. The stencil system includes a working area at which the circuit boards are stenciled and includes a stencil having two patterns formed thereon. In one embodiment, the stencil system includes a solder dispensing system for dispensing solder paste onto the stencil.

Claims

1. A method for processing circuit boards in a stenciling system having two tracks, each track having a loader for accepting circuit boards and advancing said boards to like positions within said tracks, said stenciling system comprising a solder dispensing mechanism, for dispensing solder on a stencil disposed over said tracks and for removing excess solder from said stencil, said method comprising the steps of:

a). receiving a pair of boards, each one of said pair of boards on a different one of said tracks;

b). engaging said pair of boards, said stencil and said solder dispensing mechanism;

c). advancing said solder dispensing mechanism over said stencil over a first one of said pair of circuit boards on a first one of said tracks to dispose solder through said stencil onto said first one of said pair of circuit boards;

d). removing, by said solder dispensing mechanism, excess solder from said stencil;

e). advancing said solder dispensing mechanism to a second one of said tracks; and

f). advancing said solder dispensing mechanism over said stencil over said second one of said pair of circuit boards on said second one of said tracks to dispose solder through said stencil onto said second one of said pair of circuit boards.

2. The method according to claim 1, wherein said solder dispensing mechanism comprises a carriage, disposed above said two tracks for traversing across said tracks, said carriage including at least one blade coupled orthogonally to said carriage to engage said stencil during said advancing steps, said carriage also including a solder gathering head coupled to said carriage via an advancement rod and a pivoting rod, said solder gathering head including a pivoting member coupled to a shovel device, the step of removing excess solder from said stencil further comprises the steps of:

advancing said pivoting rod towards said carriage to cause said solder gathering head to pivot relative to said stencil;

advancing said advancement rod towards said carriage to cause said shovel of said solder gathering head to be propelled along said screen towards said at least one blade, said shovel gathering said solder as a result of said advancement of said advancement rod.

3. A method for processing circuit boards in a stenciling system having two tracks, each track having a loader for accepting circuit boards and advancing said boards to a printing position on said tracks, said stenciling system comprising a solder dispensing mechanism, for dispensing solder paste on a stencil disposed over said tracks said method comprising steps of:

a). receiving a first circuit board on a first one of said tracks;

b). receiving a second circuit board on a second one of said tracks;

c). disposing said first circuit board and said second circuit board beneath the stencil; and

d). passing said solder dispensing mechanism across said stencil over said first circuit board and over said second circuit board such that solder is extruded through openings of said solder dispensing mechanism, through said stencil and onto said first circuit board and said second circuit board.

4. The method of claim 3, further comprising a step of lifting the solder dispensing mechanism off of the stencil to remove excess solder paste from the stencil.

5. The method of claim 4, wherein the stencil has a first pattern of holes for printing on the first circuit board and a second pattern of holes for printing on the second circuit board, and wherein the method further comprises steps of moving the solder dispensing mechanism to a position between the first pattern and the second pattern, lowering the solder dispensing mechanism towards the stencil, and moving the solder dispensing mechanism across one of the first pattern and the second pattern to print on a third circuit board located beneath the stencil.