Granted in theMetal Finishing FieldPrinted copies of patents are furnished by the Patent and Trademark Office for $3.00 each.Address orders to: Commissioner of Patents and Trademarks, Washington, D.C. 20231.

PRINTED CIRCUIT BOARDU.S. Patent 6,003,225. Dec. 21, 1999S. Yoon, assignor to HughesElectronics Corp., Los Angeles

A method for fabrication of alumi­num-backed printed wiringboards with plated holes.

POWDER COAnNG GUNU.S. Patent 6,003,779. Dec. 21, 1999M.A Robidoux, assignor to TheEastwood Co., Malvern, Pa.

A method for electrostatic spray­ing of a powder onto a workpiecehaving a broad surface.

CARBON DIOXIDE CLEANINGPROCESSU.S. Patent 6,004,400. Dec. 21, 1999P.W. Bishop and AJ. Harrouer,assignors to Phillips W. Bishop,Chandler, Ariz.

A method for cleaning contami­nant particles from a surface of ametal part including preliminar­ily cleaning with an abrasive ma­terial and then cleaning with fro­zen carbon dioxide pellets.

SOLVENT CLEANING SYSTEMU.S. Patent 6,044,403. Dec. 21, 1999D.J. Gray and P.T.E. Gebhard,assignors to Gebhard GrayAssociates, Providence, R.I.

A closed circuit solvent cleaningmethod comprising placing an ob­ject to be cleaned in a chambersealable with respect to the atmo­sphere; applying a negative gaugepressure to the chamber to re­move air and other noncondens­able gases; introducing a solventto the evacuated chamber; clean­ing the object while maintainingan airless environment within thechamber; recovering the solvent

January 2001

from the object and chamber; andprocessing and cleaning contami­nated solvent within the closedcircuit.

RECYCLING CLEANING SOLVENTU.S. Patent 6,004,434. Dec. 21, 1999E. Kiany, assignor to Safety-KleenCorp., Elgin, Ill.

A method comprising cleaningand recycling a mixture of a clean­ing solvent and a treating compo­sition, said cleaning solvent hav­ing been contaminated withimpurities through use and com­prising not more than 209(; aro­matic solvents and the remainderaliphatic solvents, and having aflashpoint of 100 to 250°F.

CURRENT CONTROL SYSTEM FORAN ELECTROPLAnNG APPARATUSU.S. Patent 6,004,440. Dec. 21, 1999K.M. Hanson et al., assignors toSemitool lnc., Kalispell, Mont.

A current thief for use in electro­plating a wafer, the current thiefcomprising a plurality of conduc­tive segments disposed to sub­stantially surround a peripheralregion of the wafer; a first plural­ity of resistance devices each as­sociated with a respective one ofthe plurality of conductive seg­ments; and regulating currentthrough the respective conductivesegments during electroplating ofthe wafer.

ELECTROFORMING PROCESSU.S. Patent 6,004,447. Dec. 21, 1999P. Bischoping et al., assignors toXerox Corp., Stamford, Conn.

An electroform prepared by a pro­cess comprising the steps of elec­troforming a layer of metal on an

inner surface of a mandrel havinga duct therein, thereby formingan electroform with a hollow inte­rior; and removing the electro­form from the mandrel.

DEPOsmON OF CHROMIUMOXIDESU.S. Patent 6,004,448. Dec. 21, 1999N.M. Martyak, assignor to AtotechUSA Inc., N.J.

A process for deposition of chro­mium oxides from a trivalentchromium solution containing acomplexing agent for a buffer.

GALVANIZING EQUIPMENTU.S. Patent 6,004,507. Dec. 21, 1999J.A Morando, assignor to AlphatechInc., Grosse Isle, Mich.

A material formulation for galva­nizing equipment submerged inmolten aluminum and/or zincmelts.

COIL COAnNG PROCESSU.S. Patent 6,004,629. Dec. 21, 1999W.V. Madigan, Bayville, N.Y.

A process for coating a continuousmoving length of sheet metal com­prising cleaning with a water­based solution to remove surfacecontaminants that may interferewith the coating adhering to thesheet metal; applying a water­based pretreatment solution tothe moving length of sheet metalto promote adhesion of the coatingto the surface of the sheet metal;applying an electron-beam-cur­able coating to the moving lengthof sheet metal; and exposing themoving length of sheet metal toan electron beam to cure the coat­ing.

99