Electrodeposition without Internal Deposit Stress.
Patent, Filed 5 Jan 88, patented 22 Nov 88,
DEPARTMENT OF THE AIR FORCE WASHINGTON DC
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An apparatus and method are described for electrodepositing an electroform with near zero internal stress. A voltage controlled power supply supplies current to both a mandrel, upon which a primary electroform is deposited, and to a deformable thin disk substrate, upon which a secondary deposit is formed. A strain gage on the deformable substrate measures any deformation caused by internal stress in the secondary deposit. The strain gage is connected to a strain gage transducer to produce an output signal to a proportional controller. The proportional controller in turn supplies a strain-proportional voltage signal to the power supply. A current mask ensures an even current density over the mandrel. After initially adjusting electroforming bath parameters to provide a zero internal stress in the starting electroform, the output from the strain gage causes proportional changes in the bath current to the mandrel to maintain a constant near zero internal stress in the primary electroform. Patents. JES
- Fabrication Metallurgy