Method of and apparatus for plating using controlled progressive immersion

Apparatus for plating an essentially uniform thickness of an electrically conductive material on an electrically conductive portion of an article, which comprises:

• an anode;
• means for mounting the anode and the electrically conductive portion of the article in spaced opposed relationship above an electroplating bath containing the electrically conductive material such that lower ends of the article portion and the anode are adjacent the electroplating bath;
• means for electrically contacting the electrically conductive portion of the article and the anode adjacent only upper ends of the article portion and the anode, to apply electrical plating potential across the article portion and the anode;
• drive means for lowering the mounting means and progessively immersing the article portion and the anode, lower ends first, at a preselected rate into the electroplating bath simultaneously as the plating potential is being applied across the article portion and the anode, such that successive sections of the article portion between the upper and lower ends thereof are continuously immersed in the electroplating bath for progressively increasing time periods, with the lower end of the article portion being continuously immersed in the electroplating bath for the longest time period and the upper end of the article portion being continuously immersed in the electroplating bath for the shortest time period, respectively, to form a layer of the electrically conductive material of an essentially uniform thickness on the article portion;
• and
• means responsive to the lowering of the mounting means for de-energizing the drive means when the article portion has become fully immersed in the electroplating bath.

A method of plating an essentially uniform thickness of an electrically conductive material onto an electrically conductive portion of an article, which comprises the steps of:

• supporting the article adjacent an electroplating bath containing the electrically conductive material such that the electrically conductive portion of the article has an upper end and a lower end;
• electrically contacting the electrically conductive portion of the article adjacent only the upper end thereof, to apply electrical plating potential to the article portion;
• and
• immersing the article portion in the electroplating bath in a manner such that successive portions of the article portion between the upper and lower ends of the article portion are immersed in the electroplating bath for progressively increasing time periods as the electrical plating potential is being applied to the article portion, with the lower end of the article portion being continuously immersed in the electroplating bath for the longest time period and the upper end of the article portion being continuously immersed in the electroplating bath for the shortest time period, respectively, to form a layer of the electrically conductive material of an essentially uniform thickness on the article portion.