Abstract: An electrochemical machining apparatus is disclosed for removing material from a workpiece. The electrode has a conical tip and an electrolyte is supplied around the outer periphery of the electrode to a gap between the electrode and the workpiece. The combination of the conical tip and the electrolyte being supplied around the outer periphery of the electrode ensures that the gap between the electrode and the workpiece will be maintained at a predetermined distance preventing short-circuiting or uneven drilling of the workpiece.

Abstract: A method of and apparatus for electrolytically forming relatively narrow grooves which may extend either part way or entirely through a workpiece, in which excessive groove width is avoided by reducing electrical current density between major sides of the electrode disk and side surfaces of the groove as the groove is being formed. To reduce the density of electrical current between the side surfaces of the groove and the major sides of the electrode disk, the electrode disk is provided with openings which extend between the major sides of the disk, and are positioned radially inwardly from the periphery of the disk. The openings reduce the side surface area of the disk available for the establishment of current flow to thereby tend to minimize the extent to which the sides of the groove are electrolytically eroded during formation of the groove.

Abstract: An electrode guide is used in an apparatus for electrochemically drilling an axial hole in a longitudinally extending workpiece such as a suture needle. An electrode is telescopically received in one end of the tubular guide and the workpiece in the other. Electrically non-conductive inserts are provided in the guide to position the electrode and the workpiece in axial alignment. The depth of the hole to be drilled is limited by one of the inserts which abuts the end of the needle to prevent further axial motion when the hole has reached a predetermined depth. A plurality of the electrodes are disposed in a side by side arrangement. The inlet end portions of adjacent electrodes diverge to facilitate connecting an electrolyte conducting conduit to each electrode.

Abstract: Method and apparatus for providing a glass tube with a uniform nozzle portion, i.e., one which has a true centerline. The method involves suspending the tube on vertically space suspension points therealong, with the lower of the suspension points being arranged to apply a dead weight to the tube. The tube is rotated at the upper of the suspension points as it is heated above its vertical center to a temperature at which it becomes slightly plastic, but below the temperature at which the dead weight could significantly stretch the tube. This heating to the point of plasticity allows the dead weight to straighten out any axial deviations in the tube. Following the straightening, the tube is heated centrally to a higher drawing temperature sufficient to allow the dead weight to stretch the tube to a predetermined length and thereby provide a uniform necked down portion centrally of the tube. The necked down portion can then be severed at its midpoint to provide two glass electrode tubes.

Abstract: An improved filter assembly is advantageously utilized in association with an apparatus which electrolytically removes material from a workpiece. The apparatus includes one or more nozzles each of which tapers from a relatively large inside diameter to a relatively small inside diameter to direct a flow of electrolyte toward a workpiece. The improved filter assembly is utilized to remove particles from the electrolyte before it is conducted to the nozzles. The filter assembly includes a housing which is divided into an inlet chamber and an outlet chamber by a transverse wall. A plurality of tubes extend through the wall and are effective to conduct electrolyte from the inlet chamber to the outlet chamber along a plurality of spaced apart flow paths. Each of these tubes has an inlet end portion with a cross sectional area which is less than the minimum cross sectional area of each of the nozzles.

Abstract: Method of electrochemical drilling of the type in which an insulating hollow electrode is positioned in closely spaced relation to an anodically charged workpiece and a cathodically charged electrolyte is passed through the electrode to impinge on the workpiece, utilizing a pulsating negative voltage on the electrolyte, the voltage having a substantial negative DC component and negative pulses superimposed thereon.