Electrochemical machining method for rotors or stators for moineau pumps

An electrochemical manufacturing apparatus, comprising:

• at least one continuously extending closed shaped electrode defining an opening therethrough and further comprising at least one lobe skewed with respect to an axis of a relative axial movement of said closed shaped electrode with respect to a workpiece, a relative rotation of said closed shaped electrode relative to said workpiece coupled with said relative axial movement results in the production of at least one continuous lobe that has a desired pitch on the workpiece, said opening being smaller at least in part than an initial outermost workpiece periphery such that relatively rotating and relatively axially moving said electrode within the initial outermost workpiece periphery to make a continuous axial cut along a longitudinal axis of the workpiece removes from an outermost initial peripheral portion of the workpiece at least one separable excess piece located outside said closed shaped electrode thus defining a finished outermost workpiece periphery which is smaller than said initial outermost workpiece periphery;
• or
• at least one continuously extending closed shaped electrode defining an opening therethrough and further comprising at least one lobe skewed with respect to an axis of a relative axial movement of said closed shaped electrode with respect to a tubularly shaped workpiece, a relative rotation of said closed shape electrode relative to said workpiece coupled with said relative axial movement results in the production of at least one continuous lobe that has a desired pitch on said workpiece, said opening being larger at least in part than an initial innermost workpiece periphery of said workpiece such that relatively rotating and relatively axially moving said electrode outside the initial innermost workpiece periphery to make a continuous axial cut along a longitudinal axis of the workpiece removes from an innermost initial peripheral portion of the workpiece at least one separable excess piece located inside said closed shaped electrode thus defining a finished innermost workpiece periphery which is larger than said initial innermost workpiece periphery of the workpiece;
• or
• at least one continuously extending closed shaped electrode defining an opening therethrough and further comprising at least one lobe skewed with respect to an axis of a relative axial movement of said closed shaped electrode with respect to a workpiece, a relative rotation of said closed shape electrode relative to said workpiece coupled with said relative axial movement results in the production of at least one continuous lobe that has a desired pitch on the workpiece, said opening being smaller at least in part than an initial outermost workpiece periphery such that relatively rotating and relatively axially moving said electrode within the initial outermost workpiece periphery to make a continuous axial cut along a longitudinal axis of the workpiece removes from within an outermost initial peripheral portion of the workpiece at least one separable excess piece located inside said closed shaped electrode thus creating a tubular shape with a finished innermost workpiece periphery;
• a power system for said electrode;
• an electrolyte delivery system delivering electrolyte adjacent to said electrode to produce said at least one cut;
• an advancing element configured to move at least one of said electrode and the workpiece so that said electrode advances into said cut.

An electrochemical manufacturing apparatus, comprising:

• a workpiece and at least one electrode configured to move relative to each other;
• a power system for said electrode;
• an electrolyte delivery system delivering electrolyte adjacent to said electrode;
• wherein said electrode creates a cut in said workpiece when an electrolyte is delivered by said electrolyte delivery system, said cut defining a machined workpiece and at least one excess piece from said workpiece;
• said electrode comprises multiple segments;
• said multiple segments are hollow and abutted to create a hollow closed shaped electrode.