Electrolysis: processes – compositions used therein – and methods – Electrolytic coating – Coating selected area
Patent
1997-06-30
1999-02-02
Phasge, Arun S.
Electrolysis: processes, compositions used therein, and methods
Electrolytic coating
Coating selected area
205128, 205131, 205150, 205641, 216 84, B23H 300
Patent
active
058659773
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP95/04020 filed Oct. 12, 1995.
FIELD AND BACKGROUND OF THE INVENTION
The invention relates to a method for the electrochemical treatment of metal workpieces, in particular of their flow channels, by means of a tool inserted into the flow channel and an electrolyte flow between the tool and the wall of the flow channel.
Such method is known from DE 40 40 590 C1. Subject matter of the known method is the continuous measurement of the electrical voltage at the working gap between tool and workpiece, wherein with increasing gap width due to the erosion of the material, the operating current is increased in order to reduce the work time. In such method it has already been suggested to make the end of the working process dependent on attaining a nominal final voltage at the working gap. Since according the known method, the operating current during the treatment procedure is to be raised continuously, for the regulation of the current increase a physical variable has been suggested which varies with increasing size of the working gap. In the simplest case, as the physical variable the gap voltage is addressed there. Alternatives are the throughflow volume and the pressure of the electrolyte.
When deburring workpieces which comprise narrow flow channels, in particular nozzle bodies with intersecting bores, the suitable length of time of treatment for the removal of the burrs is determined in several test runs. But no calibration can be achieved with this method.
The result is that in spite of constant electrochemical treatment, tolerances on the order of magnitude of 8% of the nominal throughflow, are present. Each individual nozzle must subsequently be calibrated with test oil under high pressure wherein the actual oil throughflow is measured. Depending on the measured values, the nozzle bodies are subsequently divided into different tolerance groups.
SUMMARY OF THE INVENTION
It is the task of the invention to perform the calibration of such workpieces comprising flow channels already during the electrochemical rounding-off of workpiece edges so that the electrochemically treated workpieces have the same throughflow values and the subsequent calibration with test oil can thus be omitted.
This task is solved according to the invention in that a workpiece is treated electrochemically in a test run and at least one physical electrolyte value, including the volume flow of the electrolyte and its pressure, is measured and placed into intermediate storage. The workpiece is calibrated with test oil under high pressure in that the actual throughflow is determined and compared with the nominal throughflow. In the event of deviation, further test runs are carried out with longer treatment time and/or higher operating current until, at the calibration, the actual throughflow agrees with the nominal throughflow, and the electrolyte value determined from the last test run is stored as the nominal value and is used for the subsequent series treatment of the workpieces as control variable for the termination of the treatments.
The task according to the invention could not be solved with the known methods because it was found that the gap voltage at the working gap does not have a fixed relation to the through flow resistance in the flow channel. However, it was surprisingly found that the value of the electrolyte throughflow allows for a reproducible determination for the subsequent calibration with test oil under high pressure to be made. It is furthermore surprising that the gas formation of the electrolyte in the working gap does not generate inaccuracies of any significance so that here also no random dependence develops.
The essential inventive concept thus comprises the calibration of the workpieces, in particular nozzle bodies, in combination with the electrochemical treatment. Due to the detected interdependence of test oil throughflow and electrolyte throughflow, with the method according to the invention, precise throughflow values of the nozzle bodies can be ensured after the
REFERENCES:
patent: 4995949 (1991-02-01), Rhoades
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