A kind of air film shielding micro-electrochemical machining processing method and special purpose device thereof
(1) technical field
The inventive method relates to a kind of micro-electrochemical machining processing method and special purpose device thereof.
(2) background technology
Along with the development of micromechanics and MEMS, miniature parts and micro-dimension constitutional detail demand in modern industry constantly increase, as structures such as micropore, microflute, slits, these physical dimensions are generally tens to hundreds of micron, therefore more and more come into one's own for the research of Micrometer-Nanometer Processing Technology.The feature that micro-electrochemical machining process technology is removed material with the form of ion, make it there is important application prospect in fine manufacture field, but due to the existence of stray electric field, in processing, unavoidably there is dispersion corrosion, cause Electrolyzed Processing precision not high.Along with the development of electronic technology, the industrially developed country such as the U.S., Germany, Japan, Korea S and China have all carried out the micro-electrochemical machining process technology research based on high frequency pulse power supply in succession in recent years, take full advantage of the charging and discharging effects of the pulse power, can preferably electric field be limited near tool-electrode, greatly improve the Precision of Micro-ECM of micron order yardstick.But micro-electrochemical machining process technology based on high frequency pulse power supply is in obtaining high manufacturing accuracy, because unit interval discharge energy is few, it is lower that material is removed speed, can not meet enterprise's high efficiency, high accuracy, short period, process requirements cheaply, it is particularly necessary that exploitation precision processing method high, that efficiency is high seems.
(3) summary of the invention
The technical problem to be solved in the present invention is to provide a kind of air film shielding micro-electrochemical machining processing method and special purpose device thereof, improves locality, stability, precision and the efficiency of micro-electrochemical machining processing.
Adopt technical scheme to be specifically described to the present invention below.
The invention provides a kind of air film shielding micro-electrochemical machining processing method, described method is: tool-electrode connects power cathode and it passes from electrolyte fluid hole center, workpiece connects positive source, makes workpiece just to fluid hole, retains certain machining gap between workpiece and tool-electrode; Be the venthole of annular one of the peripheral encirclement of fluid hole, fluid hole is positioned at the inner circle of venthole, and electrolyte is ejected into workpiece from fluid hole, makes gases at high pressure be ejected into workpiece from venthole simultaneously, after switching on power, carry out Electrolyzed Processing, obtain desired structure at surface of the work.
The method of the invention, due to gases at high pressure effect, limits the electrolyte jeting area of fluid hole ejection, forms air film shielding action.By adopting the method for air film shielding, control electrolyte and be distributed in tool-electrode just in the region of workpiece as far as possible, change the distribution character (as shown in Figure 2) of micro-electrochemical machining processing electrolyte at surface of the work, surface of the work Flow Field Distribution is followed successively by electrolyte---> gas-liquid mixed flow field---> airflow field (as Fig. 3), thereby the current density regularity of distribution on workpiece under change electric field action, control electric field energy and more concentrate on tool-electrode just in the region of workpiece, process machining accuracy and the working (machining) efficiency in the micron order yardstick range of work to improve micro-electrochemical machining.From process principle Fig. 2, under air film shielding, the electrolyte scope that is ejected into workpiece is dwindled (chain-dotted line is electrolyte distributed area under airless), simultaneously in electrolyte stream neighboring area because air-flow is sneaked into and is formed gas-liquid mixed flow field, this part electrolytic conductivity is less than simple electrolyte flow field, and corresponding material removing rate reduces herein; And the just right surface of the work region of electrolyte stream is because airless disturbs, can keep high conductivity and high material clearance, thereby control more concentration of energy in the dissolving of specific region material, improve material and remove speed; In this processing method processing, between tool-electrode and workpiece, gap can arbitrarily regulate simultaneously, can realize the processing of little gap, without adopting higher electric machining parameter.
The present invention also provides a kind of special purpose device of described air film shielding micro-electrochemical machining processing method, and described special purpose device comprises gas-liquid separation device, and described gas-liquid separation device comprises air chamber, fluid chamber, tool-electrode and the fixture for setting tool electrode; Described fluid chamber is inner concavity structure, in the outer chamber wall of described fluid chamber, is provided with liquid inlet, and the bottom of described fluid chamber is provided with fluid hole; Described fixture is arranged on the interior recess of fluid chamber, and the internal chamber wall that the tool-electrode of being fixed by fixture penetrates fluid chamber enters fluid chamber and passes from fluid hole center; Described air chamber is arranged on the peripheral of fluid chamber and isolates by outer chamber wall and the fluid chamber of fluid chamber, in the outer chamber wall of described air chamber, be provided with gas access, the bottom of described air chamber is provided with venthole, described venthole is annular and surrounds fluid hole, and fluid hole is positioned at the inner circle of venthole.
Gas-liquid separation device of the present invention, fluid chamber is except liquid inlet and fluid hole are without other openings, and air chamber is except gas access and gas outlet are without other openings.Described gases at high pressure are provided by air compressor, and electrolyte is provided by electrolyte circulation system.
In the present invention, by the setting party of tool-electrode to centered by direction of principal axis, described venthole, fluid hole, tool-electrode are circular concentric on cross section.
Further, described fluid hole and venthole are less than respectively liquid inlet and gas access.
Further, the internal chamber wall of described fixture and fluid chamber laminating.
In the present invention, described gas-liquid separation device is arranged on machine tool chief axis, does feed motion with machine tool chief axis, is moved and is adjusted the machining gap between tool-electrode tip and workpiece by machine tool chief axis; Described workpiece is arranged on platen, carrys out controlled working structure by machine tool motion, can process nick hole, microflute, micro three-dimensional structure etc.
Therefore, compared with prior art, the inventive method adopts gas-liquid separation device to carry out micro-electrochemical machining processing, electrolyte is focused on particular process region by gases at high pressure, can be in improving the locality of micro-electrochemical machining processing, realize metal surface micro-structural high efficiency, high stability, the better processing of precision.
(4) brief description of the drawings
Fig. 1 is the cross section structure schematic diagram of the gas-liquid separation device of embodiment of the present invention employing;
Fig. 2 is gap flow field distribution map;
Fig. 3 is surface of the work various flows field distribution administrative division map;
Label title in Fig. 1: 1, workpiece, 2, gas-liquid separation device, 3, fluid chamber, 4, air chamber, 5, fixture, 6, liquid inlet, 7, gas access, 8, tool-electrode, 9, the outer chamber wall of fluid chamber, 10, the internal chamber wall of fluid chamber, 11, the outer chamber wall of air chamber;
Label title in Fig. 2: 13, fluid hole, 14, venthole, 15, airflow field, 16, gas-liquid mixed flow field, 17, electrolyte flow field, 18, electrolyte distributed areas when airless;
Label title in Fig. 3: 19, corresponding region, electrolyte flow field, 20, airflow field corresponding region, 21, corresponding region, gas-liquid mixed flow field, 22, border, electrolyte distributed areas when airless.
(5) detailed description of the invention
Further set forth technical scheme of the present invention with specific embodiment below, but protection scope of the present invention is not limited to this:
The structure of the gas-liquid separation device that the embodiment of the present invention adopts as shown in Figure 1, selecting workpiece 1 material is stainless steel, be arranged on platen, the tip diameter 50 μ m tungsten micro-electrodes of tool-electrode 8 for adopting electrochemical erosion method to prepare, be clamped on fixture 5 and be installed in gas-liquid separation device 2 centre bores, the internal chamber wall no-float of fixture 5 and fluid chamber, can ensure that tool-electrode 8 passes from fluid hole center, gas-liquid separation device 2 is arranged on machine tool chief axis, do feed motion with machine tool chief axis, moving by machine tool chief axis, to adjust machining gap between the most advanced and sophisticated and workpiece 1 of tool-electrode 8 be 20 microns, connect high-pressure pump and pressure 0.1MPa be set by mass concentration 10%NaNO
3the fluid chamber 3 of electrolyte inhaling air liquid separating apparatus also flows into machining gap through fluid hole 13, start air compressor simultaneously, 0.1MPa gases at high pressure are pressed into the air chamber 4 of gas-liquid separation device 2, flow into machining gap and form mixed flow with electrolyte through venthole 14.Connect positive pole at workpiece 1, tool-electrode 8 connects in negative pole situation, connect processing power source machining voltage 10V is set, processing starts to carry out, machine tool feed speed 600 μ m/min are set, measuring workpieces shaping surface structure after 5 minutes, groove width 100 μ m, the degree of depth 35 μ m, process is stable, occurs without short circuit phenomenon.
Comparative example
Reference example 1, voltage 10V, electrolyte quality concentration 10%NaNO
3, feed speed 6mm/min (this speed is far above several microns---the common micro-electrochemical machining processing of tens micro-ms/min), machining gap 20 μ m, stroke 30mm, tool-electrode diameter 200 μ m, observe after testing that process is stable to be occurred without short circuit, after processing, measure groove width 317.2 μ m, dark 77.1 μ m, working groove stroke overall length 30mm, after processing, grooved uniformity is better, and without excessive erosion phenomenon, accurate to dimension is high; While shielding without air film, after processing there is serious excessive erosion phenomenon in groove periphery, and process monitoring shows short circuit phenomenon, processes unstablely, measures groove width 320.7 μ m after processing, dark 54.1 μ m, and working (machining) efficiency reduces by 41.7% while having air film.In addition, under air film shielding action, the ratio of groove depth/groove width will be when without air film, and visible air film shielding micro-electrochemical machining processing locality is improved.