RU204285U1 - Device for piercing precision holes in gaskets of cells with diamond anvils - Google Patents

Abstract

The proposed technical solution relates to a device for EDM piercing of precision holes of small size in parts made of thin sheet metal, and can be used for EDM piercing of precision small-diameter holes of a wide range of details, for example, gaskets of cells with diamond anvils, in microelectronics or the manufacture of precision machine parts. The device contains a horizontal stationary support with a vertical support fixed on it, to which it is perpendicularly fixed, adjustable in height relative to the vertical support, a translator support with a two-coordinate translator located on it, containing precision actuators oriented relative to each other at an angle of 90 ° in the form of micrometric screws. On the two-coordinate translator there is a bowl for a dielectric liquid, above the bowl there is a working tool feeding mechanism fixed on a vertical support, consisting of a stepper motor connected to a microcontroller with a working tool holder attached to it. The holder is made of a dielectric material and has a hollow body with a hole at the end for accommodating a working tool, which is made in the form of a high-melting metal wire. The technical result is to simplify the design of the device for expanding the arsenal of devices for electroerosive piercing of small-sized holes in details. 1 wp f-ly, 1 dwg.

Description

The proposed technical solution relates to electrical discharge machining, namely to a device for electroerosive piercing of precision small-diameter holes of parts made of thin sheet metal, and can be used for electroerosive piercing of precision small-diameter holes of a wide range of parts, for example, gaskets of cells with diamond anvils, in microelectronics, or the manufacture of precision machine parts.

At present, precision devices for piercing holes in thin sheet metal parts are known, which achieve high accuracy due to special devices for positioning parts (SU865588A1, EP1184123A1) and feeding a wire electrode (SU379352 A1), or through the use of additional effects of ultrasound or vibration (RU2522864C2, US20130248495A1). Typically they are designed for a wide range of workpiece and hole sizes (SU486887A1), which entails special requirements for the workpiece positioning system and electrode delivery system, and leads to a high complexity and costly design.

The closest to the proposed technical solution is a system for microerosive machining of metal parts, including a gasket, a Microelectricdischarge machining system (model # MEDM01) manufactured by Hylozoic products (Seattle, Washington, USA), (http://geoweb.princeton.edu/ archival / duffy / private / -EDM_3-2-09.pdf, PDF document created on 22.07.2010), chosen by the applicant as a prototype. The device implies control of the drilling process using an optical microscope fixed on a stationary base plate. The stationary support is mounted on rubber feet for anti-slip and electrical insulation. The device itself rotates on the Rotating base plate at an angle of ± 45 ° relative to the stationary support around the Base plate pivot bolt on the Base plate bearing pad. This allows you to visually control the process from different sides by turning the device relative to the microscope. The device is attached to the turntable by means of two vertical fixed supports (Main column), on which the upper housing (Upper housing) with the working parts of the device mounted in it is installed. The working tool (electrode, tool) is fixed in the holder of the tool (tool holder), which is attached to the upper body with the rod (tool rod). High-voltage wires, an optical encoder and a servo drive are attached to the stem in the upper body, the latter allows you to accurately move the tool in height. The tool is fixed in the holder before being placed in the installation using an accessory.

The workpiece is in a dielectric fluid cup and is attached with a special holder to the bottom and the workpiece holder lead wire. The dielectric bowl is fixed on a two-dimensional translator (stage), which is moved in the horizontal plane by means of two precision actuators (stage actuator). The two-axis translator is fixed on a metal plate - the stage plate, which in turn is attached to two workpiece holder mounting post. These posts can be adjusted in height in the post holder, while the position of the rods is fixed by the clamping bolts (klamping konb). On the surface of the upper block there is a connector for a connector cable to electronics unit DB9, which connects the generator and the tool control unit, as well as the controls for the high voltage generator: polarity switch for selecting the processing of the part in the holder of the fixed tool, or high voltage shutdown, Discharge energy switch and Peak power switch.

The generator and tool control box (electronics box) contains the high voltage generator, power switch and tool controls.

The prototype device has the functionality of creating recesses of complex shapes in the part, as well as tools responding to the recesses, allows you to accurately monitor the depth of processing of the part, the size of the gap and the current parameters due to the presence of a precision installation for positioning the working tool, an electronics unit that provides the ability to vary the operating modes of the power supply working tool, as well as the possibility of using a microscope to control the process of piercing parts. However, in the case of electroerosive piercing of small-diameter precision holes in small-sized parts made of thin sheet material, including gasket - a thin gasket between diamond anvils in high-pressure cells, there is no need to process the tool, the need to accurately monitor the parameters current and behind the size of the gap, and when piercing the part through and through, as in the cases of gaskets, and for a given depth of processing, the use of such expensive and complex equipment is impractical.

The technical problem, the solution of which is provided by the claimed utility model, is the creation of a new cost-effective, structurally laconic and easy-to-use device for electroerosive piercing of precision holes of small size in parts made of thin sheet metal, including gaskets of cells with diamond anvils, expanding the arsenal of devices for electroerosive piercing of parts.

The technical result consists in simplifying the design of the device, including the exclusion of high-precision expensive elements from it, since the claimed device is designed exclusively for electroerosive piercing of precision small-sized holes of small parts made of thin sheet metal, pierced through in places of crushing. The technical result also consists in expanding the range of devices for electroerosive piercing of holes in details.

The technical problem is solved, and the technical result is achieved by the inventive device for electroerosive piercing of precision holes of small size of parts made of thin sheet metal, including gaskets of cells with diamond anvils, including a horizontal stationary support with a vertical support fixed on it, to which it is horizontally perpendicularly fixed height-adjustable translator support with respect to the vertical support with a two-coordinate translator located on it containing precision actuators oriented relative to each other at an angle of 90 °, on which a bowl with a dielectric liquid for placing the workpiece in it is located, an electrode feeding mechanism fixed to the vertical support is located above the bowl, consisting of a motor connected to the electronic control unit of the working tool with a fixed tool holder with an inserted working tool, which is equal to but like the workpiece, it is connected via a lead wire to the generator.

The peculiarity of the device claimed as a useful model is that micrometric screws are used as precision actuators, a stepper motor is used as a motor, a working tool holder is a hollow body made of dielectric material with a hole at the end for placing a working tool (electrode) in it. , which is used as a wire made of a refractory material (for example, tungsten, rhenium or iridium), as an electronic control unit for a working tool - a microcontroller.

The diagram of the proposed device is shown in the figure.

The device consists of a horizontal stationary support 1 with a vertical support 2 fixed to it at a right angle - a stand to which, using a fixing screw (not numbered in the figure), the translator support 3 is horizontally fixed, the location of which is adjustable in height relative to the vertical support 2. On the platform 3 there is a two-coordinate translator 4, with two micrometric screws as precision actuators 5, located relative to each other at an angle of 90º. On the two-coordinate translator 4 there is a bowl 6 with a dielectric liquid. The position of the bowl 6 is adjusted in the horizontal plane using micrometric screws 5. On the vertical support 2 there is a mechanism for feeding the working tool, consisting of a motor 7 with a holder 8 of the working tool fixed through the coupling on the sliding screw, into which the working tool 9 (electrode) is inserted - a wire ... The motor 7 is connected to an electronic unit 10 for controlling the working tool, which controls the voltage on the electrode-wire (working tool 9), as well as the rotation of the motor. The working tool 9 (wire) is connected by a lead wire to the generator 11, as well as the workpiece 12, placed in the bowl 6 with a dielectric liquid.

The operation of the proposed device is illustrated by a specific example of the implementation of a device for electroerosive piercing of precision holes in the gasket.

For a specific device were used:

as a horizontal stationary support 1 and vertical support 2 (racks) - a laboratory stand,

as a support for the translator 3 - an aluminum plate 2 mm thick,

two-coordinate translator 4 can be optionally (as in the example of the device implementation) fixed with a fixing screw on the translator support 3 and is a linear translator (in our case MT1, Thorlabs, free travel 12mm) with actuators located relative to each other at an angle of 90º, controlling the position in the horizontal plane of the workpiece, in which holes are pierced (for example, cell gaskets for diamond anvils);

as actuators 5 - micrometer screws (micrometer heads, for example, 150-801 Mitutoyo or Thorlabs DRV8);

as a bowl 6 with a dielectric liquid - a glass Petri dish filled with white spirit;

as motor 7 - a Tamagawa TS3216N17E1 stepper motor, 800 steps per revolution, with a flexible transition sleeve and a screw rod;

as the holder 8 of the working tool, a hollow body made of dielectric material with a hole at the end is used, the size of which is suitable for placing the working tool inside the holder 8 of the working tool (we used a case made of ABS plastic printed on a 3D printer, or a body from a ballpoint pen);

as a working tool 9 - tungsten wire with a diameter of 0.1 mm;

as an electronic unit 10 for controlling the working tool - a microcontroller based on arduino uno;

as a generator 11 - a homemade high-voltage power supply (standard RC-circuit, output voltage no more than 2000 V).

The preparation of the gasket can be divided into two stages: indentation and drilling. At the stage of pressing, a gasket 0.2 - 0.5 mm thick is compressed between the anvils to obtain an imprint of the culet (usually a few tenths of a millimeter thick). As a result, excess metal is squeezed out, forming an annular bead that fixes the position of the gasket and anvils. After pressing in the resulting print, you need to drill a hole - a chamber for the sample. The simplest and cheapest drilling method is EDM drilling.

For electroerosive piercing of a precision hole, a pre-crimped part 12 (gasket) is placed in the bowl 6 of the inventive device. A dielectric liquid is poured into bowl 6 so that the gasket is completely covered with it. The working tool 9 (wire) is fixed in the lower hole of the working tool holder 8 and connected by a wire located inside the working tool holder 8 with the high voltage generator 11. Provide contact of the workpiece 12 with the lead wire from the generator 11, for example, using soldering or a mechanical clamp. The holder 8 of the working tool is installed on the sliding screw connected through the coupling to the motor 7. The bowl 6 with the dielectric liquid is brought under 9 (wire), after having pulled out the working tool 9 (wire) from the holder 8 of the working tool by a few millimeters for better visualization. Visually controlling, for example, using a microscope, a magnifying glass or a smartphone camera, the position of the bowl 6 with a dielectric liquid with the workpiece 12 (gasket) placed in it, with the help of precision actuators 5 - micrometric screws bring the depressed gasket 12 as accurately as possible under the working tool 9 ( wire) so that the working tool 9 - the wire is in the center of the extruded metal bead. Visually controlling, for example, using a microscope, a magnifying glass or a smartphone camera, the position of the working tool 9, the holder 8 of the working tool is lowered by means of a stepping motor 7 along a screw transmission. The speed of movement of the working tool 9 is controlled by the electronic unit 10 for controlling the working tool by changing the windings.

Unlike expensive complex structures for electroerosive piercing of precision holes, such as, for example, in the prototype, where the electrode is moved so that the value of the current and voltage lies in certain ranges, in the claimed device, the electronic unit 10 for controlling the working tool controls only the smoothness stroke, and the distance between the wire and the workpiece, the feed rate of the working tool 9 is controlled visually, since due to the fact that the workpiece being pierced is made of thin sheet metal, there is no need to maintain high vertical accuracy, as well as the requirement for high accuracy of the high voltage generator.

Unlike the prototype, the control of drilling and the position of the part relative to the tool is performed entirely visually by the operator. Visual control is carried out using a smartphone camera in macro mode, a magnifying glass or an optical microscope. Unlike the prototype, the position of the observer is not fixed, therefore, the position of the workpiece 12 (gaskets) can be controlled faster and easier without rotating the entire installation on a turntable, as in the prototype. Adjustment of the position of the working tool 9 in height also occurs visually, which makes it possible to get rid of the optical encoder used in the prototype.

Since the inventive device is intended exclusively for piercing small-diameter precision holes in details made of a thin metal material of small size, the dimensions and thickness of the gasket are known in advance and are in the range of diameter - about 10 mm, thickness - up to 0.5 mm, - then There is no need for a special fastening of the workpiece 12 (gaskets) in the bowl 6 with a dielectric liquid, it is enough to simply provide contact of the workpiece 12 with the lead wire from the generator 11, for example, by soldering or a mechanical clamp. This is also a difference from the device according to the prototype, where a special bolting of the part to the bowl 6 with a dielectric liquid is used, and in which the lead wire from the generator 11 is connected directly to the workpiece 12 and to the bowl 6 with a dielectric liquid. The difference in the holder 8 of the working tool should also be noted. The prototype uses a working tool holder, which requires a special device for attaching and placing the working tool in the working tool holder, and also allows you to fix complex-shaped tools. In the claimed utility model, a structurally simple plastic holder 8 of the working tool is used, and the current is supplied directly to the working tool 9 - a wire electrode, which makes it possible to get rid of complex auxiliary tools. The wire withstands current pulses due to the fact that the workpiece is thin, and the thickness of the working tool 9 - the wire is specially selected in advance so that it does not burn out during operation.

Thus, a new device for electroerosive piercing of small-sized parts made of thin sheet material is declared, inexpensive, structurally simple and convenient to use, expanding the arsenal of known devices for this purpose. The proposed device allows the use of significantly cheaper elements for positioning parts (two translators with micrometric screws as actuators) and feeding a wire electrode (a stepper motor with a microcontroller based on Arduino, a hollow plastic case with a hole for a working tool) due to its narrow specialization - taking into account the dimensions (thickness) of the workpiece, special preliminary pressing of the gasket, through piercing, which does not require control of the drilling depth of the part, and visual control of the hole piercing (through a microscope, or even a smartphone camera). Since parts with a diameter of less than 50 mm and a thickness of less than 2 mm do not require expensive precision installations for positioning the electrode and special operating modes of the generator, the design of both the power supply and the electrode is maximally simplified.

Claims (2)

1. A device for electroerosive piercing of precision holes of small size in a part made of thin sheet metal, containing a horizontal stationary support with a vertical support fixed on it, to which a translator support with a two-coordinate translator located on it is perpendicularly fixed, adjustable in height relative to the vertical support containing precision actuators oriented relative to each other at an angle of 90 °, while on the two-coordinate translator there is a bowl for a dielectric liquid made with the possibility of placing a workpiece in it, and above the bowl there is a working tool feed mechanism fixed on a vertical support, consisting of a working tool connected to the electronic control unit of the working tool of the engine with the holder of the working tool attached to it, and the holder is designed to be connected by means of the supply wires of the working tool placed in it with a generator, which is made with the possibility of connecting by means of supply wires to the workpiece, characterized in that the precision actuators are made in the form of micrometric screws, and the motor is in the form of a stepping motor, while the holder of the working tool is made of a dielectric material and has a hollow body with a hole at the end for accommodating the working tool, which is made in the form of a wire made of refractory metal, and the electronic control unit for the working tool is made in the form of a microcontroller. 2. The device according to claim 1, characterized in that the working tool is made of tungsten.

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