CN114535732A - Forced liquid pumping and chip removal machining device and method for high-speed electric spark small hole machining - Google Patents

Abstract

The invention discloses a high-speed electric spark small hole machining forced liquid extraction and chip removal machining device and method, wherein the machining device includes an electric spark machining device and a liquid extraction device. The electric discharge machining device includes an electrode with an inner through hole, and the liquid pumping device communicates with the inner through hole, so as to extract the working fluid between the electrode and the workpiece to the outside. Compared with the prior art, the present invention extracts the working fluid containing the eroded particles in the discharge area through a liquid pumping device, changes the chip removal direction of traditional high-speed EDM small hole machining, avoids secondary discharge, and improves hole machining accuracy. Improve discharge stability.

Description

High-speed EDM small hole machining device and method for forced pumping and chip removal

technical field

The invention relates to the technical field of electric spark machining, in particular to a high-speed electric spark small hole machining device and method for forced liquid pumping and chip removal.

Background technique

High-speed EDM small hole machining technology is often used in the machining process of tiny hole features in parts such as air film cooling holes and engine fuel injection nozzles. , No macro cutting force, high efficiency, low cost and other characteristics, is a widely used small hole processing method.

In this process, deionized water or spark oil is usually added to the liquid tank where the electrode and the workpiece are located, or the high-pressure internal flushing of the hollow electrode is used to act as a dielectric and accelerate gap cooling. On the other hand, the fast flow of the working fluid can bring the eroded particles away from the discharge area in time, that is, to promote chip removal and ensure the continuous discharge machining process. A large number of studies have shown that the timely discharge of discharge products is of great significance to maintain the stability of the machining process and reduce secondary discharges. Therefore, the flow form of the working fluid and the closely related chip removal effect will have a better effect on the final machining efficiency and surface quality. big impact.

At present, EDM small hole machining usually adopts the working fluid flow method combining internal and external flushing. External flushing is achieved through nozzles. In this way, the high-pressure working fluid moves to the discharge area at a relatively high speed along the hollow pipe inside the electrode, forming a large impact force on the eroded particles generated in the area, forcing them to strike the machined surface of the workpiece and the outer sidewall of the electrode. The formed narrow side area moves in the opposite direction of the feed and is finally discharged. Although this method can bring the eroded particles away from the discharge gap in time, the eroded particles moving along the narrow side area are easily contacted with the workpiece or the electrode, or suspended in the side gap, resulting in an increase in the local electric field strength of the area. , resulting in secondary discharge on the machined surface of the workpiece and the outer sidewall of the electrode, which affects the surface quality of the workpiece and causes electrode loss. affect the processing speed. When the processing depth of the small hole gradually increases, the eroded particles accumulated in the narrow side area are more difficult to be discharged in a short time, so the secondary discharge phenomenon will also increase significantly, which will deteriorate the stability of the processing process. To a certain extent, it restricts the development of EDM small hole machining to a larger aspect ratio.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a high-speed EDM small hole machining device and method for forced pumping and chip removal, which can extract the working fluid containing the eroded particles in the discharge area through the pumping device to avoid causing secondary discharge, thereby improving the discharge rate. stability.

For achieving the above object, the present invention provides following scheme:

The invention discloses a high-speed electric spark small hole machining forced liquid extraction and chip removal machining device, comprising an electric spark machining device, the electric spark machining device comprising an electrode with an inner through hole, and further comprising:

A liquid pumping device, which is communicated with the inner through hole, so as to extract the working fluid between the electrode and the workpiece to the outside.

Preferably, the electrical discharge machining device further comprises:

bracket;

a feed spindle, which is mounted on the support and connected with the electrode, so as to drive the electrode closer to and away from the workpiece;

A guide, which is fixed on the bracket, so as to guide the electrode when the electrode moves, so that the electrode moves in a straight line.

Preferably, the electrical discharge machining device further comprises a immersion tank, and the immersion tank is located below the electrode.

Preferably, the electrical discharge machining device further includes a liquid supply device, and the liquid supply device is used for stably outputting the working liquid to the discharge area of the workpiece.

Preferably, the liquid suction device includes a liquid suction pipe and a liquid suction pump, the first end of the liquid suction pipe is connected with the suction end of the liquid suction pump, and the second end of the liquid suction pipe is connected with the suction end of the liquid suction pump Internal vias are connected.

Preferably, the electrode is in the shape of a round tube.

The invention also discloses a high-speed electric spark small hole machining method for forced liquid extraction and chip removal, comprising the following steps:

S1. Install an electrode with an internal through hole on the feed spindle, and restrict the movement direction of the electrode through a guide;

S2. Connect the liquid pumping device to the internal through hole to ensure that the working fluid between the electrode and the workpiece can be forcibly discharged from the internal through hole through the liquid pumping device;

S3, the workpiece is always completely immersed in the working fluid; or a liquid supply device is installed, so that the liquid supply device can stably output working fluid for the discharge area of the workpiece, and the liquid supply device and the liquid pumping device are turned on, Set the initial liquid pumping flow rate of the liquid pumping device, and then continuously increase the liquid supply flow rate of the liquid supply device until the discharge area is always in a liquid immersion state;

S4, carry out EDM small hole processing, in the process of gradually increasing the drilling depth, gradually increase the liquid pumping flow rate and the liquid supply flow rate, and keep them all the time;

S5. Collect the inter-electrode voltage and current information during the machining process, and calculate the spark discharge rate. When the electrode has frequent short-circuit retreat and the spark discharge rate is greatly reduced, adjust the pumping flow and pumping pressure to ensure that stable discharge.

The present invention has achieved the following technical effects with respect to the prior art:

The invention discharges the eroded particles in the discharge gap between the electrode and the workpiece through the internal through hole by means of suction, and the eroded particles will not contact the machined surface of the workpiece, so secondary discharge will not be caused. The discharge only occurs at the electrode and the bottom of the hole, and the discharge stability is significantly improved. Since the accumulation of eroded particles in the discharge gap and the outer sidewall of the electrode is avoided, it is beneficial to maintain a stable and continuous discharge process on the electrode end face, and the ability of EDM technology to process parts with large aspect ratio holes is improved.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the schematic diagram of the high-speed EDM small hole processing device for forced pumping and chip removal according to the present embodiment;

Fig. 2 is the position schematic diagram of liquid supply device;

Description of reference numerals: 1-feed spindle; 2-electrode; 3-guider; 4-immersion tank; 5-liquid suction pipe; 6-liquid suction pump; 7-discharge gap; 8-removal of particles; 9 - Working fluid; 10 - Workpiece; 11 - Liquid supply device.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The purpose of the present invention is to provide a high-speed EDM small hole machining device and method for forced pumping and chip removal, which can extract the working fluid containing the eroded particles in the discharge area through the pumping device to avoid causing secondary discharge, thereby improving the discharge rate. stability.

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Referring to FIGS. 1 to 2 , this embodiment provides a high-speed EDM small hole machining forced liquid pumping and chip removal machining device (hereinafter referred to as a machining device), which is especially suitable for small holes with a diameter of 0.1-3 mm and a large aspect ratio. , including EDM and pumping devices. The electric discharge machining device includes an electrode 2 with an inner through hole, and the liquid pumping device communicates with the inner through hole, so as to extract the working fluid 9 between the electrode 2 and the workpiece 10 to the outside.

The principle of the processing device is as follows: the hole wall of the small hole on the workpiece 10 is the machined surface, the hole bottom of the small hole is the surface to be machined, and one end of the electrode 2 extends into the small hole. Under the suction effect of the liquid pumping device, the eroded particles 8 in the discharge gap 7 between the electrode 2 and the workpiece 10 are discharged through the internal through holes, and will not contact the machined surface (ie the hole wall) of the workpiece 10, so they will not A secondary discharge is caused, and the discharge only occurs at the electrode 2 and the bottom of the hole, and the discharge stability is significantly improved. The processing device can avoid the accumulation of eroded particles 8 in the discharge gap 7 and the outer sidewall of the electrode 2, which is conducive to maintaining a stable and continuous discharge process on the end surface of the electrode 2, and improves the ability of EDM technology to process parts with large aspect ratio holes.

In this embodiment, the EDM device further includes a bracket, a feed spindle 1 and a guide 3 . The feed spindle 1 is mounted on the bracket and connected to the electrode 2 to drive the electrode 2 to approach and away from the workpiece 10 . The guide 3 is fixed on the bracket and sleeved on the outside of the electrode 2 to guide the electrode 2 when the electrode 2 moves, so that the electrode 2 moves in a straight line.

Further, in this embodiment, the electric discharge machining device further includes a liquid immersion tank 4 , and the liquid immersion tank 4 is located below the electrode 2 . The liquid immersion tank 4 accommodates the working liquid 9 , and the workpiece 10 is placed in the liquid immersion tank 4 to ensure that the discharge area of the workpiece 10 always covers the working liquid 9 . However, actual embodiments are not limited to this. For example, those skilled in the art can also provide a liquid supply device (eg, a liquid spray device), so that the liquid supply device can stably output the working fluid 9 to the discharge area of the workpiece 10 .

In this embodiment, the liquid suction device includes a liquid suction pipe 5 and a liquid suction pump 6. The first end of the liquid suction pipe 5 is connected to the suction end of the liquid suction pump 6, and the second end of the liquid suction pipe 5 is connected to the internal through hole. connected. According to different actual needs, those skilled in the art can also choose other types of liquid pumping devices, as long as they can achieve the liquid pumping function.

In this embodiment, the shape of the electrode 2 is preferably a circular tube shape, and those skilled in the art can also choose other types of the shape of the electrode 2 such as a square tube.

The present embodiment also provides a high-speed EDM small hole machining method for forced liquid extraction and chip removal (hereinafter referred to as the machining method), which uses the above-mentioned machining device and includes the following steps:

S1. Install the electrode 2 with an internal through hole on the feed spindle 1 to realize the linear feeding of the electrode 2, and set the guide 3 on the outside of the electrode 2 to constrain the movement direction of the electrode 2;

S2. Connect the liquid pumping device to the internal through hole to ensure that the working fluid 9 between the electrode 2 and the workpiece 10 can be forcibly discharged from the internal through hole through the liquid pumping device;

S3. Always completely immerse the workpiece 10 in the working fluid 9; or install a liquid supply device, so that the liquid supply device can stably output the working fluid 9 for the discharge area of the workpiece 10, turn on the liquid supply device and the pumping device, and set the pumping device The initial pumping flow of the device, and then the liquid supply flow of the liquid supply device is continuously increased until the discharge area is always in a state of immersion;

S4, carry out EDM small hole processing, and gradually increase the pumping flow and supply flow in the process of gradually increasing the drilling depth, and maintain it all the time;

S5. Collect the inter-electrode voltage and current information during the processing, and calculate the spark discharge rate. When the electrode 2 has frequent short-circuit retreat and the spark discharge rate is greatly reduced, adjust the pumping flow and pumping pressure to ensure stable discharge.

Because this processing method also uses the liquid pumping device to extract the working fluid 9 containing the eroded particles 8 on the surface of the workpiece 10, the eroded particles 8 are discharged through the internal through holes, and will not contact the processed surface of the workpiece 10, and will not cause any secondary problems. discharge. Therefore, the effect of the processing method is the same as that of the processing device, which will not be repeated here.

In this specification, specific examples are used to illustrate the principles and implementations of the present invention, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention; There will be changes in the specific implementation manner and application scope of the idea of the invention. In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (7)

1. a high-speed EDM small hole machining forced liquid pumping and chip removal processing device, comprising an EDM device, and the EDM device includes an electrode with an internal through hole, is characterized in that, also comprises: A liquid pumping device, which is communicated with the inner through hole, so as to extract the working fluid between the electrode and the workpiece to the outside. 2. The high-speed EDM small hole machining device for forced liquid extraction and chip removal according to claim 1, wherein the EDM device further comprises: bracket; a feed spindle, which is mounted on the support and connected with the electrode, so as to drive the electrode closer to and away from the workpiece; A guide, which is fixed on the bracket, so as to guide the electrode when the electrode moves, so that the electrode moves in a straight line. 3 . The high-speed EDM small hole machining forced liquid pumping and chip removal machining device according to claim 2 , wherein the EDM device further comprises a liquid immersion tank, and the liquid immersion tank is located below the electrode. 4 . 4. The high-speed EDM small hole machining forced liquid pumping and chip removal machining device according to claim 1, characterized in that, the EDM device further comprises a liquid supply device, and the liquid supply device is used for the workpiece The discharge area stably outputs the working fluid. 5. The high-speed EDM small hole machining forced liquid pumping and chip removal processing device according to claim 1, wherein the liquid pumping device comprises a liquid pumping pipe and a liquid pumping pump, and the first end of the liquid pumping pipe is connected with the suction end of the liquid suction pump, and the second end of the liquid suction pipe is connected with the internal through hole. 6 . The high-speed EDM small hole machining device for forced pumping and chip removal according to claim 1 , wherein the electrode is in the shape of a circular tube. 7 . 7. A high-speed EDM small hole machining method for forced pumping and chip removal, characterized in that it comprises the steps: S1. Install an electrode with an internal through hole on the feed spindle, and restrict the movement direction of the electrode through a guide; S2. Connect the liquid pumping device to the internal through hole to ensure that the working fluid between the electrode and the workpiece can be forcibly discharged from the internal through hole through the liquid pumping device; S3, the workpiece is always completely immersed in the working fluid; or a liquid supply device is installed, so that the liquid supply device can stably output working fluid for the discharge area of the workpiece, and the liquid supply device and the liquid pumping device are turned on, Set the initial liquid pumping flow rate of the liquid pumping device, and then continuously increase the liquid supply flow rate of the liquid supply device until the discharge area is always in a liquid immersion state; S4, carry out EDM small hole processing, in the process of gradually increasing the drilling depth, gradually increase the liquid pumping flow rate and the liquid supply flow rate, and keep them all the time; S5. Collect the inter-electrode voltage and current information during the machining process, and calculate the spark discharge rate. When the electrode has frequent short-circuit retreat and the spark discharge rate is greatly reduced, adjust the pumping flow and pumping pressure to ensure that stable discharge.

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