CN112756720B - A compound machining method suitable for threaded holes of carbide shank - Google Patents

Abstract

The invention discloses a compound machining method suitable for a threaded hole of a cemented carbide cutter bar. The compound machining method is performed in sequence according to the following steps: machining a threaded bottom hole on a cemented carbide cutter stem by means of laser or electric spark machining. ; Process the external thread on the copper rod as the electrode; install the electrode on the main shaft of the EDM machine tool, and install the carbide shank on the worktable of the EDM machine tool, and drive the electrode through the main shaft on the X axis and the Y axis. The formed horizontal plane translates, and the internal thread is processed by EDM, and the translation trajectory is a circle concentric with the bottom hole of the thread. Compared with the prior art, the invention has the following advantages: it can not only ensure the machining efficiency and machining accuracy of the threaded hole of the cemented carbide tool shank, but also avoid the machining dimensional error of the threaded hole caused by the electrode loss, and can only process the threaded hole through one electrode. Threaded holes in various diameters.

Description

A compound machining method suitable for threaded holes of carbide shank

technical field

The invention relates to the technical field of cemented carbide material processing, in particular to a compound processing method suitable for a threaded hole of a cemented carbide tool shank.

Background technique

In recent years, with the development of the machinery industry, the application requirements of high-hardness materials have become more and more extensive, and more and more challenges have been raised for its processing technology. The hardness, strength and wear resistance make it not only used on the tool, but also on the toolholder of the superhard tool, such as diamond tool or cubic boron nitride tool, the tool itself is extremely hard, in order to further reduce the tool Vibration, carbide material is ideal for toolholders.

Since the installation of superhard material inserts requires threaded holes on the carbide shank for fixing, the processing of the internal thread of the carbide shank has always been a technical problem. The traditional internal thread processing methods include tapping and cold extrusion. Forming and milling, but for the carbide tool holder due to its high hardness and small thread hole diameter, it is difficult to use the traditional internal thread processing method normally. Although the internal thread of the cemented carbide tool holder can be formed by special molding, because the green compact needs to be fired, it will eventually produce non-uniform shrinkage, and it is difficult to ensure the size and accuracy of the internal thread of the cemented carbide tool holder after shrinkage. Therefore, The machining of the internal thread of the carbide shank can only be done by subsequent machining.

The internal thread of EDM is generally realized by the rotation and translation of the main shaft with the electrode, mainly through the axial helical precession. The processing efficiency is low during the processing, and the electrode loss will also affect the processing accuracy of the internal thread. Therefore, how to improve the efficiency of cemented carbide internal thread machining and ensure the machining accuracy is the key to solving the internal thread machining of cemented carbide toolholders, and it is also an important link to realize the development of superhard material internal thread machining technology.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a composite machining method suitable for the threaded hole of the cemented carbide tool bar, aiming at the technical difficulties existing in the machining of the threaded hole on the cemented carbide tool bar.

The present invention is achieved through the following technical solutions:

A compound machining method suitable for a threaded hole of a cemented carbide tool holder, the compound machining method is performed in sequence according to the following steps:

Step 1. A threaded bottom hole is machined on the cemented carbide tool shank by means of laser or EDM, and the threaded bottom hole is a circular smooth hole that penetrates up and down;

Step 2: Select a copper rod as the material, and process the external thread on the copper rod as the electrode. The external thread on the copper rod and the internal thread of the threaded hole that needs to be machined in the carbide shank have the same number of threads, direction of rotation and pitch. ;

Step 3: Install the cemented carbide tool holder on the worktable of the EDM machine tool, install the electrode on the main shaft of the EDM machine tool, and make the outer thread section of the electrode extend into the thread bottom of the cemented carbide tool holder In the hole, keep the axial centerline of the electrode coincident with the axial centerline of the cemented carbide threaded bottom hole;

Step 4. The main shaft drives the electrode to move along the X-axis direction to fit with the inner side wall of the threaded bottom hole. At this time, the electrode is at the starting point of the first feed path circle, and the first feed path circle is the same as the cemented carbide cutter. The threaded bottom hole of the rod is a concentric circle, and then the electrode starts to discharge machining. At the same time, the spindle drives the electrode to translate in the horizontal plane along the trajectory of the first feed path circle, so that the external thread on the electrode always walks against the inner wall of the threaded bottom hole. One circle, until the electrode returns to the starting point of the first feed path circle, and the first EDM is completed. At this time, the first internal thread is machined on the inner side wall of the threaded bottom hole of the carbide tool holder;

Step 5. The main shaft drives the electrode to move along the X-axis direction to fit with the first internal thread. At this time, the electrode is at the starting point of the second feed path circle, and the second feed path circle is the same as the first feed path circle. The trajectory circle is concentric, and then the electrode starts to discharge machining. At the same time, the spindle drives the electrode to translate in the horizontal plane along the trajectory of the second feed trajectory circle, so that the external thread on the electrode always walks a circle against the inner wall of the first internal thread. , until the electrode returns to the starting point of the second feed path circle, and the second EDM is completed;

Repeat step 5 above to increase the radius of the feed path circle successively until the machining of the internal thread on the carbide shank is completed.

Further, the threaded hole of the cemented carbide tool holder is a 60-degree triangular internal thread.

Further, the profile height of the external thread of the electrode is greater than the profile height of the internal thread of the threaded hole that needs to be machined on the cemented carbide tool shank.

Further, the axial length of the external thread of the electrode is greater than the axial length of the internal thread of the threaded hole that needs to be machined in the carbide tool shank.

Compared with the prior art, the present invention has the following advantages:

1. The present invention provides a compound machining method suitable for threaded holes of cemented carbide tool shanks, which adopts a compound machining method of laser machining and EDM. The EDM method processes the inner thread on the inner side wall of the threaded bottom hole, which improves the machining efficiency while ensuring the machining accuracy of the inner thread.

2. The present invention provides a compound machining method suitable for threaded holes of carbide shank. In the process of machining internal threads by EDM, the main shaft drives the electrode only in the horizontal plane composed of the X axis and the Y axis. Translation does not produce displacement and rotation in the Z-axis direction, which further simplifies the movement mode of the EDM spindle; and each translation trajectory of the electrode is a concentric circle that is concentric with the threaded bottom hole. During this process, the electrode can be guaranteed. All the external threads can play a role, and the discharge time of the electrode in all directions is uniform, which reduces the machining error caused by local electrode wear and further improves the machining accuracy of the internal thread.

3. The present invention provides a composite machining method suitable for threaded holes of cemented carbide tool shanks. During the electrode production process, the external thread on the electrode only needs to keep the number of threads, the direction of rotation, The pitch can be the same. There is no requirement for the major diameter and minor diameter of the external thread on the electrode, and the electrode fabrication is simpler.

4. The present invention provides a compound machining method suitable for threaded holes of cemented carbide shanks. The radius of the feed path circle is gradually increased. Through the progressive electric discharge machining method layer by layer, it is possible to process a variety of workpieces with only one electrode. The diameter of the threaded hole can realize the processing of various sizes of internal threads that are lower than the profile height of the external thread on the electrode, and has a wide range of applications.

Description of drawings

FIG. 1 is a front sectional view of the electric discharge machining according to the present invention.

FIG. 2 is a plan view of the threaded hole of the cemented carbide shank of the present invention in a state to be machined.

Fig. 3 is a plan view of the state of threaded hole machining of the cemented carbide shank of the present invention.

FIG. 4 is a schematic top view of the electrode feed path of the threaded hole machining of the cemented carbide tool holder of the present invention.

Labels in the figure: 1 electrode, 2 external thread, 3 carbide shank, 4 threaded bottom hole, 5 electrode movement direction, 6 first feed path circle, 7 second feed path circle.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and provides detailed implementation modes and specific operation processes, but the protection scope of the present invention is not limited to the following implementations example.

Referring to FIGS. 1 to 4 , the present embodiment discloses a composite machining method suitable for threaded holes of cemented carbide toolholders. The composite machining method is performed in sequence according to the following steps:

Step 1. The threaded bottom hole 4 is machined on the cemented carbide tool shank 3 by means of laser or EDM, and the threaded bottom hole 4 is a circular smooth hole that penetrates up and down; because both laser cutting and EDM can achieve superhardness For the efficient machining of materials, a circular smooth hole is machined on the carbide shank 3 to facilitate subsequent EDM threading.

Step 2: Select a copper rod as the material, process the external thread 2 on the copper rod as the electrode 1, the number of threads and the direction of rotation of the external thread 2 on the copper rod and the internal thread of the threaded hole that needs to be processed in the cemented carbide shank 3 , the pitches are the same; in this embodiment, the threaded hole of the carbide shank 3 is a 60-degree triangular internal thread, and the tooth profile height of the external thread 2 of the electrode 1 is greater than the threaded hole that needs to be processed in the carbide shank 3. The tooth profile height of the internal thread, the axial length of the external thread 2 of the electrode 1 is greater than the axial length of the internal thread of the threaded hole that needs to be machined in the cemented carbide tool holder 3, so that the electrode 1 can be easily cut during the EDM process. The external thread 2 can completely cover the internal thread to be machined in the axial direction.

Step 3: Install the cemented carbide cutter bar 3 on the worktable of the EDM machine tool, install the electrode 1 on the main shaft of the EDM machine tool, and make the second section of the external thread of the electrode 1 extend into the cemented carbide cutter. In the threaded bottom hole 4 of the rod 3, the axial centerline of the holding electrode 1 and the axial centerline of the cemented carbide threaded bottom hole 4 coincide.

Step 4. The main shaft drives the electrode 1 to move along the X-axis direction to fit with the inner side wall of the threaded bottom hole 4. At this time, the electrode 1 is at the starting point of the first feed path circle 6, and the first feed path circle 6 is: A circle concentric with the threaded bottom hole 4 of the cemented carbide tool shank 3, and then the electrode 1 starts electrical discharge machining. The external thread 2 always walks around the inner side wall of the threaded bottom hole 4 until the electrode 1 returns to the starting point of the first feed path circle 6, and the first EDM is completed. A first internal thread is machined on the inner side wall of the threaded bottom hole 4. The electrode movement direction 5 may be either a clockwise direction or a counterclockwise direction, and a clockwise direction is adopted in this embodiment.

Step 5. The main shaft drives the electrode 1 to move along the X-axis direction to fit with the first internal thread. The distance that the electrode 1 moves in the X-axis direction is the distance removed by the first EDM. At this time, the electrode 1 is at the starting point of the second feed path circle 7, the second feed path circle 7 is a circle concentric with the first feed path circle 6, and then the electrode 1 starts EDM, and the spindle drives the electrode 1 along the second feed path. The trajectory of the feed path circle 7 translates in the horizontal plane composed of the X-axis and the Y-axis, while the spindle does not generate displacement and rotation in the Z-axis direction, so that the external thread 2 on the electrode 1 always sticks to the inner wall of the first internal thread Walk for one circle until the electrode 1 returns to the starting point of the second feed path circle 7, and the second EDM is completed.

Repeat the above step 5, increase the radius of the feed path circle successively, and complete the EDM for many times until the machining of the internal thread on the cemented carbide tool shank 3 is completed. Through this step-by-step electrical discharge machining method, the machining of threaded holes of various diameters can be realized.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. Inside.

Claims (3)

1. a compound machining method applicable to a threaded hole of a cemented carbide tool holder, is characterized in that: the compound machining method is carried out successively according to the following steps: Step 1. A threaded bottom hole is machined on the cemented carbide tool shank by means of laser or EDM, and the threaded bottom hole is a circular smooth hole that penetrates up and down; Step 2: Select a copper rod as the material, and process the external thread on the copper rod as the electrode. The external thread on the copper rod and the internal thread of the threaded hole that needs to be machined in the carbide shank have the same number of threads, direction of rotation and pitch. , the profile height of the external thread of the electrode is greater than the profile height of the internal thread of the threaded hole that needs to be machined in the carbide shank; Step 3: Install the cemented carbide tool holder on the worktable of the EDM machine tool, install the electrode on the main shaft of the EDM machine tool, and make the outer thread section of the electrode extend into the thread bottom of the cemented carbide tool holder In the hole, keep the axial centerline of the electrode coincident with the axial centerline of the cemented carbide threaded bottom hole; Step 4. The main shaft drives the electrode to move along the X-axis direction to fit with the inner side wall of the threaded bottom hole. At this time, the electrode is at the starting point of the first feed path circle, and the first feed path circle is the same as the cemented carbide cutter. The threaded bottom hole of the rod is a concentric circle, and then the electrode starts to discharge machining. At the same time, the spindle drives the electrode to translate in the horizontal plane along the trajectory of the first feed path circle, so that the external thread on the electrode always walks against the inner wall of the threaded bottom hole. One circle, until the electrode returns to the starting point of the first feed path circle, and the first EDM is completed. At this time, the first internal thread is machined on the inner side wall of the threaded bottom hole of the carbide tool holder; Step 5. The main shaft drives the electrode to move along the X-axis direction to fit with the first internal thread. At this time, the electrode is at the starting point of the second feed path circle, and the second feed path circle is the same as the first feed path circle. The trajectory circle is concentric, and then the electrode starts EDM. At the same time, the spindle drives the electrode to translate in the horizontal plane along the trajectory of the second feed trajectory circle, so that the external thread on the electrode always walks a circle against the inner wall of the first internal thread. , until the electrode returns to the starting point of the second feed path circle, and the second EDM is completed; Repeat step 5 above to increase the radius of the feed path circle successively until the machining of the internal thread on the carbide shank is completed. 2. A compound machining method suitable for a threaded hole of a cemented carbide shank according to claim 1, wherein the threaded hole of the cemented carbide shank is a 60-degree triangular internal thread. 3. A compound machining method suitable for a threaded hole of a carbide shank as claimed in claim 1, wherein the axial length of the external thread of the electrode is greater than the thread that needs to be machined on the carbide shank The axial length of the internal thread of the hole.

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