IN-SITU SPARK EROSION DRESSING SYSTEM AND METHOD THEREOF

An in-situ spark erosion dressing system includes a working platform, a moving platform, a cutting device, a spark erosion dressing device and a controller. The moving platform is coupled to the working platform and configured to load a work piece. The cutting device is coupled to the working platform and has a first cutting position and a first dressing position. The cutting device includes a wheel blade and the wheel blade cuts the work piece on the first cutting position. The spark erosion dressing device is coupled to the moving platform and includes a dressing electrode. The dressing electrode contacts the wheel blade on the first dressing position, and the spark erosion dressing device applies the discharge energy on the dressing electrode to dress the wheel blade. The controller controls the cutting device to move to the first cutting position according to a cutting resistance value.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an in-situ spark erosion dressing system, especially to an in-situ spark erosion dressing system which can increase cutting efficiency and reduce production cost.

Description of the Prior Art

In recent years, the semiconductor technology has been well-developed and played a crucial role in many applications, such as 5G industries, electric vehicle industries, and artificial intelligence. And, the die division of wafer has been one of the important processes in the semiconductor processes. However, in the society that tends to miniaturize electronic products, the process requirements for tiny electronic components (such as ICs and semiconductor components) tend to be miniaturized, efficient, and low-cost. Therefore, in the process of die division, the quality and accuracy standards of each die are also improved, and how to effectively cut the die is one of the key technologies in the semiconductor process.

In general, the die division is mainly based on the laser processing technology and the traditional diamond wheel blade cutting method. Although the laser processing technology can achieve subtle, efficient and high-precision processing quality, the laser processing equipment is expensive. Besides, it is easy to generate heat-affected zones after laser processing, thereby causing damage to the die surface and reducing cutting quality. Therefore, in the current die-diving technology, the die is still cut by a conventional diamond wheel blade.

In the diamond wheel blade cutting equipment, most of its wheel blades use electroformed diamond wheel blades. However, since the electroformed diamond wheel blade has low diamond particle content and a low rigidity of the substrate, the eccentricity of the wheel blade is easily generated when the electroformed diamond wheel blade is disposed on the high speed spindle, and the wheel blade easily generates vibration during the cutting process, thereby affecting the quality of the die. Furthermore, when the wheel blade needs to be trimmed or dressed, the wheel blade needs to be removed from the wheel bearing, and the dressed wheel blade needs to be recalibrated and repeatedly tested whether it is concentric with the spindle, thereby affecting the production efficiency. Moreover, when the cutting portion of the wheel blade is stuffed by the chips, the wheel blade has to be directly discarded due to the loss of the cutting ability. Therefore, the production cost is also remarkably increased.

Therefore, it is necessary to develop a dressing equipment which can effectively improve cutting efficiency and reduce production cost to solve the problems of the prior art.

SUMMARY OF THE INVENTION

Therefore, one category of the present invention is to provide an in-situ spark erosion dressing system which can in-situ correct and dress the wheel blade and remove the chips generated while cutting, to solve the problems of the prior art.

In one embodiment of the present invention, the in-situ spark erosion dressing system includes a working platform, a moving platform, a cutting device, a spark erosion dressing device and a controller. The moving platform is coupled to the working platform in a movable manner relative to the work platform, and the moving platform is configured to load a work piece. The cutting device is coupled to the working platform and has a first cutting position and a first dressing position. The cutting device includes a wheel blade, and the wheel blade cuts the work piece at the first cutting position. The spark erosion dressing device is coupled to the moving platform. The spark erosion dressing device includes a dressing electrode, and the dressing electrode contacts the wheel blade located at the first dressing position. The spark erosion dressing device applies a discharge energy on the dressing electrode to dress the wheel blade. The controller is connected to the moving platform and the cutting device. The controller controls the cutting device to move to the first dressing position with a moving path according to a cutting resistance value generated by the movement of the moving platform relative to the working platform while the cutting device cuts the wheel blade, to make the spark erosion dressing device dress the wheel blade with the discharge energy.

Wherein, the controller pre-stores an impedance threshold value. The controller controls the cutting device to move to the first dressing position when the cutting resistance value detected by the controller is greater than the impedance threshold value.

Wherein, the controller pre-stores the moving path, and the moving platform has a second cutting position and a second dressing position. The moving path includes a first moving platform path and a first cutting device path. The controller respectively controls the moving platform and the cutting device to move from the first cutting position and the second cutting position to the first dressing position and the second dressing position with the first moving platform path and the first cutting device path according to the moving path, to make the dressing electrode of the spark erosion dressing device couple to the wheel blade.

Furthermore, the controller pre-stores a dressing path. The dressing path includes a second moving platform path and a second cutting device path. The controller respectively controls the moving platform and the cutting device to move from the first dressing position and the second dressing position with the second moving platform path and the second cutting device path, to make the spark erosion dressing device dress the wheel blade by the dressing electrode.

Furthermore, the controller respectively controls the moving platform and the cutting device to move to the first cutting position and the second cutting position with the moving path after controlling the moving platform and the cutting device to move with the second moving platform path and the second cutting device path.

Wherein, the discharge energy includes a first discharge energy and a second discharge energy. The spark erosion dressing device corrects the wheel blade with the first discharge energy first, and then dresses the wheel blade with the second discharge energy. The first discharge energy is greater than the second discharge energy.

Furthermore, the in-situ spark erosion dressing system includes a sensor configured on the cutting device. The sensor is configured to sense a sensing value of the movement state of the wheel blade. The controller controls the spark erosion dressing device to dress the wheel blade with the second discharge energy according to the sensing value.

Wherein, the material of the wheel includes a conductive material, and the second discharge energy is greater than the melting point of the conductive material.

Wherein, the moving platform includes a plurality of positioning holes, and the spark erosion dressing device includes a plurality of positioning pins corresponding to the plurality of positioning holes. The spark erosion dressing device is detachably configured on the moving platform by the plurality of positioning pins.

Another one category of the present invention is to provide an in-situ spark erosion dressing method which can in-situ correct and dress the wheel blade and remove the chips generated while cutting, to solve the problems of the prior art.

In another one embodiment, the in-situ spark erosion dressing method includes the following steps of: detecting a cutting resistance value generated by a moving platform while a cutting device cuts a work piece on the moving platform at the cutting position; controlling the cutting device to move to a dressing position with a moving path according to the cutting resistance value, to make a dressing electrode of a spark erosion dressing device couple to a wheel blade of the cutting device; correcting the wheel blade with a first discharge energy according to a dressing path; sensing a sensing value of the movement state of the corrected wheel blade; dressing the wheel blade with the dressing path and a second discharge energy according to the sensing value; and controlling the corrected wheel blade of the cutting device to move to the cutting position with the moving path.

In summary, the in-situ spark erosion dressing system can determine the dressing timing according to the cutting resistance of the moving platform and dress without removing the wheel blade for maintaining the precision of the wheel blade, thereby increasing the production efficiency. Moreover, the in-situ spark erosion dressing system sequentially corrects and dresses the wheel blade by two different discharge energy to effectively increase the cutting quality of the wheel blade and reduce the production cost, thereby solving the problems of the prior art.

DETAILED DESCRIPTION OF THE INVENTION

For the sake of the advantages, spirits and features of the present invention can be understood more easily and clearly, the detailed descriptions and discussions will be made later by way of the embodiments and with reference of the diagrams. It is worth noting that these embodiments are merely representative embodiments of the present invention, wherein the specific methods, devices, conditions, materials and the like are not limited to the embodiments of the present invention or corresponding embodiments. Moreover, the devices in the figures are only used to express their corresponding positions and are not drawing according to their actual proportion.

Please refer toFIG. 1andFIG. 2.FIG. 1shows a schematic diagram of an in-situ spark erosion dressing system1in an embodiment of the present invention.FIG. 2shows a schematic diagram of another one perspective of the in-situ spark erosion dressing system1inFIG. 1. As shown inFIG. 1andFIG. 2, the in-situ spark erosion dressing system1includes a working platform11, a moving platform12and a cutting device13. The moving platform12is coupled to the working platform11in a movable manner relative to the work platform11, and the moving platform12is configured to load a work piece2. In practice, the moving platform12can be a component with sliding rail, guiding rail, sliding block or roller, and the working platform11can include the structural component matched to the component of the moving platform12. Therefore, the moving platform12can be configured on the working platform11and move relatively to the working platform11. Moreover, the moving platform12can move on the plane formed by X axial and Y axial relative to the working platform11(as shown inFIG. 2). The work piece2can be a wafer or an uncut object. The work piece2can be configured on the moving platform12and disposed corresponding to the other side of the working platform11. When the moving platform12moves on the working platform11, the work piece2configured on the moving platform12also moves in the moving direction of the moving platform12.

The cutting device13is coupled to the working platform11and has a first cutting position. The cutting device includes a wheel blade131, and the wheel blade131can cut the work piece2at the first cutting position. In practice, the cutting device13is configured on the upper side of the moving platform12and on the same side with the work piece2. In other words, the work piece2is located between the moving platform12and the cutting device13. The cutting device13can includes a rotatable wheel bearing, and the wheel blade131is configured on the wheel bearing. The cutting device13can move perpendicularly to the plane of the working platform11. Furthermore, the cutting device13can move in the Z axial direction (as shown inFIG. 2). The first cutting position can be the wheel blade position which the wheel blade131contacting and cutting the work piece2. Therefore, the cutting device13can perpendicularly move to the first cutting position relative to the working platform11to make the wheel blade131cut the work piece2.

Please refer toFIG. 3andFIG. 4.FIG. 3shows an exploded diagram of the in-situ spark erosion dressing system1inFIG. 1.FIG. 4shows a schematic diagram of the in-situ spark erosion dressing system1at the dressing position ofFIG. 1. In this embodiment, the cutting device13further has a first dressing position, and the in-situ spark erosion dressing system1further includes a spark erosion dressing device14coupled to the moving platform12. The spark erosion dressing device14includes a dressing electrode141, and the dressing electrode141contacts the wheel blade131located at the first dressing position. The spark erosion dressing device14applies a discharge energy on the dressing electrode141to dress the wheel blade131. In practice, the spark erosion dressing device14can be fixed on the moving platform12, also can be movably configured on the moving platform12. The dressing electrode141can be a wire electrode. When the spark erosion dressing device14dresses the wheel blade131, the spark erosion dressing device14applies the discharge energy on the wire electrode, and the wire electrode contacts and dresses the wheel blade131in a continuous moving method (a loop by delivering wire and collecting wire). It is worth to notice that the shape of the dressing electrode141is not limited to thereof. The shape of the dressing electrode141can be a block, and can be designed as requirements. In one embodiment, the moving platform12includes a plurality of positioning holes121, and the spark erosion dressing device14includes a plurality of positioning pins142corresponding to the plurality of positioning holes121. The spark erosion dressing device14is movably configured on the moving platform12by the plurality of positioning pins142. The spark erosion dressing device14can be a wire electrical spark erosion machine. The spark erosion dressing device14is configured on the moving platform12and located on the same side with the work piece2. That is to say, the spark erosion dressing device14and the cutting device13are located on the same side of the moving platform12. The first dressing position can be the wheel blade position which the wheel blade131contacts the dressing electrode141. Therefore, the cutting device13can perpendicularly move to the first dressing position to make the wheel blade131contact the dressing electrode141of the spark erosion dressing device14.

In this embodiment, in addition to the cutting device13has the first cutting position and the first dressing position, the moving platform12has a second cutting position and a second dressing position. In practice, the moving platform12can move in parallel to the plane of the working platform11. Moreover, the moving platform12can move in the X axial and Y axial directions (as shown inFIG. 2). The second cutting position can be the moving platform position which the work piece2contacts the wheel blade131. The second dressing position can be the moving platform position which the dressing electrode141of the spark erosion dressing device14configured on the moving platform12contacts the wheel blade131. Therefore, when the moving platform12moves to the second cutting position which matches to the first cutting position, the wheel blade131of the cutting device13can contact and cut the work piece2on the moving platform12. When the moving platform12moves to the second dressing position which matches the first dressing position, the dressing electrode141of the spark erosion dressing device14can contact the wheel blade131of the cutting device13to dress the wheel blade131.

In this embodiment, the moving platform12generates a cutting resistance value while the moving platform12moves relatively to the working platform11. In practice, the in-situ spark erosion dressing system1can drive the moving platform12to move at a current value by a power module. The minimum value of the force applied on the moving platform12should be equal to the static friction force of the moving platform12, so as to make the moving platform12move. In other words, the minimum value of the current value of the power module applied on the moving platform12should be equal to the cutting resistance value of the moving platform12, so as to make the moving platform12move. Furthermore, a kinetic friction force is generated between the wheel blade131and the work piece2when the wheel blade131contacts and cuts the work piece2. The minimum value of the force applied on the moving platform12should be equal to the summary of the static friction force and the kinetic friction force, so as to make the moving platform12move. Therefore, the moving platform12can generate different cutting resistance values in different conditions. It is worth to notice that the types of the cutting resistance values are not limited thereto. The cutting resistance value can be speed value.

Please refer toFIG. 1. In this embodiment, the in-situ spark erosion dressing system1further includes a controller15connected to the moving platform12and the cutting device13. The controller15controls the cutting device13to move to the first dressing position with a moving path according to the cutting resistance value generated by the movement of the moving platform12relative to the working platform11, to make the spark erosion dressing device14dress the wheel blade131with the discharge energy. In practice, the controller15can be a computer or CNC controller. The controller15can respectively control the moving platform12and the cutting device13to move to the second cutting position and the first cutting position to make the wheel blade131cut the work piece2. The controller15can detect the cutting resistance value generated by the moving platform12, and can respectively control the moving platform12and the cutting device13to move to the second dressing position and the first dressing position according to the cutting resistance value.

Furthermore, in this embodiment, the controller15pre-stores an impedance threshold value. The controller15controls the cutting device13to move to the first dressing position when the cutting resistance value detected by the controller15is greater than the impedance threshold value. In practice, the impedance threshold value can be pre-stored in the controller15, and the controller15can control the cutting device13to move to the first dressing position according to the cutting resistance value to dress the wheel blade131. Since the cutting device13only can move in Z axial direction, the moving platform12should move on the working platform11to make the wheel blade131cut the work piece2. When the wheel blade131contacts and cuts the work piece2, the controller15detects the cutting resistance value generated by the movement of the moving platform12. However, the chips generated by the wheel blade131while cutting the work piece2will be filled in the wheel blade131since the wheel blade131cuts the work piece for a long time. Besides, the sharpness of the wheel blade131is getting poor, so that the cutting resistance value of the moving platform12is increasing. That is to say, the current value required for controller15to drive the moving platform12to move is also increasing. Therefore, when the current value required for controller15to drive the moving platform12is greater than the impedance threshold value, the controller15controls the cutting device13to move to the first dressing position to dress the wheel blade131.

In this embodiment, the controller15pre-stores a moving path, and the moving path includes a first moving platform path and a first cutting device path. The controller15respectively controls the cutting device13and the moving platform12to move to the first dressing position and the second dressing position according to the moving path to make the dressing electrode141of the spark erosion dressing device14couple to the wheel blade131. In practice, the moving path can be a CNC path and include the moving path of the cutting device13and the moving platform12. The first moving platform path includes the second cutting position and the second dressing position, and the first cutting device path includes the first cutting position and the first dressing position. When the controller15determines the wheel blade131of the cutting device13required to be dressed according to the cutting resistance value, the controller15respectively controls the cutting device13and the moving platform12to move from the first cutting position and the second cutting position to the first dressing position and the second dressing position with the first cutting device path and the first moving platform path. Therefore, the wheel blade131can be dressed directly by the movements of the cutting device13and the moving platform12without removing from the cutting device13, so that the wheel blade131configured on the wheel bearing can maintain the concentricity and the cutting device13can maintain the cutting precision.

Please refer toFIG. 4,FIG. 5andFIG. 6.FIG. 5shows a schematic diagram of the wheel blade131and the dressing electrode141in the embodiment ofFIG. 4.FIG. 6shows a schematic diagram of another one perspective of the wheel blade131and the dressing electrode141ofFIG. 5. In this embodiment, the controller15pre-stores a dressing path, and the dressing path includes a second moving platform path and a second cutting device path. In practice, the dressing path can include a dressing position A, dressing position B and dressing position C of theFIG. 4. Moreover, the second moving platform path and the second cutting device path both include the dressing position A, dressing position B and dressing position C. In addition to the second moving platform path and the second cutting device path include the dressing position A, dressing position B and dressing position C, the second cutting device path includes the first dressing position, and the second moving platform path includes the second dressing position. Therefore, the controller15respectively controls the moving platform12and the cutting device13to move with the second moving platform path and the second cutting device path after controlling the moving platform12and the cutting device13to move to the second dressing position and the first dressing position, to make the dressing electrode141of the spark erosion dressing device14dress the wheel blade131. The order of the dressing path can be dressing position A, dressing position B and dressing position C, and can be dressing position A, dressing position B, dressing position C, dressing position B and dressing position A. Furthermore, the controller15can execute the dressing path multiple times to cause the spark erosion dressing device14to dress the wheel blade131multiple times. In one embodiment, the dressing position A can be the position that the wheel blade131contacts the dressing electrode141when the cutting device is located at the first dressing position and the moving platform is located at the second dressing position.

In this embodiment, after the controller15respectively controls the moving platform12and the cutting device13to move according to the dressing path to make the spark erosion dressing device14dress the wheel blade131, the controller15respectively controls the moving platform12and the cutting device13to move to the first cutting position and the second cutting position according to the moving path. In practice, the controller15can pre-store a wheel blade dressing path. The wheel blade dressing path includes the moving path and the dressing path, and the order of the dressing path is moving path, dressing path and moving path. Moreover, the controller15can control the moving platform12and the cutting device13to move with the wheel blade dressing path according to the cutting resistance value. Therefore, when the controller15detects that the cutting resistance value is greater than the impedance threshold value, the controller15respectively controls the moving platform12and the cutting device13to move to the first dressing position and the second dressing position first. Then the controller15respectively controls the moving platform12and the cutting device13with the dressing path to make the spark erosion dressing device14dress the wheel blade131. Then, the controller15respectively controls the moving platform12and the cutting device13to move to the first cutting position and the second position with the moving path. It is worth to notice that the executing time of the dressing path of the wheel blade dressing path is not limited to once, the executing time of the dressing path can be more than once. Therefore, when the wheel blade131needs to be dressed caused by cutting the work piece2for a long time, the in-situ spark erosion dressing system1can dress the wheel blade131by the spark erosion dressing device14without removing wheel blade131, so that the wheel blade131configured on the wheel bearing can maintain the concentricity and the cutting device13can maintain the cutting precision.

In this embodiment, the aforementioned discharge energy includes a first discharge energy and a second discharge energy. The spark erosion dressing device14corrects the wheel blade131with the first discharge energy first, and then dresses the wheel blade131with the second discharge energy. Wherein, the first discharge energy is greater than the second discharge energy. In practice, the discharge energy can include a discharge waveform having a frequency, a peak value and a pulse width. After the controller15respectively controls the moving platform12and the cutting device13to move to the first dressing position and the second dressing position, the spark erosion dressing device14applies the discharge energy on the dressing electrode141and the controller15respectively to control the moving platform12and the cutting device13with the dressing path to make the dressing electrode141dress the wheel blade131. Since the discharge energy is applied on the dressing electrode141to cause the dressing electrode141generating a high temperature, the high temperature of the dressing electrode141generated by the discharge energy melts the melting point of the material of the wheel blade131to make the dressing electrode141correct and dress the wheel blade131. In practice, the first discharge energy can be greater than the melting point of the material of the wheel blade131. When the wheel blade131cuts the work piece2for a long time, the shape of the wheel blade131may be broken or damaged. Therefore, the spark erosion dressing device14can apply the first discharge energy on the dressing electrode141to correct the wheel blade131to maintain the concentricity and avoid skew. The second discharge energy can be smaller than the melting point of the material of the wheel blade131. When the spark erosion dressing device14corrects the wheel blade131with the first energy, the wheel blade131may generate burrs and residues. Therefore, the spark erosion dressing device14can apply the second discharge energy on the dressing electrode141to dress the wheel blade131for maintaining the precision.

Furthermore, the spark erosion dressing device14can dress the wheel blade131with the first discharge energy and the second discharge energy as the controller15executes once of the dressing path. For example, when the orders of the dressing path are dressing position A, dressing position B, dressing position C, dressing position B and dressing position A, the spark erosion dressing device14can correct the wheel blade131at the paths of dressing position A, dressing position B and dressing position C, and the spark erosion dressing device14can dress the wheel blade131at the paths of dressing position C, dressing position B and dressing position A. In another one embodiment, the controller15executes the dressing path twice, and the spark erosion dressing device14respectively dresses the wheel blade131with the first discharge energy and the second discharge energy on each dressing path.

The aforementioned material of the wheel blade131includes a conductive material, and the second discharge energy is greater than the melting point of the conductive material. In practice, the conductive material can be a strong conductive material (such as Copper, Cobalt and Nickel) and weak conductive material (such as cermets), but it is not limited thereto. The wheel blade131can include the diamond material and the conductive material, and the wheel blade131can be formed by connecting the diamond with the conductive material as a binder or a catalyst. When the spark erosion dressing device14corrects the wheel blade131with the first discharge energy, the first discharge energy is greater than the melting point of the diamond and the conductive material, so that the dressing electrode141can correct the shape of the wheel blade131. When the spark erosion dressing device14corrects the wheel blade131with the second discharge energy, the second discharge energy is between the melting point of the diamond and the conductive material. Therefore, the dressing electrode141can melt the conductive material to expose the diamond, thereby improving the sharpness of the wheel blade131.

In one embodiment, the material of the wheel blade is a polycrystalline diamond. In practice, the first discharge energy can be greater than the melting point of the diamond. When the spark erosion dressing device14corrects the wheel blade with the first discharge energy, the dressing electrode141carbonizes the polycrystalline diamond of the wheel blade and corrects the wheel blade along the dressing path. When the spark erosion dressing device14dresses the wheel blade with the second discharge energy, the dressing electrode141only melts and removes the graphite metamorphic layer on the surface of the wheel blade to expose the diamond blade, thereby improving the sharpness of the wheel blade. Moreover, when the spark erosion dressing device14dresses the wheel blade with the second discharge energy, the melting grooves are generated between the diamonds. Therefore, the chips generated by the wheel blade cutting the work piece will be filled into the melting grooves of the wheel blade, thereby reducing the cutting resistance value of the moving platform.

In this embodiment, the in-situ spark erosion dressing system1further includes a sensor16configured on the cutting device13. The sensor16is configured to sense a sensing value of motion state of the wheel blade131. The controller15controls the spark erosion dressing device14to dress the wheel blade131with the second discharge energy according to the sensing value. In practice, the sensor16can be a vibration sensor. When the spark erosion dressing device14corrects the wheel blade131with the first discharge energy, the cutting device13generates vibration since the dressing electrode141contacting and correcting the wheel blade131. Therefore, when the vibration sensing value sensed by the sensor16has a significant change, the controller15still controls the spark erosion dressing device14to correct the wheel blade131with the first discharge energy. When the vibration sensing value sensed by the sensor16does not change significantly, it means that the wheel blade has been corrected. At this time, the controller15controls the spark erosion dressing device14to dress the wheel blade131with the second discharge energy.

Please refer toFIG. 7andFIG. 4.FIG. 7shows a flow diagram of an in-situ spark erosion dressing method in an embodiment of the present invention. In this embodiment, the in-situ spark erosion dressing method can be executed by the in-situ spark erosion dressing system ofFIG. 4. As shown inFIG. 7, the in-situ spark erosion dressing method of this embodiment includes the following steps: in the step S1, detecting a cutting resistance value generated by a moving platform12while a cutting device13cuts a work piece2on the moving platform12at the cutting position; in the step S2, controlling the cutting device13to move to a dressing position with a moving path according to the cutting resistance value, to make a dressing electrode141of a spark erosion dressing device14couple to a wheel blade131of the cutting device13; in the step S3, correcting the wheel blade131with a first discharge energy according to a dressing path; in the step S4, sensing a sensing value of the movement state of the corrected wheel blade131; in the step S5, dressing the wheel blade131with the dressing path and a second discharge energy according to the sensing value; and in the step S6, controlling the corrected wheel blade131of the cutting device13to move to the cutting position with the moving path. The functions of the components or devices mentioned in this embodiment are the same with those of the components or devices mentioned in aforementioned embodiments, and will not be further described herein.

In summary, the in-situ spark erosion dressing system can determine the dressing timing according to the cutting resistance of the moving platform, and controls the moving platform and the cutting device without removing the wheel blade to make the dressing electrode of the spark erosion dressing device dress the wheel blade for maintaining the precision of the wheel blade, thereby increasing the production efficiency. Moreover, the in-situ spark erosion dressing system sequentially corrects and dresses the wheel blade by two different discharge energy to effectively increase the cutting quality of the wheel blade and reduce the production cost, thereby solving the problems of the prior art.

With the examples and explanations mentioned above, the features and spirits of the invention are hopefully well described. More importantly, the present invention is not limited to the embodiment described herein. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.