TWI911421B - Processing device - Google Patents

Abstract

[Problem] To provide a machining apparatus that can detect early-stage defects hindering the rotation of the spindle within a machining unit (cutting or grinding unit). [Solution] The control unit that controls the motor that rotates the spindle includes a determination unit. This determination unit determines whether there is a defect in the machining unit based on information obtained by rotating the spindle at a pre-set specified rotation speed. This allows for early detection of defects hindering the rotation of the spindle within the machining unit.

Description

Processing device

This invention relates to a processing apparatus for processing a workpiece.

Chips for devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are indispensable components in various electronic machines such as mobile phones and personal computers.

Such a chip is manufactured by, for example, using a cutting device, dividing a workpiece such as a wafer with multiple devices formed on its front side into individual regions containing the devices (see, for example, Patent 1). This cutting device has a cutting unit, which has, for example, a spindle with a cutting blade (tooling) mounted at its front end, and a motor that rotates this spindle.

Furthermore, this cutting insert has a ring-shaped cutting edge (working stone) with dispersed abrasive grains. Moreover, the cutting device rotates the cutting insert mounted on the front end of the spindle by a motor, while the cutting edge of the cutting insert contacts the workpiece to cut and divide the workpiece.

Furthermore, the workpieces used in the manufacture of wafers are mostly thinned before dicing, with the aim of miniaturizing and reducing the weight of the wafers. This grinding device has a grinding unit, which has, for example, a spindle with a grinding wheel (with a tool) mounted at the front end, and a motor that rotates this spindle.

Furthermore, this grinding wheel has an annular wheel base and a plurality of grinding stones (working stones) fixed to one side of this wheel base. The grinding apparatus rotates the grinding wheel mounted on the front end of the spindle via a motor, while simultaneously bringing the plurality of grinding stones into contact with the workpiece, thereby grinding and thinning the workpiece. Prior Art Documents Patent Documents

Patent Document 1: Japanese Patent Application Publication No. 2010-129623

The problem to be solved by the invention

In machining apparatuses such as cutting and grinding devices, if the workpiece is machined (cutting or grinding) at a low rotational speed of the tool (cutting insert or grinding wheel), the load applied to the workpiece (machining load) will increase.

Furthermore, in this case, there are concerns that processing defects such as cracks (defects) and gaps may occur in the workpiece, thereby reducing the quality of the chips manufactured by dividing the workpiece.

In view of this, the purpose of this invention is to provide a machining apparatus that can detect, as early as possible, malfunctions that impede the rotation of the spindle contained in the machining unit (cutting unit or grinding unit). Means for solving the problem

According to one aspect of the present invention, a processing apparatus for processing a workpiece can be provided, the processing apparatus comprising: a processing unit having a spindle with a grinding stone mounted at its front end and a motor for rotating the spindle; and a control unit for controlling the operation of the motor, the control unit includes a determination unit that determines whether there is a malfunction in the processing unit based on information obtained by rotating the spindle at a pre-set specified rotational speed.

Furthermore, preferably, the present invention also includes a rotation speed measuring unit for measuring the rotation speed of the spindle. After the determination unit calculates the time required from the moment the motor is activated to make the spindle rotate until the spindle reaches the specified rotation speed, based on the rotation speed of the spindle measured by the rotation speed measuring unit, it determines whether there is a defect in the machining unit by checking whether the required time exceeds a preset threshold.

Alternatively, and more preferably, this invention further includes a load current measurement unit. This load current measurement unit measures the load current of the motor that causes the spindle to rotate. The determination unit determines whether there is a malfunction in the machining unit by checking whether the load current value measured by the load current measurement unit exceeds a preset threshold when the spindle is constantly rotating at the specified rotational speed. Invention Effects

In this invention, the control unit that controls the motor that rotates the spindle includes a determination unit. This determination unit determines whether there is a malfunction in the machining unit based on information obtained by rotating the spindle at a pre-set specified rotation speed. Therefore, in this invention, malfunctions that hinder the rotation of the spindle contained in the machining unit (cutting unit or grinding unit) can be detected as early as possible.

The form used to implement the invention

The embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 is a perspective view schematically showing one example of the machining apparatus (cutting apparatus) of the present invention. Furthermore, the X-axis direction (forward and backward direction, machining feed direction) and the Y-axis direction (left and right direction, indexing feed direction) shown in Figure 1 are mutually perpendicular directions on the horizontal plane, and the Z-axis direction (up and down direction) is perpendicular to the X-axis direction and the Y-axis direction (vertical direction, infeed direction).

The cutting device 2 shown in Figure 1 has a base 4 that can accommodate all the components. A cover 6 is mounted on the upper part of the base 4, covering the upper surface of the base 4. A cutting unit (machining unit) 8 for cutting the workpiece 11 is housed inside the cover 6. This cutting unit 8 is connected to a cutting unit moving mechanism (not shown) and can move, for example, along the Y-axis and Z-axis directions. Furthermore, details regarding the cutting unit 8 will be described later.

A worktable 10 for holding the workpiece 11 is provided below the cutting unit 8. The worktable 10 is connected to a worktable moving mechanism (not shown) and can move, for example, along the X-axis. Furthermore, the worktable 10 is connected to a rotating mechanism (not shown) and can rotate with a straight line substantially parallel to the Z-axis as the axis of rotation.

A cartridge worktable 12 is provided at the corner of the base 4. A cartridge 14 capable of holding a plurality of workpieces 11 is placed on the upper surface of the cartridge worktable 12. This cartridge worktable 12 is connected to a cartridge worktable moving mechanism (not shown) and can move, for example, along the Z-axis. This cartridge worktable moving mechanism adjusts the height of the cartridges 14 placed on the cartridge worktable 12 so that the workpieces 11 can be properly moved in and out.

A monitor 16, serving as a user interface, is provided on the side 6a of the cover 6. Furthermore, a warning light (pilot lamp) 18 is provided on the upper surface 6b of the cover 6. The aforementioned components of the cutting device 2 are connected to a control unit (not shown in FIG1). This control unit has a central processing unit (CPU) and a memory device including main memory (volatile memory) and auxiliary memory (non-volatile memory), and can control the operation of the aforementioned components of the cutting device 2.

Figure 2 is a schematic partial cross-sectional side view of the cutting unit (machining unit) 8. The cutting unit 8 has a spindle 20 that rotates about a straight line that is generally parallel to the Y-axis. This spindle 20 is housed in the space inside a cylindrical shell 22. An air supply passage 22a that is generally parallel to the rotation axis of the spindle 20 is provided inside the shell 22 (inside the wall material).

Air supply path 22a is connected to an external air supply source (not shown) through air supply port 22b. Furthermore, air supply path 22a is connected to the radial air bearing 24 through the first supply path 22c, and to the thrust air bearing 26 through the second supply path 22d.

The main shaft 20 can be kept suspended within the inner space of the housing 22 by supplying high-pressure air to the radial air bearing 24 and the thrust air bearing 26 from an air supply source. For example, the radial air bearing 24 maintains the position of the main shaft 20 in a direction perpendicular to the rotation axis by spraying air toward the main shaft 20 in a direction perpendicular to the rotation axis.

On the other hand, the thrust air bearing 26 maintains the position of the main shaft 20 in a direction parallel to the rotation axis by spraying air toward the disc-shaped thrust plate 20a disposed on the main shaft 20. The radial air bearing 24 and the thrust air bearing 26 can stably support the high-speed rotating main shaft 20.

An opening 22e is provided at one end (front end) of the casing 22. The main shaft 20 has one end (front end) 20b inserted into the opening 22e, so that it protrudes from the casing 22. That is, the front end 20b of the main shaft 20 protrudes outward from the opening 22e of the casing 22. Figure 3 is an exploded perspective view schematically showing the structure of the front end of the main shaft 20.

A mounting base 28 is provided at the front end of the main shaft 20. The mounting base 28 has a disc-shaped flange portion 30 and a cylindrical support shaft 32 protruding from the center of the front surface 30a of the flange portion 30. An annular protrusion 30b protruding from the front surface 30a is provided on the outer periphery of the flange portion 30. The front end face 30c of the protrusion 30b is formed to be substantially parallel to the front surface 30a.

A toothed edge 32a is formed on the outer peripheral surface of the support shaft 32. A recess 32b is formed at the center of the front end face of the support shaft 32. An annular cutting insert (tooling tool) 34 for cutting the workpiece 11 can be mounted on the support shaft 32. The cutting insert 34 has an annular base 36 made of a metal material such as aluminum (Al) and an annular cutting edge (machining stone) 38 formed along the outer peripheral edge of the base 36.

An opening 36a is provided in the center of the base 36, extending through the base 36 in the thickness direction to allow the support shaft 32 to be inserted. Furthermore, an annular protrusion 36b is provided around the opening 36a of the base 36, protruding towards the front side along the thickness direction of the base 36. The cutting edge 38 is formed by fixing abrasive grains made of diamonds, for example, with a nickel plating layer. However, there are no limitations on the abrasive grains of the cutting edge 38 or the material of the bonding material, and they can be appropriately selected according to the material of the workpiece 11 or the processing requirements.

The groove 32a of the support shaft 32 can be fastened with an annular nut 40 for fixing the cutting tool 34. A circular opening 40a corresponding to the diameter of the support shaft 32 is formed in the center of the nut 40. A groove corresponding to the groove 32a already formed on the support shaft 32 is formed in this opening 40a.

The cutting insert 34 is installed in the mounting base 28 by inserting it into the support shaft 32 through the opening 36a of the base 36. Furthermore, when the nut 40 is screwed into and tightened onto the toothed edge 32a of the support shaft 32, the cutting insert 34 is held between the front end face 30c of the flange portion 30 and the nut 40. In this way, the cutting insert 34, including the cutting edge (machining stone) 38, can be installed at one end (front end) 20b of the spindle 20.

As shown in Figure 2, a motor 42, which provides the force to rotate the main shaft 20, is connected to the other end of the main shaft 20. The motor 42 includes a stator 44 fixed to the inside of the housing 22 and a rotor 46 integrated with the main shaft 20.

Then, the main shaft 20 will rotate in response to the magnetic force acting between the stator 44 and the rotor 46. Furthermore, although the main shaft 20 and the rotor 46 are integrated here, they can also be connected separately.

A portion of the air supplied to the radial air bearing 24 and the thrust air bearing 26 can be discharged (ejected) to the outside of the housing 22 through the gap (part of the opening 22e) between the front end 20b of the spindle 20 and the housing 22. This airflow can seal the gap between the front end 20b of the spindle 20 and the opening 22e of the housing 22 (air seal).

Here, if foreign objects are mixed into the air supplied to the radial air bearing 24 and the thrust air bearing 26, and/or the air pressure drops suddenly, the spindle 20 may come into contact with foreign objects and/or the housing 22, resulting in damage. Furthermore, the spindle 20 may also be damaged due to improper operation during the maintenance of the cutting unit 8 (e.g., rotating the spindle 20 before air is supplied to the radial air bearing 24 and the thrust air bearing 26).

This type of damage is also known as spindle scratch and will hinder the rotation of spindle 20. Furthermore, if motor 42 has deteriorated, it will also hinder the rotation of spindle 20. In view of these points, the cutting device 2 includes a determination unit in the control unit, which determines whether there are any defects in the cutting unit 8 that hinder the rotation of spindle 20.

Figures 4 and 5 are schematic diagrams showing the components of the cutting device 2 used to determine whether there is a malfunction in the cutting unit 8 that obstructs the rotation of the spindle 20. The control unit 48 shown in Figures 4 and 5 can control the operation of the motor 42 housed in the housing 22 and cause the cutting blade 34 mounted on the front end of the spindle 20 to rotate.

Furthermore, in the cutting device 2 shown in Figure 4, a rotational speed measuring unit 50 is provided to measure the rotational speed of the spindle 20. The rotational speed of the spindle 20 measured by this rotational speed measuring unit 50 can be input to the control unit 48 at any time. Moreover, the control unit 48 has a determination unit 48a, which uses the information input from the rotational speed measuring unit 50 to determine whether there is a malfunction in the cutting unit 8 that obstructs the rotation of the spindle 20.

The information used in this determination is, for example, the rotational speed of the spindle 20 measured by the rotational speed measuring unit 50. Specifically, the determination unit 48a calculates the time required from the moment the motor 42 is activated to rotate the spindle 20 until the spindle 20 reaches a specified rotational speed, based on the rotational speed of the spindle 20 measured by the rotational speed measuring unit 50. Then, the determination unit 48a determines whether there is a malfunction in the cutting unit 8 that obstructs the rotation of the spindle 20, based on whether the calculated required time exceeds a preset threshold. Alternatively, this threshold can be pre-memorized in the memory device of the control unit 48.

Figure 6 is a graph schematically showing an example of the change in the rotational speed of the spindle 20 over time, as measured by the rotational speed measuring unit 50, until the spindle 20 reaches a specified rotational speed V. When the rotational speed of the spindle 20, as measured by the rotational speed measuring unit 50, changes in the form of the dashed line A shown in Figure 6, the calculated required time will not exceed the threshold T1. In this case, the determination unit 48a will determine that there is no defect in the cutting unit 8 that obstructs the rotation of the spindle 20.

On the other hand, if the rotational speed of the spindle 20, as measured by the rotational speed measuring unit 50, changes in the form of a one-point chain B as shown in Figure 6, the calculated required time will exceed the threshold T1. In this case, the determination unit 48a will determine that there is a malfunction in the cutting unit 8 that is obstructing the rotation of the spindle 20. Furthermore, in this case, the control unit 48 will control the monitor 16 and/or the warning light 18, and notify the operator of the cutting device 2 of the malfunction in the cutting unit 8.

Furthermore, in the cutting device 2 shown in Figure 5, a load current measurement unit 52 is provided to measure the load current value of the motor 42 that rotates the spindle 20. The load current value of the motor 42 measured by the load current measurement unit 52 can be input to the control unit 48 at any time. Moreover, the control unit 48 has a determination unit 48b, which uses the information input from the load current measurement unit 52 to determine whether there is a malfunction in the cutting unit 8 that obstructs the rotation of the spindle 20.

The information used in this determination is, for example, the load current value of the motor 42 measured by the load current value measuring unit 52 when the spindle 20 is rotating constantly at a specified rotational speed, without cutting the workpiece 11 by the cutting unit 8. Specifically, the determination unit 48b determines whether there is a malfunction of the cutting unit 8 that is obstructing the rotation of the spindle 20, based on whether this load current value exceeds a preset threshold. Alternatively, this threshold value can be pre-memorized in the memory device of the control unit 48.

Figure 7 is a chart schematically showing an example of the change over time of the load current value of the motor 42, as measured by the load current value measuring unit 52, until the spindle 20 rotates at a constant specified speed. When the load current value of the motor 42, as measured by the load current value measuring unit 52, changes as shown by the dashed line C in Figure 7, the load current value of the motor 42 when the spindle 20 rotates at a constant specified speed will not exceed the threshold T2. In this case, the determination unit 48b will determine that there is no defect in the cutting unit 8 that obstructs the rotation of the spindle 20.

On the other hand, if the load current value of motor 42, as measured by load current value measuring unit 52, changes in the form of a one-point chain D as shown in Figure 7, the load current value of motor 42 when spindle 20 rotates at a constant specified rotation speed will exceed the threshold T2. In this case, determination unit 48b will determine that there is a malfunction in cutting unit 8 that obstructs the rotation of spindle 20. Furthermore, in this case, control unit 48 will control monitor 16 and/or warning light 18, and notify the operator of cutting device 2 of the malfunction in cutting unit 8.

In the cutting device 2 described above, the control unit 48 that controls the motor 42 that rotates the spindle 20 includes a determination unit 48a or a determination unit 48b. The determination unit 48a or determination unit 48b determines whether there is a malfunction in the cutting unit 8 based on information obtained by rotating the spindle 20 at a pre-set specified rotation speed. In this way, in the cutting device 2 described above, malfunctions that hinder the rotation of the spindle 20 contained in the cutting unit 8 can be detected as early as possible.

Furthermore, the cutting device 2 described above is one example of the machining device of the present invention, and the machining device of the present invention is not limited to the cutting device 2. For example, the machining unit of the machining device of the present invention may also be the following cutting unit: having a spindle and a motor that rotates the spindle, and the aforementioned spindle is equipped with a washer-type cutting insert (a cutting insert consisting only of annular cutting edges (machining stones)) at its front end.

Furthermore, the processing device of the present invention can also be a grinding device, which includes: a processing unit having a spindle and a motor for rotating the spindle, wherein the spindle is provided with a grinding wheel containing a plurality of grinding stones (processing grinding stones) at its front end; and a control unit for controlling the operation of the motor.

Furthermore, the processing apparatus of this invention may also include a control unit 48 comprising a determination unit 48a and a determination unit 48b, a rotational speed measuring unit 50, and a load current measuring unit 52. In addition, the structure and method of the above-described embodiments can be appropriately modified to be implemented as long as they do not depart from the purpose of this invention.

2: Cutting device 4: Base 6: Cover 6a: Side surface 6b: Top surface 8: Cutting unit (machining unit) 10: Workpiece clamp 11: Workpiece 12: Tablet/cassette 14: Cassette 16: Monitor 18: Warning light (indicator light) 20: Spindle 20a: Thrust plate 20b: One end (front end) 22: Housing 22a: Air supply path 22b: Air supply port 22c: First supply path 22d: Second supply path 22e: Opening section 24: Radial air bearing section (radial air bearing) 26: Thrust Air Bearing Section (Thrust Air Bearing) 28: Mounting Base 30: Flange 30a: Front Side 30b, 36b: Protrusion 30c: Front End Face 32: Support Shaft 32a: Chamfer 34: Cutting Insert 36: Base 36a, 40a: Opening 38: Cutting Edge 40: Nut 42: Motor 44: Stator 46: Rotor 48: Control Unit 48a, 48b: Judgment Unit 50: Rotational Speed Measurement Unit 52: Load Current Measurement Unit A, C: Dashed Line B, D: Single-Point Link T1, T2: Threshold V: Specified Rotational Speed X, Y, Z: Direction

Figure 1 is a perspective view schematically showing one example of a machining apparatus. Figure 2 is a partial cross-sectional side view schematically showing one example of a machining unit. Figure 3 is an exploded perspective view schematically showing one example of the structure of the front end of a spindle. Figure 4 is a diagram schematically showing one example of the components of a cutting apparatus used to determine whether there are malfunctions in the cutting unit that obstruct spindle rotation. Figure 5 is a diagram schematically showing another example of the components of a cutting apparatus used to determine whether there are malfunctions in the cutting unit that obstruct spindle rotation. Figure 6 is a graph schematically showing an example of the change in spindle rotation speed over time until the spindle reaches a specified rotation speed. Figure 7 is a chart schematically showing an example of how the load current value of a motor changes over time until the spindle rotates at a constant specified speed.

10: Worktable

20: Spindle

22: Shell

34: Cutting inserts

48: Control Unit

48a: Judgment Department

50: Rotational speed measurement unit

Claims (2)

A machining apparatus for machining a workpiece, the machining apparatus comprising: a machining unit having a spindle with a grinding stone mounted at its front end, radial air bearings and thrust air bearings supporting the spindle by air supplied from an air supply source, and a motor for rotating the spindle; a control unit for controlling the operation of the motor; and a rotational speed measuring unit for measuring the rotational speed of the spindle. The control unit includes a determination unit that determines whether there is a malfunction in the machining unit based on information obtained by rotating the spindle at a pre-set specified rotational speed. The determination unit calculates the time required from the moment the motor starts rotating the spindle until the spindle reaches the specified rotational speed, based on the spindle's rotational speed measured by the rotational speed measuring unit. Then, it determines whether there is a malfunction in the processing unit by checking whether the required time exceeds a preset threshold. The malfunction is damage to the spindle that hinders its rotation. A processing apparatus for processing a workpiece, the processing apparatus comprising: a processing unit having a spindle with a grinding stone mounted at its front end, radial air bearings and thrust air bearings supporting the spindle by air supplied from an air supply source, and a motor for rotating the spindle; a control unit for controlling the operation of the motor; and a load current measuring unit for measuring the load current value of the motor when the spindle rotates. The control unit includes a determination unit that determines whether there is a malfunction in the machining unit based on information obtained by rotating the spindle at a preset specified rotation speed. The determination unit determines whether there is a malfunction in the machining unit by checking whether the load current value measured by the load current value measuring unit exceeds a preset threshold when the spindle is constantly rotating at the specified rotation speed. The malfunction is damage to the spindle that hinders the rotation of the spindle.