Drill bit machining device

Abstract

The invention provides a drill bit machining device capable of detecting deterioration of a spring applying force to a collet chuck and improving machining precision. A drill bit processing device includes: a rotor shaft to which rotation is transmitted from a drive unit; a collet chuck which is provided at the tip of the rotor shaft and which can be switched between a closed state in which the collet chuck is pressed against the rotor shaft and holds the drill bit and an open state in which the collet chuck is separated from the rotor shaft and releases the holding of the drill bit; the spring is arranged in the rotor shaft and applies force to the collet chuck towards the closed state; the pushing and pressing mechanism overcomes the acting force of the spring to push and press the collet chuck to the open state; and a control device. The control device measures the number of times of opening and closing of the collet chuck, compares the number of times of opening and closing with a first threshold value, and when the number of times of opening and closing is equal to or greater than the first threshold value, performs at least one of warning and stopping of the device.

Description

Technical Field

[0001] The invention relates to a drill processing device for performing hole opening processing using a drill bit. Background Art

[0002] Conventionally, drilling devices for drilling holes in printed circuit boards and the like are known. For example, as described in Patent Document 1, a drilling device has multiple drill bits arranged on the top surface of a table. The drill bits are attached to the front end of a rotor shaft, which is rotated by a drive unit.

[0003] The rotor shaft is equipped with a collet chuck and a spring that biases the collet chuck. The collet chuck has multiple slits arranged parallel to the axial direction and a tapered surface formed on its outer circumference, allowing it to open and close in the radial direction. The spring forces the tapered surface formed on the inner circumference of the rotor shaft against the tapered surface of the collet chuck. This pressure forces the collet chuck to close, retaining the drill bit.

[0004] To replace the drill bit, the piston rod attached to the rotor shaft descends, overcoming the spring force and pushing the collet chuck downward. The tapered surface on the collet's outer circumference separates from the tapered surface of the rotor shaft, opening the collet. This frees the collet from retaining the drill bit, allowing it to be replaced. Once a new drill bit is installed in the collet, the piston rod is raised. As the piston rod rises, the collet is again biased by the spring, pressing its tapered surface against the tapered surface of the rotor shaft, closing the collet.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-213827 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] However, in the drill processing device described in Patent Document 1, the collet chuck is pushed down against the spring's biasing force when the drill is replaced. Consequently, the spring degrades with each drill replacement. Degradation of the spring biasing the collet chuck reduces the force holding the drill. This reduced force causes the drill to slip radially and axially relative to the collet during drilling, reducing machining accuracy and ultimately, lowering product quality.

[0010] An object of the present invention is to provide a drill processing device capable of detecting deterioration of a spring urging a collet chuck and improving processing accuracy.

[0011] Means used to solve problems

[0012] To achieve the above-mentioned object, the drill bit processing device of the present invention is characterized by comprising: a rotor shaft to which rotation is transmitted from a driving unit; a collet chuck disposed at a front end portion of the rotor shaft and capable of switching between a closed state in which the collet is pressed against the rotor shaft to hold the drill bit, and an open state in which the collet is released from the rotor shaft to release the drill bit; a spring disposed within the rotor shaft to bias the collet chuck toward the closed state; a pressing mechanism to press the collet chuck toward the open state against the biasing force of the spring; and a control device; the control device measures the number of times the collet is opened and closed, compares the number of times the collet is opened and closed with a first threshold value, and issues at least one of a warning and device shutdown when the number of times the collet is opened and closed exceeds the first threshold value.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to detect deterioration of a spring that urges a collet chuck, thereby improving machining accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of a drill processing device according to an embodiment.

[0016] Figure 2 It is a longitudinal section view of the main part of the spindle.

[0017] Figure 3 This is a three-dimensional view of the collet chuck and drill bit.

[0018] Figure 4 This is a flowchart explaining the process of detecting spring deterioration. DETAILED DESCRIPTION

[0019] [Structure of the drill processing device]

[0020] like Figure 1 As shown, the drill processing device 1 according to the present invention includes a device base 11, a processing table 12, and a gate-shaped column 13. The processing table 12 is driven in the X direction by a driving mechanism (not shown) on the device base 11. A plurality (two in this embodiment) of printed circuit boards 10, which serve as the workpiece, are placed on the processing table 12.

[0021] A portal column 13 is mounted on the apparatus base 11. It is arranged so as to straddle the processing table 12. A cross slide 15 driven in the Y direction by a drive mechanism (not shown) is mounted on one of the vertical surfaces of the portal column 13. Multiple spindles 16 are provided on the cross slide 15.

[0022] The spindles 16 correspond to the printed circuit boards 10 placed on the processing table 12 and are mounted slidably on the gate pillars 13. The plurality of spindles 16 are driven in the vertical direction (Z direction) in synchronization with each other by a vertical drive mechanism (not shown).

[0023] A drill bit 17 is held on the spindle 16. The drill bit 17 is used to drill holes in the printed circuit board 10. A sub-chuck 18 is attached to the spindle 16. The sub-chuck 18 moves in the Z direction along with the spindle 16. Furthermore, a supply tool post 19, a discharge tool post 20, a drill box 21, and a drill checker 22 are provided on the processing table 12. The drill box 21 stores new and old drill bits separately. The drill checker 22 has the function of detecting the diameter and cutting edge position of the drill bit 17 held by the spindle 16 and is activated by inserting the drill bit 17 from above. Each of the supply tool post 19, the discharge tool post 20, the drill box 21, and the drill checker 22 is provided near the printed circuit board 10 to be processed, corresponding to the spindle 16.

[0024] Each part of the drill processing device 1 is controlled by a control device 25. The control device 25 is realized by, for example, a program-controlled processor. A display unit 26 is connected to the control device 25. The display unit 26 displays various information to be conveyed to the operator.

[0025] The control device 25 includes a storage unit 27. The storage unit 27 stores programs, display data, and the collet chuck 32 (see Figure 2 and Figure 3 ) opening and closing times, as well as a predetermined threshold, are stored in, for example, nonvolatile memory. The control device 25 measures the opening and closing times of the collet chuck 32 and issues a warning or stops the device when the opening and closing times exceed a first threshold. These controls performed by the control device 25 will be described later.

[0026] [Structure of the main shaft 16]

[0027] like Figure 2 As shown, the main shaft 16 is controlled by the control device 25 and has an integrated structure with the motor. The main shaft 16 includes a rotor shaft 31, a collet chuck 32, a spring 33, a guide bushing 34, a piston rod 35, and a pushing mechanism 36. The rotor shaft 31 is rotatably supported by a bearing not shown. The rotor shaft 31 is coupled to a rotor (rotating member) not shown. The rotor can rotate relative to a stator coil (fixed member) not shown. If power is supplied to the stator coil under the control of the control device 25, the rotor and the rotor shaft 31 rotate as one. Thus, the rotor shaft 31 is rotated by the motor serving as the driving unit.

[0028] The rotor shaft 31 has a first tapered surface 31A formed on its inner circumference. The inner diameter of the first tapered surface 31A increases toward the distal end of the rotor shaft 31 (the side where the drill bit 17 is located). The collet chuck 32 is provided at the distal end of the rotor shaft 31, specifically, at a position surrounded by the inner circumference of the rotor shaft 31. A spring 33 is provided within the rotor shaft 31.

[0029] The collet chuck 32 is coupled to the piston rod 35 via a guide bushing 34. The guide bushing 34 is slidably engaged with the rotor shaft 31 in the axial direction (Z direction) of the rotor shaft 31. This restricts radial movement of the piston rod 35. The rotor shaft 31, collet chuck 32, and drill bit 17 are coaxially arranged. Hereinafter, the axial direction of the rotor shaft 31, collet chuck 32, and drill bit 17 will be simply referred to as the "axial direction."

[0030] The spring 33 is composed of stacked disc springs and can apply a force in the direction in which the disc springs are stacked. The spring 33 is located within the rotor shaft 31. Specifically, the spring 33 is positioned on the inner circumference of the rotor shaft 31, between the abutment surface 31B and the guide bushing 34, which is located near the tip. As a result, the spring 33, via the guide bushing 34, urges the collet chuck 32 toward its closed position (described later), i.e., toward its axial base end (opposite the drill bit 17).

[0031] The piston rod 35 is coupled to a pressing mechanism 36. The pressing mechanism 36, for example, is an air cylinder that pushes the piston rod 35 toward an open position (described later), i.e., toward the axially distal end, against the force of the spring 33. When the pressing mechanism 36 presses the piston rod 35, the collet chuck 32 moves toward the axially distal end. Furthermore, when the pressing mechanism 36 releases its pressure on the piston rod 35, the collet chuck 32 moves toward the axially proximal end due to the force of the spring 33. The pressing mechanism 36 is controlled by the control device 25. The control device 25 stores the number of times the pressing mechanism 36 has operated in the storage unit 27 as the number of times the collet chuck 32 has been opened and closed (described later).

[0032] [Structure of collet chuck 32]

[0033] like Figure 3 As shown, the collet chuck 32 has a second tapered surface 32A, a plurality of slits 32B arranged parallel to the axial direction, and an inner circumferential surface 32C that matches the outer circumferential surface 17A of the drill bit 17. The second tapered surface 32A is formed on the outer circumferential surface of the collet chuck 32 and expands toward the front end of the collet chuck 32. The second tapered surface 32A contacts the first tapered surface 31A of the rotor shaft 31.

[0034] When the pressing mechanism 36 releases the pressing force, the collet chuck 32 is urged toward the base end in the axial direction by the spring 33 as described above. As a result, the collet chuck 32 is sunk into the rotor shaft 31, and the second tapered surface 32A is pressed against the first tapered surface 31A, thereby reducing the radial dimension of the collet chuck 32 and bringing the collet chuck 32 into a closed state (by the Figure 2 As the inner diameter of the inner peripheral surface 32C is reduced, the collet chuck 32 comes into close contact with the outer peripheral surface 17A of the drill bit 17, thereby holding the drill bit 17.

[0035] On the other hand, when the collet chuck 32 is pushed toward the front end by the pushing mechanism 36, it overcomes the biasing force of the spring 33 and protrudes from the front end of the rotor shaft 31. The second tapered surface 32A of the collet chuck 32 protruding from the front end of the rotor shaft 31 is separated from the first tapered surface 31A, and the radial dimension of the collet chuck 32 is expanded, and the collet chuck 32 is in the open state (by Figure 2 By increasing the inner diameter of the inner peripheral surface 32C, the collet chuck 32 is separated from the outer peripheral surface 17A of the drill bit 17, thereby releasing the drill bit 17 from its grip.

[0036] By switching the collet chuck 32 from a closed state to an open state, the drill bit 17 can be released from its holding state. Therefore, the drill bit 17 can be removed from the collet chuck 32. As described above, the collet chuck 32 can be switched between a closed state in which it is pressed against the rotor shaft 31 and holds the drill bit 17, and an open state in which it is separated from the rotor shaft 31 and releases its holding state.

[0037] After the collet chuck 32 is opened and a new drill bit 17 is inserted into the inner circumferential surface 32C of the collet chuck 32, the pressing mechanism 36 is released, and the collet chuck 32 is again biased by the spring 33 and moves toward the proximal end of the rotor shaft 31. The collet chuck 32, having moved to the proximal end of the rotor shaft 31, sinks into the interior of the rotor shaft 31, causing the second tapered surface 32A to press against the first tapered surface 31A. This reduces the radial dimension of the collet chuck 32, placing it in a closed position and enabling it to hold the new drill bit 17.

[0038] As described above, the control device 25 measures the number of times the collet chuck 32 is opened and closed and stores the number of times the collet chuck 32 is opened and closed and stored in the storage unit 27. Specifically, the control device 25 monitors the operation of the pressing mechanism 36. When the pressing mechanism 36 presses the collet chuck 32 to move toward the distal end, and then the pressing of the pressing mechanism 36 is released, the collet chuck 32 moves toward the proximal end and returns to the initial position, the control device 25 assumes that the collet chuck 32 has been opened and closed once and counts the number of times the collet chuck 32 is opened and closed.

[0039] The control device 25 measures the number of times the collet chuck 32 is opened and closed and compares the number of times with a first threshold value. When the number of times the collet chuck 32 is opened and closed exceeds the first threshold value, the control device 25 issues a warning and performs control to stop the drill processing device 1 .

[0040] The value used by the control device 25 as the first threshold value is, for example, determined in advance through durability testing, by determining the critical value at which the collet chuck 32 is opened and closed until the spring 33 degrades. This critical value is then multiplied by a coefficient α (0<α<1). For example, the coefficient α is 0.95. If the collet chuck 32 is opened and closed beyond the critical value, the spring 33 degrades, leading to a decrease in machining accuracy. Therefore, it is considered that a warning or a shutdown of the device may be issued before this occurs.

[0041] As a warning from the control device 25, an alarm sound or the like is generated. This allows the user to recognize that the spring is deteriorating. The coefficient α can be appropriately modified depending on the type of spring 33, the force applied to the spring 33 by the piston rod 35, and other factors. Furthermore, in this embodiment, when the number of times the collet chuck 32 is opened and closed exceeds a first threshold, the control device 25 both issues a warning and stops the device. However, the present invention is not limited to this, and at least one of these actions may be performed.

[0042] Furthermore, the control device 25 compares the number of times the collet chuck 32 is opened and closed with a second threshold value. If the number of times the collet chuck 32 is opened and closed exceeds the second threshold value, a warning display is displayed. The value used by the control device 25 as the second threshold value is calculated by multiplying the first threshold value by a coefficient β (0<β<1). For example, the coefficient β is 0.9. If the collet chuck 32 is opened and closed beyond the first threshold value, the spring 33 will enter a state of deterioration. In other words, since maintenance such as replacement of the spring 33 is required, it is considered to display a warning display before this. As a warning display, a warning message such as "It's time to replace the spring" can be displayed on the display unit 26. The coefficient β is appropriately changed according to the type of spring 33, the force applied to the spring 33 by the piston rod 35, and other factors.

[0043] [Processing of detecting spring deterioration]

[0044] Figure 4 This is a flowchart of the process for detecting deterioration of the spring 33 performed by the drill processing device 1 according to this embodiment. The control device 25 measures the number of times the collet chuck 32 is opened and closed from the initial state of the drill processing device 1 (S1). After starting to measure the number of openings and closings, the control device 25 compares the number of openings and closings with a second threshold value. If the number of openings and closings exceeds the second threshold value ("Yes" in S2), a warning message is displayed (S3). If the number of openings and closings is less than the second threshold value ("No" in S2), the warning message is not displayed and the process returns to measuring the number of openings and closings (S1).

[0045] After displaying the warning, the control device 25 compares the number of opening and closing times with a first threshold. If the number of opening and closing times exceeds the first threshold ("YES" in S4), a warning is issued and the drill processing device 1 is stopped (S5). The warning and the device stop allow the user to recognize the deterioration of the spring 33. If the number of opening and closing times is less than the first threshold ("NO" in S4), no warning is issued or the device is stopped, and the process returns to counting the number of opening and closing times (S1).

[0046] As described above, the drill processing device 1 measures the number of times the collet chuck 32 is opened and closed. When the number of opening and closing times exceeds a first threshold, the spring 33 is detected as deteriorating, allowing the user to recognize this. Upon recognizing the deterioration of the spring 33, the user can perform maintenance such as replacing the spring 33. If the deteriorated spring 33 is used without maintenance, the force holding the drill bit 17 decreases, leading to reduced machining accuracy. In contrast, with the drill processing device 1, the user can perform maintenance before the spring 33 deteriorates. Since the deteriorated spring 33 is not used, drilling can be prevented while the drill processing device 1 is operating with reduced machining accuracy, thereby preventing degradation in product quality.

[0047] Furthermore, in the drill processing device 1, a warning display is displayed when the number of opening and closing times reaches or exceeds the second threshold before reaching or exceeds the first threshold. This allows the user to recognize that the spring 33 is approaching deterioration. This prevents the use of a deteriorated spring 33, more reliably preventing a decrease in the processing accuracy of the drill processing device 1 and a decrease in the quality of the product.

[0048] The initial state for starting the measurement of the number of opening and closing times is not limited to the start of the operation of the drill processing device 1. The measurement of the number of opening and closing times may also be started when the spring 33 is replaced with a new one. In this case, the drill processing device 1 preferably has a function of resetting the number of opening and closing times stored in the storage unit 27 when the replacement of the spring 33 with a new one is detected.

[0049] The above-mentioned embodiments are examples for explaining the present invention, and the scope of the present invention is not limited to these embodiments. A person skilled in the art can make appropriate changes without departing from the scope of the present invention.

[0050] Description of Reference Numerals

[0051] 1Drill processing device

[0052] 10Printed substrate

[0053] 11 device base

[0054] 12 processing tables

[0055] 13 door column

[0056] 15 horizontal sliding rack

[0057] 16 spindles

[0058] 17 drill bits

[0059] 17A outer surface

[0060] 18 pairs of chucks

[0061] 19 Supply tool rack

[0062] 20 discharge tool rack

[0063] 21 drill bit box

[0064] 22 drill bit checker

[0065] 25 control devices

[0066] 26 Display unit

[0067] 27 Storage Department

[0068] 31 rotor shaft

[0069] 31A first cone

[0070] 31B contact surface

[0071] 32 collet chuck

[0072] 32A second cone

[0073] 32B slit

[0074] 32C inner surface

[0075] 33 spring

[0076] 34 guide bushing

[0077] 35 piston rod

[0078] 36 Pushing mechanism

Claims

1. A drill bit processing device, characterized in that: have: a rotor shaft, which is rotated by the driving unit; a collet chuck disposed at the front end of the rotor shaft and capable of switching between a closed state in which the drill bit is held by being pressed against the rotor shaft and an open state in which the drill bit is released from the rotor shaft; a spring disposed inside the rotor shaft to bias the collet chuck toward the closed position; a pushing mechanism for overcoming the force of the spring to push the collet chuck toward the open state; as well as control devices; The aforementioned control device Measure the number of times the collet chuck is opened and closed. The number of opening and closing operations is compared with a first threshold value, and when the number of opening and closing operations becomes equal to or greater than the first threshold value, at least one of a warning and a device shutdown is performed.

2. The drill bit processing device according to claim 1, wherein: The rotor shaft has a first tapered surface that expands toward the front end formed on the inner circumference surrounding the collet chuck. In the aforementioned collet chuck, there is formed A plurality of slits arranged parallel to the axial direction and The second tapered surface on the outer circumference expands toward the front end. The aforementioned collet chuck By being pressed by the pressing mechanism and protruding from the front end of the rotor shaft, the second tapered surface separates from the first tapered surface and the collet chuck enters the open state. When the pressing by the pressing mechanism is released, the collet chuck is sunk into the interior of the rotor shaft by the biasing force of the spring, and the second tapered surface is pressed against the first tapered surface, so that the collet chuck enters the closed state.

3. The drill bit processing device according to claim 1, wherein: The aforementioned control device When the number of opening and closing times becomes equal to or greater than a second threshold value obtained by multiplying the first threshold value by a coefficient greater than 0 and smaller than 1, a display calling attention is performed.

4. The drill bit processing device according to claim 1, wherein: The control device starts measuring the number of opening and closing times from a state where the spring is replaced.

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