JPS62120905A - Drill break detecting device - Google Patents

Abstract

PURPOSE:To make photoelectric converting and detect drill breaking by constituting a captioned device in such a way that the reflected beam caused by the luminous projection to the drill end extracted from a workpiece after drilling by means of an optical fiber is received by means of a second optical fiber in a position and direction where the drill end is not detected in the case of drill breaking. CONSTITUTION:When the drilling position on a print circuit board 1 is decided, a pressure foot 5 is lowered to make a foot section 8 fix the print circuit board 1, and a slider 4 is lowered to perform drilling. After drilling, the slider 4 is raised, and the moment a drill 2 is extracted from the workpiece, a detecting circuit becomes ON projecting a beam from the luminous projection fiber of an optical fiber 9 to the end of the drill 2, and the reflected beam is received by the luminous receptible fiber 9. when the luminous receptible fiber 9 is on the left end in the direction of a chain line 52, a normal drill in the area enclosed with a curved line 51 is detected and a broken drill in the area enclosed with a curved line 53 is detected. When the drill 2 is positioned in the area 54 which is the area excluding the area 53, a reflected beam is, therefore, not input in the case of drill breaking so that drill breaking may be detected by photoelectric converting.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a drill breakage detection device.

[Technical Background of the Invention and Problems Therewith] With the development of printed circuit board manufacturing technology, the drilling of holes using a drill, for example, into printed circuit boards, is becoming increasingly miniaturized. In the past, a drill of 1 mm or more was used, but recently it has become practical to use a drill of 1 mm to 0.3 mm.

This drilling process is executed automatically based on NC data, and what is important is that it immediately detects any abnormality caused by damage or breakage of the drill to prevent it from proceeding to the next process. management. Due to this need, many proposals have been made for methods of detecting breakage of tools such as drills. For example, there are many methods such as electrical detection, ultrasonic detection, and photoelectric detection, but as the diameter of drills becomes smaller, the charging detection method is also an effective method. In this photoelectric detection method, a light guiding and receiving method using an optical fiber is an effective method for detecting even the above-mentioned small diameter drill. This method includes the method disclosed in Japanese Patent Publication No. 55-25020 and Utility Model Application No. 100270-1982. A method is disclosed in which tool damage is detected by emitting light from a fiber, receiving reflected light with an optical fiber, and performing photoelectric conversion.

However, this method involves indirect photoelectric detection of damage to the tool from the workpiece, and is a method in which damage to the tool is detected only after the workpiece is incompletely machined, resulting in the workpiece being defective. Moreover, this method causes a considerable time delay in detection, and is a method that requires improvement when applied to automated lines.

Furthermore, there is no technical disclosure regarding drill breakage in cutting tool damage detection.

In addition, the latter publication discloses a wear detection device for a grinding wheel for a grinding machine, in which the grinding wheel, which is a tool, is directly irradiated with light from an optical fiber, the reflected light is received by the optical fiber, and is charged and converted. Wear is detected by electrical processing.

However, this method uses a large-diameter grindstone and detects it in an almost flat state when viewed from the optical fiber, and there is no technical disclosure regarding the detection of drill breakage.

[Purpose of the invention]

The present invention provides a method for detecting drill breakage.

[Summary of the invention]

In a device that optically detects breakage of the drill by irradiating the drill with light from a first optical fiber, after the hole is drilled by the drill, the first optical fiber is attached to the tip of the drill separated from the body. means for irradiating light from the drill, means for receiving and photoelectrically converting the light reflected from the drill by this means into a second optical fiber, and means for detecting drill breakage from an electrical signal by this means. means for executing the drill each time the drill is separated from the body; To obtain a drill breakage detection device which is provided with a means for setting the second optical fiber light receiving end so that the drill tip is located outside the drill detectable area when the drill tip retreats from the plane due to breakage. It is.

That is, the present invention has the following features so that even a small-diameter drill can detect breakage.

■ Light is received from the optical illumination light by the optical fiber, and the reflected light from the drill is particularly suitable for detecting breakage of a small diameter drill of 1 mm or less.

■ The setting position of the Hikari 7 Eyeper must be in the area shown in Figure 5.

■ The detection operation should be performed every time the drilling operation is completed and the drill tip separates from the object to be drilled.

■ Monitoring minute breakages that occur at the tip of the drill.

etc.

Regarding the above item (2), as is well known, optical detection methods include transmission detection methods in addition to reflection detection methods.

This transmission type detection method uses a drill to set the light receiving part in the transmitted light path, but if the diameter of the drill is smaller than the diameter of the light beam from the light source side, it becomes impossible to block the light path with the drill during normal operation, and the The distinction between state and broken state is Tanashi. Using a condensing lens, the allowable amount of trilunar deviation is approximately 1, and if the drill position deviates even slightly from the fiber axis, it becomes undetectable. (Here, the above-mentioned X direction is a direction perpendicular to the optical axis, and the above-mentioned Y direction is the direction of the optical axis.) On the other hand, if the reflected light from the drill is received by the optical fiber °, the side of the drill Since the method uses a method in which a portion of this reflected light is detected by a light receiving fiber, there is no need to focus the light beam with a lens, and detection is possible even if the light beam is not necessarily perpendicular to the drill.

Quantitatively, the drill detectable area is as shown in FIG. 4 (G), and compared to FIG.

Regarding (■) above, we investigated the detectable area by the light-receiving optical fiber in an optical system in which the irradiated light from the optical fiber is projected onto the tip of the drill and the reflected light from the drill is received by the light-receiving optical fiber. is shown in Figure 5. That is, the horizontal axis is the axial position of the light-receiving optical fiber, and the vertical axis is the position of the light-receiving surface of the light-receiving optical fiber in the direction perpendicular to the axial direction of the optical fiber.

In FIG. 5, when the tip of the drill is located on a plane consisting of the fiber axis and an axis perpendicular to it, the detection area where the light-receiving optical fiber receives the reflected light from the drill is a curve t51). This is the area surrounded by . That is,
If the drill is present within the area surrounded by curve 61), the light receiving fiber will detect the reflected light. The one-dot chain line indicates six optical fiber shafts.

Further, when the drill breaks and the drill tip retreats upward from the optical fiber axis 752, the detectable area by the light receiving optical fiber is the area surrounded by the curve 531.

Therefore, it was found that breakage could not be detected unless the drill measurement (breakage detection) position 3 was set in the light-receiving optical fiber detection area 64) within the range surrounded by curve 6υ and excluding the range surrounded by curve 531. .

Regarding ■■, instead of measuring the middle part of the drill, the tip of the drill is used as the measuring position in order to detect damage as well.

This is based on the fact that most of the drilling process is completed only at the tip, and when damage occurs, the initial phenomenon occurs at the tip.

In order to measure the tip of the drill in this way, we measure the period during which the tip of the drill is exposed as the driller moves away from his body in order to move to the work position for the next driller. The method is to utilize, irradiate, and measure.

[Embodiments of the invention]

Next, an embodiment of the device of the present invention will be described with reference to the drawings. A workpiece, such as a printed circuit board (1), is placed on a base, such as an X-Y table (not shown).

The movement of this X-Y table is controlled in accordance with pre-programmed NC data and the like in the drilling of holes by the drill (2) in the order of processes and the order of machining.

1 on the printed circuit board (1) whose movement is controlled in this way.
mm or less drill, e.g. Q, 3 mm drill (
This is a configuration example based on 2). This drill (2) is chucked to a rotating main shaft (3), and this main shaft (3) is attached to a slider (4) that moves up and down. This slider (4) is provided so as to slide within a cylindrical pressure foot (5).

An annular collar (7) is integrally attached to the bottom (6) of the pressure foot (5). An annular foot portion (8) is provided to engage with the inner end of the collar (7), and by moving the pressure foot (5) downward, the foot portion (8) is moved downwardly through the collar (7). It is configured so that it can be moved and the printed circuit board (1) can be fixed.

With the printed circuit board (1) fixed, move the slider (4) downward and drill a hole using the drill (2) by perpendicularly entering the position determined by the NC data on the printed circuit board (1). do.

This drilling is done after the work is completed, and the next drilling is the period from when the drill is moved to the working position equipment.
At a predetermined position where the tip of is separated, do+J/I/(1
) to detect breakage.

This breakage detection is performed by setting the optical fiber (9), which is a bundle of a first optical fiber for light emission and a second optical fiber for light reception, in a positional relationship that satisfies the conditions shown in Figure 5. In FIG. 1, the measurement position, that is, the tip end of the optical fiber (9) and the drill (2) are set in an oblique state.

That is, using the light 7 eye angle ψ as a parameter, 0.3 mm
Detection area under drill rotation condition. This is shown in Figure 2. When 9 is gradually increased by 4 from QO, the detectable area becomes longer in the Y direction (ψ=6”, 13°), and further ψ
Increasing (ψ=28°) results in shrinkage again.

This phenomenon is not clear, but it seems that the flute of the drill has some influence. Like this ψ
Since the detectable area is greatly affected by changing ψ, the optimal positional relationship between the fiber and the drill tip for detecting drill breakage is also affected by ψ.

Further, drilling with the drill (1) generates chips, but in order to prevent these chips from adhering to the tip of the optical fiber (9), a flange is removed from the side wall of the pressure foot (5). A cleaning air outlet aυ is provided through (7),
Cleaning air is jetted towards the tip of the optical fiber (9). In this case, the structure may be such that a suction port is used instead of the jet port aυ to suck the chips.

Furthermore, when the slider (4) is located at the bottom dead center, the installation position of the optical fiber (9) is set so that the drill (2) and the optical fiber (9) do not interfere with each other. The operation and effect will be explained with reference to the drawings.

The X-Y table is moved based on the NC data, and each time the position of the hole in the printed circuit board (1) is determined, the pressure 7 (5) is lowered at the timing shown in the third drawing, and the foot part (8) is moved. ) to fix the printed circuit board (1). 7
From the time when the screw (5) comes into contact with the printed circuit board (1) and is fixed, lower the slider (4) at the timing shown in Figure 3 (to) to insert a hole in the determined position of the printed circuit board (1). Ming does the work. After this operation, the slider (4) is raised to remove the drill, and the slider (5) is also raised to prepare for the next hole drilling. This is the preparation period. In the evening, time the slider (4) to rise while the slider (4) is rising, and input the power to the drill breakage detection circuit at the timing shown in Figure 3 (q). In other words, input the power to the drill breakage detection circuit at the timing shown in Figure 3 (same as q - Figure 3 0). Light is projected onto the drill (2) from the light projection optical fiber of the optical fiber (9).

The reflected light from the tip of the drill (2) due to this projection is received by a light-receiving optical fiber, and the presence or absence of breakage of the drill is detected.

If it is broken, there will be no input of reflected light or it will be significantly reduced. This determination is converted into an electrical signal by a photoelectric conversion element (not shown) provided at the other end of the light-receiving optical fiber, and electrically processed and determined by comparison with a predetermined destination value.

For example, it is assumed that the hole shown by the X mark in FIG. 3(b) of the second cycle breaks during work. In this case, during the predetermined drilling work period, even if the drilling work cannot actually be performed, breakage cannot be discovered. Then, the breakage detection described above is performed during the rising period of the slider (4) after the end of the work assignment period. That is, the signal shown in FIG. 3 is output and the process ends.

Various effects can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, even a small diameter drill can be detected under optimal conditions.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of an embodiment of the device of the present invention, Fig. 2 is a diagram showing the mounting angle range of the optical 7 eyeper in Fig. 1, Fig. 3 is an explanatory diagram of the operation of Fig. FIG. 1 is a diagram for comparing and explaining the setting ranges of the reflective type and the transmission type, and FIG. 5 is an explanatory diagram of the setting positional relationship between the drill and the optical fiber in FIG. 1. 1... Printed circuit board, 2... Drill, 4... Slider, 5... Pressure foot, 9... Optical fiber agent, patent attorney Norihiko Ken Yudo, Takehana Kikuo No. 1 Figure fiber axial direction Ymm 72 Mouth 3 Fig. Drill flea cpvm (A) Drill kettle f mm (B) Z 4 Fig.

Claims (1)

[Claims] In a device that optically detects breakage of the drill by irradiating the drill with light from a first optical fiber, the drill tip separated from the drilled object after drilling with the drill is provided with light from the first optical fiber. A detection operation consisting of a means for irradiating light, a means for receiving and photoelectrically converting the light reflected from the drill by this means with a second optical fiber, and a means for detecting drill breakage from an electric signal by this means is performed on the drilled object. a means for executing the drill each time the drill is separated from the optical fiber; and means for setting the drill measurement position in an area other than an area where the drill can be detected when the tip of the drill moves away from the plane.