JP2006095656A - Boring machine for printed board and method for deciding boring condition of printed board using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boring machine for a printed board and a method for deciding boring conditions of a printed board using it, by which abnormality such as breakage of a drill can be quickly detected and boring conditions can be accurately decided on the basis of temperature data. <P>SOLUTION: An infrared sensor 50, which measures a temperature of a blade face of the drill 45, is provided to the surface of the printed board or a pressing part 46 for pressing the surface of a backing plate arranged to the surface of the printed board. By this configuration, the temperature of the drill 45 can be directly measured by the infrared sensor 50. Therefore, the temperature of the drill can be accurately measured. Quick detection of the abnormality of the drill and accurate decision of the boring conditions can be executed by using the measured temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a drilling machine for a printed circuit board that continuously drills a large number of holes in a printed circuit board using a drill, and a method for determining a drilling condition for a printed circuit board using the drilling machine.

  It is necessary to form a large number of through holes in a printed circuit board on which electronic components are mounted. For this processing, a drilling machine for a printed circuit board that is equipped with a drill and repeatedly moves up and down at high speed has been conventionally used. This printed circuit board drilling machine continuously forms a large number of through holes on the printed circuit board while operating at high speed, so if any trouble occurs in the drill, the printed holes are drilled after that. The substrate becomes a defective product. Therefore, conventionally, the drilling machine is stopped at a predetermined interval, the drill is inspected, and the drill is replaced early. Since this inspection work takes time, it has contributed to a decrease in drilling efficiency.

  In order to solve this problem, there has been proposed a printed circuit board drilling machine as described in Patent Document 1 (Japanese Patent Laid-Open No. 9-1499). In this printed circuit board drilling machine, a temperature sensor is provided inside a chuck on which a drill is mounted. When the temperature measured by the temperature sensor exceeds a predetermined value, it is determined that some abnormality has occurred in the drill, and the rotation of the drill is stopped and an alarm is issued.

On the other hand, in drilling a printed circuit board, it is necessary to determine the number of stacked printed circuit boards to be processed at the same time, select a drill, select a contact plate, and the like. These processing conditions are currently determined based on the experience of the operator. Moreover, it is determined by inspecting or the like in a subsequent process whether the holed product is a good product or a defective product.
JP-A-9-1499

  In the printed circuit board drilling machine described in Patent Document 1 described above, the temperature of the drill can be indirectly measured by measuring the temperature inside the chuck. It is impossible to measure the temperature itself. Therefore, for example, even when the drill is broken, there is a time lag until the temperature inside the chuck changes, and there is a problem that the discovery is delayed. Further, when the temperature is measured in the chuck, it is easily affected by the heat of the processing machine main body, so that there is a problem that the temperature of the drill becomes inaccurate.

  Moreover, since the processing conditions in the drilling are determined based on the experience of the operator, the processing conditions may not be appropriate. If the machining conditions are set to be safer than necessary, the cost of drilling will be unnecessarily long, or the drilling and backing plate used for drilling will be unnecessarily expensive. There is a problem that increases. On the other hand, if the processing conditions are too strict, even if the processing time can be shortened, problems such as deterioration of the surface roughness of the inner peripheral surface of the through hole, deterioration of the position accuracy of the through hole, and residual cutting waste may occur. In addition, if the machining conditions are selected incorrectly, the temperature of the drill during drilling may increase extremely. In that case, the Young's modulus of the epoxy resin that is the base material of the printed circuit board is lowered by being heated by a high-temperature drill, and as a result, the glass fiber that is the reinforcing material is torn or dug up. Problems such as peeling of the inner layer circuit may occur.

  Furthermore, since it is determined in the inspection of the subsequent process whether the punched product is a non-defective product or a defective product, there is a problem that waiting time occurs during the process and the processing efficiency is lowered. Further, when processing is continued in parallel with the inspection, there is a problem that a large number of defective products are generated.

  The present invention has been made in order to solve the above-described problems, and can accurately measure the temperature of a drill or chips, and can quickly detect an abnormality such as breakage of a drill. It is an object of the present invention to provide a printed circuit board drilling machine and a printed circuit board drilling condition determination method using the same, which can accurately determine processing conditions during processing based on data.

  A printed circuit board drilling machine based on the present invention is a printed circuit board drilling machine that continuously drills a large number of holes in a printed circuit board using a drill, and is configured to control the temperature of the drill blade surface and / or chips. An infrared sensor for measuring temperature is provided. According to this structure, since the temperature of a drill and / or the temperature of a chip can be directly measured with an infrared sensor, these exact temperatures can be measured quickly. Thereby, breakage of the drill can be detected at an early stage by detecting whether or not the temperature of the drill and / or the chip is measured in a predetermined time. Moreover, since the temperature of a drill or a chip can be measured accurately, higher quality control becomes possible by utilizing these temperature data as processing monitor information.

  In the printed circuit board drilling machine, a pressing portion that presses the surface of the printed circuit board or the surface of the backing plate disposed on the surface of the printed circuit board, and a ventilation pipe that guides chips generated by the drilling process to the dust collector; The infrared sensor may be provided in the pressing portion and / or the ventilation pipe.

  When an infrared sensor is provided in the pressing part, the infrared sensor is located in the vicinity of the drill and the chip generating part, so that more accurate temperature measurement is possible. On the other hand, the ventilation pipe is normally stationary except for the tip portion. However, when a temperature sensor is provided on the ventilation pipe, an infrared sensor can be disposed at a stationary position, so that there is an impact applied to the infrared sensor. This can reduce the life of the infrared sensor.

  The printed circuit board drilling machine may further include storage means for storing temperature data measured by the infrared sensor. By accumulating temperature data in the storage means, it becomes possible to check the temperature of drills and chips when a problem occurs and the temperature change up to the occurrence of the problem. Data for determining processing conditions and performing high quality control of processed products can be obtained.

  In the printed board drilling machine, the storage means may store temperature data measured by the infrared sensor for each preset number of holes. According to this configuration, since the temperature data is stored with a predetermined number of holes drilled, it is possible to accumulate temperature data over a long period of time without unnecessarily increasing the amount of data.

  The printed circuit board drilling machine further includes a comparison unit and a warning unit, and the comparison unit can compare the temperature data measured in advance and the latest temperature data in a series of drilling processes. The warning means may issue a warning when the temperature difference exceeds a predetermined range. According to this structure, the abnormality which generate | occur | produced in the drill can be detected rapidly.

  The printed circuit board drilling machine further includes a comparison unit and a warning unit, and the comparison unit can compare temperature data of two or more drills that perform drilling at the same time, and the warning unit includes: If the temperature difference exceeds a predetermined range, a warning may be issued. According to this structure, the abnormality which generate | occur | produced in the drill can be detected rapidly.

  The printed circuit board drilling machine further includes an operation control means for controlling the operation of the comparison means and the drill, and the comparison means can compare a preset upper limit temperature with the latest measured temperature data. When the latest temperature data measured exceeds the upper limit temperature, the above-mentioned operation control means increases the height of the drill top dead center, extends the waiting time at the top dead center of the drill, drill rotation speed The temperature of the drill may be lowered by performing a single or a plurality of controls selected from the reduction of the drill speed and the reduction of the drill feed speed.

  According to this configuration, the drill temperature can be lowered before reaching a temperature at which a problem occurs in the drill or the printed circuit board, so that the drilling process quality can be stabilized. Further, since the drill temperature can be kept low, the drill life can be extended.

  The printed circuit board drilling machine further includes a comparison unit and a display unit, and the comparison unit can compare a reference temperature range set in advance with temperature data measured by the infrared sensor, and display the display. The unit may display whether or not the temperature data is within the reference temperature range. By using the printed circuit board drilling machine having this configuration, predetermined processing conditions can be determined by the following procedure.

  First, drilling is performed under the first processing condition, and temperature data under the first processing condition is acquired by the infrared sensor. The comparison means compares the obtained temperature data with the reference temperature range, determines that the first processing condition is appropriate if it is within the reference temperature range, and adopts the first processing condition. If the temperature is out of the reference temperature range, the processing condition is changed to acquire temperature data, and the acquisition of temperature data is repeated until the temperature is within the reference temperature range.

  Examples of the predetermined processing conditions include the number of printed circuit boards that are simultaneously drilled, the configuration of a contact plate disposed on the surface of the printed circuit board, and the configuration of a drill to be used.

  According to the printed circuit board drilling machine and the printed circuit board drilling condition determination method using the printed circuit board drilling machine according to the present invention, it is possible to accurately measure the temperature of the drill and chips and to quickly detect abnormalities such as breakage of the drill. In addition, the processing conditions for drilling can be accurately determined based on the data.

  Hereinafter, a printed circuit board drilling machine and a printed circuit board drilling condition determination method using the printed circuit board drilling machine according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9.

  FIG. 1 is a perspective view showing the overall structure of a printed circuit board drilling machine. As shown in FIG. 1, the printed circuit board drilling machine includes a bed assembly 11, a table assembly 21, a Z unit assembly 31, and a cross beam assembly 81. The table assembly 21 has a horizontal plane to which the printed circuit board is fixed. The table assembly 21 is configured to be movable in the X direction with respect to the bed assembly 11. A Z unit assembly 31 is attached to a cross beam assembly 81 that is fixed to the bed assembly 11 and extends in the horizontal direction so as to be movable in the Y direction.

  The Z unit assembly 31 is provided with a plurality of spindle units 41, and the spindle unit 41 is attached to the Z unit assembly 31 so as to be movable up and down in the Z direction. The bed assembly 11, the Z unit assembly 31, and the spindle unit 41 are provided with servo motors (not shown). A controller is connected to the servo motor, and the bed assembly 11, the Z unit assembly 31, and the spindle unit 41 are driven in the X, Y, and Z directions, respectively, under the control of the controller.

  FIG. 2 is a perspective view showing the structure of the spindle unit. The spindle unit 41 has a spindle unit main body 42 with a built-in motor for driving a drill. The spindle unit main body 42 is held by side frames 56 located on both sides. The side frames 56 are fixed to the upper frame 58 via shafts 57, respectively. A ball screw 59 is screwed into the upper frame 58, and a servo motor 60 is provided at the upper end of the ball screw 59. The side frame 56 and the upper frame 58 are attached by a linear guide 61 so as to be slidable in the Z direction. The spindle unit main body 42 can be moved up and down by driving the ball screw 59 by the servo motor 60. Thereby, feed can be given to the drill held by the spindle unit main body 42.

  FIG. 3 is a longitudinal sectional view showing the structure of the spindle unit main body and its periphery. A drill 45 is attached to the spindle unit main body 42. Around the drill 45, there is provided a pressing unit 46 that presses the surface of the printed circuit board to be processed or the surface of the backing plate. The pressing unit 42 has a cylindrical shape in which an opening through which the drill 45 is inserted is provided on the lower surface, and a space is formed therein. The upper end portion of the pressing unit 42 is not fixed to the outer periphery of the lower end of the spindle unit main body 42. The pressing unit 46 descends together with the spindle unit main body 42. However, when it comes into contact with the surface of the printed circuit board, only the spindle unit main body 42 is processed, and the pressing unit 46 continues to press the printed circuit board and does not descend any further. The space formed inside the pressing unit 46 is provided with a vent pipe connecting portion 46a communicating with the space. A vent pipe 47 that guides chips generated by drilling to the dust collector is connected to the vent pipe connecting portion 46a.

  FIG. 4 is a longitudinal sectional view showing the structure of the lower end portion of the pressing unit. A hole 48 through which the drill 45 passes is formed in the bottom plate at the lower end of the pressing unit 46. The bottom plate at the lower end of the pressing unit 46 is provided with a sensor mounting hole 49 that communicates with the inner peripheral surface of the hole 48 and extends in the horizontal direction. The sensor mounting hole 49 is provided such that its central axis intersects the central axis of the drill 45. An infrared sensor 50 that detects the temperature of the drill 45 and the temperature of the chips is provided inside the sensor mounting hole 49. As this infrared sensor 50, for example, a sensor incorporating a pyroelectric element can be used. When the chip temperature is mainly detected by the infrared sensor 50, the sensor mounting hole 49 may be provided to be inclined in the lower left direction in FIG. By mounting the infrared sensor 50 in the sensor mounting hole 49, the detection direction of the infrared sensor 50 can be directed to the place where the most chips are generated.

  FIG. 5 is a longitudinal sectional view showing the structure of the lower end portion of a pressing unit according to a modification. In the example shown in FIG. 4, the sensor mounting hole 49 is provided in the lower end portion of the pressing unit 46 and the infrared sensor 50 is mounted in the sensor mounting hole 49, but in FIG. 5, the sensor mounting hole 49 is formed in the side surface of the pressing unit 46. The infrared sensor 50 is attached to the sensor mounting hole 49. In this modified example, since the position of the sensor mounting hole 49 is located considerably above the lower surface of the pressing unit 46, the central axis of the sensor mounting hole 49 is obliquely downward so that the detection direction of the infrared sensor 50 faces the drill 45. Inclined in the direction.

  A sensor holding portion 49 a for mounting the infrared sensor 50 is provided on the outer peripheral side of the sensor mounting hole 49 so as to protrude from the side surface of the pressing unit 46. The sensor holding portion 49a has a cylindrical space inside, and the infrared sensor 50 is inserted into the space. The infrared sensor 50 is held such that its tip is exposed toward the space inside the pressing unit 46.

  According to this modification, since the infrared sensor 50 is provided so as to be inclined to the side surface of the pressing unit 46, the dimensional restriction of the infrared sensor to be used is reduced, and a relatively large infrared sensor can be used. Thereby, the infrared sensor which has a more suitable characteristic can be selected, and the precision of temperature measurement can be improved.

  FIG. 6 is a longitudinal sectional view showing an example in which an infrared sensor is provided in a ventilation pipe. In the above two examples, the infrared sensor 50 is provided in the pressing unit 46, but the infrared sensor 50 may be provided in the ventilation pipe 47 shown in FIG. One end of the ventilation pipe 47 is connected to the ventilation pipe connection part 46 a of the pressing unit 46. The other end of the ventilation pipe 47 is connected to a dust collector (not shown). When the dust collector is operated, chips are sucked through the ventilation pipe 47. A portion of the ventilation pipe 47 connected to the pressing unit 46 is configured by a pressure-resistant flexible pipe 47a. Thereby, when the pressing unit 46 moves up and down, the flexible pipe 47a is deformed to follow the movement. The opposite end of the flexible pipe 47a is connected to a fixed pipe 47b connected to a dust collector. Even when the pressing unit 46 moves up and down, only the flexible pipe 47a moves while being deformed, and the fixed pipe 47b on the downstream side of the flexible pipe 47a is stationary.

  The fixed pipe 47b is provided with a sensor attachment hole 49 for attaching the infrared sensor 50 as shown in FIG. The sensor mounting hole 49 opens in a direction orthogonal to the direction in which chips flow, and the temperature of the chips flowing in the ventilation pipe 47 can be measured by attaching the infrared sensor 50 to the sensor mounting hole 49. By attaching the infrared sensor 50 to the ventilation pipe 47 in this way, it is possible to measure only the chip temperature without being affected by the temperature of the drill 50. Further, when the infrared sensor 50 is provided in the pressing unit 46, the infrared sensor 50 is also moved up and down as the pressing unit 46 is moved up and down. However, by attaching the infrared sensor 50 to a stationary portion of the ventilation pipe 47, the infrared sensor 50 is moved up and down. The impact applied to the infrared sensor 50 can be reduced. Thereby, the lifetime of the infrared sensor 50 can be lengthened.

  The infrared sensor 50 may be attached only to the pressing unit 46 or only to the ventilation pipe 47, but may be attached to both of them.

  The infrared sensor 50 attached as described above is connected to the controller 51 and controlled thereby. The controller 51 includes a storage unit configured by a memory or the like that stores the temperature detected by the infrared sensor 50, and a comparison unit that compares the temperatures. The temperature measurement by the infrared sensor 50 is performed in synchronization with the feed of the drill 45. Thereby, the temperature of the specific position of the drill 45 can be measured, and the temperature of the drill 45 during the process from the start of cutting to the end of cutting can be constantly measured. When the temperature of the drill 45 is measured, the position at which the drill 45 is to be measured and at what timing may be determined according to the purpose of the measurement.

  Next, the usage method of the printed circuit board drilling machine of this Embodiment is demonstrated. First, the case where the infrared sensor 50 is attached to the pressing unit 46 and breakage of the drill 45 is detected will be described. In this case, the temperature is measured by the infrared sensor 50 at the timing when the tip of the normal drill 45 crosses the detection position of the infrared sensor 50 under the control of the controller 51. When the drill 45 is normal, the temperature that the drill being processed normally has is measured, and the temperature is within a predetermined temperature range. However, when the drill 45 is broken, the time for passing the detection position of the infrared sensor 50 is delayed. Then, the temperature detected by the infrared sensor 50 at the above timing is extremely lower than the normal temperature range.

  Thus, the breakage of the drill 45 can be detected by detecting that the temperature detected by the infrared sensor 50 is outside the predetermined temperature range. When breakage of the drill 45 is detected, the controller 51 stops the drilling machine and issues a warning. This warning is performed by sounding a warning buzzer, turning on a warning lamp, displaying a warning on the display unit, or the like.

  As described above, in the printed circuit board drilling machine of the present embodiment, the temperature of the drill 45 is directly detected in a non-contact and non-contact manner using the infrared sensor 50. Can be detected. Thereby, generation | occurrence | production of inferior goods can be minimized.

  Moreover, in the said embodiment, although the temperature of the drill 45 is detected, even if it detects the temperature of the chip generated from a printed circuit board, it can be operated similarly. Specifically, the infrared sensor 50 detects the position where the surface of the printed circuit board and the tip of the drill 45 are in contact, that is, the temperature of the surface opening of the through hole formed in the printed circuit board. When the drill 45 has a normal length, chips are generated from the surface opening of the through hole at a predetermined time, and at the same time, this temperature can be detected by the infrared sensor 50, so that the drill 45 is normal. Can be confirmed. When the drill 45 is broken, the time at which chips are generated is delayed, so that the temperature at the predetermined detection time deviates from the normal temperature range. Thereby, it can be detected that the drill 45 is broken.

  The method described above is not limited to breakage of the drill 45, but can also detect abnormal wear due to poor coating of the drill 45. When abnormal wear occurs, the drill 45 becomes extremely hot than the normal temperature range. If it is detected that the temperature detected by the infrared sensor 50 is higher than a predetermined temperature range, it can be determined that such an abnormality has occurred. Thus, by always detecting the temperature of the drill 45, the abnormality of the drill 45 can be detected quickly.

  Even when the infrared sensor 50 is attached to the ventilation pipe 47, breakage of the drill 45 can be detected by the same method. That is, in a normal state, the time from the start of cutting by the drill 45 until the chips generated thereby pass the detection position of the infrared sensor 50 is substantially constant. Therefore, the breakage of the drill 45 can be detected by measuring the chip temperature at the timing when the chips pass in a normal state. Further, when the drill 45 breaks, the chip temperature is different from the normal temperature. Therefore, it is possible to detect the abnormality of the drill including the broken drill by detecting this.

  Furthermore, when drilling is simultaneously performed by a plurality of drills 45, an abnormality can be detected by comparing the temperature of the drill 45 and the temperature of the chips. For example, when drilling with three drills under the same conditions at the same time, if only one drill or chip becomes extremely hot compared to the other, it can be seen that some abnormality has occurred. .

  The temperature of the drill measured by the infrared sensor 50 is stored in the storage unit, and the abnormality of the drill 45 can be detected by comparing the preceding temperature data in the series of machining steps with the latest temperature data. . Normally, when drilling is continued, the temperature of the drill gradually increases due to wear of the drill 45. However, if any abnormality occurs, the temperature rises greatly beyond the normal temperature range. Thus, for example, an abnormality can be detected by sequentially comparing the drill temperature in the previous 100 holes and the latest drill temperature and detecting whether a temperature difference equal to or greater than a predetermined temperature difference has occurred.

  In the measurement of these drill temperatures, it is not necessary to determine how many degrees the drill temperature is, and it is sufficient if an index capable of relatively comparing the drill temperatures is obtained. By doing in this way, the infrared sensor 50 and the controller 51 can be simplified.

  Next, a case where a warning is issued when the machining conditions are not appropriate will be described. There are various types of printed circuit boards, and the processing accuracy required for each product varies. Therefore, it is necessary to select machining conditions according to this, but even if the machining conditions are set inappropriately, if the state can be detected immediately, the occurrence of defective products is minimized. Can be limited.

  As an example, a case where the number of printed circuit boards is inappropriate will be described. FIG. 7 is a graph showing the relationship between the number of drilling operations and the drill temperature in three types of overlapping numbers. In this measurement, a printed circuit board containing Technora (registered trademark), which is a kind of aramid fiber, was used as the reinforcing fiber, and the cutting speed of the drill was set to 157 m / min. As can be seen from FIG. 7, the drill temperature increases as the number of holes drilled increases. This is considered to be because the sharpness of the drill becomes dull as the number of drilled holes increases, and heat is easily generated by friction. In addition, the drill temperature increases as the number of stacked sheets increases.

  For example, assuming that the permissible maximum temperature of a printed circuit board to be drilled is 250 ° C. and 3000 holes are continuously drilled, the upper limit of the number of stacked sheets is 2 as apparent from the graph shown in FIG. If three holes are drilled, the drill temperature exceeds 250 ° C. when the number of holes exceeds 1,700.

  By measuring the temperature of the drill 45 by the infrared sensor 50 every time drilling is performed, it is possible to immediately detect that the drill temperature has exceeded 250 ° C. When this is detected, the controller 51 stops the drilling machine and issues a warning in the same manner as when the drill breaks. This warning is performed by sounding a warning buzzer, turning on a warning lamp, displaying a warning on the display unit, or the like.

  Furthermore, according to the drilling machine of the present embodiment, the temperature of the drill 45 and chips can be measured while drilling, so that the machining state can be monitored through the measured temperature. This makes it possible to finely adjust the processing conditions and to guarantee the quality of the processing hole.

  A case where appropriate processing conditions are set using the printed circuit board drilling machine of the present embodiment will be described below.

  First, a description will be given of a case where the number of printed circuit boards to be simultaneously punched is determined. In drilling a printed circuit board, the number of sheets that can be processed simultaneously varies depending on the material of the base material of the printed circuit board, the thickness of the printed circuit board, the surface finish, the required accuracy, and the like. Therefore, first, a suitable number of printed circuit boards are set in a drilling machine, drilling is performed on a trial basis, and the drill temperature is measured. Whether or not the number of stacked sheets is appropriate is determined based on whether or not the measured drill temperature is within a predetermined range. The determination of suitability is performed by the comparison unit of the controller 51 and the result is displayed on the display unit.

  An example of this will be described with reference to FIG. As described above, the drill temperature increases as the number of holes drilled increases. In addition, the drill temperature increases as the number of stacked sheets increases. This tendency does not change from the start of drilling to the end of machining regardless of the number of drilling. Here, assuming that the permissible maximum temperature of the printed circuit board to be drilled is 250 ° C. and 3000 holes are continuously drilled, the upper limit is 2 sheets. In addition, when the number of stacked sheets is one, the processing time twice as long as that in the case of two sheets is required, so the optimal number of stacked sheets in this case is two.

  For example, when the first lot is punched with three sheets as the first processing condition, the allowable maximum temperature of the printed circuit board is exceeded before reaching 3000. Therefore, the second lot is punched with two overlapping sheets as the second processing condition. In this case, up to 3000 pieces can be drilled without exceeding the allowable maximum temperature. Thereby, it is determined that the number of overlapped sheets 2 in the second processing condition is appropriate. Subsequent lots are processed with this number of stacked sheets.

  Thus, since the machining conditions are determined based on the measured drill temperature data, the conditions can be determined accurately. In addition, since the infrared sensor can directly measure the temperature of the drill blade surface in a non-contact manner, the processing conditions can be determined based on the accurate temperature.

  By storing data indicating the relationship between the drill temperature and the number of holes to be drilled as shown in FIG. 7 in the storage unit, the processing conditions can be determined more efficiently in the next processing. For example, when 1500 holes are drilled and the other conditions are the same as those in FIG. 7, in the case of 1500, even if three sheets are stacked, the temperature does not exceed 250 ° C. Therefore, if the number is 1500, it can be determined that the three-layer overlap is the most efficient processing condition. As described above, by accumulating drill temperature data under various conditions, the machining conditions can be determined more efficiently. When data is stored in the storage unit, if all the data is stored, the amount of data becomes enormous. For example, it may be stored for every 100 drilling man-hours. As a result, the amount of data can be reduced to one-hundred, so that temperature data can be accumulated over a long period of time without unnecessarily increasing the amount of data.

  The above-described processing condition determination method can also be applied when determining other processing conditions. A case where a backing plate is selected as the processing condition will be described. When drilling a printed circuit board, a backing plate is used as necessary. As the backing plate, a metal plate such as aluminum is usually used, but when it is necessary to lower the processing temperature of the printed circuit board, an aluminum plate having a lubricant layer on the surface is used. For example, a product called LE sheet manufactured by Mitsubishi Gas Chemical Co., Ltd. is used. However, since a cauldron having this lubricant layer is more expensive than a normal aluminum cauldron, its use is preferably minimized.

  FIG. 8 is a graph showing the relationship between the number of holes drilled and the drill temperature when using a contact plate with a lubricant layer or a contact plate without a lubricant layer. In this measurement, FR-4, which is a kind of glass epoxy substrate, was used as a printed circuit board, a drill cutting speed was set to 62 m / min, and a through hole having a diameter of 0.6 mm was processed.

  For example, assuming that the allowable maximum temperature is 130 ° C. and 6000 through holes are machined, it is necessary to use an LE sheet according to the graph shown in FIG. If, for the first lot, a contact plate that does not have a lubricant layer is selected as the first processing condition, the number of holes to be drilled is about 2000 and exceeds 130 ° C. In that case, a backing plate having a lubricant layer is selected as the second processing condition for the second lot. Thus, since 6000 pieces can be drilled without exceeding 130 ° C., it is possible to determine the use of a backing plate having a lubricant layer for subsequent lots.

  Next, a case where a drill used for drilling is selected will be described. Usually, a drill called a straight drill having a constant shaft diameter is used as the drill. When it is necessary to lower the temperature during processing of the printed circuit board, this is called an undercut drill, in which only the tip has a normal diameter and the other part has a small diameter to reduce the contact area with the inner peripheral surface of the through hole. A drill is used. However, since this undercut drill is more expensive than a straight drill, its use is preferably minimized.

  FIG. 9 is a graph showing the relationship between the number of holes drilled and the drill temperature when a straight drill and an undercut drill are used. In this measurement, FR-4, which is a kind of glass epoxy substrate, was used as a printed circuit board, a drill cutting speed was set to 62 m / min, and a through hole having a diameter of 0.6 mm was processed.

  As shown in FIG. 9, when an undercut drill is used, drilling can be performed at a considerably lower temperature than when a straight drill is used. One of the drills can be selected as necessary. In this way, the drill temperature can be accurately measured, so that the drill can be selected accurately.

  In the above description, the case where three processing conditions are determined has been described. However, these are merely examples, and the processing conditions that can be accurately determined by the printed circuit board drilling machine according to the present invention are these. It is not limited to.

  Moreover, in the printed circuit board drilling machine according to the present invention, the infrared sensor can directly measure the temperature of the drill and chips during cutting, so that not only can the abnormality be detected quickly. Since these accurate temperatures can be measured, by accumulating the measured temperature data, a high level of quality control becomes possible.

  Subsequently, a case will be described in which the latest temperature data measured is used to control the printed circuit board drilling machine during a continuous drilling process so that the drilling process can be continued without causing any problems.

  In this case, the controller 51 includes an operation control unit that controls the operation of the comparison unit and the drill. An upper limit temperature can be set in advance in this comparison unit, and comparison is always made with the latest measured temperature data. As this upper limit temperature, an upper limit temperature at which no problem occurs even if machining is continued is set.

  When the latest measured temperature data exceeds the preset upper limit temperature, the operation control unit performs any of the following or a combination of these controls. First, by increasing the height of the top dead center of the drill, the drilling interval is lengthened, the time for the drill to be cooled is secured, and the temperature of the drill is lowered. Secondly, the waiting time at the top dead center of the drill is extended, the interval between drilling operations is lengthened, the time for the drill to be cooled is secured, and the temperature of the drill is lowered. Third, the temperature of the drill is lowered by reducing the number of revolutions of the drill to suppress heat generation during drilling. Fourth, the feed rate of the drill is reduced to suppress heat generation during drilling, thereby lowering the temperature of the drill.

  By performing either of these controls or a combination thereof, the drill temperature can be lowered to a temperature lower than the upper limit temperature. The same control is performed when the machining is continued and the drill temperature again exceeds the upper limit temperature. By repeating such control, the drill temperature can be lowered to a normal temperature in the drilling process before the drill temperature reaches a temperature that causes a problem in the drilling process.

  Next, an embodiment in which the above control is performed will be described. Here, as an example, control was performed to change the top dead center position of the drill. In drilling, an undercut drill having a diameter of 1 mm was used as a drill, the cutting speed of the drill was 188 m / min, and the feed rate of the drill was 1800 mm / min. As a printed circuit board to be processed, a 1.6 mm thick substrate containing technola was used. As the upper limit temperature, 150 ° C., which is the glass transition temperature of the resin used for the printed circuit board, was adopted.

  FIG. 10 is a front view showing the top dead center height Z of the drill. The drill top dead center height indicated by Z in FIG. 10 starts at 3 mm initially, and every time the upper limit temperature of 150 ° C. is exceeded, the height of the drill top dead center is increased at intervals of 3 mm by the operation control unit. Controlled.

  FIG. 11 is a graph showing the relationship between the number of holes drilled and the drill temperature when the drill top dead center height is controlled to increase every time the upper limit temperature is exceeded. As is clear from FIG. 11, the drill temperature could be lowered by about 30 ° C. by increasing the top dead center height by 3 mm when the upper limit temperature of 150 ° C. was exceeded. By repeating such control, the drill temperature can be lowered before the drill temperature reaches a high temperature causing a malfunction. Thereby, processing quality can be stabilized. Further, since the drill temperature can be prevented from becoming an abnormally high temperature, the life of the drill can be extended.

  Here, the case of increasing the height of the top dead center of the drill has been described, but even when control is performed to extend the waiting time at the top dead center of the drill, reduce the number of drill revolutions, or reduce the drill feed speed, Similar results are obtained.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It does not become the basis of limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the claims. Further, all modifications within the meaning and scope equivalent to the scope of the claims are included.

It is a perspective view which shows the whole structure of the drilling machine for printed circuit boards in embodiment based on this invention. It is a perspective view which shows the structure of the spindle unit in embodiment based on this invention. It is a longitudinal cross-sectional view which shows the structure of the spindle unit main body in the embodiment based on this invention, and its periphery. It is a longitudinal cross-sectional view which shows the structure of the lower end part of the press unit in embodiment based on this invention. It is a longitudinal cross-sectional view which shows the structure of the lower end part of the press unit of the modification in embodiment based on this invention. It is a longitudinal cross-sectional view which shows the example which provided the infrared sensor in embodiment based on this invention in the ventilation pipe. It is a graph which shows the relationship between the drilling number and drill temperature in three types of overlap sheets. It is a graph which shows the relationship between the number of drilling processes, and drill temperature at the time of using the contact plate which has a layer of lubricant, or the contact plate which does not have a layer of lubricant. It is a graph which shows the relationship between the drilling number and drill temperature at the time of using a straight drill and an undercut drill. It is a front view which shows the definition of drill top dead center height. It is a graph which shows the relationship between the number of drilling processes, and drill temperature at the time of controlling to increase a drill top dead center height whenever it exceeds upper limit temperature.

Explanation of symbols

  45 drill, 46 pressing unit, 47 vent pipe, 50 infrared sensor, 51 controller.

Claims (10)

A printed circuit board drilling machine that continuously drills a large number of holes in a printed circuit board with a drill,
A drilling machine for a printed circuit board, comprising an infrared sensor for measuring a temperature of a blade surface and / or a chip temperature of the drill. A pressing portion that presses the surface of the printed circuit board or the surface of the backing plate disposed on the surface of the printed circuit board, and a ventilation pipe that guides chips generated by drilling to the dust collector,
The printed circuit board drilling machine according to claim 1, wherein the infrared sensor is provided in the pressing portion and / or the ventilation pipe.   The printed circuit board drilling machine according to claim 1, further comprising storage means for storing temperature data measured by the infrared sensor.   The printed circuit board drilling machine according to claim 3, wherein the storage unit stores temperature data measured by the infrared sensor for each preset number of holes.   Comparing means and warning means are further provided, and the comparing means is capable of comparing the temperature data measured in advance and the latest temperature data in a series of drilling steps, and the warning means The printed circuit board drilling machine according to any one of claims 1 to 4, wherein a warning is issued if the temperature difference exceeds a preset range.   Comparing means and warning means are further provided, and the comparing means can compare temperature data of two or more drills that perform drilling at the same time, and the warning means has a temperature difference within a preset range. The printed circuit board drilling machine according to any one of claims 1 to 4, wherein a warning is issued when the value exceeds 1. Further comprising a comparison means and an operation control means for controlling the operation of the drill, the comparison means is capable of comparing the preset upper limit temperature with the latest measured temperature data,
When the latest temperature data measured for the upper limit temperature is exceeded, the operation control means increases the height of the drill top dead center, extends the waiting time at the top dead center of the drill, reduces the drill rotation speed, and The drilling machine for a printed circuit board according to any one of claims 1 to 4, wherein the drill temperature is lowered by performing single or plural control selected from reduction of a drill feed rate.   Comparing means and a display section are further provided, the comparing means is capable of comparing a preset reference temperature range and temperature data measured by the infrared sensor, and the display section is configured to measure the measured temperature data. The printed circuit board drilling machine according to any one of claims 1 to 4, which displays whether or not the temperature is within a reference temperature range. A method for determining a predetermined processing condition in drilling a printed circuit board using the printed circuit board drilling machine according to claim 8,
Drilling in the first processing condition and acquiring temperature data in the first processing condition by the infrared sensor,
The comparison means compares the obtained temperature data with a reference temperature range, and determines that the first processing condition is appropriate if it is within the reference temperature range, and if it is outside the reference temperature range, A method for determining drilling conditions for a printed circuit board, in which temperature data is acquired by changing the conditions, and the acquisition of the temperature data is repeated until the temperature falls within a reference temperature range.   The predetermined processing condition is any one of a number of printed circuit boards to be simultaneously drilled, a configuration of a contact plate disposed on the surface of the printed circuit board, a configuration of a drill to be used, or a combination thereof. Item 10. A method for determining drilling conditions for a printed circuit board according to Item 9.

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