JP5698994B2 - Drill break detection program - Google Patents

Description

  The present invention relates to a drill breakage detection program suitable for drilling a printed circuit board using a drill.

  In the method of detecting drill breakage during drilling in a printed circuit board drilling machine, the amount of chips discharged during machining is determined by a detector to determine whether the drill is broken (see, for example, Patent Document 1). ) However, after drill breakage, the drilling operation for several holes ends. Therefore, it is necessary for the operator to visually determine the restart position when processing is continued again after replacing the drill with a new one. Further, in a state where the cutting edge is partially broken, such as chipping, chip breakage is discharged, so that it is not possible to determine drill breakage. For this reason, when processing several substrates, a situation occurs in which no hole is formed in the lowermost substrate.

  As a method for solving these problems, the axial voltage generated in the spindle rotor shaft is detected through a printed circuit board that is in contact with the drill (at least the uppermost layer has a conductor layer). There is a proposal for a method of accurately drilling a hole with a bottom (blind hole) by recognizing the Z-axis coordinates and cutting a specified amount from that position. It is disclosed that it is determined in advance that the drill is broken when the shaft voltage cannot be detected within a predetermined time after the holder is lowered after the holder is lowered (patent). Reference 2).

JP 59-134635 A JP 2001-341052 A Paragraph 0030

  In the method disclosed in Patent Document 2, it cannot be detected when breakage occurs after the drill enters the printed circuit board, and the detection of the contact signal between the drill and the printed circuit board is affected by noise or the printed circuit board. It is also difficult to detect chipping in which only the tip portion of the blade is partially lost due to variations due to thickness variations and the flatness of the table.

  The present application is to solve such a problem and to provide a drill breakage detection program capable of detecting a partial breakage such as chipping with high accuracy.

In order to solve the above problems, a voltage is applied to a drill for drilling a workpiece having a conductor layer on the surface, and a height for detecting a voltage generated when the drill contacts the conductor layer is set. In the program for detecting breakage of a drill that determines whether or not the drill breaks based on whether the detected height is within a predetermined allowable value from the measured reference height, the entry side reference at which the drill enters the workpiece as the reference height The entry side reference height is set by performing a predetermined number of reference determination operations when the height and the exit side reference height of the exit side are set, respectively, at the start of machining, when exchanging the drill, or when the workpiece has moved a predetermined distance or more. the release side reference height and the respective lowest position, drill breakage detection program, characterized in that to perform normal processing operation, when the drill pre It is broken after rush Doo substrate was able to be detected even in the event of.

  According to the program of the present invention, it is possible to detect even when breakage occurs after the drill enters the printed circuit board, and it is possible to detect partial breakage such as chipping with high accuracy.

It is a flowchart of the program of this invention. It is a flowchart of the subroutine of normal processing which concerns on the program of this invention. It is a figure which shows operation | movement of the drill in the normal processing which concerns on the program of this invention. It is a flowchart of the subroutine of the process and signal detection which concern on the program of this invention. It is a flowchart of the subroutine of the reference determination concerning the program of this invention. It is a figure which shows operation | movement of the drill in the reference determination which concerns on the program of this invention. It is a flowchart of the subroutine of the signal for reference determination detection which concerns on the program of this invention. It is a flowchart of the subroutine of the reference determination and drill break determination which concern on the program of this invention. It is a figure which shows the dispersion | variation in the contact signal in the reference determination based on the program of this invention. It is a flowchart of the subroutine of drill exchange which concerns on the program of this invention.

  The present invention will be described below with reference to the drawings. FIG. 1 shows a flowchart of the program of the present invention. The workpiece is a printed board having at least a surface layer made of a conductor. After the program starts, it is first determined whether or not machining is started (S101). In the case of NO, it is next determined whether or not the drill has been replaced (S102). In the case of NO, it is determined whether or not the drill has moved more than a predetermined distance (S103). This is because if the drill moves beyond a predetermined distance, the reference height must be changed according to the thickness of the workpiece and the flatness of the table. Usually, the predetermined distance may be set to 50 mm or more. In the case of NO, it is next determined whether or not the reference determination operation so far is less than a predetermined number of times (S104). This is because a standard signal and a drill break determination (S400), which will be described later, must be performed several times because the height signal for standard determination varies. Usually, the predetermined number of times may be set to five. This is equivalent to performing the reference determination operation five times.

  If any of the above steps S101 to S104 is YES, it is determined whether or not the standard determination is the first time (S105), then B: standard determination (S300) in the first time, and C: standard in the subsequent time Determination and drill breakage determination (S400) are performed. Of course, these may be incorporated in the main program instead of the subroutine. The same applies to other subroutines. After completion of B: standard determination (S300) or C: standard determination and drill breakage determination (S400), it is determined whether or not the processing is completed (S106).

  When all of the above steps S101 to S104 are NO, A: normal machining (S200) is performed, and it is determined whether or not machining is completed after completion (S106). If NO, the process returns to step S101, and if YES, the process ends.

  Next, each subroutine will be described. First, a flowchart of A: normal processing (S200) will be described with reference to FIG. The operation of the drill at this time and the definition of each parameter are shown in FIG. A: When normal machining is started, first, D: machining and signal detection are performed (S500). Here, a flowchart of D: processing and signal detection (S500) will be described with reference to FIG. D: When machining and signal detection are started, first, a spindle lowering command is started (S501), and an encoder output of a spindle up / down drive motor (not shown) (actual response position of the spindle, hereinafter referred to as a response position) is previously stored. When the set detection start height is reached (S502), signal detection is started (S503). Here, the signal means a voltage (hereinafter referred to as “contact signal” or simply “signal”) generated in the surface conductor layer when the drill to which the axial voltage is applied contacts the surface conductor layer of the workpiece. The axial voltage applied to the drill may be an axial voltage generated on the rotor shaft by applying an alternating current to the stator coil.

  When the command position reaches the lowest point (Z point) (S504), a spindle ascent command is started (S505), and when the response position reaches a preset detection end height (S506), signal detection is performed. The process ends (S507). Here, the detection end height is preferably higher than the detection start height by Δh. The heights are all measured as negative values with the reference point (R point) set to 0.

  Returning to FIG. 2, after detecting the signal by D: machining and signal detection (S500) as described above, the process proceeds to step S201, the signal is analyzed, and the response position reaches the preset detection limit height. It is determined whether a signal has been detected before. In the case of NO, it is determined that the drill is broken, and the process proceeds to F: Drill exchange (S700).

  In the case of YES, the process proceeds to step S202, and the height at which the drill starts to contact the workpiece 1 having the conductor layer on the surface and the contact signal becomes greater than 0 (hereinafter referred to as “entry side signal detection height”). It is judged whether it is higher than the entry side allowable height. Here, the entry side allowable height will be described with reference to FIG. The entry side allowable height is a height obtained by adding the entry side allowable value Δhin to the entry side reference height 2 determined by reference determination (S300, S400) described later. That is, (the entry side allowable height) = (the entry side reference height) + (the entry side allowable value). The entry side allowable value is about −0.1 mm, and the entry side reference height is about −20.0 mm. It is desirable to switch the entry side allowable value according to the thickness of the drill. If NO in this step, it is determined that the drill is broken, and the process proceeds to F: Drill exchange (S700).

  When YES is determined in the step S202, the process proceeds to a step S203 to determine whether or not a contact signal is detected in the missing side detection section. As shown in FIG. 3, the missing side detection section is a section from the lowest point of the response position of the drill until reaching the detection end height. If no contact signal is detected during this time, it is determined that the drill is broken, and the process proceeds to F: Drill replacement (S700). This step S203 is intended to prevent erroneous determination that a later-described missing side signal detection height is higher than a missing side allowable height when it is broken immediately after the drill enters.

  If YES in step S203, the process proceeds to step S204, and whether the height at which the drill comes out of the workpiece 1 and the contact signal becomes 0 (hereinafter referred to as “missing side signal detection height”) is higher than the allowance side allowable height. Determine. As shown in FIG. 3, the allowance side allowance height is obtained by adding the allowance side allowance value Δhout to the exit side reference height 3 determined by reference determination (S300, S400) to be described later in the same manner as the entry side allowance height described above. It is height. That is, (missing side allowable height) = (missing side reference height) + (missing side allowable value). The removal side allowable value is about -0.1 mm, and the removal side reference height is about -20.0 mm. It is desirable to switch the allowable value on the withdrawal side according to the thickness of the drill as well as the allowable height on the entry side. If NO in this step, it is determined that the drill is broken, and the process proceeds to F: Drill exchange (S700). If YES, the subroutine ends.

  Next, B: reference determination (S300) will be described with reference to FIG. The same steps as those in FIG. 2 are denoted by the same step numbers and description thereof is omitted. FIG. 6 shows the drill operation and the definition of each parameter at this time. B: When the standard decision is started, E: First, a standard decision signal is detected (S600). Here, the flowchart of E: reference determination signal detection (S600) will be described with reference to FIG. FIG. 5 is a flowchart similar to FIG. 4, and the same steps are denoted by the same step numbers and description thereof is omitted. E: The reference determination signal detection is started, the spindle lowering command is started, and when the command position reaches a preset detection start height (S601), the machining command is stopped for a predetermined time (BH point dwell). (S602). Thereafter, the descent command is resumed and signal detection is started (S603). The subsequent steps are the same as in FIG. The reason for stopping the descent for a predetermined time in the reference determination is to detect the reference height as accurately as possible.

  Returning to FIG. 5, after detecting the contact signal by performing E: reference determination signal detection (S600) as described above, the entry side signal detection height is set to entry side reference height 2 in step S301, and in step S302. The exit side signal detection height is set to the exit side reference height 3.

  Next, C: reference determination and drill breakage determination (S400) will be described with reference to FIG. The same steps as those in FIG. 2 or FIG. The drill operation and the definition of each parameter at this time are the same as those in FIG. C: When reference determination and drill breakage determination are started, first, E: reference determination signal detection is performed as in FIG. 5 (S600). E: After detecting the contact signal in the reference determination signal detection (S600), in step S401, it is determined whether the entry side signal detection height is lower than the entry side reference height (set so far). In the case of YES, the entry side signal detection height is set to the entry side reference height 2 in step S402. Thereafter, the process proceeds to step S403 through a signal detection determination step (S203) within the missing side detection section, and a judgment step (S204) as to whether the missing side signal detection height is higher than the missing side allowable height. It is determined whether or not is lower than the reference side height (set so far). If YES, the missing side signal detection height is set to the missing side reference height 3 in step S404.

  That is, as shown in FIG. 9, the entry side signal detection height and the exit side signal detection height vary each time. It is preferable to set the height 2 and the removal side reference height 3.

  Finally, F: Drill replacement procedure will be described with reference to FIG. When the drill change is started, first, the drill moves to the drill changer (S701), and it is determined whether the drill breakage is true or not using a drill diameter measuring device (see, for example, Japanese Patent Laid-Open No. 6-24669) attached to the drill changer. (S702). If YES, the drill is replaced (S703), and if NO, it is not replaced.

  Although an example of the program according to the present invention has been described above, it is natural that the inequality sign may include an equal sign in each determination. (Example: <→ ≦)

1 Workpiece with conductor layer on the surface 2 Entry side reference height 3 Pull-out side reference height

Claims (1)

A voltage is applied to a drill for drilling a workpiece having a conductor layer on the surface, and a height for detecting a voltage generated when the drill comes into contact with the conductor layer is a predetermined reference height from a set reference height. In the drill breakage detection program for determining breakage of the drill according to whether it is detected by a height within an allowable value,
The entry side reference height at which the drill enters the workpiece and the exit side reference height at the exit side are set as the reference height,
When starting machining, exchanging drills, or when the workpiece has moved a predetermined distance or more, by performing a predetermined number of reference determination operations, the entry side reference height and the withdrawal side reference height are set to their lowest positions,
A program for detecting breakage in a drill characterized by performing normal machining operations.

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