Continuous contactless printed circuit boards back drilled hole depth inspection device

Abstract

A continuous non-contact circuit board back-drilling depth detection device is used to measure the drilling depth of back-drilled holes in circuit boards, and includes a detection module, a non-contact sensing module, and a signal processing module. The detection module drives a measurement probe to move vertically. The non-contact sensing module performs non-contact sensing towards the printed circuit board. When measuring the back-drilled hole, the signal processing module receives an initial position signal and the non-contact sensing module generates a starting coordinate value. When the measurement probe enters the back-drilled hole and contacts residual copper inside the hole, the signal processing module receives a residual copper contact signal and the non-contact sensing module generates a residual copper coordinate value. The signal processing module subtracts the absolute value of the difference between the starting coordinate value and the residual copper coordinate value from a calibration distance to calculate the drilling depth.

Claims

1. A continuous non-contact circuit board back-drilling depth detection device for measuring the drilling depth (ΔH) of a back-drilled hole (210) of a printed circuit board (200), and the continuous non-contact circuit board back-drilling depth detection device comprises: A detection module (110) has a measurement probe (112), wherein the detection module (110) is used to drive the measurement probe (112) to move along a vertical direction (D1); a non-contact sensing module (120) is disposed on one side of the detection module (110) and is used to perform non-contact sensing toward the printed circuit board (200); and a signal processing module (130) is electrically connected to the detection module (110) and the non-contact sensing module (120), wherein when measuring the back drill hole (210) of the circuit board, the signal processing module (130) is used to receive an initial position signal and the non-contact sensing module (120) is used to sense and generate an initial coordinate value (H1), and When the detection module (110) moves along the vertical direction (D1) to allow the measurement probe (112) to enter the back drill hole (210) of the circuit board and contact a residual copper (230) inside the hole, the signal processing module (130) receives a residual copper contact signal and the non-contact sensing module (120) senses and generates a residual copper coordinate value (H2), and subtracts the absolute value of the difference between the starting coordinate value (H1) and the residual copper coordinate value (H2) from a correction distance (L) to calculate the drilling depth (ΔH).

2. The continuous non-contact circuit board back-drilling depth detection device as described in claim 1, wherein the non-contact sensing module (120) is an optical displacement sensor.

3. The continuous non-contact circuit board back-drilling depth detection device as described in claim 1, wherein the non-contact sensing module (120) is a capacitive displacement sensor.

4. The continuous non-contact circuit board back-drilling depth detection device as described in claim 1, wherein the signal processing module (130) calculates the drilling depth (ΔH) using the following formula.

5. The continuous non-contact circuit board back-drilling depth detection device as described in claim 1, wherein when the measuring probe (112) of the detection module (110) is spaced apart from a calibration plane (300) by the calibration distance (L), the non-contact sensing module (120) is used to sense and generate the starting coordinate value (H1).

6. The continuous non-contact circuit board back-drilling depth detection device as described in claim 5, wherein when the detection module (110) moves along the vertical direction (D1) to make the measurement probe (112) contact the correction plane (300), the non-contact sensing module (120) is used to sense and generate a surface contact value (H3), and the signal processing module (130) is further used to calculate the absolute value of the difference between the starting coordinate value (H1) and the surface contact value (H3) to obtain the correction distance (L).

7. The continuous non-contact circuit board back-drilling depth detection device as described in claim 5, wherein the correction plane (300) is a printed circuit board surface (220) of the printed circuit board (200) or a separately provided correction reference plane.

8. The continuous non-contact circuit board back-drilling depth detection device as described in claim 1, wherein the residual copper contact signal received by the signal processing module (130) is generated based on the resistance conduction change or capacitance induction change between the measurement probe (112) and the residual copper (230) in the hole.

9. The continuous non-contact circuit board back-drilling depth detection device as claimed in claim 1, wherein the detection module (110) is further connected to a displacement unit (116) for driving the detection module (110) to move along the vertical direction (D1).

10. The continuous non-contact circuit board back-drilling depth detection device as described in claim 1, wherein the non-contact sensing module (120) and the measuring probe (112) are arranged side by side, and the sensing axis of the non-contact sensing module (120) is parallel to the vertical direction (D1).

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