Dual-Surface Imaging for Workpiece Cutting Defect Detection
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Solution Overview
Problem
Conventional workpiece cutting methods often produce defective chips due to excessive chipping, oblique cutting, or positional deviations on both the upper and lower surfaces of the workpiece, as they primarily focus on the upper surface during kerf check, neglecting potential defects on the lower surface.
Innovation Solution
A workpiece cutting method that involves attaching a tape to the lower surface, holding the workpiece on a transparent plate, and using both upper and lower cameras to image the dividing grooves from both sides, allowing for a comparison of the groove width and position to detect and address defects on both surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If only the upper surface is checked during kerf check, then the inspection process is simple and fast, but defective chips may be produced due to undetected defects on the lower surface
Solution Approach 1:
The inspection system is segmented into two independent imaging paths: an upper imaging unit for capturing images of the upper surface and a lower imaging unit for capturing images of the lower surface. This segmentation allows simultaneous inspection of both surfaces without compromising inspection speed, while ensuring that defects on either surface are detected to prevent defective chip production.
Solution Approach 2:
The inspection approach transitions from a single-dimensional (upper surface only) inspection to a two-dimensional inspection by adding the lower surface imaging dimension. The lower imaging unit captures images through the transparent holding plate from the opposite side, enabling comprehensive detection of dividing groove defects including chipping, oblique cutting, and positional deviations on both surfaces.
2Measurement precision
If both upper and lower surfaces are imaged, then defect detection capability is improved, but the device complexity increases
Solution Approach 1:
The holding plate serves multiple functions: it acts as a support structure for the workpiece, provides a transparent window for lower surface imaging, and serves as a mounting base for the lower imaging unit. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while enabling dual-surface inspection capability.
Solution Approach 2:
The transparent holding plate acts as an intermediary medium that allows light to pass through from the lower imaging unit to capture images of the lower surface. This intermediary approach enables lower surface imaging without requiring direct access to the bottom side of the workpiece, simplifying the overall imaging system architecture.
3Measurement precision
If the holding plate is made transparent for imaging, then lower surface imaging is enabled, but the holding strength may be reduced
Solution Approach 1:
The holding plate is constructed from transparent materials such as glass or transparent resin that provide sufficient mechanical strength for holding the workpiece while maintaining optical transparency for imaging. This composite material approach balances the conflicting requirements of structural integrity and optical permeability, enabling both strong holding capability and lower surface imaging functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively reduces the production of defective chips by enabling the detection and correction of defects on both the upper and lower surfaces, thereby minimizing the likelihood of producing large amounts of defective chips.
Implementation Method 1
imaging the part of the dividing groove from the lower surface side of the workpiece through the imaging area of the holding plate and the tape by using a lower camera portion located below the holding plate
Data Source
AI summary
A workpiece cutting method includes attaching a tape to a lower surface of the workpiece, holding the lower surface through the tape on a holding table including a holding plate, at least a part of a holding surface of the holding plate being an imaging area formed of a material transparent to visible light, cutting the workpiece held on the holding table to divide the workpiece, thereby forming a dividing groove, and imaging at least a part of the dividing groove from a upper surface side of the workpiece by using an upper camera portion located above the holding plate, thereby obtaining an upper image, and also imaging the above part of the dividing groove from the lower surface side of the workpiece through the imaging area of the holding plate and the tape by using a lower camera portion located below the holding plate, thereby obtaining a lower image.