Polygonal Chuck Table Grinding With Load-Matched Thickness Control
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Solution Overview
Problem
Existing grinding apparatuses face challenges in achieving uniform thickness variation reduction during the grinding of rectangular substrates due to material and structural differences between the chuck table holding surface and the substrate, leading to inconsistencies in the ground shape.
Innovation Solution
A grinding apparatus with a chuck table having a polygonal holding surface and a controller that uses load detection units and motors to control grinding parameters, ensuring consistent load application during both holding surface and substrate grinding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the holding surface is ground in advance to reduce thickness variations in the substrate, then the shape difference between ground holding surface and ground substrate is reduced, but the material and structural differences between ceramics and epoxy resin make it difficult to achieve complete shape matching
Solution Approach 1:
The patent employs feedback control by detecting the load applied to the chuck table during substrate grinding and adjusting grinding parameters accordingly. The load detection unit measures the actual grinding load, and this information is fed back to the controller which modifies grinding parameters to maintain optimal conditions, ensuring consistent thickness reduction while accounting for material differences between the ceramic holding surface and epoxy resin substrate.
Solution Approach 2:
The patent changes grinding parameters (such as rotational speed, feed rate, or grinding wheel position) based on detected load variations. By dynamically adjusting these parameters in response to load changes during substrate grinding, the system compensates for material differences and achieves uniform thickness reduction despite the inherent differences between ceramic holding surface and epoxy resin substrate properties.
2Productivity
If the grinding area alternately increases and decreases during chuck table rotation, then the entire one side of the substrate is ground, but thickness variations occur with corners becoming relatively thick and other portions becoming relatively thin
Solution Approach 1:
The patent applies dynamics by making the grinding system adaptive during rotation. The grinding wheel's position or the chuck table's rotational speed is dynamically adjusted based on real-time load detection feedback. This dynamic adjustment compensates for the varying grinding area during rotation, ensuring uniform material removal rate across different regions of the substrate including corners and edge portions.
Solution Approach 2:
The patent utilizes periodic action by synchronizing parameter adjustments with the rotational period of the chuck table. Grinding parameters are modulated periodically to match the rotation cycle, ensuring that each portion of the substrate receives appropriate grinding pressure and duration. This periodic control compensates for the alternating increase and decrease in grinding area, achieving uniform thickness reduction throughout the substrate.
3Manufacturing precision
If load detection and control are implemented to maintain consistent load during grinding, then shape difference between ground holding surface and ground substrate is reduced, but device complexity increases due to additional sensors and control systems
Solution Approach 1:
The patent implements feedback control using a load detection unit that measures the actual grinding load applied to the chuck table. This detected load information is fed back to the controller, which automatically adjusts grinding parameters to maintain consistent load conditions. This feedback mechanism ensures shape consistency between ground holding surface and substrate while managing system complexity through automated control rather than manual intervention.
Solution Approach 2:
The grinding system performs self-adjustment by using the load detection unit to automatically monitor and regulate its own grinding process. The controller modifies grinding parameters based on real-time load feedback without external intervention, enabling the system to self-correct deviations and maintain optimal grinding conditions. This self-service capability achieves shape consistency while minimizing the need for complex external control mechanisms.
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
The solution effectively reduces the difference in shape between the ground holding surface and the ground substrate, minimizing thickness variations and achieving uniform grinding results.
Implementation Method 1
a load detection unit that detects a load applied to one of or both the grinding unit and the chuck table
Implementation Method 2
a first motor that rotates the chuck table about the rotational axis
Implementation Method 3
a spindle motor that rotates the spindle
Implementation Method 4
a circular ring-shaped grinding wheel is mounted on a lower end portion of the spindle... a circular ring-shaped grinding surface formed by trajectories of the plurality of grindstones passes over a center of the holding surface
Data Source
AI summary
A grinding apparatus including a chuck table whose holding surface is polygonal, a grinding unit, a moving unit, a load detection unit, and a controller, wherein the controller includes a load storage section, a holding surface grinding command section that controls a load applied to one (or both) the grinding unit and the chuck table, by controlling a parameter related to grinding processing when the holding surface is ground, and a workpiece grinding command section that controls a load that is the same type of load as that controlled by the holding surface grinding command section, by controlling the parameter related to grinding processing when a workpiece held on the holding surface is ground, and the controller controls the parameter related to grinding processing such that the load controlled by the holding surface grinding command section and the load controlled by the workpiece grinding command section have the same value.