Workpiece Grinding via Contact Area Variation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing grinding methods for wafers and ingots with uneven surface roughness lead to excessive wear of grindstones and a high probability of breakage due to prolonged heavy load, especially when using grindstones resistant to wear.
Innovation Solution
A workpiece grinding method that involves a grinding apparatus with a chuck table and spindle, where the workpiece is held with one surface exposed, and the area of contact between the workpiece and grindstones is varied by adjusting the spacing or angle between the spindle and chuck table, allowing for alternating increase and decrease in contact area to reduce load and promote self-sharpening of grindstones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If grindstones resistant to wear are used to reduce excessive wear during grinding, then the wear resistance of grindstones is improved, but the self-sharpening capability of grindstones deteriorates and the probability of workpiece breakage increases due to prolonged heavy load
Solution Approach 1:
The patent applies periodic action by alternating between two grinding modes: a first grinding mode where the grindstone grinds the workpiece surface under heavy load, and a second grinding mode where the grindstone is lifted or moved away to allow self-sharpening. This periodic switching prevents continuous heavy load on the workpiece, reducing breakage probability while maintaining wear resistance of the grindstone.
Solution Approach 2:
The patent implements dynamics by making the contact between the grindstone and workpiece variable rather than constant. The grinding system dynamically adjusts the engagement between grindstone and workpiece surface, switching between contact and non-contact states, which allows the grindstone to maintain its cutting edge through self-sharpening during non-contact periods while preserving wear resistance.
2Productivity
If the area of contact between workpiece and grindstones is increased to improve grinding efficiency, then the productivity is improved, but the load on the workpiece increases and the probability of breakage increases
Solution Approach 1:
The patent uses periodic action to alternate between high-productivity grinding phases with larger contact area and low-load phases with reduced contact area or grindstone lifting. This periodic variation maintains high overall productivity while preventing sustained heavy load that would cause workpiece breakage.
Solution Approach 2:
The patent applies partial action by using multiple grindstones where only a portion of the grindstone array contacts the workpiece at any given time. During the second grinding mode, even fewer grindstones or none contact the workpiece, allowing partial grinding action that maintains productivity while reducing load to prevent breakage.
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 reduces the probability of workpiece breakage by minimizing the load through controlled contact area variation and accelerating grindstone self-sharpening, thereby extending the grinding process without excessive wear or breakage.
Implementation Method 1
grinding one surface side of a workpiece in which surface roughness on the one surface side is greater than the surface roughness on the other surface side, by bringing a plurality of grindstones into contact with the one surface side of the workpiece
Data Source
AI summary
A workpiece grinding method includes a holding step of holding the other surface side of a workpiece on a holding surface of a chuck table in such a manner that one surface side of the workpiece is exposed, a first grinding step of grinding the one surface side of the workpiece until the one surface side of the workpiece is flattened, after the holding step, and a second grinding step of grinding the one surface side of the workpiece while modifying a region to be ground of the workpiece by repeating increase and decrease in an area of contact between the workpiece and a plurality of grindstones.