Laser Cutting of Silicon Nitride Green Sheets to Prevent Chips and Cracks
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Solution Overview
Problem
The existing methods for manufacturing ceramic boards using strip-shaped green sheets, which involve cutting with a blade, often result in chip generation, blade wear, unevenness defects, and cracks near the cut surfaces, leading to decreased yield and quality issues.
Innovation Solution
A method involving the intermittent irradiation of a strip-shaped green sheet with a laser beam to cut and separate it into single sheet-type green sheets, using a carbon dioxide laser with a moving mechanism to minimize chip and crack formation, and subsequent sintering to form a silicon nitride sintered body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a cutting blade is used to cut the strip-shaped green sheet, then the single sheet-type green sheets can be obtained, but chips are generated from the cut surfaces and metal powder is generated due to blade wear
Solution Approach 1:
The patent replaces the mechanical cutting blade system with a laser beam cutting system. The laser beam cuts the green sheet without physical contact, eliminating blade wear and metal powder generation. The laser energy vaporizes or melts the material along the cut line, achieving clean cuts without mechanical contamination.
Solution Approach 2:
The patent introduces a laser beam as an intermediary between the cutting source and the green sheet. This intermediary transfers energy to cut the material without requiring direct mechanical contact, thereby preventing chip generation and metal powder contamination while maintaining cutting effectiveness.
2Manufacturing precision
If the cutting blade pressurizes the strip-shaped green sheet during cutting, then the cut surfaces are formed, but cracks are generated near the cut surfaces due to pulling by the blade edge
Solution Approach 1:
The patent replaces the mechanical pressing and pulling action of the cutting blade with laser beam energy delivery. The laser heats and cuts the material without applying mechanical pressure or pulling forces, thereby preventing crack generation near the cut surfaces while maintaining precise cut quality.
Solution Approach 2:
The patent employs intermittent laser irradiation with periodic on-off cycles. This periodic action allows controlled heating and cooling, preventing thermal stress cracks while maintaining clean cut edges. The laser is turned on to cut and off to allow cooling, avoiding excessive heat accumulation that could cause cracking.
3Ease of manufacture
If chips and metal powder adhere to the surfaces of single sheet-type green sheets during lamination, then the laminate is formed, but unevenness defects occur in the green sheets
Solution Approach 1:
The patent replaces mechanical cutting with laser cutting to eliminate the source of chips and metal powder. Without these contaminants, the lamination process produces uniform surfaces without unevenness defects, while maintaining the ability to form laminates efficiently.
4Object-generated harmful factors
If a laser beam is used to cut the strip-shaped green sheet, then chip and metal powder generation is avoided, but the laser beam may cause thermal damage to the green sheet
Solution Approach 1:
The patent uses intermittent laser irradiation with periodic on-off cycles. The laser is activated to cut the green sheet and then deactivated to allow cooling, preventing excessive heat accumulation and thermal damage while maintaining effective cutting. This periodic action controls thermal input to avoid burning or warping the material.
Solution Approach 2:
The patent applies just enough laser energy to cut the green sheet without excessive heating. By controlling the laser power and exposure time to the minimum required for cutting, the process achieves clean cuts without causing thermal damage such as burning, melting, or warping of the green sheet.
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 approach effectively reduces chip and crack generation, maintains surface quality, and enhances the yield of ceramic boards by avoiding metal powder contamination and surface irregularities, resulting in improved manufacturing efficiency and product quality.
Implementation Method 1
an irradiation step of intermittently irradiating the transported strip-shaped green sheet with a laser beam to cut and separate the strip-shaped green sheet
Data Source
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AI summary
A method for manufacturing a single sheet-type green sheet of the present invention includes a transporting step of transporting a strip-shaped green sheet that contains ceramic along a longitudinal direction thereof, and an irradiation step of irradiating the transported strip-shaped green sheet with a laser beam to cut the strip-shaped green sheet, thereby obtaining a single sheet-type green sheet.