Flat Sheet Charting Using Constraint Logic and Mixed Integer Linear Programming
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Solution Overview
Problem
The flat-sheet industry faces inefficiencies in charting raw rolls and sheets to meet customer demands due to manual processes, high waste generation, and underutilization of defective stock, leading to increased inventory costs and complexity in handling varying dimensions and defects.
Innovation Solution
A method utilizing constraint logic programming and mixed integer linear programming to generate and select optimal charting patterns that maximize the utilization of both good and defective raw rolls and sheets, minimizing waste and optimizing stock usage by considering operational requirements such as defect positions and equipment limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual charting processes are used to handle varying dimensions and defects, then operational flexibility is maintained, but charting efficiency and productivity deteriorate
Solution Approach 1:
The patent replaces manual charting processes with an automated computer-based system that uses optimization algorithms to generate charting patterns. The system automatically processes customer orders, raw roll specifications, and defect information to determine optimal cutting patterns, eliminating manual intervention while maintaining the ability to handle varying dimensions and defects through programmable logic.
Solution Approach 2:
The system enables the charting process to serve itself by automatically generating patterns and identifying suitable raw rolls without human intervention. The optimization algorithm independently evaluates multiple constraints and objectives to produce charting solutions, making the process self-directed while improving efficiency.
2Reliability
If good raw rolls are selectively charted while defective raw rolls are excluded, then product quality is maintained, but stock utilization deteriorates
Solution Approach 1:
The patent converts defective raw rolls from waste material into usable resources by incorporating them into charting patterns. The system identifies defects in raw rolls and generates cutting patterns that strategically avoid defective areas while still utilizing the majority of each raw roll, thereby transforming previously discarded material into valuable product output.
Solution Approach 2:
The system changes the utilization parameter of defective raw rolls from zero (completely excluded) to a positive value (partially utilized). By modifying how defective rolls are treated in the optimization algorithm, the system enables their incorporation into production while maintaining quality standards through strategic pattern generation that avoids defective regions.
3Device complexity
If multiple separate charting processes are run for each shift, then operational complexity is reduced, but overall charting efficiency deteriorates
Solution Approach 1:
The patent merges multiple separate shift-based charting processes into a single integrated optimization system that operates continuously across all shifts. The system consolidates customer orders and raw roll inventory into a unified database, allowing patterns to be generated and updated continuously rather than being recalculated separately for each shift, thereby improving overall efficiency while managing complexity through centralized control.
Solution Approach 2:
The system enables continuous charting operations across all shifts without interruption or recalculation. Once patterns are generated, they remain valid and can be continuously applied to production, eliminating the need to stop and restart charting processes between shifts. This continuous operation maximizes productivity while the system manages complexity through persistent data structures and state maintenance.
4Reliability
If larger quantity of raw stock is maintained to account for defects, then ability to fill orders is maintained, but inventory costs deteriorate
Solution Approach 1:
The system changes the effective utilization rate parameter of raw stock from a conservative estimate (assuming defects render large portions unusable) to an optimized value based on actual defect locations and pattern generation capabilities. By modifying how inventory is valued and planned, the system reduces the safety stock buffer needed while maintaining order fulfillment capability.
Solution Approach 2:
The system incorporates feedback from actual defect locations and charting pattern performance to continuously improve inventory planning. By monitoring how effectively defective rolls are being utilized and adjusting patterns accordingly, the system provides feedback that reduces the need for excessive inventory buffers, thereby lowering inventory costs while maintaining reliability.
Data Source
AI summary
Raw rolls and/or sheets of flat sheet stock are charted by a processing system that generates charting patterns using constraint logic programming, that matches the charting patterns and available raw rolls and/or sheets of flat sheet stock, and that selects the optimal patterns from those matching charting patterns and available raw rolls and/or sheets using mixed integer linear programming.