CNC Cutting Path Generation for Complex Shapes
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Solution Overview
Problem
Current CNC machining methods are inefficient in removing material from complex shapes and corners, leading to increased machining time and potential tool damage due to excessive engagement angles and varying cutting path lengths.
Innovation Solution
A method that generates multiple cutting paths with varying stepovers and backfill paths to maintain constant feedrate and prevent tool overload, using offset calculations and empirical rules to optimize the number of cutting paths and backfill passes based on corner angles and material characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional single cutting path method is used, then the machining process is simple, but the machining time increases and material removal efficiency decreases
Solution Approach 1:
The patent divides the material removal process into multiple cutting paths with different stepovers. Instead of using a single cutting path, the method segments the machining operation into several passes, each removing a portion of the material. This segmentation allows for more efficient material removal by optimizing each individual path while maintaining constant feedrate, thereby reducing total machining time and improving productivity.
2Productivity
If large stepover is used to remove material faster, then productivity improves, but tool engagement angle exceeds maximum limit causing tool damage
Solution Approach 1:
The patent dynamically adjusts the stepover between different cutting paths based on the engagement angle constraints. The first cutting path uses a first stepover value, while subsequent cutting paths use different stepover values calculated to maintain constant feedrate and prevent excessive engagement angles. This dynamic adjustment of parameters ensures tool safety is maintained while optimizing material removal rate across multiple passes.
Solution Approach 2:
The method changes the stepover parameter between different cutting paths. The first cutting path uses an initial stepover, and subsequent paths use modified stepover values that are calculated based on the previous path's performance and the need to maintain constant feedrate. This parameter change allows the system to remove material efficiently while keeping engagement angles within safe limits, preventing tool damage.
3Reliability
If cutting paths are optimized for constant feedrate, then tool overload is prevented, but the complexity of path generation increases
Solution Approach 1:
The patent performs preliminary calculations to determine the sequence of cutting paths and their respective stepover values before actual machining begins. The system pre-calculates the engagement angles and feedrates for each path segment, ensuring that constant feedrate can be maintained throughout the operation. This preliminary action simplifies the machining process by providing a ready-made optimized path sequence that prevents tool overload without requiring complex real-time adjustments during machining.
4Productivity
If multiple cutting paths with varying stepovers are used, then material removal efficiency improves, but the number of paths and computation increases
Solution Approach 1:
The patent ensures continuity of useful action by maintaining constant feedrate across all cutting paths. Each subsequent cutting path is designed to follow the previous one without interruption, with stepover values calculated to ensure smooth transitions and continuous material removal. This continuity maximizes productivity by eliminating idle time and ensuring the tool is always engaged in useful cutting action, justifying the increased number of paths through efficient utilization of machining time.
Data Source
AI summary
A method of generating a plurality of cutting paths for a material remover, which generates a set of offsets from the perimeter of the model for each corner region of the model; creates, for each offset within each of the sets, a subset of cutting paths based upon each offset with each cutting path within the subset separated from a neighbouring cutting path within the subset by a stepover, wherein a portion of a first cutting path in one of the subsets has a distance of greater than the stepover to the last cutting path in a previous subset; joins cutting paths from within a subset at each corner region forming complete cutting paths causing a material remover to move between corner regions; and creates backfill cutting paths used to remove material from between subsets of cutting paths in the portion greater than the stepover between the subsets.