Pocket Toolpath Computation for Trochoidal High-Speed Machining
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Solution Overview
Problem
Current machining techniques for 2.5D pockets, such as 2.5D roughing toolpaths, face inefficiencies due to sharp corners that slow down machining time and wear down tools, and lack the ability to generate toolpaths for complex geometries, especially with high-speed machining requirements.
Innovation Solution
A method and system for computing a toolpath that involves rendering 2D pixel representations of machining tools and pockets, determining start points, calculating tool engagement values, identifying cutting and non-cutting sections, and generating trochoidal region groups to create a complete toolpath that minimizes tool engagement and handles complex geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If contour-parallel or direction-parallel toolpaths are used for pocket machining, then the machining process is simple and commonly used, but the tool needs to be slowed down at sharp corners causing increased machining time and tool wear
Solution Approach 1:
The patent applies curvilinear toolpaths that replace sharp corners with curved transitions. The toolpath computation generates smooth curved segments instead of straight lines with abrupt direction changes, allowing the tool to maintain higher speeds throughout the machining process while reducing tool wear at corner regions.
Solution Approach 2:
The patent dynamically adjusts the toolpath geometry based on pocket characteristics. The system computes curvilinear toolpaths that adapt to the specific shape and size of the pocket, optimizing the curvature and transition regions to maintain optimal tool engagement while enabling high-speed machining throughout the operation.
2Productivity
If curvilinear toolpath generation techniques are used for high-speed machining, then machining speed is improved, but the techniques lack capability to generate toolpaths for complex geometries and have software unavailability issues
Solution Approach 1:
The patent segments the pocket machining into distinct phases: roughing passes that remove bulk material and finishing passes that achieve final dimensions and surface quality. The toolpath computation separately handles boundary following segments and interior curvilinear segments, allowing each to be optimized for its specific function while maintaining overall capability for complex geometries.
Solution Approach 2:
The patent extends 2D curvilinear toolpath techniques into 3D by computing multi-layer toolpaths for pockets with varying depths. The system calculates tool engagement volumes and adjusts toolpath geometry across multiple Z-layers, enabling high-speed machining of complex 3D pocket geometries while maintaining the benefits of curvilinear paths.
3Reliability
If trochoidal moves are used to machine corner regions, then sharp corners are avoided and tool engagement is maintained, but the machining process becomes more complex and time-consuming
Solution Approach 1:
The patent merges boundary following moves with curvilinear interior moves into a unified toolpath computation. Instead of separately generating trochoidal moves for corners and spiral moves for interiors, the system computes a continuous curvilinear toolpath that naturally transitions between boundary regions and interior regions, maintaining consistent tool engagement while simplifying the overall toolpath structure.
Data Source
AI summary
The invention relates to method and system for machining a pocket on a raw material body. The method includes rendering 2-dimensional pixel representation corresponding to cross-section of machining tool and pocket; determining start point for toolpath from 2D pixel representation; for computing each of subsequent segments in toolpath, determining tool engagement values corresponding to potential moves of machining tool with raw material body, and one of, selecting move with corresponding tool engagement value closest to required tool engagement value, or selecting next move that follows boundary of pocket; identifying cutting sections and non-cutting sections; identifying trochoidal region groups from cutting sections and boundary region groups from non-cutting sections in the raw toolpath; for each of trochoidal region groups in raw toolpath, joining end point of first curvilinear cutting section with start point of second curvilinear cutting section through link move to obtain trochoidal toolpath; computing complete toolpath from raw toolpath.