Relief Machining from Point Clouds Without Surface Interpolation
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Solution Overview
Problem
Current methods for machining high-resolution relief models are limited by the size and solidity of tools, leading to restricted resolution and computational overload, resulting in artifacts and inefficiencies in subtractive and additive manufacturing processes.
Innovation Solution
A method involving sampling a high-definition point set to reduce the number of points, calculating NURBS surfaces from the sampled set, and using a finishing tool to directly follow the original points, allowing for high-resolution machining without interpolation and minimizing computational demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-resolution machining is performed with sufficiently large tools, then manufacturing precision is improved, but device complexity increases due to the need for prior surface interpolation
Solution Approach 1:
The patent applies preliminary action by performing rough machining first to remove the majority of material, then using finishing tools for high-resolution work. This preparatory roughing step simplifies the subsequent finishing process and enables high precision without requiring complex interpolation algorithms for the entire surface.
Solution Approach 2:
The machining process is segmented into distinct stages: rough machining and finishing. Each stage uses appropriately sized tools for its specific purpose, avoiding the need to use large tools for high-resolution work throughout the entire process. This segmentation eliminates the need for complex prior surface interpolation.
2Ease of manufacture
If surface interpolation is performed to enable large tool machining, then ease of manufacture is improved, but manufacturing precision deteriorates due to smoothed surfaces
Solution Approach 1:
The patent segments the machining process into roughing and finishing stages. The roughing stage uses larger tools for ease of manufacture, while the finishing stage uses smaller tools to preserve and achieve high surface resolution. This segmentation allows both ease of manufacture and high precision without requiring surface interpolation that would smooth important details.
3Productivity
If the point cloud is divided into portions for separate surface calculation, then productivity is improved, but manufacturing precision deteriorates due to discontinuities at junctions
Solution Approach 1:
The patent segments the machining process into roughing and finishing operations rather than segmenting the point cloud for separate surface calculations. This approach maintains surface continuity because the finishing operation works on the entire surface using the original point cloud data, eliminating junction discontinuities while still improving productivity through efficient roughing.
4Ease of manufacture
If standard interpolation methods are used to generate surfaces, then ease of manufacture is improved, but manufacturing precision deteriorates due to artifact generation
Solution Approach 1:
The patent extracts and removes the problematic surface interpolation step from the manufacturing process. By using point-cloud-based direct machining methods, it eliminates the source of interpolation artifacts while maintaining ease of manufacture through direct toolpath generation from the original point cloud data.
Data Source
Figure 1
Figure 2
Figure 3~4b
AI summary
The invention relates to a method for processing a point cloud (40) created by measuring a three-dimensional object prior to a machining step in which the movements of a cutting tool (42) comprising a tip are expressed in the form of a tool path (43) along mutually perpendicular axes X, Y and Z within a grid in a plane XY calculated from a point cloud (40) which includes a plurality of points (40a); in said method, the point cloud (40) is standardized to obtain a grid of standardized points (40c) through which the cutting tool (42) has to move, the tool path (43) being generated by sequentially following said grid of points (40c).