Free-Form Tool Path Planning for Coupled Two-Sided Dental Machining
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Solution Overview
Problem
Existing double-spindle dental tool machines with kinematic axis coupling face limitations in generating free-form tool paths that conform to individual target geometries, resulting in reduced choices for simultaneous two-sided machining and potential collisions between tool spindles.
Innovation Solution
A computer-implemented method that determines transformations to convert the kinematic axis coupling into a common parameter for both tool spindles, allowing for the generation of free-form tool paths with identical coupling parameters in time, enabling a variety of tool paths, including arc-shaped and trochoidal paths, while considering calibration and collision avoidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If arc-shaped or circular tool paths are used in double-spindle dental tool machines with kinematic axis coupling, then the mechanical construction is simplified, but the choice of possible tool paths is reduced and free-form surfaces cannot be adequately formed
Solution Approach 1:
The patent introduces dynamic tool path generation where the coupled axis movement is no longer fixed to predetermined arc-shaped or circular paths. Instead, the system dynamically calculates and adjusts tool paths based on the target geometry, allowing free-form surfaces to be formed while maintaining the simplified mechanical construction with kinematic axis coupling.
Solution Approach 2:
The patent changes the parameters of tool path generation by transitioning from fixed geometric paths (arc-shaped or circular) to adaptive free-form paths. The system modifies the movement parameters of the coupled axis to match the specific requirements of each target geometry, thereby increasing versatility without complicating the mechanical structure.
2Device complexity
If the coupled axis movement is determined independently from the target geometry, then the mechanical construction is simplified, but the tool paths cannot precisely match individual target geometries
Solution Approach 1:
The patent implements a feedback mechanism where the target geometry information is fed into the tool path planning system. The system continuously adjusts the coupled axis movement based on the target geometry requirements, ensuring that tool paths precisely match the desired form while maintaining the simplified mechanical construction.
Solution Approach 2:
The patent performs preliminary calculation and planning of tool paths before machining begins. The system pre-determines the optimal movement of the coupled axis based on the target geometry, allowing precise tool path generation without requiring complex real-time mechanical adjustments during machining.
3Productivity
If multiple tool spindles are used for simultaneous two-sided machining, then the machining time is reduced, but the risk of collisions between tool spindles increases
Solution Approach 1:
The patent introduces an intermediary planning system that coordinates the movements of multiple tool spindles. This intermediary software layer calculates and synchronizes the tool paths of all spindles, ensuring they operate simultaneously without colliding, thereby maintaining both high productivity and safety.
Solution Approach 2:
The patent performs preliminary collision detection and path optimization before machining begins. The system pre-calculates the tool paths for all spindles, identifying and resolving potential collision points in advance, which allows simultaneous two-sided machining to proceed safely and efficiently.
Data Source
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Figure 3A~3D
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AI summary
The present invention provides a computer-implemented method of planning of the shapes of free-form tool paths (P) for simultaneous two-sided machining of a dental restoration (1) having an individual free-form target geometry from a workpiece (2) by using a dental tool machine (3) comprising at least two tool spindles each having at least one tool (4) arranged on a different side of the workpiece (2) which is simultaneously movable along an axis (y) relative to the tools (4) and thereby imposing a kinematic axis coupling, characterized by further comprising: a step of determining transformations (T´, T´´) of the target geometry by which the kinematic axis coupling is converted into a common coupling parameter for both tools (4); and a step of generating dependent on these transformations (T´, T´´) the shapes of the free-form tool paths (P) in which the common coupling parameter is identical in time for all participating tool spindles that are driven simultaneously.