Dental Workpiece Bridge Placement for Undercut-Free Machining
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Solution Overview
Problem
In dental manufacturing, the placement of connecting webs often results in undercuts, making it difficult or impossible for machining tools to access certain areas, leading to increased material consumption, tool wear, and higher production costs due to the need for larger release areas and specialized tools.
Innovation Solution
The method involves determining a position for the transition point on the workpiece contour such that it is visible in a line of sight parallel to the machining axis, allowing the digital connecting bridge to be placed at a maximum distance from the central longitudinal axis, preventing undercuts and enabling all areas to be reached by the machining tool, thus reducing the size of the required release area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If connecting webs are placed at or near the edge of the cap (largest circumference), then the denture remains connected to the blank, but undercuts are created that make machining difficult or impossible
Solution Approach 1:
The patent applies preliminary action by determining the optimal position for the transition point before placing the connecting web. The method calculates the line of sight parallel to the machining axis and identifies positions where the transition point is visible from both top and bottom, preventing undercut formation before machining occurs. This advance planning ensures both connection strength and machining accessibility are optimized.
Solution Approach 2:
The patent changes the positional parameter of the transition point from conventional locations (edge or largest cross-section) to optimized locations determined by line-of-sight calculations. By varying the position parameter based on visibility requirements from top and bottom, the method achieves both strong connection and undercut-free surfaces that are accessible to machining tools.
2Ease of operation
If a larger release area is provided to access undercut areas, then machining tools can reach more areas, but material consumption and construction costs increase
Solution Approach 1:
The method performs preliminary determination of the transition point position based on line-of-sight visibility before machining begins. By pre-calculating positions where the transition point is visible from both top and bottom, the method eliminates the need for enlarged release areas, maintaining standard machining parameters and reducing material consumption.
Solution Approach 2:
The patent converts the potential harm of restricted machining access into a benefit by using the line-of-sight constraint to optimally position the transition point. This approach transforms what could be a limiting factor into a design criterion that simultaneously ensures machining accessibility and prevents undercut formation, eliminating the need for material-intensive solutions.
3Ease of operation
If sharply inclined machining tools are used to reach undercut areas, then access to difficult areas is improved, but tool wear increases and tools must be exchanged more often
Solution Approach 1:
The method pre-determines the transition point position based on line-of-sight visibility requirements before machining starts. By ensuring the transition point is visible from both top and bottom, the method guarantees that standard machining tools with normal inclination angles can access all necessary areas, eliminating the need for sharply inclined tools and thereby reducing tool wear and increasing tool durability.
4Adaptability or versatility
If the blank is rotated to machine different areas, then more surfaces can be accessed, but partial areas remain unreachable due to tool position constraints
Solution Approach 1:
The patent applies preliminary action by determining the transition point position based on line-of-sight visibility from both top and bottom before any machining operations. This advance calculation ensures that all workpiece surfaces are accessible to the machining tool in its standard position, eliminating the need for complex blank rotations and ensuring complete surface coverage with simplified operations.
Data Source
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AI summary
Method for producing a dental workpiece (1) from a blank (2) having a top (O) and a bottom (U), comprising the steps of defining at least one reference point of a digital blank contour (R) of the blank (2), defining a digital workpiece contour (W) of the at least one dental workpiece (1), placing the digital workpiece contour (W) relative to the reference point, in particular in the digital blank contour (R), exposing a clearance area (F) around the digital workpiece contour (W), and placing at least one digital connecting bridge (V) in the clearance area (F), wherein the at least one connecting bridge (V) is connected to the digital workpiece contour (W) via a transition point (Ü), comprising the further step of determining a position (P) on the digital workpiece contour (W) for the transition point (Ü).so that in a graphical representation the transition point (Ü) is visible in a line of sight (S) aligned parallel to a machining axis (Z) of a machining device (3) from the top (O) and from the bottom (U), wherein the placement of the at least one digital connecting bridge (V) depending on the determined position (P) is carried out such that the digital connecting bridge (V) is connected to the digital workpiece contour (W) at the determined position (P).