Milling Insert Indexing Mechanism for Precise Automatic Repositioning
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Solution Overview
Problem
Existing milling tools with internal indexing mechanisms face challenges in precisely and reliably indexing multi-sided indexable cutting inserts due to tolerance chain inaccuracies, leading to imprecise fitting and operational inefficiencies, especially when using polygonal shaped inserts with flat side contact surfaces.
Innovation Solution
A milling tool with an internal indexing mechanism that provides rectilinear movement and allows the multi-sided indexable cutting insert to freely turn in both directions, combined with an external indexing device using a central punch and annular geometry to ensure precise positioning, enabling automatic and reliable indexing without manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an internal indexing mechanism with turning means is used to transform rectilinear motion into simultaneous turning of the indexable cutting insert, then the indexing operation can be automated, but the tolerance chain becomes long and inaccurate, involving the risk of imprecise fitting of the insert into the seat
Solution Approach 1:
The indexing operation is divided into two separate stages: first, the rectilinear movement that pushes the insert out of contact with the side contact surfaces, and second, the rotational movement that turns the insert to the next index position. This segmentation allows each movement to be optimized independently, reducing the cumulative tolerance errors that would occur in a combined single-stage mechanism.
Solution Approach 2:
The mechanism separates the linear displacement function from the rotational indexing function by introducing a cam surface that converts the linear push into rotational motion at a different spatial dimension. The cam surface profile is designed to provide the precise rotational movement after the insert has been fully displaced axially, thereby eliminating the tolerance chain accumulation that would occur in a direct coupled turning mechanism.
2Manufacturing precision
If a complex geometry seat is provided for the indexable cutting insert to achieve precise turning, then the indexing precision is improved, but the device complexity increases
Solution Approach 1:
A cam surface with a curved profile is used to transform the rectilinear motion into rotational motion. The cam surface geometry is designed to provide the precise angular displacement needed for indexing while maintaining a relatively simple overall seat structure. The curvature of the cam surface naturally guides the insert through the indexing rotation without requiring complex multi-faceted seat geometries.
Solution Approach 2:
The cam surface acts as an intermediary element between the pushing mechanism and the insert. Instead of directly coupling the linear push to rotational indexing, the cam surface mediates the motion transformation, allowing precise indexing to be achieved through a simple curved surface rather than a complex multi-dimensional seat geometry.
3Ease of manufacture
If manual indexing operation is performed by detaching and remounting each indexable cutting insert, then the indexing can be done with simple tools, but the operation is time-consuming and the milling tool is taken out of operation
Solution Approach 1:
The indexing mechanism is designed to be actuated by the milling machine itself during operation. The cam surface is engaged by the machine's existing motion mechanisms, allowing the insert to be automatically indexed without requiring external manual intervention or specialized indexing tools. The system uses the machine's own operational movements to perform the indexing function.
Solution Approach 2:
The indexing operation is integrated into the continuous operation of the milling machine. The insert can be indexed automatically during idle periods or between cutting operations without requiring the tool to be removed from the machine. This maintains continuous productivity by eliminating the downtime associated with manual indexing and tool removal.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables precise and reliable indexing of multi-sided indexable cutting inserts, improving machining efficiency by allowing continuous operation and reducing manual labor, while ensuring accurate alignment and retraction of cutting inserts during the indexing process.
Implementation Method 1
wherein the shaft member is forced toward the inner supported position by a compression spring
Data Source
AI summary
A milling tool includes an internal indexing mechanism arranged to displace an indexable cutting insert between an inner supported position and an outer indexing position. The indexable cutting insert has a multi-sided shape as seen in the direction of an insert centre axis and side support surfaces are included in the sides of the multi-sided indexable cutting insert. The internal indexing mechanism is arranged to provide a rectilinear movement along the shaft centre axis, between the inner supported position and the outer indexing position, wherein the indexable cutting insert is free to turn in both directions around the insert centre axis in the outer indexing position. An external indexing device for the milling tool and an indexing system is also provided. A disc member is configured with an annular geometry arranged to engage one of the side support surfaces and turn the indexable cutting insert toward the next index position.