Milling Insert Indexing with External Rotation and Precise Seating
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Solution Overview
Problem
Milling tools with internal indexing mechanisms for multi-sided indexable cutting inserts face precision issues due to complex geometries and tolerance chains, leading to imprecise fitting and operational inefficiencies, especially when manually indexing polygonal shaped inserts.
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 for precise positioning, enabling automatic and reliable indexing without the need for internal turning mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an internal indexing mechanism with turning means is used to automatically index multi-sided cutting inserts, then the indexing operation is automated and time is saved, but the tolerance chain becomes long and inaccurate, leading to imprecise fitting of the insert into the seat
Solution Approach 1:
The patent extracts the turning function from the internal indexing mechanism and relocates it to an external indexing device. The internal mechanism only performs linear displacement of the insert, while the external device provides the turning motion. This separation eliminates the accumulation of tolerances that would occur if both functions were integrated internally, thereby maintaining high fitting precision while achieving full automation.
Solution Approach 2:
The patent introduces an external indexing device as an intermediary between the internal indexing mechanism and the multi-sided cutting insert. This external device acts as a mediator that receives the linearly displaced insert and performs the turning operation externally, avoiding the complex tolerance chain that would result from integrating turning means internally.
2Ease of manufacture
If a conventional multi-sided or polygonal shaped indexable cutting insert is used with side contact surfaces, then the insert geometry is simple and easy to manufacture, but imprecise turning in the indexing operation causes incorrect fitting and prevents the insert from being pulled back into the seat
Solution Approach 1:
The external indexing device serves as an intermediary that ensures precise turning of the multi-sided insert before it is returned to the seat. This external mechanism provides the necessary rotational accuracy that cannot be achieved through internal mechanisms alone, thereby ensuring reliable seating while maintaining the simplicity of the insert geometry.
Solution Approach 2:
Instead of performing the turning operation internally within the tool body, the patent inverts the approach by performing the turning operation externally. This reversal allows for higher precision in the turning mechanism while keeping the insert geometry simple and the internal mechanism straightforward.
3Measurement precision
If manual indexing operation is performed, then each cutting insert can be individually indexed with human judgment, but the milling tool is taken out of operation and the process is time-consuming
Solution Approach 1:
The patent implements self-service indexing through the combined internal and external indexing mechanisms. The system automatically performs the indexing operation without requiring operator intervention, with the internal mechanism displacing the insert linearly and the external mechanism turning it to the correct position. This automation maintains indexing accuracy while eliminating the need to take the tool out of operation.
Solution Approach 2:
The indexing operation is performed continuously during the machining process without interrupting the milling operation. The internal mechanism displaces the insert while the tool remains in operation, and the external mechanism completes the turning operation, ensuring continuous productive action without downtime.
Data Source
Figure 1a
Figure 1b
Figure 2a~2b
AI summary
The present invention relates to a milling tool (1) comprising an internal indexing mechanism (6) arranged to displace an indexable cutting insert (4) between an inner supported position (S) and an outer indexing position (I), wherein the indexable cutting insert (4) has a multi-sided shape as seen in the direction of an insert centre axis (C2) and side support surfaces (4a, 4b) are included in the sides of the multi-sided indexable cutting insert (4). The internal indexing mechanism (6) is arranged to provide a rectilinear movement (L) along the shaft centre axis (C3), between the inner supported position (S) and the outer indexing position (I), wherein the indexable cutting insert (4) is free to turn in both directions around the insert centre axis (C2) in the outer indexing position (I). The invention also relates to an external indexing device (20) for the milling tool (1), wherein a disc member (22) is configured with an annular geometry (23) arranged to engage one of the side support surfaces (4a, 4b) on the indexable cutting insert (4) and turn the indexable cutting insert (4) around the insert centre axis (C2) toward the next index position. The invention also relates to an indexing system comprising the milling tool (1) and the external indexing device (20).