Gear Machining with Milling and Skiving for Precision
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Solution Overview
Problem
Conventional gear machining methods, such as milling and skiving, face challenges in achieving precise surface geometry and efficient material removal, particularly in producing complex gear geometries like worm gears, which often require specialized and costly machines.
Innovation Solution
A method combining milling and skiving processes on the same gear cutting machine, allowing for sequential or simultaneous use of milling and skiving tools with adjustable axis angles, to produce gear geometries with reduced cycle time and tool changes, thereby enhancing material removal efficiency and surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If milling process is used for gear machining, then high material removal rate is achieved, but surface geometry precision deteriorates with relatively high tolerances
Solution Approach 1:
The gear machining process is segmented into two distinct stages: roughing by milling and finishing by skiving. The milling process removes the majority of material to achieve high productivity, while the subsequent skiving process corrects surface geometry deviations and achieves precise tolerances. This segmentation allows each process to optimize for its specific function without compromise.
Solution Approach 2:
The milling process performs preliminary action by removing the bulk of material and creating a near-final gear geometry. This preliminary roughing establishes the basic tooth form and removes excess material, preparing the workpiece for the precision finishing stage. The preliminary action enables the subsequent skiving process to focus solely on achieving surface precision rather than removing large amounts of material.
2Productivity
If milling process is used for gear machining, then high material removal is achieved, but lead and overrun distances must be large
Solution Approach 1:
The machining process is divided into milling for bulk material removal and skiving for final tooth formation. The skiving process requires significantly shorter lead and overrun distances compared to milling, as it uses a rolling scraping movement rather than the feed motion required by milling. This segmentation allows the overall process to achieve high material removal while minimizing the critical lead and overrun distance requirements.
Solution Approach 2:
The process transitions from milling parameters (with large lead and overrun requirements) to skiving parameters (with minimal lead and overrun requirements). By changing the machining method for the finishing stage, the critical dimensional parameters of lead and overrun distances are significantly reduced while maintaining high overall material removal efficiency.
3Length of moving object
If skiving process is used for gear machining, then lead and overrun distances are reduced, but tool wear increases significantly
Solution Approach 1:
The process segments the workload between milling and skiving. Milling handles the heavy material removal with its robust cutting edges, while skiving performs light finishing work that generates minimal tool wear. This segmentation ensures that skiving operates in a low-wear regime, extending tool life despite the inherent scraping mechanism.
Solution Approach 2:
The skiving process performs only partial action, removing just the necessary allowance left by milling rather than attempting to remove all material. This limited, controlled material removal minimizes the mechanical stress and friction on the skiving tool, thereby reducing wear and extending tool life while still achieving the desired precision.
4Loss of time
If milling and skiving are carried out by the same gear cutting machine with same workpiece clamping, then cycle time is reduced, but device complexity increases
Solution Approach 1:
The gear cutting machine is designed with multi-functionality to perform both milling and skiving operations. The machine tool holder can accommodate different tool types (milling cutters and skiving tools), and the control system can execute both machining processes. This universality eliminates the need for separate dedicated machines, reducing cycle time by avoiding workpiece re-clamping and machine changeovers, while the added complexity is managed through integrated design.
Solution Approach 2:
The milling and skiving functions are merged into a single gear cutting machine platform. The workpiece clamping system, positioning mechanisms, and control architecture are combined to support both processes. This merging consolidates what would otherwise require separate machines and setup procedures into one integrated system, significantly reducing total cycle time despite the increased operational versatility.
Data Source
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AI summary
The present invention relates to a method for gear machining of a workpiece, in which the workpiece is milled to produce a gear geometry, wherein the workpiece is additionally gear-machined by skiving in addition to milling.