Threaded Hole Tapping With Radial Offset to Reduce Tool Load
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Solution Overview
Problem
The existing single-shot tapping process results in high tool load and reduced tool life due to simultaneous production of the pilot hole and internal thread, leading to increased process time and potential tool failure.
Innovation Solution
The method involves separating the pilot hole drilling and internal thread production into distinct strokes, with the pilot hole drilled during the drilling stroke and the internal thread generated in a subsequent independent tapping stroke, allowing for a reversing and offset motion to reduce tool load and synchronize speeds effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pilot hole and internal thread are produced simultaneously in a single-shot tapping process, then the process time is reduced, but the tool load increases and tool life is reduced
Solution Approach 1:
The patent divides the single-shot tapping process into two separate strokes: a drilling stroke for creating the pilot hole and a tapping stroke for generating the internal thread. This segmentation allows each operation to be performed independently with optimized parameters, reducing the peak tool load while maintaining overall process efficiency.
2Productivity
If the internal thread is generated during the reversing stroke, then the process time is reduced, but the tapping tool is subjected to tensile force reducing load capacity
Solution Approach 1:
The patent introduces an offset stroke before the tapping stroke where the tapping tool is radially displaced outward to position the thread generating section correctly. This preliminary action ensures that the tapping teeth engage the workpiece in compression during the tapping stroke, avoiding tensile forces that would reduce tool load capacity.
3Reliability
If the tapping tool is guided completely out of the pilot hole in the reversing stroke, then the tool load is reduced, but the speed adjustment time increases
Solution Approach 1:
The patent employs dynamic speed control where the tapping tool rotates at drilling speed during the drilling stroke, then transitions to tapping speed during the offset and tapping strokes. The circular path motion during the offset stroke allows smooth acceleration and deceleration phases, minimizing speed adjustment time while ensuring the tool is properly positioned and loaded before thread generation begins.
Data Source
AI summary
A method for producing a workpiece threaded hole by a tapping tool, with a drilling stroke, in which the rotating tapping tool is driven into the workpiece in a drilling direction to a nominal drilling depth, and so forming a thread-free pilot hole, and with a tap-ping stroke in which the tapping tool produces an internal thread in the pilot hole with a tapping feed rate and a tapping speed synchronized therewith. The drilling stroke is followed by a reversing stroke in which the tapping tool is guided out of the pilot hole in a reversing direction opposite to the drilling direction. The tapping tool is then radially displaced by a radial offset in an offset stroke. Then, in the tapping stroke, the radially controlled, rotating tapping tool is guided in a circular rotary motion along a circular path around the hole axis.