Bidirectional Thread Cutting Without Idle Return Strokes
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Solution Overview
Problem
The existing methods for producing threads on cylindrical, conical, or frustoconical surfaces are time-consuming, particularly due to the need for the cutting tool to make idle movements back to the starting point, which increases machining time and production costs.
Innovation Solution
A method that involves rotating the workpiece in one direction, using a cutting tool with two edges that machined the thread in both directions along the longitudinal axis, reversing the rotation, and positioning the second edge to continue machining without returning to the starting point, thereby eliminating idle movements and optimizing tool usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cutting tool makes idle movements back to the starting point after each pass, then the tool can reposition for the next pass, but the machining time increases significantly
Solution Approach 1:
The patent applies bidirectional threading where the cutting tool machines in both forward and reverse directions along the workpiece. After completing a pass in the forward direction, the tool immediately machines in the reverse direction without returning to the starting point, thereby eliminating idle movements and maintaining continuous useful action throughout the threading process
Solution Approach 2:
The patent utilizes the reverse direction of tool movement, which is traditionally idle time, as productive machining time. By machining in both forward and reverse directions, the patent inverts the conventional unidirectional approach and converts what was previously wasted time into valuable productive action
2Manufacturing precision
If multiple passes are made to achieve the required thread depth, then the thread dimensions can be controlled precisely, but the number of tool changes and repositioning operations increases
Solution Approach 1:
The bidirectional threading process allows multiple passes to be executed with minimal interruption. The tool machines forward, then immediately machines reverse, creating a continuous sequence of productive operations that maintains precision while improving production rhythm by eliminating idle repositioning time between passes
3Manufacturing precision
If the tool remains in contact with the workpiece for extended periods, then machining precision can be maintained, but tool heating and burr formation increase
Solution Approach 1:
The bidirectional threading creates a periodic machining pattern where the tool alternates between forward and reverse directions. This periodic action allows the tool to engage and disengage from the workpiece in a rhythmic manner, providing periodic relief from continuous contact that reduces cumulative heat buildup and burr formation while maintaining machining precision through repeated controlled engagement
Data Source
AI summary
The invention relates to a method of making a thread or tap on a cylindrical, conical or frustoconical piece to be machined.According to the invention, this method comprises the steps of:a) driving in rotation the piece to be machined in one direction),b) carrying out a relative displacement of a first cutting edge of a tool relative to the piece to be machined until this first cutting edge is flush with the surface to be threaded of the workpiece at the beginning of the section to be threaded,c) carrying out a relative displacement of the tool relative to the piece to be machined so that the first cutting edge machines the piece to be machined,d) carrying out a relative displacement of the tool along the longitudinal axis of the piece to be machined, in one direction until the end of the section to be threaded,e) moving away, by a relative displacement, the first cutting edge of the tool from the piece to be machined,and it has the particularity of further comprising the steps of:f) reversing the rotation of the piece to be machined to drive this piece in rotation in the direction opposite to the direction, while positioning or not the second cutting edge,g) moving, by relative displacement, a second cutting edge towards the piece to be machined until this second cutting edge penetrates the thread pitch,h) carrying out a relative displacement of the second cutting edge relative to the workpiece so that it continues the machining of the thread in the piece to be machined,i) carrying out a relative displacement of the second cutting edge in a direction opposite to the direction, until the beginning of the section to be threaded,j) moving, by a relative displacement, the second cutting edge away from the workpiece to be machined,k) reversing the rotation of the piece to be machined, while positioning or not the first cutting edge thenl) repeating steps b) to k), while continuing the machining of the thread, until the thread reaches its final dimensions, while positioning the first cutting edge in step b) in such a way that it penetrates the thread pitch already machined.