Bidirectional Threading Method for Workpiece Machining
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Solution Overview
Problem
Traditional threading processes in turning parts are time-consuming, representing a significant portion of machining time, and are not efficiently optimized with the dynamics of modern motor spindles, especially due to the need for tool repositioning and empty return movements.
Innovation Solution
A method that involves rotating a workpiece in one direction, using a first cutting edge to machine a thread, reversing the rotation, and then using a second cutting edge to continue machining in the opposite direction, eliminating the need for tool repositioning and reducing the time required for threading by machining along both directions of translation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional threading method with single-direction machining is used, then the threading process is simple to implement, but the production time is excessive and productivity is low
Solution Approach 1:
The workpiece rotation direction is periodically reversed during the threading process. The method machines the thread in the forward direction, then reverses rotation to machine in the opposite direction, creating a periodic action pattern that eliminates idle return movements and continuously utilizes the cutting tool for productive machining.
Solution Approach 2:
By reversing the workpiece rotation and continuing to machine in the opposite direction, the cutting tool performs useful machining action during what would traditionally be idle return movements. This continuity eliminates non-productive time and maximizes the utilization of the cutting edge throughout the entire threading cycle.
2Ease of manufacture
If traditional single-direction threading is used, then the tool setup is simple, but the tool undergoes excessive heating and wear
Solution Approach 1:
The periodic reversal of workpiece rotation alternates the direction of cutting forces and heat generation. This prevents continuous unidirectional heating of the tool and distributes thermal load more evenly, reducing overall tool temperature and extending tool life.
Solution Approach 2:
The method inverts the traditional approach by machining in both forward and reverse directions rather than only forward. This inversion allows the tool to cut in opposite directions, distributing heat generation and reducing cumulative thermal buildup in the tool.
3Ease of operation
If traditional threading with repeated tool repositioning is used, then the machining process is straightforward, but burr formation and chip accumulation increase
Solution Approach 1:
The continuous machining action in both directions prevents the tool from stopping and repositioning repeatedly. This continuity reduces interruptions that cause burr formation and minimizes chip accumulation by maintaining constant material removal without idle periods where chips can build up.
Solution Approach 2:
By machining in the reverse direction after forward machining, the method effectively removes material from both directions of the thread. This bidirectional approach prevents burr formation that occurs with single-direction machining and facilitates continuous chip evacuation without accumulation.
Data Source
Figure 1
Figure 2a~5
Figure 6~7
AI summary
The invention relates to a method for creating a thread or tap on a cylindrical, conical or frustoconical workpiece. According to the invention, this method comprises the steps of: a) rotating the workpiece (P) in direction (A), b) moving a first cutting edge (6) of a tool (5, 11, 20, 29, 32) relative to the workpiece (P) until this first cutting edge (6) is flush with the surface to be threaded on the workpiece (P) at the beginning (7) of the threading section, c) moving the tool (5, 11, 20, 29, 32) relative to the workpiece (P) so that the first cutting edge machines the workpiece (P), d) moving the tool (5, 11, 20, 29, 32) along the longitudinal axis of the workpiece (P) in direction (L) to the end (8) of the threading section, e) moving away relative to the first cutting edge (6) of the tool (5,11,20,29,32) of the workpiece (P), and it is particular in that it further comprises the steps of: f) reversing the rotation of the workpiece (P) to rotate it in the direction (B) opposite to the direction (A), while positioning or not the second cutting edge (9), g) bringing a second cutting edge (9) towards the workpiece (P) by relative displacement until this second cutting edge (9) enters the thread pitch, h) making a relative displacement of the second cutting edge with respect to the workpiece so that it continues machining the thread in the workpiece, i) making a relative displacement of the second cutting edge (9) in a direction (M) opposite to the direction (L), until the beginning of the section (8) to be threaded, j) moving the second cutting edge (9) away from the workpiece (P) by relative displacement, k) reversing the rotation of the workpiece to machine (P),while positioning or not the first cutting edge (6) then l) repeat steps b) to k) continuing the machining of the thread, until the thread reaches its final dimensions, positioning in step b) the first cutting edge in such a way that it enters the pitch of the thread already machined.