Articulating Head Linear Movement Assembly for Milling Precision
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Solution Overview
Problem
Current articulating heads in computer-controlled milling machines suffer from lack of precision due to instability and free play in their actuating devices, leading to inaccuracies during part machining.
Innovation Solution
An articulating head with a linear movement assembly utilizing a precision ball screw and ball nut mechanism, driven by a servo motor, which provides precise rotation by converting linear motion into rotational motion, thereby enhancing stability and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a servo motor driven worm and ring gear is used as an actuating device, then the articulating head can rotate, but instability and free play develop during machining leading to loss of precision
Solution Approach 1:
The patent replaces the traditional worm and ring gear mechanical system with a linear movement assembly comprising a ball screw and ball nut mechanism. This substitution eliminates the inherent free play and instability of the worm gear system while maintaining the rotational function, thereby improving both reliability and manufacturing precision simultaneously
Solution Approach 2:
The invention changes the fundamental operating parameter of the actuating device from rotational gear engagement to linear ball screw movement. This parameter change transforms the mechanism from one prone to backlash and instability to one providing precise, stable, and repeatable motion control throughout the machining process
2Device complexity
If a traditional worm and ring gear actuating device is used, then the structure is simple, but lash or free play develops leading to tool inaccuracy
Solution Approach 1:
The patent substitutes the simple but flawed worm and ring gear system with a ball screw and ball nut mechanism. Although the ball screw system is slightly more complex in construction, it eliminates the problematic lash and free play, achieving superior tool position accuracy that far outweighs the minor increase in structural complexity
3Ease of operation
If a servo motor driven worm and ring gear is used, then rotation of the articulating head is achieved, but repeatability of rotation is poor under machining stress
Solution Approach 1:
The invention replaces the worm and ring gear system with a ball screw mechanism that maintains excellent repeatability under load. The ball screw's precision threading and ball recirculation mechanism ensure consistent, repeatable rotation of the articulating head even during high-stress machining operations, eliminating the repeatability problems of the gear system
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves improved precision and repeatability in the rotation of the articulating head, addressing the instability issues of existing actuating devices and enabling more accurate machining of complex parts.
Implementation Method 1
The linear movement assembly comprises a threaded rod mounted as a screw, a ball nut which threads onto the screw
Implementation Method 2
a ball nut which threads onto the screw and has a ball bearing that allows linear movement of the ball nut along the threaded rod
Data Source
AI summary
An articulating head that includes a linear movement assembly. There is a pivot plate that includes a first connection point. There is a pivot arm rotatably attached to the pivot plate. The pivot arm has a second connection point. There is a linear movement assembly mounted to and between the first connection point of the pivot plate and the second connection point of the pivot arm to cause rotation of the pivot arm about the pivot plate. The linear movement assembly comprises a threaded rod mounted as a screw, a nut which threads onto the screw and a motor interconnected to one of the screw and nut to cause motion between the screw and the nut. The screw and the nut are mounted between the pivot plate and the pivot arm, whereby the motion induced between the screw and nut causes the pivot arm to rotate about the pivot plate.