Tool Spindle Vibration Absorber for High-Speed CNC Machining
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Solution Overview
Problem
CNC processing machines face challenges in designing tool holders that balance high-speed operation with high process forces, leading to undesirable vibrations due to conflicting requirements, which affect processing quality and increase demands on the machine, particularly with multi-axis linear guides reducing rigidity and allowing vibrations to resonate through the machine frame.
Innovation Solution
A passive vibration damping device is integrated into the processing unit, specifically a rotatable tool spindle, using a vibration absorber with a damping element and auxiliary mass supported by an elastic element, attached directly to the dynamic element or guide arrangement, to dampen vibrations close to their origin, reducing resonance and stress on the machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a tool holder is designed for high-speed operation with small tools, then high rotational speed capability is achieved, but rigidity and ability to absorb high process forces deteriorate
Solution Approach 1:
The tool holder is divided into multiple functional segments: a rigid base structure for absorbing process forces, a flexible intermediate section with vibration damping elements, and a lightweight upper section for high-speed rotation. This segmentation allows each part to optimize for its specific function without compromising the other.
Solution Approach 2:
The tool holder employs composite material construction combining high-strength rigid materials (such as hardened steel) for the force-absorbing sections with lightweight high-stiffness materials (such as carbon fiber reinforced polymers or titanium alloys) for the rotating sections. This composite approach enables simultaneous optimization of rigidity and rotational speed capability.
2Strength
If a tool holder is designed for high process forces with large tools, then rigidity and force absorption capability are improved, but rotational speed capability deteriorates
Solution Approach 1:
The tool holder is divided into multiple functional segments: a rigid base structure for absorbing process forces, a flexible intermediate section with vibration damping elements, and a lightweight upper section for high-speed rotation. This segmentation allows each part to optimize for its specific function without compromising the other.
Solution Approach 2:
The tool holder employs composite material construction combining high-strength rigid materials (such as hardened steel) for the force-absorbing sections with lightweight high-stiffness materials (such as carbon fiber reinforced polymers or titanium alloys) for the rotating sections. This composite approach enables simultaneous optimization of rigidity and rotational speed capability.
3Ease of operation
If multi-axis linear guides are used to suspend the processing unit, then operational flexibility and positioning precision are improved, but rigidity deteriorates allowing vibrations to resonate through the machine frame
Solution Approach 1:
A passive vibration damping device is introduced as an intermediary element between the processing unit and the machine frame. This damping device acts as a mediator that allows the linear guides to provide positioning precision while blocking the transmission of vibrations to the machine frame, preventing resonance amplification.
Solution Approach 2:
The vibration damping device converts the harmful vibrations and resonance into beneficial damping effects. By using materials and structures that dissipate vibrational energy (such as viscoelastic materials or tuned mass dampers), the system transforms the problematic vibration transmission into active vibration suppression, improving overall machine performance.
4Reliability
If active vibration damping systems with sensors and actuators are installed in the tool holder, then vibration compensation capability is improved, but device complexity and acquisition costs increase
Solution Approach 1:
The invention replaces expensive, complex active vibration damping systems with simple, inexpensive passive damping elements that can be easily integrated into the tool holder. These passive elements (such as damping materials or simple mass-spring-damper structures) provide effective vibration reduction without requiring sensors, actuators, or complex control systems, significantly reducing both acquisition costs and system complexity.
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
This solution effectively and cost-efficiently damps vibrations without the need for complex active control systems, reducing manufacturing costs and enhancing processing quality by preventing vibration propagation and resonance, thus improving the overall performance of CNC processing machines.
Implementation Method 1
a damping element (7) which acts on the auxiliary mass (8) or on the dynamic element (3)
Implementation Method 2
a damping element (7) which acts on the auxiliary mass (8) or on the dynamic element (3)
Implementation Method 3
an elastic support element (9), by means of which the auxiliary mass (8) is supported
Implementation Method 4
The auxiliary mass (8) is surrounded by a damping and elastic layer. In order to achieve the required parameters such as stiffness and damping coefficient with a given additional mass and a specific main system, a defined pressure must be exerted on the elastic and damping layer.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a machining device (1), in particular a CNC machining device, for machining preferably planar workpieces (W) that are preferably composed of wood, wood material, plastic, and/or glass at least in parts, comprising: a machining assembly, which has a dynamic element; a first guide assembly, by means of which the machining assembly can be moved in a spatial direction; and at least one vibration-damping device. Vibrations of the dynamic element (3) can be passively damped by means of the at least one vibration damper device.