Volumetric MQL Lubrication for Stable Through-Spindle Flow
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Solution Overview
Problem
Current MQL systems face challenges in delivering a consistent and continuous lubrication flow due to viscosity changes with temperature and high backpressure, especially in through-the-spindle metal-cutting environments, where existing pumps are either impractical or inaccurate at low flow rates and high pressures.
Innovation Solution
A system utilizing a volumetric flow pump with a controller to supply a continuous and constant lubricant flow rate, independent of air supply, and a high modulus of elasticity lubricant supply line to minimize volume changes and entrapped air, ensuring precise and consistent lubrication delivery even under high backpressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a metered volumetric dosing approach is used to ensure consistent fluid delivery, then measurement precision is improved, but device complexity increases and the system cannot deliver fluid at the full range of rates and pressures required in high-pressure through-the-spindle MQL systems
Solution Approach 1:
The patent replaces complex mechanical metering pumps with a simpler positive displacement piston pump actuated by compressed air. The pump uses a piston, cylinder, and check valves to deliver precise volumetric dosing without the complexity of traditional metering mechanisms. The pump chamber volume is precisely controlled mechanically, providing consistent fluid delivery while maintaining simplicity.
Solution Approach 2:
The patent changes the operating parameters of the pump system by using compressed air pressure (up to 10 bar or higher) to drive the piston, enabling the system to deliver fluid at the full range of rates and pressures required in through-the-spindle MQL applications. This parameter change allows the simple pump design to achieve both precision and high-pressure capability.
2Reliability
If positive displacement single piston pumps are used to work reliably at given conditions, then reliability is improved, but the output becomes pulsed rather than continuous, causing inconsistent lubrication
Solution Approach 1:
The patent uses periodic action of compressed air to the piston, which is controlled by a valve that opens and closes several times a second. This periodic actuation creates a high-frequency pulsed output that approximates continuous flow, providing both reliable operation and consistent lubrication delivery.
Solution Approach 2:
The patent achieves continuity of useful action by operating the piston pump at high frequency with compressed air actuation. The rapid reciprocating strokes create a near-continuous fluid delivery that eliminates the inconsistency of low-frequency pulsed output, ensuring stable lubrication throughout the machining operation.
3Productivity
If a valve opens and closes rapidly to control fluid flow rate, then productivity is improved, but measurement precision deteriorates due to sensitivity to viscosity changes and calibration requirements
Solution Approach 1:
The patent makes the system self-service by using compressed air to automatically actuate the piston pump without requiring external electrical controls or complex valve timing mechanisms. The compressed air pressure directly drives the piston through pressure differential, eliminating the need for rapid valve opening/closing and associated calibration issues while maintaining precise volumetric delivery.
4Manufacturing precision
If metering elements are used to control fluid flow, then manufacturing precision is improved, but ease of operation worsens due to manual calibration requirements and sensitivity to fluid property changes
Solution Approach 1:
The positive displacement piston pump is inherently self-regulating and self-calibrating. Each piston stroke delivers a precise volume determined by the pump chamber geometry, eliminating the need for manual calibration. The system automatically compensates for viscosity changes because it is volume-based rather than flow-rate-based, greatly simplifying operation.
Solution Approach 2:
The patent uses inexpensive check valves and simple piston components that can be easily replaced if needed, rather than expensive precision metering elements requiring careful calibration and maintenance. This approach prioritizes operational simplicity and robustness over extreme precision in individual components.
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 system achieves precise and continuous lubrication delivery, reducing errors and maintaining flow rates across a wide range of conditions, including high pressures and varying temperatures, thereby improving the consistency and accuracy of lubrication in MQL systems.
Implementation Method 1
A volumetric flow pump fluidly couples to the lubricant supply line and supplies a supply of lubricant at a lubricant flow rate through the lubricant supply line
Implementation Method 2
a high modulus of elasticity lubricant supply line to minimize volume changes and entrapped air
Implementation Method 3
to atomize the lubricant within the supplied air internally of the tool holder assembly
Data Source
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AI summary
A MQL system (10) for accurately measuring and controlling a volume and pressure of a lubricating fluid provided to a machining tool (88) during minimum quantity lubrication machining operations. The MQL system (10) can further include measuring and controlling a volume and pressure of air provided during machining such that atomization of the lubricating fluid with the air can be controlled. Use of a volumetric continuous flow pump (60) provides a continuous flow of lubricating fluid to the tool (88) during machining operations.