Machine Tool Cooling Nozzle Pressure Feedback Control
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Solution Overview
Problem
Machine tools experience frequent stoppages due to tool wear, breakage, and clogging with swarf, despite the use of cooling devices, which limits tool lifetime and increases downtime.
Innovation Solution
A method for controlling a cooling device for cutting tools, involving a pump, drive motor, and nozzle, where the fluid flow rate is maintained at a constant setpoint, and the motor adjusts based on measured pressure to ensure adequate impact force for swarf separation, reducing tool wear and clogging by maintaining optimal fluid pressure and flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cooling device is used to spray and lubricate cutting tools, then tool wear is limited and the risk of breakage is reduced, but machine tools continue to be stopped due to tool wear, breakage, or clogging with swarf
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the fluid flow rate through the nozzle based on measured impact force. The system modifies the flow rate parameter in real-time to maintain optimal swarf removal conditions, preventing clogging and reducing stoppages while extending tool life.
Solution Approach 2:
The patent implements feedback control by measuring the impact force of the cooling fluid on swarf and using this measurement to adjust the pump flow rate. The measured parameter is fed back to the control system, which automatically modifies the fluid delivery to maintain effective swarf separation and prevent tool clogging.
2Productivity
If the fluid flow rate is increased to improve swarf removal, then swarf separation improves and tool clogging reduces, but the constant flow rate may not account for pressure variations affecting impact force
Solution Approach 1:
The system measures the actual impact force produced by the cooling fluid and uses this feedback to adjust the flow rate. This ensures that despite pressure variations in the system, the impact force remains consistent and effective for swarf removal, resolving the contradiction between maintaining high productivity and ensuring reliable impact force.
Solution Approach 2:
The patent transitions from a static constant flow rate system to a dynamic system that continuously adjusts the flow rate based on measured impact force. This dynamic adaptation allows the system to maintain optimal swarf removal efficiency while compensating for pressure variations, thereby ensuring consistent impact force.
3Stability of the object's composition
If the pump is controlled to maintain constant flow rate, then transient phenomena are avoided and control stability improves, but pressure drops may occur that reduce impact force on swarf
Solution Approach 1:
The system uses feedback control to monitor the actual impact force and adjust the flow rate accordingly. When pressure drops reduce the impact force below the desired threshold, the system automatically increases the flow rate to compensate, maintaining effective swarf separation while preserving flow rate stability through controlled adjustment.
Solution Approach 2:
The patent dynamically changes the flow rate parameter in response to measured impact force variations. By adjusting the flow rate within controlled parameters, the system maintains stable operation while compensating for pressure drops, ensuring consistent impact force on swarf without introducing harmful transient phenomena.
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 method reduces the mean length of swarf, minimizing tool clogging and wear, thereby decreasing machine tool stoppages and extending tool lifetime by effectively managing swarf separation and impact force.
Implementation Method 1
a pump connected to the supply; a drive motor for driving the pump; at least one machining fluid transfer duct connecting the pump to an input of the nozzle
Implementation Method 2
measuring a parameter P representative of a fluid outlet pressure from the nozzle; The nozzle feed pressure parameter is important since it determines the impact force at the outlet from the nozzle and consequently encourages separation of swarf from the part being machined
Implementation Method 3
By delivering a stream of machining fluid into the region where the tool comes into contact with the part being machined, it is possible to reduce friction and to cause the heat that is produced to be dissipated in the stream of cooling fluid
Data Source
AI summary
A method of controlling a cooling device for cooling a cutting tool in a machine tool. The method comprising the steps of:controlling the motor to drive the pump in such a manner that the pump feeds the nozzle with machining fluid at a constant flow rate D1 that is equal to a first flow rate setpoint;measuring a parameter P representative of a fluid outlet pressure from the nozzle; andcomparing an estimated outlet pressure Pestim as estimated from the parameter P with a first predetermined pressure threshold Ps1, and controlling the motor so as to increase the fluid flow rate D1 as delivered by the pump if the estimated output pressure drops below the first pressure threshold Ps1.