Bridge Milling Head Tilt Compensation Using MEMS Inclinometers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Numerical-control bridge milling machines face limitations in precision due to thermal expansions of metal components, especially in large-sized machines where errors in determining the absolute position of the tool exceed 0.1 mm, affecting machining accuracy.
Innovation Solution
Incorporation of MEMS inclinometer sensors to measure and correct the spatial orientation of the tool-holder head, allowing real-time compensation for thermal deformations and maintaining precise tool positioning and orientation during machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If large-sized bridge milling machines are used to machine large pieces, then the machining capacity and versatility are improved, but the precision deteriorates due to thermal expansions of the crossbeam and other large-sized pieces
Solution Approach 1:
The patent changes the physical state of the supporting structure by applying active deforming forces to counteract thermal expansions. Sensors detect thermal deformation parameters and the control system adjusts the structure's shape parameters in real-time to maintain positioning precision despite the large size of the machine
Solution Approach 2:
The patent implements a feedback control system where sensors continuously monitor the position and thermal state of the supporting structure, and the control system adjusts the deforming forces accordingly to compensate for thermal expansions and maintain machining precision in large-sized machines
2Manufacturing precision
If thermal stabilization systems are added to limit thermal expansions, then the positioning precision is improved, but the device complexity increases
Solution Approach 1:
The patent replaces traditional passive thermal stabilization systems (cooling channels, thermal barriers) with an active mechanical deforming system controlled by sensors and actuators. This substitution allows for more precise compensation of thermal effects while providing better control and adaptability
Solution Approach 2:
The patent introduces sensors and a control system as intermediaries between the thermal environment and the supporting structure. These intermediaries detect thermal changes and mediate the compensation process by applying controlled deforming forces to counteract thermal expansions
3Manufacturing precision
If complex cooling systems are used to counteract thermal expansions, then the machining precision is improved, but the manufacturing cost increases
Solution Approach 1:
The patent extracts the essential function of thermal compensation from complex cooling systems and implements it through a simpler sensor-based active deforming system. This removes the need for elaborate cooling infrastructure while achieving the same precision goal
Solution Approach 2:
The patent enables the machine tool to self-correct thermal deformations through integrated sensors and control systems that automatically detect and compensate for thermal expansions during operation, eliminating the need for external cooling systems and reducing manufacturing costs
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
Enhances machining precision by minimizing errors caused by thermal expansions, enabling accurate machining even in large machines, and potentially reducing the need for complex cooling systems, thereby lowering costs.
Implementation Method 1
one or more MEMS inclinometer sensors, placed on the distal end of the head-holder beam, close to the spindle-holder plate, and adapted to measure the tilt of the spindle-holder plate relative to an immobile reference inertial plane
Implementation Method 2
The electronic control device is electronically connected to the MEMS inclinometer sensors, so as to detect errors in the spatial position and/or orientation of the tool-holder head, and to command, during the machining of the piece, the moving members of the movable supporting structure so as to compensate for the detected errors in the spatial position and/or orientation of the tool-holder head
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A numerical-control machine tool (1) comprising: a tool-holder head (30) which is provided with a tool-holder spindle (20) and is capable of rotating/tilting said tool- holder spindle (20) about two different rotation axes (C, D) inclined to one another; a movable supporting structure (2, 3, 6, 10, 14, 101, 104, 107) that supports the tool- holder head (30) and is provided with moving members (7, 11, 15) adapted to move the tool-holder head (30) in the space around the piece to be machined, during the machining of the piece; one or more inclinometer microsensors (22) that are located on the movable supporting structure (2, 3, 6, 10, 14; 101, 104, 107) of the machine, next to said tool-holder head (30), and are adapted to measure/determine the tilt of the element on which the same sensors are mounted, relative to a reference inertial plane immobile in the space; and an electronic control device (21) that commands the various moving members of the movable supporting structure and of the tool-holder head (7, 11, 15, 17), is electronically connected to said one or more inclinometer microsensors (22) and is adapted to control, during the machine of the piece, the different moving members of the movable supporting structure and of the tool-holder head (7, 11, 15, 17) based on the signals arriving from said inclinometer microsensor/s (22), so as to correct the spatial position and/or the orientation of the tool-holder spindle (20) based on the signals arriving from said one or more inclinometer microsensors (22).