In the past, a finished or semi-finished workpiece had to be removed from the production line for offline measurement as a quality control step. However, it is time-consuming and sometimes even impossible to position the measured workpiece to exactly the same spot on the machine for further machining. In precision machining, slight displacement of a workpiece on the production line may damage the workpiece and ruin the upcoming process.
In recent years, certain machine tool manufacturers have produced on-line measurement modules to be attached to their machines. Yet, these measurement modules may not be compatible with other machines, and complicated algorithms are involved in deriving measurements from coordinate information of the motion axes of machine tools.
This invention provides a universal solution to the above-mentioned problems. It is a non-contact 3D measurement tool that can conduct live measurement in the production line. This can minimize the time needed for and the error of quality control measurement of semi-finished products.
The patented multisensor 3D measurement system is made up of three components: a sensor module, control box, and computer software. The sensor module combines a motion sensor and laser scanners. The module works independently from the machine tool. It excels in complicated surface scanning without interfacing with the motion control system of the machine tools. The motion sensor detects the locations of the laser scanners to calibrate the scanned results and reconstruct the scanned shape.
As the sensor module is attached right next to the tool, any workpiece within the compatible size range can also be measured. Apart from its large measurement range, the system is also powerful because of its high resolution and precision. For instance, when measuring a workpiece the size of 100 mm (long) x 50 mm (width), the measurement uncertainty is 10 micrometers, that is 1/10 of the average diameter of a human hair.
(1) In-situ 3D measurement portable apparatus on various machine tools, e.g. Computer Numerical Control (CNC) machine tools, 3D printers, etc.
(2) In-process metrology for workpieces not amenable to offline measurement
(3) Robotic arms for production automation
(4) Automatic inspection on production lines
(5) Multi-sensor measurement probes for Coordinate Measurement Machines (CMM)
With further development, it can even communicate with cyber-physical systems wirelessly via Bluetooth to instruct a tooling machine to fix unqualified workpieces without manual intervention. It can then be hooked up wirelessly with cyber-physical systems in an Industry 4.0 factory and communicate with all other machines via cloud servers. By then, the scanned results can be compared with the CAD design data right away, and unqualified workpieces can be re-tooled automatically.
There is still much room for improvement in the existing offline and in-process 3D measurement solutions. Customers can benefit from the innovative multisensory in-situ 3D measurement system because of the system’s portability and precision in quality checking. Additionally, the system is compatible with almost any tooling machine. The technology can eventually benefit the manufacturers by saving the production time and cost.