Method and apparatus for monitoring thermal processing of a workpiece in accordance with a measured capacitance frequency distribution
US5694046A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 27, 1995 |
| Grant date | Dec 2, 1997 |
| Priority date | — |
| Expiry date | Nov 27, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K26/125
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method and apparatus for monitoring thermal processing of a workpiece using a sensor electrode which can be positioned relative to the workpiece and to which an alternating electric signal is applied in order to determine a measured capacitance (C.sub.meas) present between the sensor electrode and workpiece by evaluating a change in the alternating signal as a consequence of the measured capacitance (C.sub.meas). A measured capacitance frequency distribution is formed from a number of determined measured capacitances (C.sub.meas). The measured distribution is compared with a reference distribution. If a deviation is present between the two distributions, process parameters can be appropriately readjusted. It is preferable to use a laser beam for processing the workpiece.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.