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Up Topic Welding Industry / Technical Discussions / Welding process monitoring and control
- By Grahovac Date 04-13-2001 18:40
Our national R&D laboratory needs your professional opinion.

Is there a technical need for the new technology described below?

It is suitcase-sized but could be miniaturized to hand-held or embedded.

Sincerely,

Paul Grahovac, Senior Account Executive
Technology Transfer and Commercialization
Idaho National Engineering and Environmental Laboratory (INEEL)
Bechtel BWXT Idaho, LLC (BBWI)
P. O. Box 1625
2525 North Fremont Avenue
Idaho Falls, ID 83415-3805
Telephone: (208) 526-3488
Fax: (208) 526-0876
E-mail: pg2@inel.gov
Web site: http://www.inel.gov


Commerce Business Daily

A- Welding process monitoring and control. This is a potential technology development and licensing opportunity with Lockheed Martin Idaho Technologies Company (LMITCO), the prime operating contractor for the Department of Energy at the Idaho National Engineering and Environmental Laboratory (INEEL).

The Portable Diagnostic System (PDS) is a rugged, highly functional monitoring system designed to acquire input analog and digital data simultaneously, as well as provide output signals that can be used for process control. The PDS has been reduced to practice in arc welding applications where data are input from voltage, current, and wire feed speed sensors in a multiple torch gas metal arc welding process.

The PDS acquisition hardware has also been modified to acquire and monitor current data during the gas tungsten arc welding process. The acquired sensor data can be stored for post-acquisition viewing as well as analysis. Using acquired welding data, which is communicated to the operator through a user interface, the PDS enhances the welding process by providing 1) the welding engineer or machine operator with real-time graphical data output, 2) plant floor troubleshooting hardware for problem diagnosis (i.e., variability in wire feed speed, power supply component failure, etc.) and 3) determination of welding performance on a per torch or per input parameter basis.

The PDS hardware and software system design provides the user with variable bandwidth, multiple torch as well as multiple parameter data acquisition capabilities, and the ability to expand the number of data inputs as additional analog and digital inputs are available to monitor other welding parameters (i.e., travel speed, gas flow, bar code scanned part identification, etc.) as well as other parameters related to the manufacturing process.

In many industrial welding applications, the weld procedure developed for a particular application is not followed or is not based on sound welding practices. The weld parameters are routinely adjusted to "refine" the process according to the weld operator's preference and the parameters as well as the welding procedure are often modified on the fly in the attempt to correct problems that result in poor weld quality and weld defects manifested as rejected parts.

The source of the welding problem may be related to maintenance procedures (e.g., worn contact tip, dirty gas cup, poor grounding), problems with weld fixtures (e.g., misalignment, fixture cleaning, poor fixture maintenance allowing for part misalignment), problems related to the welding robot (e.g., reprogramming of welding robots without consideration of the effects on weld parameters), automation fallibility (e.g., poor fit-up), procurement of low quality consumables such as weld wire, or the degradation of the welding equipment itself (e.g., wire feeder, power supply, etc) due to internal component failure or poor maintenance practices. With the cause of the defect often unknown, the weld parameters are often adjusted until the problem "goes away."

This practice does not necessarily correct the problem. Instead, as this process of "correction" proceeds, the weld process may eventually drift so far out of the parameter space established by the initially established weld procedure that weld defects become difficult to diagnose and eliminate resulting in higher defect rates than one would encounter maintaining the process using sound welding practice.

Diagnostic tools to monitor the welding process and to assist the weld engineer maintain the welding process in the desired parameter space are needed in high product volume, defect prone, safety critical applications. The solution to the problem of controlling weld defect rates is to provide the weld engineer/operator real-time monitoring of the weld process as well as output signals to modify the welding process. The real-time monitoring allows the weld operator to identify and eliminate problems in the welding process before they get out of control.

The system can monitor multiple torches simultaneously. In addition, the system provides the functionality of monitoring sensor input from all three sensors (current, voltage, and wirefeed speed), or the user can select to monitor any combination of the sensor inputs from multiple torches.

The monitoring system has been developed to provide the user with many additional channels of both analog and digital input. This provides an adequate number of analog or digital inputs to expand the system beyond the monitoring function. This facilitates incorporation of the PDS into a control system in a manufacturing process where additional process inputs besides welding parameters will be required.

The system also provides the user with tunable bandwidth to provide the user with the ability to acquire data at up to a 100KHz if the welding event of interest requires a high sampling rate to diagnose that welding process.

The PDS also has the capability of generating output signals that can be used in process control applications. Using the current data acquisition hardware, 8 digital lines are available for data output. Output data could be used to alarm an audible or visual device, issue commands to a robot, adjust a power supply parameter, control a paint spraying process, update a master control system about weld station status, etc.

An additional feature of the PDS is its user-friendly interface. The system is Windows based and the monitoring code was developed in LabView--providing the user with a familiar operating system. In addition, if the user of an INEEL-developed PDS purchases LabView source code software, modifications can be made to the acquisition program by an engineer at the user's facility familiar with LabView. The other systems do not provide the user with that level of software flexibility.

The PDS can be used to monitor the weld process and provide the weld engineer/operator the means to identify and proactively mitigate problems in the welding process before the process moves out of the desired parameter space. The monitoring functionality offered by the PDS can result in improved welding practices with higher quality welds and a reduced defect rate. The ultimate benefits of improved welding practices resulting from utilization of the PDS in commercial applications are a reduction of fabrication costs and a reduced chance that a defective (welding related) product makes it to the market place. The PDS can also be used in a manufacturing process where there is a need for process control as the PDS is capable of providing output signals for control.

The PDS can find application in most any facility where process monitoring involves the acquisition of analog and/or digital input signals. Use of the PDS for the monitoring of gas metal and tungsten arc welding processes is of interest, ranging from research facilities to high-volume production plants. Due to the elevated fabrication costs associated with weld defects, industrial manufacturing facilities that employ gas metal arc welding in its production practice would benefit from this technology. As evidenced by their participation in the Cooperative Research and Development Agreement where the PDS was developed, the automobile manufacturers are interested in the benefits of this technology.

The data acquisition, signal conditioning and isolation components are assembled into a sub-chassis that provides a compact, electrically shielded enclosure for the PDS. The sub-chassis is enclosed in a rugged suitcase with integral wheels, and telescoping handle. The ruggedness of the PDS makes it suitable for exposure on an industrial production floor and its portability facilitates transporting from one plant location to another.

LMITCO is soliciting a written indication of interest from industry partners interested in funding a collaborative technology development project and or entering into a license agreement for the purpose of developing and commercializing this technology. We are filing a patent application on this technology soon. License terms will include an up-front licensing fee and a running royalty based on use or a percentage of sales.

This is not an opportunity to provide goods or services to LMITCO or the Department of Energy. This Request for Interest (RFI) will close to response 30 days after publication.

Interested parties should send e-mail to pg2@inel.gov (Paul Grahovac, Account Executive, Technology Transfer Office, LMITCO). If you do not have e-mail access, send regular mail to Paul Grahovac, Account Executive, Technology Transfer Office, LMITCO, P. O. Box 1625, Idaho Falls, ID 83415-3805.

Up Topic Welding Industry / Technical Discussions / Welding process monitoring and control

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