The DPE (Digital Pulse Echo) AUT Weld Inspection System was released in early 2007 with the requirement that it replicate all of the functionality of the USIP/CIM system and add certain enhancements that resulted from the implementation of an all-digital system. The DPE provides significantly better noise immunity over the older analog USIP/CIM system, as well as additional system flexibility, higher resolution data presentations and additional mapping channels.

DPE functions in the same manner as the USIP/CIM system, but there are differences in mechanical form factors, associated wiring, digitization, and operator interfaces. The DPE combines all of the functionality of the USIP /CIM pulser preamps and TOFD digitizers into one small electronics module. The result is not only reduced cabling and simplified connectivity but improved reliability as well.

In DPE, digitization is performed in the electronics module, and data is sent to the system over a high speed Ethernet connection. Both USIP/CIM and DPE process analog RF signals are essentially the same, and subsequently digitize the analog signals for presentation of data using SPS’s InFocus software program. DPE has the distinction of performing all digitization within a single electronics module. In contrast, the USIP system performs digitization within the USIP (peak data), within the CIM (mapping), and within the system computer (TOFD).

DPE also utilizes the same scanners and bulkhead as USIP / CIM. Consequently, a scanner run on a USIP / CIM system can be disconnected and reconnected to a DPE system with no change to either the scanner or the bulkhead.

Scanner calibration and configuration are also unchanged. The operator interface is more software-based.The DPE utilizes SPS’s proprietary IFSettingsConfig and CAUT software programs as, well as SPS’s InFocus program. In contrast to the USIP / CIM, DPE presents A-scan waveforms on a computer monitor. Resolution is equivalent (and even better in many cases) to the CRT based USIP, but without the linearity error, fixed size, and limited visibility of the USIP. The DPE A-scan display is superior to the USIP in that it incorporates on-screen measuring tools, dynamic zoom, and screen capture functions. DPE utilizes identical databases and data presentation engines as USIP/CIM due to the fact that both systems use SPS’s InFocus software.

DPE is also superior to USIP/CIM because the DPE electronics combined with SPS’s CAUT software program results in more extensive, and flexible, signal filtering functions than USIP, plus, the DPE / CAUT also has extensive signal averaging and post-rectification filtering functions to further deal with RF noise.

A formal system validation of the DPE was performed under typical conditions of a weld sizing program. The program was completed over a 6-week period prior to engineering release. Running in tandem with a USIP/CIM system, the DPE system was compared to the USIP/CIM in sizing and repeatability trials. Numerous seeded defect welds (K-prep, J-Prep) were manufactured and inspected using the USP/CIM. The details of the defects were recorded but not shown to the attending AUT Supervisor. The DPE was then set up identical to the USIP/CIM and used to scan the seeded welds.The data results were recorded for comparison to the USIP/CIM system.

The USIP/CIM was set up directly from the ISGS sheet and run using SPS’s InFocus software program. The DPE was set up using SPS’s proprietary IFSettingsConfig software program, which replicates the standard ISGS file, then runs using SPS’s proprietary CAUT and InFocus programs. The DPE system ran for 10 hours/day, 7 days/week for a period of 15 days. The system was subsequently tested for an additional 15 days of continuous 10-hour per day useage. No special arrangements were made to exclude dust and dirt particles from the area.

During the tests, no breakdowns of any kind were experienced. Testing was carried out in direct proximity to 6 welding stations without issue. Upon final analysis of welds between the two inspection systems, the DPE system proved to replicate the USIP/CIM system.