From: Marsh, Darren S. [marsh@SLAC.Stanford.EDU]
Pursuant to the Tracker Production Readiness Review, an onsite visit to G&A Engineering occurred on October 4, 2002. The purpose of the visit was to perform a post-production review of 10 ladders manufactured with encapsulation materials that are NASA flight approved and to review and assess quality processing documentation.
The following individuals were participants in the meeting held at G&A Engineering.
Alessandro Brez - INFN-PISA Development Engineer, Production Supervisor
Tom Borden, Tracker System Engineer
Darren Marsh, LAT Mission Assurance
Francesco Belli, INFN-Rome Physicist/Test Engineer
Luigi Valentini, G&A Engineering, Technical Staff
Giorgia Ponteri, G&A Engineering, Technical Staff
Antonio Ponteri, G&A Engineering, Technical Staff
Gianfranco Grifom, G&A Engineering, Quality Assurance
The following information is provided regarding the meeting.
1. As previously reported by Robert Johnson in the LAT Project Weekly Report Ending 10/3/02, shipping the NASA flight approved encapsulation material to Italy has proved to be very difficult due to the hazardous material classification of the Nusil CV-2500. The review of the 10 ladders which were to be completed prior to the visit of the LAT review team was not possible. It was clear in discussions with G&A Engineering personnel they have concerns regarding their ability to develop a robust encapsulation process utilizing the new encapsulation material due to the viscosity properties of materials. Consequently, it would have been imprudent to be begin production without a thorough encapsulation process development effort by G&A Engineering. It now appears the new encapsulation material will be delivered to G&A Engineering this week as initial quantities have made it to Italy. Once G&A Engineering receives the materials, they will begin a process development effort utilizing
marginally acceptable Silicone Strip Detector's (SSDs) and SSD cut-outs provided by INFN. The process development will take 4 weeks and it is now planned to have a lot of 10 ladders complete and tested utilizing the "new" material by the second week of November.
2. It was clearly evident by a detailed review of the ladder processing documentation that G&A Engineering has a very good handle on ensuring the ladder manufacturing process is carried out under controlled conditions. Specifically, the G&A Tracker Ladder Production Ladder Traveler along with internal G&A Quality Procedures were reviewed and deemed to be suitable and adequate to ensure process capability. Internal Quality Procedures reviewed include, Personnel Training and Qualification, Handling and Packaging, In-Process Inspection (including wire bonding equipment verification) and Configuration Management. Also, Tracker Ladder Assembly Procedure, LAT-PS-635 was discussed. The source inspection requirement was negotiated to meet LAT requirements and G&A concerns over unexpected inspections. SLAC personnel will be provided the G&A internal traveler upon formal request (the equivalent of a nondisclosure agreement).
3. A concern surfaced in the Ladder PRR regarding the manufacture of a large quantity of ladders prior electrical testing. It was previous proposed by Robert Johnson that no more than 20 ladders may be wire bonded before electrical testing begins on the lot. G&A Engineering has concerns over this proposal as they would not be able to optimize their ladder production flow. They indicated a contract modification would be necessary to cover the added cost of this requirement. It was agreed that no more than 300 ladders would be wire bonded before electrical testing begins. It should be noted that the way the current contract is structured, G&A is allowed 5% defective ladders. The cost of any ladder rejections over the 5% has to be absorbed by G&A Engineering so they are quite aware of the need to assure the ladders meet all requirements.
4. Based on the detailed review of ladder production activities at G&A Engineering, Messrs. Brez, Borden and Marsh approved the release of 246 flight ladders for production up through the encapsulation process. Upon completion of the encapsulation process development effort and the manufacture of 10 production ladders utilizing the NASA approved encapsulation material, a post-production reviewed will take place to evaluate ladder conformance to specification requirements. The 246 flight ladders will be released for encapsulation and final testing after approval by the PRR Committee.
5. A new action was generated for INFN to ensure all INFN personnel are adequately trained and qualified to perform the ladder testing activity at G&A Engineering and at Mipot. In addition, it is necessary for INFN personnel who are involved with handling and inspection and test activities to meet NASA ESD requirements.