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Max-Planck-Institut für Astronomie, Heidelberg. Chopper. PACS Instrument Baseline Design Review 27/28 Feb 2002 MPE, Garching. R. Hofferbert D. Lemke, U. Grözinger, O. Krause J. Katzer (ZEISS). actuator. electrical I/F. mechanical I/F. mirror. housing. T-sensor. flex pivot.
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Max-Planck-Institut für Astronomie, Heidelberg Chopper PACS Instrument Baseline Design Review 27/28 Feb 2002 MPE, Garching R. Hofferbert D. Lemke, U. Grözinger, O. Krause J. Katzer (ZEISS)
actuator electrical I/F mechanical I/F mirror housing T-sensor flex pivot P-sensor Design Status • LM: • QM: • Major changes • ITT Cannon/GORE pigtail • Cover with straylight baffles • “Vacuum cleaner” magnet • Black coating on housing and cover • Pre-qualified parts • Minor changes • FP bushings • Cable routing • Grounding pins • T-sensor internal Chopper
Design Status - Details • Manufacture procedures completed: • Cryo motor coils • High purity Al wires, laminated, pre-tempered Cryoperm cores, microscope controlled coiling, ~1100 windings • Position sensor • Precision gluing of magneto resistive field plates, optically aligned, cryo-qualified soldering • Rotor • Precision gluing of drive/sense magnets and flex pivots, ZEISS in-house procedures for mirror coating incl. Au diffusion blocker cryo motor coil P-sensor Chopper rotor
AIV QA Activities • KIP 1: QA checks… • Procurement/material certificates • Event records (“Logbuch”) • Inspection certificates • Non-compliances • MIP 1: QA checks… • Event records (“Logbuch”) • Inspection reports • Non-compliances • As built documentation • MIP 2: QA checks… • Event records (“Logbuch”) • Qualification or acceptance reports • Non-compliances • Final inspection Chopper
Testmatrix • 4 independent models • Test items: • Performance at 4K, 77K, 300K • Lifetime • Vibration capability • EMC • Thermal cycling • Bake-out Chopper
„dummy chopper“ The 5th Model • Engineering model: • pre-tests of parts and unit • Determination of control parameters • Preparation of test procedures • Handling of chopper wrt. cleanliness, storage, mounting in cryostats, cool-down/warm-up requirements • Dummy for first compatibility tests with warm electronics (MEC, CSL) Chopper
LM Verification Flowchart Chopper
CuBe double-stage flex pivot actuator laser control FP rotor Engineering Lifetime Test of Flex Pivots • Test at Fraunhofer LBF (Darmstadt): • 300K environment: Worst case scenario (higher loads) due to reduction of fatigue strength by factor 1.3 • 6 FPs in 3 independent rotors (simult. excitation, 50Hz, 9°, goal: 2 x lifetime = 126 Mio. cycles) • Damages of two flex pivots in first run, optical measurement indicated bad alignment of ONE FP HOLDER on mounting bench test setup has been crucially improved, second run presently underway Chopper
Schedule today Chopper
Open Points • How to order space-qualified pigtails (via TECNOLOGICA or directly) ? • When to put black coating on the chopper parts ? Chopper
Conclusion • Valuable experience wrt. flex pivot alignment and lifetime from tests at Fraunhofer LBF (Darmstadt) • LM and QM test phases practically in parallel • Fastes way of completing verification plan • Critical wrt. transfer of lessons learned • Start of cold lifetime tests in April 2002 • QM delivery in May 2002 critical due to • Tight schedule (no margins) • Pigtail procurement (GORE cables, ITT Cannon connectors + manufacture) Chopper