Epoxy adhesives are widely used in opto-mechanical joints for large optics. Much work has been done for bonding, fabricating and testing TMT M3, which is to be fabricated in CIOMP. General bonding procedures are introduced, specimen testing is taken for strength values, lower strength limit are predicted for application safety and stability. Based on these work, a 1/4 scaled prototype of the M3 and two dangerous optics at 1.5 m level for a large Fizeau interferometer to test M3 are successfully bonded, with some details given about the locating precision of the support pads. Results showed lower strength limits of tensile 51/shear 70 MPa, namely safety factors of 6 and 17 for the two optics respectively, considering stress concentration. Additionally, nominal strength limits of tensile 6. 7/shear 7.0 MPa at 99.95% reliability were expected. The team is in good readiness for M3 production.
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