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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Adhesion Between Aluminium Surface and Epoxy
Q. I am Terence SY Ong, the Manager of Chemical Engineering in Belton China. Our company is mainly manufacturing the hard disk component to Seagate and WD and most of the products are involving the bonding process with 6061Al. So I surf around the website and I am pleased that I can acquire this website for enquires. Since I am not the expert in this adhesive field, I would appreciate you can support me in some technical aspect about the bonding process.
Recently we find an occasionally drop off between the epoxy and the 6061 Al (300 dppm). The outlook for the drop off is there has no epoxy left on the 6061 Al surface. Of course, we do the surface finishing process on the Al surface with extensive aqueous cleaning w/ US in cleanroom before bonding process. Would appreciate you can provide some hints about this issue.
hard disk industry - Hong Kong
2007
Terence,
Locate the work process sheet ('shop traveler') having signatures of production workers and inspectors. Follow the processing sequence and look for deviations from your company's procedures, the customer specifications and the epoxy product bulletin. Also, check expiration dates on the epoxy materials, chemical analysis records for process solutions, equipment calibrations, adhesion test records, worker training records, etc.
ASTM D2651, 'Standard Guide for Preparation of Metal Surfaces for Adhesive Bonding,' gives a number of aluminum pretreatments which may be helpful. After most pretreatments,* bonding should be performed within 1 hour of the final drying. *Except if sulfuric acid anodized (unsealed), for which the time limit is 72 hours.
Pretreatment of aluminum by phosphoric acid anodizing (unsealed) is described in ASTM D3933-98,
'Standard Guide for Preparation of Aluminum Surfaces for Structural Adhesives Bonding (Phosphoric Acid Anodizing).'
- Goleta, California
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I'm not sure I completely understand your question, but for what it is worth you can sometimes increase the adhesion of the epoxy to the anodize by making sure that your anodize wasn't sealed. Talk with your anodizer to smooth out the process.
Good luck!
Compton, California, USA
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