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Trial Number 2

Client Number 79

Project Number 2

Trial Purpose:

To evaluate cleaners with supplied parts.

Date Run:

01/24/2002

Experiment Procedure:

Four of the top eight cleaners from previous trial were selected for testing. Each was diluted to 5% using DI water in 600 ml beakers. Water was used as a control. The solutions were heated to 140 F in a Crest 25 kHz ultrasonic tank. Five, 2.5 inch pieces of silver tape were cut from the supplied materials. Each were weighed to establish a baseline weight. The pieces were then washed in a dish washing soap for 20 seconds to remove any residue oils or dust. The pieces were reweiged to determine if parts were clean. For pieces that had significant weight change, a second washing was performed.

Once weights were constant, the parts were then submitted to contact angle goniometry. A 2 micro-liter drop of DI water was placed on the silver surface. The image of the bubble on the surface was then captured by computer software. The angle of the interface between the bubble and the silver tape was measured.
After recording the baselines for gravimetric and goniometery, the five pieces of tape were thinly coated with Richard Apex D644 CPD drawing compund. The contaminant was applied with a hand held swab and then wiped with a second clean swab to simulate the drawing process. Contaminated weights and contact angles were measured and recorded. Each piece of tape was cleaned in a solution for two 1 second intervals and rinsed in a ultrasonic tap water bath for 1 second. Parts were dried for 10 second using a heat gun at 500 F. Final weights and contact angles were measured.

Trial Results:

The weights of the parts, with and without contamination, were not conclusive enough to be used as a way to measure the cleanliness of the tape. There was not enough of an establish difference between initial and dirty weights. The weights are listed in the table below. 
Contact angle goniometry was more successful in determining the cleanliness of the silver tape. The angles were found to decrease when the tape was coated with the drawing compound. After cleaning, the contact angle returned to the initial angle. Only one product did not result in an angle equal to (or greater than) the initial contact measurement. Even though the water cleaned tape had an angle close to the initial measurement, the tape still looked like it had drawing compound on it. The angles are also listed in the table below. Images of the bubble/tape interface have also been sent.

Table 1. Gravimetric and Contact Angle Measurements

Cleaner Part Description Analysis Method Initial Dirty Clean
Exp 100 Long Gravimetric 0.6862 0.6871 0.6861
    Contact Angle 61 59 72
Beyond 2005 Bent End Gravimetric 0.7179 0.7183 0.7178
    Contact Angle 72 48 73
Crystal Simple Short Gravimetric 0.5573 0.5578 0.5578
    Contact Angle 72 48 73
Inproclean Tape Gravimetric 0.6636 0.6673 0.6624
    Contact Angle 68 49 76
Water Right Bend Gravimetric 0.6491 0.6502 0.6503
    Contact Angle 72 37 25

Success Rating:

A follow up test, usually based on company input.

Conclusion:

An additional trial will be conducted using the top three cleaners.  Operating conditions will remain the same.  An attempt to use OSEE for an analysis tool.

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