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Trial Number 0

Trial Purpose:

To evaluate two parts using OSEE and contact angle goniometry.

Date Run:

10/24/2002

Experiment Procedure:

Two cleaned parts were analyzed using OSEE and contact goniometry.
Background
OSEE: Optically Stimulated Electron Emission or PEE, Photo Electron Emission is based on the principle that metals and certain surfaces emit electrons upon illumination with ultraviolet (UV) light. These electrons can be collected, measured as current, converted to a voltage and digitally displayed. A surface contaminant will either enhance or attenuate this signal, depending on it own photo emissive nature. While OSEE will not identify a contaminant, it is a good comparative tool to determine the degree of contamination. This method is best suited for thin films (oils, etc.) and not particulate matter (dust, for example).

Goniometry: Like OSEE, laser or optical contact angle goniometry is the measurement of a secondary effect to extrapolate surface cleanliness. A small drop of deionized water is placed on the substrate of interest. A light is shown to reflect the droplet's interface with the surface. Usually, the higher the contact angle (that is, the height of the bubble), the greater the contamination. Conversely, water dropped on a clean surface generates a much smaller, flatter contact angle. An example of this effect is noticeable after waxing and then washing a car; the remaining wax acts as a contaminant and the residual water on the surface of the car 'bubbles up.' The technique is limited in that only the cleanliness under the tiny drop is measured so that several readings must be taken. Flat surfaces are more conducive to accuracy with this method.
OSEE readings were taken on five of the six sides for the smaller part (part 1) and on all six sides for the larger part (part 2). Five readings were recorded on each side. Overall averages were calculated for each of the two cleaned parts and the dirty part as well.
Contact angle measurements were taken from four of six sides for both cleaned parts. Eight readings were made for Part 1 and 7 for Part 2. Average values were calculated and compared.

Oil- Blaser Swisslube Inc Blasocut 2000 Universal (64742-52-5, 68608-26-1, 61790-44-1, 61791-12-6, 61789-76-9, 8016-28-2, 61788-66-7)

Trial Results:

Table 1 lists the OSEE readings for all three parts

OSEE Readings    
  Dirty BCS Cleaned Evercycle Cleaned
Side 1 267 984 483
  258 959 498
  283 896 494
  295 515 459
  323 531 597
Side 2 277 656 392
  230 982 471
  310 805 430
  291 536 406
  268 983 484
Side 3 274 982 494
  309 721 547
  316 555 594
  290 984 404
  284 508 574
Side 4 262 793 284
  294 848 269
  300 895 304
  289 513 361
  327 939 326
Side 5 227 529 481
  224 295 300
  278 265 367
  220 951 348
  211 707 245
Side 6     416
      525
      199
      301
  276 733 416

Table 2 lists the measured contact angle for the two cleaned parts.

Table 2. Contact Angle Measurements

BCS Evercycle  
69 72  
68 72  
70 64  
59 63  
65 62  
67 73  
72 72  
68    
67 68 Average

Success Rating:

A cleanliness study, addressing only various analytical techniques.

Conclusion:

Contact angle measurements of both parts resulted in nearly identical readings. The BCS cleaned part had an average angle of 67 and the Evercycle cleaned part had an average angle of 68. No difference in cleanliness can be found using this methodology.
OSEE measurements resulted in higher values for the BCS cleaned part than for the Evercycle part. The dirty part had a lower reading than both cleaned parts. From this comparison, the results would suggest that the BCS cleaned part was cleaner than the Evercycle part. The BCS part had an average OSEE reading of 733, the Evercycle part reading was 416 and the dirty part had a reading of 276.

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