2.1Clean per Appendices A or BCAUTION: To prevent recontamination, components shall be handled with clean-room compatible gloves. Contact with any chemical solution other than DI water is prohibited, following the bead-blasting step.2.2Bead-blast only those areas specified on the drawing and mask off other areas to protect from over spray. Use aluminum oxide at the pressure required for achieving desired roughness. This is generally 20-45 psi for a pressure driven blaster and 60-80 psi for a siphon driven blaster. Blast the part at a 45 degree angle, keeping the nozzle a nominal 4-6 inches away from the part. Blast in a sweeping motion keeping the nozzle a steady 4-6 inches away from the part. Make sure to cover the entire bead-blasted surface equally in order to achieve a uniform surface roughness. Unless otherwise specified on the drawing, the roughness specification is 180 to 240 micro inches Ra.It is recommended that a sample of the appropriate material be bead-blasted and its roughness (Ra) measured to ensure that the pressure setting is correct.2.3Thoroughly blow off the part with a filtered nitrogen or CDA to remove loose grit.2.4Thoroughly rinse components with pressurized DI water spray. Care must be taken not to deform, warp or otherwise damage parts. Use 100 psi for parts that are delicate, small, or difficult to handle at higher pressures. Use up to 1,000 psi with a 30-45 degree nozzle.2.5Rough sonication: Immerse the component in an ultrasonic tank of DI water with resistivity 4 M Ohm-cm for up to 2 minutes. Recommended sonication energy is 35-50 watts/gallon (7-15 watts/liter).Reduce processing time as necessary if mottled surface is observed.