31 October 2014
Q. I just received your chapter on cleaning SOPs and I look forward to reading it. In parallel, I was hoping to get your thoughts or a bit of advice on how to create and implement cleanliness specifications/processes for machined (PTFE) plastic parts. Cutting fluid for the machining center is basically a water soluble vegetable oil-based fluid. The use of this plastic manifold and cover is within an electro-mechanical-fluidic subsystem (“Delivery Module”). This delivery module accumulates a quantity of 59wt% Hydrogen Peroxide that has been extracted from our existing consumable, and then meters smaller quantities of hydrogen peroxide into our system for use. The hydrogen peroxide is accumulated within aPTFE manifold and held onboard for a period of days. The manifold has a cover that seals (with o-rings) the internal volumes. Hydrogen peroxide, as you may know, is very unstable when in the presence of any small amounts of organics or decomposing metals. We must ensure that these parts are very well cleaned, packaged, and assembled to prevent decomposition. The machined NXT 75 PTFE vendor’s current process related to cleaning is to wipe the parts down with a dish-soap (Ivory) solution, rinse, then run through a series of baths: 1) 10 mins in an ultrasonic bath with 1% Alcanox solution at 50 degrees, 2) Ultrasonic DI Water Rinse Bath, 3) Dead Water DI Water Rinse Bath.