Metal Cleaning Process Control – Which Method is Right for You?
Not all chemistry is created equal. –Chelsea Jewell
How often should I check the concentration of my wash? What we like to recommend when you’re initially starting up an aqueous process is to make sure that you’re checking it every day. This isn’t for the life of the process. When you’re figuring how many parts are coming through and how often you need to add chemistry, we recommend checking that daily and then you can move down to weekly.
How do I know that the bath is spent? That’s a great question. The best answer I can say is that you’ll start to notice if you’re doing NVR’s and they are getting really high, we like to say after 3 or 4% depending on the process, that can be an indication that the bath needs to be changed out. The first indicator is dropping cleaning. When you start to see residues remaining on the parts or things aren’t as clean as you’re anticipating, that is typically a sign that things need to be changed out.
How do I know that my concentration is accurate? As far as measuring concentration, you first want to make sure that the tool you’re using or the solutions you’re using are up to par. With the refractometers, you can calibrate them to zero with DI water. With the conductivity meter and pH groves, they have solutions to help make sure that everything is in spec to calibrate. If you’re using acid stabilizers or titrations, you should check when things are supposed to expire and that everything is sealed up well. If you know you’ve added a certain amount of chemistry and you control method isn’t matching, make sure that it is calibrated properly first.