It is important to understand that process verification and equipment calibration are not the same and that some types of equipment do not require calibration but may still require the development of procedures for accurate process verification.
We are often asked questions relating to calibration procedures for the various tools and equipment that we manufacture. These questions are usually asked as a result of the calibration requirements that are specified in many quality assurance program directives. The equipment that we manufacture can be accurately identified as NCR (No Calibration Required) as there are no features within this equipment which allow for calibration.
Many quality assurance programs will alsorequire the development of written procedures to outline accurate methods of verification that can be utilized to monitor the various processes that may be used for an application. Process verification can be accomplished with our equipment by knowing what measurable, variable attributes exist for the specific soldering application being reviewed.
When you are developing the process for any application it is important to identify attributes which are variable in nature that can have a direct effect on the results achieved. Once identified each of these attributes should be measured prior to and monitored during the process development in order to determine and establish an acceptable tolerance level for each of them. The information collected should be well documented in order to help establish the appropriate verification steps that can be followed to monitor the actual process once the development steps have been completed.
Time and temperature will be the two primary variable attributes for you to be concerned with when developing a process for applications using the type of tools and equipment that we manufacture. For the purpose of this document, time will be referred to in two ways; dwell time will refer to the time that is required to heat and flow solder to complete the solder joint, while idle time will refer to the time allowed between solder joints (from the completion of one joint to the beginning of the next) to recover thethermal loss from soldering irons and solder pots and to dissipate the heat accumulated in resistance soldering handpieces.