We argue that unless the use of formal ontology becomes part and parcel of Systems Engineering culture, industrial use of knowledge based systems will remain a fringe activity and consequently, success stories will remain scarce. The way towards reaping the benefits of formal ontology is to view it as the most powerful instrument for sustainable standardization and as a necessary but not sufficient, condition for building knowledge based systems. Foundational ontology may become the conceptual backbone of all interoperable systems, but it will only realize its potential when it is backed by ontology engines that compute ontological meaning from ontological descriptions. The paper charts the way from organizational practice expressed in ontologies, to the engineering discipline of building knowledge based systems and it illustrates the difficulties by some lessons learned in a semi-industrial research context in the field of mechatronics.