Nonaka and Takeuchi Model

Modelling knowledge management is one big issue for those who are in charge of gathering information, documents, professional experiences and know-how at a corporate level.
Nonaka's and Takeuchi's relevant work should allow you to understand easily and clearly how knowledge may be dealt with, transforming tacit knowledge into more explicit forms. This is one of the most famous model existing, maybe the easiest and the clearest.
"The Nonaka and Takeuchi KM model focuses on knowledge spirals that explains the transformation of tacit knowledge into explicit knowledge and then back again as the basis for individual, group, and organizational innovation and learning." (K. Dalkir)

First step: Socialization (tacit-to-tacit)

Much knowledge, perhaps 80%, lies in people's brains. The aim for the knowledge worker is to find ways to collect this tacit knowledge. Socialization consists of sharing knowledge through social interactions.
People hold indeed know-hows, secrets, personal skills that will never be shared if none work on it. It is very important to try to gather this knowledge by socializing, that is, using face-to-face communication or better, share experience directly at work through 2 roles: the tutor and the apprentice. It involves arriving at a mutual understanding through the sharing of mental models.That way, there will be little risk that the know-how of your company leaves at the same time of employees' retirement.
Socialization is a very effective means of knowledge creation, maybe one of the easiest but nethertheless the more limited. It is also very difficult and time-consuming to disseminate all knowledge using this mode only.

Second step: Externalization (tacit-to-explicit)

The process of externalization (tacit-to-explicit) gives a visible form to tacit knowledge and converts it to explicit knowledge. It can be defined as "a quintessential knowledge creation process in that tacit knowledge becomes explicit, taking the shapes of metaphors, analogies, concepts, hypotheses, or models" (Nonaka and Takeuchi, 1995). In this mode, individuals are able to articulate the knowledge and know-how and, in some cases, the know-why and the care-why.
An intermediary is often needed to execute this process. For instance, we can consider a journalist who is the typical person able to interview knowledgeable individuals in order to extract, model, and synthesize in a different way (format, lenght, ...) and thereby increase its scope (a larger audience can understand and apply this content now).

Third step: Combination (explicit-to-explicit)

Combination is the process of recombining discrete pieces of explicit knowledge into a new form.
No new knowledge is created at this step. It is rather to improve what we have gathered so far, to make synthesis or a review report, a brief analysis or a new database. The content has been basically organized logically to get more sense, consolidated.

Fourth step: Internalization (explicit-to-tacit)

The last conversion process, internalization, occurs through diffusing and embedding newly acquired and consolidated knowledge. In some way, internalization is strongly linked to "learning by doing".
Internalization converts or integrates shared and/or individual experiences and knowledge into individual mental models. Once internalized, new knowledge is then used by employees who broaden it, extend it, and reframe it within their own existing tacit knowledge.