Are we talking about accidental combustion here? Because from what I know, there is no such thing as „partial combustion“ except when only part of the material combusts, but then *this part* would be fully combusted. Wouldn't it? Otherwise I'd say you think vaporizing is something like semi-combustion, while they are two very different things. That's a bit confusing to me. :-)
So what are the temps we want to reach with our devices in order to vaporize cannabinoids? And at what temperature does combustion of plant material occur?
That is not what I mean by partial combustion. Perhaps I should call it incomplete combustion, but that's not right either, since really there is no combustion at all. Here I mean that the material is heated enough that it begins to break apart and release particulates. (There might be a better term for this but I don't know it.) Anyway, your understanding requires that some of the material has to be heated to the temperature where combustion starts, but again, by design vaporizers do not normally reach that temperature.
As for the ignition temperature, it is difficult to be exact because cannabis varies considerably in its moisture and oil content. Completely dry cannabis starts to burn somewhere around 230°C (446 funny degrees) but as we all know, many of us vapourize with temperatures set higher than this. Part of the problem here is that you cannot rely on any vapourizer to measure the actual temperature of the herb, and then of course there is the variation in dampness that I just mentioned.