moving source in heat transfer problem

Hi:

The attached images in the pdf file are from a model I'm working on. The axiymmetric model file is also attached.

Basically, it's a model of a small disc of metal that is moving in a hole in a material. This small disc is meant to represent the cutting tip of a drill, and due to cutting action, it is releasing heat. This disc is therefore made to be a kind of heat source -- by assigning a "pair boundary heat source" to the identity pair at the boundary between the disc and the surrounding cylinder of material. I have a moving mesh set up to allow the disc (drill bit) to move into the hole in the material at a chosen velocity.

The model appears to work fine, however I am confused by 2 things, as explained in the pdf file.

First, as the drill tip moves into the material via the moving mesh, it generates heat at each time point and I see the results (which to some extent make sense), but at each position of the drill tip, is the Comsol formulation solving for the temperature distribution using the original (time = 0) conditions of temperature in the surrounding cylinder, or does each solution use the temperature distribution created in the previous time step(s)?

The second question concerns the default "insulation" condition that is within the "pair boundary heat source" definition. See the pdf file for the detailed question.

Thanks very much, John