psicutrinius Oct 5, 2013:

"is fed under a high head load" Context is more than scarce, but I think that what is meant is that a part, one of whose surfaces, which is is mostly flat, is being milled and where there is, however, the possibility that [protruding] lumps may appear in it, or that it is deeply milled.

This would increase the depth of cut whenever a lump arrives, or the part may be machined purposefully at a high depth of cut, uniformly, usually to save time (and as deep as the material allows).

That, itself, will entail a high head load.

But if the above is right, rather than "high head load" I would say "high depth of cut" (cause) which entails a higher head load (consequence). I do not see how, or why, would anybody need "a high head load" and design the milling process for achieving this, but I of course see the choice of a high depth of cut, whatever strain it might impose on the head -unless I lack additional info, that is, context.