I'm interested in aluminum deep drawing (I've never done that, though). Could someone explain how the neck part of a deep drawn aluminum bottle is done, or perhaps refer to some book or other source where I could find more information about the subject?
It depends on the neck in relation to the diameter of the rest of the piece. It's always easier to stretch material than compress it so when the neck is fairly large relative to the body (like a mason jar) they tend to use an expanding die on the inside. When the neck is small or needs to be formed thicker and with threads or similar, it is compressed. Must be very controlled and the process carefully designed.
Generally, it's done as the last step of the process. Sometimes there is a final overall sizing step.
Note that to draw the initial shell probably takes several press hits in different dies. If you look on the bottom of an aluminum can (like those fuel bottles for backpacking) you can see that they have been drawn about 3 times to get the final shape.
There are other ways too, depending on the bottle shape. There are even ways to blow mold aluminum similar to the way plastic bottles are done.
Anyway, if you give more details as to your specific question or the dimensions that have you wondering about the process, I can probably scan a few pics from a pressworking book that may help.