(This content is only relavant for versions 1.1.2 and up)
From versions 1.1.2 and up, you can set the delay to select a new chip before refocusing on the input.
md-chip-append-delay attribute to set it (in milliseconds):
<md-chips md-chip-append-delay="500" ng-model="chipsModel" placeholder="Chips"></md-chips>
This is necessary for keyboard accessibility for screen readers. It defaults to 300ms and any number less than 300 can cause issues with screen readers (particularly JAWS and sometimes NVDA).