An injection molding machine assembly for use with an operating injection machine, comprising a tool unit mounting support adjacent the injection machine, a plasticizer and ejection unit mounting support adjacent said tool unit mounting support, first operating and securing coupling means associated with said tool unit mounting support for connecting a tool unit, second operating and securing coupling means associated with said ejection unit mounting support for connecting a plasticizer and ejection unit, magazine means defining at least one of an additional plasticizer and ejection unit mounting support which is substantially the same as said plasticizer and ejection unit mounting support, the first ejector and plasticizer associated with said injection unit mounting support, a first tool unit associated with said tool unit mounting support, said first ejector and plasticizer associated with said magazine means, and transport means movable between said magazine, said plasticizer and ejection unit mounting support for transporting said first ejector and plasticizer between said plasticizer and ejection unit mounting support and said magazine means.