Depending on the type of equipment involved there are several things you need to pay attention to regarding safety features and protective gear that you should wear. If you do happen to have a finger amputation, the best course of action would be to apply pressure to the stump with clean gauze and rinse the amputated finger in warm water and place in a baggy submerged in ice and report to the closest hospital. That being said, prevention should be foremost in your mind.