What kind of visa do I need if I want to work for a short period of time in china

A company in Sweden sold a special craft to a company in china. The swedish company is now asking me to come to china to assemble and train chinese personnel on that special craft. I do not work for either of these companies at the moment. I will temporarily get employed by the swedish company for this task.
What kind of entry permit do I need??

Best regards
Thomas