By Danielle MuoioThe Tesla workers that are key to ensuring the automaker meets its lofty production targets are threatening to strike, the media reported on Tuesday.Germany's industrial trade union IG Metall are calling for a worker strike at Grohmann Engineering , the German engineering company Tesla bought in November, claiming workers have been making 30% below union wages ever since Tesla acquired the company, according to the report. IG Metall could decide whether it will call for a strike by ate Tuesday in order to negotiate new wages.Tesla refuted the claim that Grohmann workers are making 30% below union wages."We continue to work directly with Tesla Grohmann employees and are prepared in the event there is an action initiated by the union," a Tesla spokesperson said. "We don't anticipate any impact on the Model 3 timeline." The California-based automaker acquired Grohmann as part of an effort to further automate ts factories and speed up production.