If an industrial droid such as a scavenger, silicon dozer or nutrient harvester, is destroyed, you may choose to build a replacement robot, rather than buy a whole new resource extractor. To do this, you'll need an Industrial Robotics Factory. Each new robot requires 2 units of refined iron and 2 advanced electronics. Once your warehouse droids have delivered these to the factory, assign a trained operative to work there. The countdown clock on the factory shows how soon the robot will be completed.