The use of mechanical devices with three or more axes that move automatically to carry out operational tasks unsupervised. Industrial uses of robots include: materials transport – loading and unloading heavy or hazardous materials; welding – fastening two pieces of metal together using heat to soften the metal and applying pressure; assembly – fitting together a group of parts into a unified whole; painting including spray finishing; and inspection and testing of products. Non-industrial applications include: security – airport surveillance; commercial cleaning; food services; health care – assisting the physically handicapped and the elderly, and supporting doctors and nurses in hospitals; and space exploration.