Abstract: A vehicle assembly line has a first line for a first mobile conveyor and a second line for a second mobile conveyor and the first line is connected to the second line with two hanger conveyor lines. Two working robots are disposed to the first mobile conveyor, one being positioned within a cabin of an upper body section and the other being positioned in front of the upper body section. The second mobile conveyor has a mechanism for altering a posture of the upper body section and a height position thereof. To the upper body section are mounted various small parts such as grommets with the first working robot during the course of running the first mobile conveyor in the first line. The second line has plural stations for mounting larger parts such as bumpers to the upper body section which is loaded on the second mobile conveyor and whose posture and position are aligned with the working robots disposed in the plural stations before entering the stations.

Abstract: An injection molded product including a plurality of internal cavities is produced by, after having injected a molten resin material into the molding cavity, injecting an inert gas with a gas pressure gradually increasing into the resin material through gas injection nozzles, which are in contact with the resin material to form the respective internal cavities inside the molten resin material. After removing the gas injection nozzles from the resin material for discharging of the inert gas directly from the resin material, any one of the gas injection nozzles, whose temperature during injection of the inert gas was lower than a predetermined temperature level, is judged to be clogged and the gas injection nozzle is cleaned by being blown out with high pressure gas.

Abstract: A method of coating an automobile body which is composed of plastic parts and sheet metal parts is provided. The plastic parts are formed with resin materials in which conductive materials are mixed. The plastic parts and the sheet metal parts are given the coating treatment after the two types of parts are assembled.