PT. Y is a company which engaged in the field of manufacturing home appliances such as refrigerator, water pump, air conditioner, radio, laundry system, and electric fan. Every product that been produced by PT.Y must be checked the quality and quantity. One of machine that used by PT. Y to make refrigerator is vacuum forming machine. That vacuum forming machine used to make inner liner for interior the refrigerator. The quantity of inner liner that been produced by vacuum forming often there are defect which can reduce production of inner liner. This problem must be dealt quickly by doing preventive maintenance for vacuum forming machine in order to optimizing production result of inner liner. This study was conducted to know the action of preventive maintenance that has been done on vacuum forming machine and to know the reduction amount of defect which has been reduced by PT. Y. The methods done with questioning the operator of vacuum forming machine and quality control who responsible of inner liner, take an actual data with direct look onto the process, and from literature review about vacuum forming machine. On the final result can be known the change on vacuum forming machine for reduce defect that happen such as changing heat system method using panel, adding cooling tools to cooling system, and many change of components on vacuum forming machine.