Lean production uses many techniques for successful implementation. They include value stream analysis, Takt time, kanban, Kaizen, visual control, total productive maintenance, one-piece flow, error proofing, standardization, autonomation, production leveling, problem-solving circles, and 5S. Machines must be in safe operating condition and have predictable process capability and uptime. Proactive, preventive (total) maintenance programs use operators and skilled trades to achieve these goals. Lean production employs teams of multi-skilled workers at all levels of the organization and uses highly flexible machines to produce high volumes and high variety. Producing too much is waste; producing too little does not meet customer needs. Overtime and fatigue cause waste. Production leveling assures a constant flow from suppliers and appropriate utilization of workers. The pull system has dramatic effects on inventory levels because it does not provide for production of any inventory until it is needed.