A lean mindset actually starts at the point of product and process design, which has many dimensions and characteristics for consideration including manufacturing line layout and equipment flexibility as well as scalability. Line design must be optimized based on available funds, costs, needed flexibility and physical workplace constraints. Factors that influences the level of cell equipment integration include pieces of equipment, number of process steps, number of operators, machines capability and production volume. Production lines should be flexible in response to variations in customer takt time. A Just-In-Time (JIT) system will produce and ship parts upon customer request. This means that upstream processes will deliver the appropriate quantity of material when required by downstream operations. Pull systems are part of a JIT mentality, preventing excessive under or overproduction by regulating the flow of parts to those required by subsequent processes. Pull systems help minimize inventory levels, controlling the cost to produce and store excess material.