Capability analysis of assembly line production

A process for identifying opportunities for improvement in assembly line production during a Kaizen event, said method comprising the steps of:

• (1) selecting an assembly line having at least two operators manufacturing in a sequence;
• (2) validating time data collected for the overall process and each operation on the assembly line through short gage R&R analysis;
• (3) conducting a capability analysis of the time data collected in step (2) by calculating the mean, standard deviation, CpK, and a first set of confidence intervals to identify opportunities for improvement in the assembly line;
• (4) identifying changes in operations based on the analysis of step (3) by eliminating the process time values in any given set of data that are greater than an upper specification tact time obtained from step (2) to decrease the standard deviation values of that operation and to shift the mean values lower than those originally obtained from step (2);
• (5) reducing process time variation identified in step (3) implementing changes selected from the group consisting of balancing assembly operations to reduce bottlenecks, improving cell layout, improving process flow, work simplification through better material handling, purchasing more equipment, consolidating assembly operations, and redistributing operators, or any combination thereof;
• (6) validating changes implemented in step (4) by calculating a second set of confidence intervals based on the improved assembly line process to compare with the first set of confidence intervals from step (2), wherein the second set of confidence intervals do not overlap with the first set of confidence intervals;
• (7) implementing a control means maintaining the changes implemented in step (5);
• and
• (8) repeating the process cycle to continually improve the assembly line process.