Assembly line Layout

Traditionally, plant layout has focused on linear lines and process-based departments. But, assembly lines have changed dramatically in recent years due to trends such as just-in-time delivery and parts sequencing.

There are nine common line layout mistakes that manufacturing engineers should avoid:

1. Poor Planning.

“In the front end, poor planning is a frequent mistake, ” says Sammy Obara, president of Honsha Associates. “At Toyota, when we put together a plan—usually on an A3 form—our Japanese sensei would scrutinize us with questions such as: ‘What other Toyota sites did you compare against?’; ‘How flexible is this line for demand fluctuation?’; and ‘How will the operator handle this part? One hand? Which one?’ Planning must be deep enough to answer all possible aspects of the new line. Otherwise, it is poor planning.”

2. Preparing Standards.

“The least glamorous part of putting together a new line or process is the standardized work part of it, ” claims Obara, who spent three years studying lean manufacturing principles in Toyota City, Japan, and another 10 years applying it at Toyota plants in Brazil, Venezuela and the United States. “Once the line is running, people tend to move to new and more visible executions. Preparing standards is not as visible and it almost hides from view. However, it is in the foundation of the house of lean. That’s a funny analogy, because in a real brick house, nobody sees the foundation. Still, it is what [keeps] the house standing firm.”

3. Material Flow.

“One common mistake is not incorporating proper material flow concepts into the layout design, ” notes Matt Zayko, an associate at the Lean Transformations Group. “There should be simple material delivery routes and pathways throughout the facility that connect the processes. Also, there needs to be a plan for flexbility and changes, since volumes and demand are variable.”