This lean sheet metal forming video comes from the creators of the Napkin Project video. The video below shows a simple sheet metal forming operation from start to finish. There are three processes in this lean work cell. Instead of banging out parts at each step, loading boxes into WIP storage and moving them to the next process, the work cell follows a single piece flow, using conveyors to link the processes and creating a finished part every 60 seconds.
Read my analysis below the video.
The first operation is a blanking machine. No operator is required here as each blank gets automatically dropped onto a conveyor and sent to the next operation.
The next operator deburrs the part, adds some components and sends it along to the next operation.
The final operator forms the part and does a complete inspection with a poke-yoke check fixture.
By linking the processes, the manufacturer has reduced internal WIP to almost zero and improved the overall cycle time from order to delivery.
Using conveyors is a great way to link your processes if it's cost prohibitive to move machines. However, conveyors are typically frowned upon in a lean implementation. Conveyors create islands where it becomes impossible to share work. If these operators were working beside each other, the work cell could become more flexible if customer demand changes. If the demand was lower, you could run with one person, or if demand increased you could add a third person. With conveyors creating two islands, you are trapping the labour and reducing opportunities for kaizen activities.
Obviously, the manufacturer has taken an existing batch process, moved to single piece flow and seen tremendous results. The benefits are clear. Reduced inventory and faster delivery times. This alone will make any manufacturer more competitive. But lean doesn't stop here. Any process can be optimized and, when cost and space allows, moving to a flexible work cell is the logical next step.
What do you think? Have you used conveyors to link machines? When does it make sense and when do we throw them away?
I've added this video to my ever growing list of free lean videos.