Are tugger trains the right solution for on-demand manufacturing?
With the manufacturing industries moving towards more efficient and sustainable operations, the concept of Industry 4.0 and lean manufacturing is becoming a reality. The fundamental concept of lean manufacturing is the reduction of wastage be it in time, effort, or inventory.
The movement of material around the workspace is one of the most important parts of the logistics journey of a company’s raw materials and finished goods. Just from its scale perspective, material movement accounts for 700k+ jobs in the US alone according to the Bureau of Labour Statistics. And one of the most time-consuming and expensive processes is the movement of materials from the warehouse to the production line and vice versa. Known as the milk run, several types of industries and operations use different equipment and processes for the same. Today, many companies, especially discrete manufacturers, are employing tugger trains to deliver these materials.
But is it the right choice?
The journey of a tugger train begins at a warehouse where varied materials are loaded onto several carts. Once all the carts have been filled the train begins its journey following a predetermined route with predefined stoppages. This route is planned out using sophisticated Vehicle Routing Protocols (VRPs) and any change in the same needs extensive planning. The train drops off the materials at the specified time at the planned lineside stations.
The milk runs are highly organized and standardized. The use of tugger trains for the milk run makes it efficient if the operations are to remain unchanged for an extended period. With the ever-changing consumer demands and increased complexities of products, a standard operation is not feasible in the long run. The automotive industry is evolving rapidly and is in constant need of upgrading. This calls for rapid changes in the operations of the industry. We have covered the effects of changing consumer demands in our previous blogs (you can check them here).
One of the metrics used to check the efficiency of a milk run is known as cycle time. It is the time taken to load the train at the warehouse, distribute the goods at the line stations and return to the warehouse to be loaded again.
The challenge is, in the tugger trains operations are coupled. Units producing different materials are supported by the same milk run. This means if there is any delay in picking or loading parts for one unit, others will also suffer as the cycle time will go up. Subsequently, some lines might deplete faster than others, leading to an imbalance in stock at each production unit. Even a study by BCG talks about how these complex operations affect even the state-of-the-art conveyor lines. Leading to issues like increasing cycle time, lower utilization of expensive assets like manipulators, and imbalance in worker utilization.
The shift to on-demand manufacturing needs solutions that are decoupled and allow flexibility to people on the shop floor to keep the production up. Lean ideology always represented adopting solutions that are best suited to the need of the hour.
Taxi style movement of material in the shop floors
One of the ways to overcome these operational problems is by switching to a more robust taxi concept which provides the operators with the required flexibility to tackle the changes and keep improving the processes. The major difference between the taxi and tugger train concept is the number of goods that are moved. Going by the common idea a taxi is a need-based service serving an individual while a train satisfies a larger pool of individuals but at the train’s desired terms (scheduled time and stops). Thus, the same concept is applied in moving the materials from the warehouse to the production line. Under the taxi concept, the goods are supplied individually to the stations as and when the stations ask for them (using frameworks like Kanban), thus establishing a pull system.
This not only removes the dependency of the goods on the other goods (part of the same milk run) but also frees up the conveyance systems as the cycle times are reduced drastically. Now, what may these conveyance systems be? One of the most logical options is to use manual trolleys to move the goods around. This provides the manufacturers with the required autonomy but is it feasible in the long run? It is estimated that the US manufacturing industry will face a labor shortage of 2.4 million by 2028.
The other alternative is the use of AMRs (Autonomous Mobile Robots) which are more efficient than the use of manual trolleys and can be repurposed easily for other operations. Peer Robotics specializes in solving these problems by building out-of-box material handling solutions that can learn from humans. To know more about how Peer Robotics empowers manufacturing industries to implement and adapt flexible operations, reach out to us at www.peerrobotics.ai.
