In most factories, one machine is used to manufacture multiple products. Therefore the machine’s modules and parameters are set up for a specific product. This setup change often takes a lot of time. The goal of the SMED method is to reduce setup changes to the lowest possible duration of often single-digit minutes, which is why it is called Single Minute Exchange of Die.
Through a reduction of setup times, machines can be more productive and manufacture more parts within a given time frame. Furthermore, products can be changed more often allowing higher flexibility and faster reaction to external fluctuations. SMED also enables the line balancing on multi-product lines and the implementation of the EPEI concept.
Every machine setup consists of multiple smaller tasks that need to be executed. First, all tasks to prepare a machine for another product are consolidated in an overview. Then the following techniques are applied:
Internal operations are executed within a machine and can therefore only be conducted if the machine has stopped.
Shifting operations from internal to external setup allows the reduction of machine downtime since setup operations can now be conducted outside the machine, while it is still running.
Setups are often conducted on multiple sides of the machines. Walk-ways around the machine account for a significant time loss. Changing the setup of a machine with two operators often reduces setup time to more than half, since walkways are saved.
A setup matrix is used to determine how long the setup changes between products are. By measuring the time from one setup to another the setup matrix is filled out.
An up-to-date setup matrix, especially on a bottleneck resource, enables the manufacturer to adjust the model mix based on customers’ needs and the fastest possible setup at the bottleneck. In this example the best model sequence can be derived as A->B->D->C (also see EPEI).
Setting up a machine for the next product can be challenging for operators due to the vast number of parameters that need to be adjusted. WORKERBASE provides line change over app solutions as digital work instructions on mobile devices to display each step in the fastest order and give operators guidance on how to execute steps. The more complex a setup, the higher the gain trough digital work instructions.
Using digital work coordination to distribute tasks (such as setups) based on skills on prioritization (the sooner an external setup needs to be executed, the higher its priority) allows time measurement of setup changes on an aggregated and anonymized level. With this data setup matrices for each machine can be generated. Based on historic and real-time data optimized model sequences are derived, leading to efficiency gains through the whole production chain.
For more examples on how to improve lean manufacturing with digital tools, please read our guide to lean digital.
Author: Marius Maier, Digital Transformation Consultant, WORKERBASE