Raising production quality and efficiency are two goals that companies have sought to perfect over time, in order to increase productivity and improve the quality of service and customer relationships.
This idea gave rise to the Single Minute Exchange of Die philosophy, known by its acronym SMED. The principle consists of reducing production times as far as possible, including the time spent changing tools or machines. In its most basic definition, the aim of this philosophy is for such changeovers to take less than ten minutes, so that work flows faster.
What is the SMED philosophy?
The principles and methodology of SMED can be applied to all kinds of machines and equipment that require optimum performance and greater agility in their production processes.
By applying this philosophy, the goal is to optimise the changeover processes carried out while the machine is stopped or idle, in order to minimise the time taken to move from one batch to the next, or to switch from one tool to another.
In other words, SMED techniques make it possible to change the tools in use in the shortest possible time, improving response times without compromising process quality. Essentially, the idea is to “eliminate” the period during which the machine is stopped, which adds no value to the process.
Stages of the SMED process
The SMED philosophy can be divided into four stages:
- Study the set-up operation: this involves observing and analysing how the batch changeover is carried out and how long it takes, in order to find the best way to reduce the changeover time, i.e. the time between producing the last part of one batch and the first part of the next. This study looks in detail at every step and movement made by operators when fetching parts, completing quality control forms, and removing and fitting the new parts to start the new batch.
- Separate internal and external tasks: at this stage, tasks carried out internally (with the machine stopped) are separated from those that can be performed while the equipment is running. During the analysis, it is important to keep a list specifying the tasks and the tools used, checking how they are performed and whether execution times are met.
- Convert internal tasks into external tasks: the team analyses the machine’s internal set-up in depth to decide which tasks can be done before stopping it, so as to reduce the changeover as much as possible. At this stage, the aim is to turn internal tasks into external ones, so that they can be carried out while the machine is running, thereby shortening the duration of internal tasks. One example is preparing the tools needed for the next batch, which can be done before the machine is stopped so that the changeover starts just in time.
- Refine the tasks: this stage involves continuing to apply the process, making fewer and fewer movements while the machine is stopped, and optimising the processes step by step.
It is worth remembering that the aim of SMED is to reduce changeover time, so that smaller batches can be produced, less raw material needs to be stored, company productivity increases and, of course, time and other resources are used more efficiently.
Benefits of the SMED philosophy
Implementing SMED techniques is ideal for changing tooling in the shortest possible time, which brings the following benefits:
- Shorter production times.
- Smaller batch sizes.
- Faster response times.
- Better customer service.
- Lower manufacturing costs.
- A more flexible production process.
- Greater company competitiveness.
- Lower inventory levels.
- A more agile company management system.
- Overall optimisation of all processes.
SMED was created to reduce tool changeover times and speed up batch production, so that the company can perform better in its activities, respond to customer requests on time and optimise all its internal and external processes.