What Does SMED Mean in Manufacturing?
Single Minute Exchange of Die (SMED) is a manufacturing tool used in production plants to reduce equipment (die) changeover time during the manufacturing of a product. Changeover time refers to how long it takes to change one piece of equipment to another while manufacturing different product types. In production plants, while making various components or parts of a product, different equipment is used at different intervals an the process of equipment transitioning while manufacturing is a changeover.
Die is a piece of manufacturing equipment that is used for stamping the design, form, shape, and size of a product on it. A die set is primarily used for cutting, bending, forming, drawing, and squeezing. Exchange refers to the exchange from die to die in the production of different products. SM stands for Single-Minute and emphasizes that the changeover time of dies should take less than 10 minutes.
In short: SMED is an approach used in certain types of production plants to streamline the changeover of dies while ensuring everything is performed within a single-digit time-frame.
SMED’s core principle is to upgrade manufacturing efficiency and quality by simplifying the process changeover time and reducing the time of uniformity and irregularity. The methodology involves implementing five processes which can be summarized as follows:
- Identifying the process needed
- Removing all external and internal element (trimming)
- Convert internal activities into external activities
- Create and standardize the process
- Continue your team’s training
These five processes make up the basic SMED methodology that sums up the changeover process and reduces the number of waste time experienced. It basically involves trimming down any unnecessary activity, while at the same time standardizing and streamlining the whole process in order to make it as fast as possible.
In this guide, we’ll discuss:
The SMED Process in 5 Steps
To successfully implement SMED in your production plant, you must follow a series of steps or processes that will help you organize your activities in order of preference. SMED basically involves finding out what you need to do on the machines or as a human to reduce changeover time. This goal can be achieved by adhering to the following 5 steps:
1. IDENTIFY THE PROCESS NEEDED
This is where various questions concerning the current condition of the changeover process are being considered. It involves identifying the human and mechanical elements affecting changeover at the current moment in time. Quality managers need to ask themselves what they need to adjust in their processes, what the most extended delays and fastest turnarounds are, and how the organization can further improve and become more efficient, etc.
After considering various questions, you’ll be able to clearly identify all external and internal elements involved in a changeover process. Identifying these elements will give you a clearer picture of what is wrong or what should be done to increase how fast the changeover of dies should take place.
2. SEPARATE EXTERNAL ELEMENTS FROM INTERNAL ELEMENTS
External elements are the tasks to be done in a changeover process while the machine is still operating or in the middle of manufacturing a product. Internal elements, on the other hand, refer to the activities in a changeover that need to be done while the machine in question is shut down or not working on any product.
Separating the external from the internal elements will enable operators or managers in charge to understand what needs to be done or eliminated in order to increase the speed and efficiency of a changeover process.
3. CONVERTING INTERNAL ACTIVITIES INTO EXTERNAL ACTIVITIES
After identifying and separating the internal and external elements, the next step is to convert internal activities into external ones. While converting, operators or managers should remember that the time saved due to the conversion must be greater than the resources it took to implement the change. If the cost (resources) of internal to external change is greater than how much time the change brought you, then the principle of SMED is compromised and defeats the purpose of the operation, nullifying all efforts.
Internal activities can be transformed into external activities using intermediate or duplicate jigs. A duplicate jig is employed in order to have another product prepared while one product undergoes processing. When the latter is processed, the former can be easily transferred to the equipment while it’s still running.
This effectively reduces the waste of time involved in changeover processes by eliminating the time it would take to switch machines off and on while manufacturing different products. Converting as many internal elements to external elements helps dramatically reduce unnecessary actions in exchanging die to die.
4. STANDARDIZED AND STREAMLINE THE PROCESS
It is nearly impossible to have all internal activities converted into external activities. However, streamlining and standardizing the changeover process means trimming down all the internal activities that could not be converted into external activities to further raise the speed of changeover. All unnecessary actions involving the rest of internal practices should be eliminated or cut down to the necessary minimum to save time.
In this stage, there needs to be an established flow of communication among team members and operators. When everyone is clear on how the project has changed and what internal activities have been converted to external activities, accomplishing and executing tasks can be done efficiently.
5. CONTINUE TEAM TRAINING
Once all processes are defined, standardized, and implemented, the last process for increasing the impact time of SMED is to train new members, employees, or operators. If new members are not trained to understand the processes and changes, machines will not be able to compensate for the lack of incompetent human supervision and support.
Investing in human elements is the most signifying way to accelerate the progress of SMED in a plant. Creating technically proficient teams rather than over-focusing on technical elements through engineering is a much more concrete approach to preserving the policy of SMED. Improving both human and technical elements still supports the Single Minute Exchange of Dies and makes it long-lasting and successful.
What Are The Benefits of SMED?
As previously touched upon, the primary objective of SMED process implementation is to reduce equipment changeover time. However, this can also create a domino effect on other manufacturing and production areas. There are five main benefits of the Single-Minute Exchange of Die Process, which are:
- Increased Work Capacity of Machines: The successful implementation of the changeover process will increase the capacity of work that equipment can do. If all unnecessary actions are eliminated, there is more time for machines to produce more goods.
- Changeover of Equipment Completed More Often: When all the processes involved in equipment changeover are being streamlined regularly, changeover of equipment can be completed more often. This is because there won’t be room for any irregularity or intrusion causing a halt in action. Operators only need to know the suitable adjustments, techniques, and measures to be iterated while changing from one die set to another.
- Reduces Production Lot Sizes: If SMED principles are being acted upon in a plant, it will cause more efficiency in the production of products because machines will only produce the amount of product demanded at the right quality and at the right time. This will reduce stock holdings, lower the level of inventory, and lessen the existence of waste. While there is less space and handling required, customer needs will be promptly addressed.
- Standardization: The Single-Minute Exchange of Die standardizes changeover procedures by improving the quality and speed of machine work. In a more standardized process, there will be less room for errors, mistakes, or accidents. Machine productivity will be consistent, and there will be little to no room for defective products.
- Low Production Cost: Thanks to proper planning and streamlining, production costs will decrease as machines no longer need much technical intervention. This means that the cost for periodic machine maintenance will reduce as equipment will not need to be checked as frequently as it used to. SMED also supports machine longevity, so all costs directed towards production and machine functionality will be minimized due to reduced equipment downtime.
Who Needs SMED?
The SMED approach might not be the right Lean tool for your production plant needs – but how can you tell? Depending on your production process and what type of product you’re manufacturing, SMED might not be applicable for efficiency or any improvement purpose. Here are things you need to consider before deciding to apply the Single-Minute Exchange of Die (SMED) approach:
- As a manufacturer, you need to consider having a system that measures manufacturing performance data. There needs to be a metric that estimates customer and employee satisfaction, internal process quality, equipment ROI, product business and technical performance, e.t.c.
- Should you have a system that measures manufacturing performance data, does it measure overall equipment effectiveness (OEE)? OEE is a gold metric for determining the effectiveness of equipment and manufacturing productivity. It focuses on 3 main elements, which are availability (how well a process runs), performance (how fast a process runs), and quality (how many good parts are being produced).
- You must have collected manufacturing performance data of at least 14 days.
- You need to consider the production time lost due to the changeover.
- After calculating the percentage of lost productive time due to changeover and discover that it is below 20%, then you should consider implementing Total Productive Maintenance (TPM) techniques rather than SMED.
- Is there familiar equipment in your plant with constraints that take an hour or longer for changeover? And does this changeover happen more than once a week?
- Is there control of inventory?
If all of the following requirements above have been met, then you can proceed to implement SMED on the changeover of equipment and reap the benefits of SMED.
SMED In Action: 2 Examples
To help you better understand the Lean Manufacturing tool SMED and its implementation, we will explore some use cases and show you how SMED can be implemented.
Example 1: Health
Say an operating room or patient room needs a bed turnover; the process of turning the over is recognized as the changeover process. The equipment involved is the operating room and the bed. The time the equipment is running is when the operating room and bed are in use, while the time the equipment is stopped is when the operating room and bed are not in use. The elements involved in the changeover process will include cleaning the operating room, disinfecting the operating room, and preparing the operating room or bed for next use.
Now, to implement the SMED process, you would first have to identify the internal and external elements in the process. The internal elements, in this case, involve disinfecting and cleaning the operating room and bed, while the external elements involve preparing the room or bed for subsequent use. Secondly, it is necessary to convert the internal process to an external process. In this stage, you can, for example, convert cleaning of the room to an external element or activity while leaving disinfecting as an internal activity because it can be harmful to disinfect the operating room while it’s in use.
Lastly, streamline the entire process by making sure that certain disinfectant and cleaning procedures are followed. Other factors like staff competency (agility, skills, etc.) and tools functionality are considered to ensure that the changeover (bed turnover process) is efficient. The main purpose of this last step is to make all internal changeover activities easier.
Example 2: Hospitality
As a second example we look at the preparation of two types of meals in a restaurant setting. In this case, transitioning from preparing meal A to meal B is the changeover. The equipment involved will be the cooking tools and ingredients. The equipment time is running when the chef is cooking and the stove is on. While the time the equipment is not running is when the chef is not cooking and the stove is off. The internal and external elements will include getting ingredients and cooking tools for meal B, and preparing cooking tools for use, respectively.
In the last step, you should perform tasks that make the changeover easier, faster, and more efficient by placing the ingredients and cooking tools for meal B on standby, preparing the ingredients (like cutting tomatoes, onions, or breaking eggs), etc. In this process, you’ll need to reduce the amount of unnecessary actions to streamline the changeover process.