1. Method Name

SMED (Single-Minute Exchange of Dies)

2. Alternative Names

Quick Changeover (QCO), OTED (One-Touch Exchange of Die)

3. Brief Description

SMED is a system designed to dramatically reduce the time required to change over a machine or production line from one product type to another. The goal is to achieve a changeover time measured in "minutes" (i.e., less than 10 minutes).

4. Purpose / When to Use

It is used to increase production flexibility, reduce batch sizes, and unlock hidden machine capacity. By shortening changeover times, costs associated with downtime are reduced, the need to maintain high inventory levels decreases, and the company can respond more quickly to changes in customer demand.

5. Procedure / How to Apply It

Phase 1: Separating Internal and External Activities
—Analyze the Current Setup: Record the entire setup process on video and analyze it with the team of operators and maintenance technicians.
- Internal Activities (Internal Setup): Steps that can only be performed when the machine is stopped (e.g., changing the mold or tool).
- External Activities (External Setup): Steps that can be prepared while the machine is still running (e.g., bringing in a new mold, tool, or material; preheating the mold).

Phase 2: Converting Internal Activities to External Ones
—Convert as many internal steps as possible to external ones. Example: Instead of looking for tools after the machine has stopped, prepare them in advance. Instead of waiting for the mold to heat up inside the machine, use an external preheating station.

Phase 3: Streamlining all activities (both internal and external)
—Optimize the remaining steps. Use Poka-Yoke, standardize tools, implement quick-release mechanisms instead of screws, eliminate the need for adjustments and measurements, and involve multiple workers simultaneously in the changeover (parallel operations).

Phase 4: Repetition and Standardization
—Standardize the new setup procedure and train all workers on it.
—Repeat the cycle and look for further opportunities for improvement.

6. A Real-World Example

The changeover of the press for the production of plastic parts took 90 minutes. Using SMED analysis, the team determined that it took 40 minutes to locate and prepare the new mold and tooling while the press was already idle (internal activity). They moved this step to external activities (preparation took place during the production of the previous batch). They saved another 20 minutes by introducing quick-release clamps instead of 16 screws and by standardizing the height of all molds, which eliminated the need for adjustment. The changeover time dropped from 90 to 8 minutes.

7. Benefits

- Increased flexibility: Allows for small-batch production and quick responses to changes in orders
.- Reduced inventory: When small-batch production is possible, there is no need to maintain large inventories of finished products.
- Increased capacity (OEE): Reducing downtime means more time for actual production
.- Cost reduction: Lower inventory levels and higher productivity lead to savings.

8. Risks / Limits

- Ignoring external activities: Teams often focus solely on internal activities and forget that preparatory work can also be made significantly more efficient.
- Inadequate preparation: If external activities are not performed correctly and on time, the entire changeover may be delayed.
- Safety risk: The pursuit of maximum speed must not come at the expense of workplace safety.
- Requires investment: Some improvements (e.g., quick-change systems, duplicate fixtures) may require an initial investment.

9. Practical Tips

- Video analysis is key: People often don't realize how much time they waste on unnecessary movements. Video reveals this without compromise.
- Start with the longest setup time: Focus on the bottleneck where reducing time will have the greatest impact.
- Teamwork is essential: Involve operators, setters, maintenance staff, and designers in the SMED workshop. They know the details best.
—The goal is not just speed, but also changeover quality: A fast but inaccurate changeover, followed by the production of defective parts, is a waste.