SMED Guide: A Roadmap to Reduce Changeover Time to Under 10 Minutes
Single Minute Exchange of Die (SMED) serves as the Lean Manufacturing gold standard for operational efficiency. In the high-mix, low-volume reality of modern packaging, the ability to reduce changeover time between SKUs is a critical competitive advantage. Unfortunately, many labeling stations remain stuck in the “craftsman era,” relying on 45-minute changeovers filled with trial-and-error adjustments.
Specifically, prolonged changeovers devastate Availability, the first pillar of Overall Equipment Effectiveness (OEE). Every minute the line sits idle waiting for a rail adjustment is a minute of lost revenue. Consequently, implementing a rigorous SMED guide protocol can effectively recover hundreds of production hours annually.
This guide provides a technical roadmap to reduce changeover time from hours to single-digit minutes. We will explore mechanical upgrades, software recipes, and operational discipline. For a broader view of how availability fits into total efficiency, reference our central hub on High-Speed Labeling Operational Excellence.
1. The Economics: Why Reduce Changeover Time?
Before implementing technical fixes, you must quantify the cost of the problem. Frequently, operations managers view changeover time as a “necessary evil.” However, in a financial context, it is pure waste. To reduce changeover time is to directly increase capacity.
Consider a line rated for 200 bottles per minute. If you perform three changeovers per day, and each takes 45 minutes, you lose 135 minutes of production daily.
135 minutes × 200 bottles = 27,000 lost units per day.
Furthermore, this downtime forces the entire upstream and downstream line to idle. Therefore, the cost of a slow labeling changeover is actually the “Burn Rate” of the entire facility. Following this SMED guide to reduce changeover time to 10 minutes per event recovers 21,000 units of capacity daily without adding new equipment. For more on capacity planning, refer to the NIST MEP Lean Manufacturing Guide.
2. SMED Guide: Internal vs. External Elements
Developed by Shigeo Shingo, SMED separates changeover activities into two distinct categories. To successfully reduce changeover time, you must understand the difference clearly.
- Internal Elements (IED): Tasks that can only be performed when the machine is stopped (e.g., swapping a timing screw, changing the physical label roll).
- External Elements (OED): Tasks that can be performed while the machine is still running the previous job (e.g., retrieving the next roll of labels from inventory, locating the change parts cart).
The fundamental goal of this SMED guide is to shift as many tasks as possible from Internal to External. Subsequently, you must drastically shorten the remaining Internal tasks to reduce changeover time effectively. You can read more about these definitions at the Lean Enterprise Institute.
3. Step 1: Separate Internal & External
The most common cause of inflated downtime is disorganization. Operators often stop the machine and then begin walking to the warehouse to find the next set of labels. This is a critical failure of process that prevents you from being able to reduce changeover time.
Implementation Strategy:
Create a “Pit Stop” mentality. Just as a racing crew prepares tires before the car arrives, your team must stage all materials for Job B while Job A is finishing.
Specifically, utilize a Changeover Cart. This cart should contain the exact guide rails, star wheels, and label rolls required for the next run. Park this cart next to the labeler 10 minutes before the line stops. Consequently, the moment the last bottle of Job A passes, the operator can immediately begin the mechanical swap. This simple step can reduce changeover time by 30% immediately.
4. Step 2: Convert Internal to External
Once you have separated the tasks, look for engineering solutions to convert Internal tasks (machine stopped) into External tasks (machine running). This is a core tenant of any effective SMED guide.
The Splicing Station:
On older machines, threading a new web requires stopping the line. However, modern systems feature independent splicing tables. An operator can load the new roll and tape it to the “standby” block while the current roll is still dispensing.
Pre-Set Guide Rails:
Instead of adjusting a single rail in and out (Internal), consider using “Drop-In” spacers or multi-position turrets. If the rail assembly is modular, an operator can assemble the rail configuration for Job B on a bench (External) and simply swap the entire assembly when the machine stops. This is how you reduce changeover time mechanically.
5. Step 3: Streamline Internal (Tool-Less)
Eventually, the machine must stop. At this stage of the SMED guide, your goal is speed. The enemy of speed is the wrench. If an operator has to find a 9/16″ spanner to loosen a bolt, you fail to reduce changeover time.
Tool-Less Engineering:
Quadrel engineers all change parts for tool-less operation. We replace standard bolts with:
- Ratchet Handles: Permanently attached levers that allow loosening by hand.
- Spring-Loaded Pins: Used for star-wheels and timing screws. Pull the pin, slide the part off, slide the new one on, release the pin.
- Quarter-Turn Locks: For guide rail brackets, allowing for instant release and securement.
By eliminating tools, you eliminate the time spent searching for tools. Furthermore, you prevent the damage caused by over-torquing bolts. To upgrade your existing machinery with tool-less components to reduce changeover time, contact our Parts Department.
6. Step 4: Eliminate Adjustments (Digital Recipes)
The longest phase of any changeover is not the mechanical swap; it is the “tweaking” phase. This occurs when the machine is running, but the operator is constantly adjusting sensors to get the label straight. This is “Tribal Knowledge” dependent and makes it impossible to reduce changeover time consistently.
The Solution: Digital Recipe Management.
Modern servo-driven systems utilize an HMI (Human Machine Interface) to store every electronic parameter. When switching SKUs, the operator selects the product name from a menu. Instantly, the servo motors reset to the exact speed, torque, start delay, and stop position verified for that product.
Digital Counters for Mechanical Axes:
For physical adjustments that cannot be servo-controlled (like head tilt), install mechanical digital counters on the handwheels. The SMED guide recipe sheet should not say “Lower the head until it looks right.” It should say “Set Head Height Axis to 145.2.” This converts a subjective “art” into an objective “science” to reduce changeover time.
7. Zero-Downtime Redundancy Strategies
The ultimate realization of SMED is Zero Changeover Time. This is achieved through redundancy.
In a “Zero-Downtime” configuration, the labeling system is equipped with two or more applicators programmed in a specific logic sequence.
- Scenario A (Roll Change): Applicator 1 runs until the roll is empty. The system detects the “Low Label” signal and instantly triggers Applicator 2 to take over. The line never slows down.
- Scenario B (Product Change): If the line runs mixed SKUs, Applicator 1 can be set up for Product A, and Applicator 2 for Product B. The vision system reads the incoming bottle and fires the correct labeler dynamically.
For high-volume facilities, this redundancy is the most effective way to reduce changeover time to absolute zero. Explore our Labeling Machine Systems to see these configurations in action.
8. Establishing Standard Work & Training
Technology fails without discipline. To sustain sub-10-minute changeovers and permanently reduce changeover time, you must document the process.
Create a Standard Work SOP that choreographs the changeover like a ballet.
Example:
1. Operator A clears the infeed (0:00 – 0:30).
2. Operator B swaps the timing screw (0:00 – 1:00).
3. Operator A loads the new recipe on the HMI (0:30 – 0:45).
Laminate these cards and attach them to the machine. Furthermore, perform regular “Pit Stop Drills” with a stopwatch to identify wasted motion and refine the SMED guide process. External training resources from organizations like the Shingo Institute can provide additional templates.
9. Required Technology Upgrades
If your current equipment relies on clutches, brakes, and potentiometers, achieving the goals of this SMED guide may be physically impossible. The following technologies are prerequisites to reduce changeover time:
- Servo Motion Control: For instant digital recall of speeds.
- Quick-Change Mounting: Dovetail or pin-lock mounts for peel plates.
- Intelligent HMI: Capable of storing 50+ recipes.
- Splicing Tables: For rapid web joining.
10. Request a SMED Audit
Is your line losing hours every day to slow changeovers? Our engineering team can audit your current setup and recommend specific SMED upgrades—from digital counters to full servo retrofits—to reduce changeover time dramatically.