How To Reduce Changeover Time In Manufacturing? Key Facts

Reducing changeover time in manufacturing means cutting the time it takes to switch a production line from making one product to making the next. The most proven method is SMED, which stands for Single-Minute Exchange of Die. This system helps teams separate internal steps, which require the machine to stop, from external steps, which can be done while the machine is still running. By moving as much work as possible to the external category, manufacturers can shrink changeovers from hours to minutes.

What Exactly Is Changeover Time?

Changeover time is the period between the last good piece of one product and the first good piece of the next product. It is not just the physical act of changing a die or a tool. It includes cleaning, adjusting, testing, and any waiting that happens during the switch.

Manufacturers measure this in different ways. Some track total downtime from stop to restart. Others measure from the last good unit to the first confirmed good unit of the new run. The second method is stricter because it includes trial runs and adjustments. Both are useful, but consistency matters more than which one you choose.

Long changeovers are expensive. Every minute the line is stopped, the company is not producing sellable goods. This is why reducing changeover time is a direct path to higher output without adding new machinery or staff.

How Does SMED Reduce Changeover Time?

SMED is a structured approach developed by Shigeo Shingo at Toyota. It treats changeover as a process that can be studied and improved, not a fixed event. The method breaks every action into two categories.

Internal actions require the machine to be stopped. Removing a mold, changing a blade, or swapping a nozzle are internal actions. External actions can happen while the machine is running. Gathering tools, preheating parts, and staging materials are external actions.

The core of SMED is simple: convert as many internal actions to external actions as possible. Then streamline the remaining internal actions so they take less time. This is not theory. It is a documented practice used across automotive, food, packaging, and electronics manufacturing for decades.

The “single minute” in SMED does not mean every changeover must be under ten minutes. It means the goal is to get changeovers into single-digit minutes. Some changeovers, especially on large equipment, will realistically take longer. The framework still applies.

What Are the First Steps to Reduce Changeover Time?

Start by watching a real changeover. Do not rely on memory or written procedures. Stand at the machine with a stopwatch and record every action, no matter how small. Note who does what, what tools they use, and where they walk.

Video recording is especially useful here. A camera captures details people miss in the moment. Reviewing the footage as a team often reveals steps that seem necessary but are actually just habits.

After documenting the current process, sort every step into internal or external. Most teams are surprised to find that a significant portion of the work could have been done before the machine stopped. For example, workers often walk to a tool crib during the changeover to fetch wrenches. That is an external step happening internally.

This first pass alone often cuts changeover time by 30 to 50 percent. No new equipment is needed. The gains come from simply doing the right work at the right time.

How Do You Convert Internal Steps to External Steps?

Conversion is the heart of SMED. The goal is to make every possible preparation happen while the machine is still producing the previous product.

Standardize tool placement. If every changeover requires the same three wrenches, keep those wrenches at the machine. Do not make workers search for them. Shadow boards with outlined tool shapes make missing tools obvious at a glance.

Pre-position the next die, mold, or material near the machine before the changeover starts. If the machine is still running, a worker can stage everything needed for the next job. When the machine stops, the team begins with everything at hand.

Perform preheating or pre-cleaning off-line when possible. Some dies need to be warm before use. Heating them while the machine is running saves minutes. Cleaning parts that are removed from the machine can happen at a bench, not on the production floor.

Checklists are a simple but powerful tool. A laminated checklist at each station ensures no step is forgotten. It also gives new workers a clear procedure to follow instead of relying on tribal knowledge.

What Role Do Parallel Operations Play?

Parallel operations mean having two or more people working on different parts of the changeover at the same time. One person removes the old tool while another adjusts the guides. This requires planning, but the time savings are substantial.

Many changeovers are done by one person sequentially. They remove, clean, install, adjust, and test one step at a time. Splitting these tasks across two workers can cut total time nearly in half, assuming the tasks do not conflict in the same physical space.

Parallel work has limits. Safety comes first. Two workers cannot be in the same pinch point or operating the same controls. The changeover plan should specify who does what and where, so workers do not get in each other’s way.

This step often requires cross-training. A team where only one person knows the changeover cannot work in parallel. Investing in training so multiple people can perform each role pays off directly in reduced downtime.

How Do You Streamline the Remaining Internal Steps?

After converting what you can, the remaining internal steps need to be faster. Look at each one and ask why it takes as long as it does.

Fasteners are a common bottleneck. A die held by twelve bolts takes longer to remove than one held by four quick-release clamps. Replacing bolts with clamps, or reducing the number of fasteners, is a mechanical change that saves time on every future changeover.

Adjustments are another major time sink. Workers often install a new tool, run a test piece, measure it, and adjust. Repeating this cycle takes time. Standardizing the installation position so the tool goes in at the correct setting the first time eliminates trial-and-error. This is sometimes called “one-touch” setup.

Consider whether adjustments can be made with dials and scales instead of guesswork. A numbered dial that records the correct setting for each product removes the need to measure and adjust from scratch.

Standard work documents every step, its order, and the time it should take. This turns the changeover into a repeatable procedure rather than a performance that varies by shift.

What Is the Role of Maintenance in Faster Changeovers?

Changeover time is heavily influenced by equipment condition. A machine that is well-maintained is easier to adjust and more predictable. Worn guides, sticky slides, and loose tolerances all add time to setup.

Regular preventive maintenance reduces the chance that a changeover reveals a broken part. Discovering a damaged component mid-changeover turns a 30-minute setup into a multi-hour repair.

Some manufacturers integrate changeover-related checks into their preventive maintenance schedule. For example, verifying that locating pins are not worn is a maintenance task that directly supports fast changeover.

Involving maintenance staff in changeover improvement projects is often necessary. They understand the equipment’s condition and can recommend design changes that make future changeovers faster.

How Do You Measure and Sustain the Improvement?

Track changeover time for every setup, not just the ones you are working on. Use a simple log or a production dashboard. The data shows whether improvements hold or drift back over time.

Set a target for each machine or line. The target should be based on what the SMED analysis suggests is possible, not an arbitrary number. Review actual times against the target on a regular basis.

Improvement is not a one-time event. Teams should periodically re-examine the changeover process and look for new waste. As products change and equipment ages, the best procedure from last year may no longer be the best one today.

Celebrate and document wins. When a team finds a way to save five minutes, write it into the standard work. That small gain compounds across every future changeover on that machine.