SMED: A Blueprint for Responsive, Small-Lot Production

By Allan Ung | Founder & Principal Consultant, Operational Excellence Consulting (OEC)

Published: 04 August 2026

Internal setup stops the machine; external setup doesn't — and once you see that trial runs and adjustments alone eat half of traditional setup time, it's obvious where the first three stages of SMED need to aim.

Allan Ung is the Founder and Principal Consultant of Operational Excellence Consulting (OEC), a Singapore-based management training and consulting firm established in 2009. With over 30 years of experience across operations and quality leadership — including senior roles at IBM, Microsoft, and Underwriters Laboratories (UL) — Allan teaches SMED as a core changeover-reduction module within his Lean Thinking and Value Stream Mapping workshops for manufacturing teams across Singapore and the region.

He holds a Bachelor of Engineering (Mechanical) from the National University of Singapore and completed advanced consultancy training in Japan as a Colombo Plan Scholar. Allan is a Certified Management Consultant (Japan), a Certified Lean Six Sigma Black Belt, and an accredited TPM Instructor.

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Every changeover I've ever timed on a shop floor takes roughly the same shape: a machine that could be producing sits idle while someone searches for a wrench, waits for a mold to heat, or nudges a gauge into position by feel. None of that idle time is inevitable — SMED exists to strip it out, one stage at a time.

Single-Minute Exchange of Die (SMED) is a theory and set of techniques, developed by Shigeo Shingo, that make it possible to perform equipment setup and changeover operations in under ten minutes — the "single-minute" range. It was worked out on die-press and machine-tool setups, but its principles apply to changeovers in any process, on any equipment. The single-minute range isn't always reached in practice, but SMED cuts setup time dramatically in almost every case regardless. I introduced SMED briefly in the JIT Support Tools guide in this series, as one of three daily disciplines that keep the Lean Production System honest on an ordinary shift. This guide is where I go deep — the full three-stage method, the techniques inside each stage, and the worked examples that make the difference between reading about SMED and actually applying it to a real changeover.

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✅ The 3-Stage Transformation Roadmap: Master the disciplined logic of Separating, Converting, and Streamlining setup operations to move from hours to under 10 minutes.

✅ Technical Execution Library: Professional blueprints for implementing Functional Clamps, Intermediary Jigs, and Parallel Operations.

✅ Target the "50% Waste": Specialized techniques to eliminate trial runs and adjustments—the largest single consumer of setup time.

✅ Facilitation-Ready Assets: Includes 5 interactive team activities and setup analysis tools (Video & Motion Study) to drive immediate results on your own equipment.

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The Trouble with Large Lots

Long setup times push companies toward large lots — running as much volume as possible per changeover, to spread that changeover cost across more units. It looks efficient on paper. In practice, large lots create four problems of their own: excess inventory sits as stock, tying up cash and floor space; the company can't respond quickly when customer demand shifts; defects hide inside a large lot until the whole lot has been processed and someone finally finds them; and carrying, storing, and handling all that excess stock adds real cost that never shows up as "changeover time" on any report.

The relationship is direct and worth stating plainly: long changeovers force large lots. Short changeovers make small lots — and the flexibility that comes with them — genuinely possible.

The benefits run in both directions once changeover time actually shrinks. For the company, quicker setups make smaller-lot, wider-variety production practical, sharpen the ability to respond to customer orders and demand changes, cut inventory carrying cost and waste, and catch fewer defects reaching the customer because lots — and the problems hiding inside them — stay small. For the person doing the changeover, quicker setups mean smoother, less stressful daily work; fewer rushed and complicated steps, which means fewer chances for injury; and fewer tools to keep track of, which means a cleaner, more organised workstation. SMED's benefits aren't a management-side argument dressed up to sound good for operators — they land on both sides of the same changeover.

Where Setup Fits Inside a Manufacturing Process

Before touching the three stages, it's worth being precise about two words that get used loosely on most shop floors: process and operation.

A process is the continuous flow in which raw materials are converted into finished products — simply put, the way something gets made. Every manufacturing process moves through four basic phases: storage, transport, processing, and inspection. An operation, by contrast, is any specific action performed by workers or machines on those materials — what you actually do to make something. Every process is built from a network of these operations, nested inside its phases.

Within the processing phase, operations split further into two kinds. Essential operations are the actual value-adding work — the real machining, forming, or assembly that changes the part into what it needs to become. Setup operations are the preparation and after-adjustment performed once before and once after each lot is processed. This guide is entirely about that second category.

Setup operations themselves split into two kinds, and this distinction is the one everything else in SMED is built on:

Internal setup can only be done while the machine is shut down — a new die can only be attached to a press when the press is stopped. External setup can be done while the machine is still running — bolts to attach to that die can be assembled and sorted while the press keeps operating on the previous lot.

Every technique in this guide builds on one core idea: move as much work as possible out of internal setup and into external setup. The reason is arithmetic, not philosophy — every minute of internal setup is a minute the machine isn't producing. And the reason there's usually room to move things is habit, not necessity: tasks are frequently done internally simply because that's how they've always been done, even though nothing about them actually requires the machine to be stopped. If a task can be prepared, moved, or checked while the machine runs, it belongs in external setup. Separating internal from external is the first and most important stage of SMED, covered in detail below.

The Four Steps Inside Every Setup — and Where the Time Actually Goes

Before SMED is applied to a setup, that setup — regardless of the equipment or the operation — breaks down into the same four steps every time:

Step 1: Preparation and checking. Ensuring all parts and tools are where they should be and functioning properly, plus the after-process period when these items are removed and returned to storage and the machinery is cleaned. This step accounts for roughly 30 percent of total setup time before improvement.

Step 2: Mounting and removing. Removing the parts and tools used for the finished lot and attaching the parts and tools for the next one. This is generally internal setup — the machine has to be stopped to do it — but it takes surprisingly little time compared to the other three steps: only about 5 percent.

Step 3: Measurements and calibrations. All the measurements and calibrations needed to perform the next production operation — centering, measuring temperature or pressure, dimensioning, and similar checks. This step accounts for about 15 percent of total setup time.

Step 4: Trial runs and adjustments. Test runs and fine-tuning performed after mounting and calibration, before full production resumes. This is the largest single consumer of setup time by a wide margin — about 50 percent — and consequently the biggest single opportunity for improvement. Stage 3 of SMED, covered later in this guide, targets it directly.

Put together, that's a 30/5/15/50 split — preparation and checking, mounting and removing, measurements and calibrations, and trial runs and adjustments, in that order. It's the exact breakdown shown in this article's cover graphic, and it's worth sitting with for a moment: the step that actually changes anything on the machine — mounting and removing — is the smallest slice of the pie. Almost everything else is preparation, checking, and fixing what wasn't quite right the first time.

Before you can apply any of the three SMED stages, you need an accurate picture of how a setup is actually performed today — not what you assume it involves. Setup analysis uses three complementary methods: videotaping the entire setup operation from start to finish, capturing every step as it actually happens; interviewing the setup person and others involved about what they did and why, step by step; and studying the time and motion involved in each step to find waste and improvement opportunities. Together, these three methods reveal what a setup truly involves, which is very often not what the people running it would tell you from memory alone.

The Three Stages of SMED, at a Glance

The SMED approach to changeover improvement runs in three stages, and the relationship between them matters as much as the content of any single one. Every stage depends on first telling internal and external setup apart — that's the foundational move. Each stage builds directly on the improvement made in the one before it — that's the progressive part. And together, the three stages take setup time from tens of minutes toward single minutes — that's the practical payoff.

Stage 1 separates internal setup from external setup. Stage 2 converts internal setup steps to external wherever the true function of the step allows it. Stage 3 streamlines everything that's left, in both categories. Before SMED, a setup has internal and external tasks tangled together, undifferentiated. Each stage narrows the gap between that starting point and a genuine single-minute changeover.

Stage 1: Separating Internal and External Setup

Stage 1 is the single most important step in the whole system, and it's also the simplest to describe: tasks that can be carried out while the machine is operating are separated from tasks that must be performed while the machine is stopped. Certain tasks can clearly be done before the machine is stopped — lining up the right people, preparing parts and tools, making repairs, bringing parts and tools closer to the equipment. In practice, it's surprising how often these tasks get done after the machine has already stopped, instead of while it's still running the previous lot. Separating these tasks and performing them as external setup, on its own, can cut changeover time by as much as 30 to 50 percent — before Stage 2 or Stage 3 are even applied.

Three practical techniques help you make this separation.

Checklists. A checklist lists everything required to set up and run the next operation — the employees needed, the parts, the tools, and the standard operating procedures to follow. Checking items off before the machine is stopped helps prevent oversights and mistakes that would otherwise surface only after internal setup has already begun, and it helps you avoid errors and multiple test runs later. The deck this guide draws from includes a sample checklist for a line changeover — employees trained for the setup, the specific parts and tools needed down to the wrench size, and the SOPs to follow — verified in full before the machine ever stops. The important discipline here is specificity: build a checklist for each machine or operation individually. A general checklist meant to cover an entire shop tends to be confusing, and it tends to get lost and ignored.

Function checks. A checklist confirms you have the tools. A function check tells you whether those tools and parts are in perfect working order. Function checks should be done well before setup begins, so that repairs can be made if something doesn't work right. If a broken die, mold, or jig isn't discovered until mounting and a test run are already underway, internal setup is delayed with the machine stopped and production waiting — exactly the outcome Stage 1 exists to prevent. The fix is to perform the function check while the machine is still running the previous lot, as external setup, so any needed repair happens before the changeover instead of during it.

Improved transport. Dies, molds, tools, jigs, and gauges have to move between storage and the machine, then back again once a lot is finished. To shorten machine downtime, that transport should happen during external setup: new parts and tools moved to the machine before it's shut down, and old parts and tools left in place — not put away — until the new ones are installed and the machine is running again.

A representative case: a press shop's die changes required a forklift trip to the die crib, but operators only called for the next die after the machine had already stopped, leaving it idle while the die was located and driven over. The team began transporting the next die to a staging area beside the press while the current lot was still running, so the machine's only remaining internal task was the mount itself. They also arranged to move the just-finished die back to storage only after the new die was mounted and running, so return trips never added to machine downtime. The result: die transport moved entirely to external setup, and internal setup shrank to mounting alone. The die still has to move — the only question Stage 1 answers is whether the machine has to wait for it.

The die still has to travel from storage to the machine either way — Stage 1 doesn't eliminate that trip, it just moves it off the machine's clock, so the only internal task left is the mount itself. Source: OEC SMED Training.

Stage 2: Converting Internal Setup to External Setup

Stage 1 alone cannot reduce internal setup into the single-minute range — it separates what's already there, but it doesn't create new options. Stage 2 is what gets you the rest of the way, and it works through a simple two-step test applied to every internal-setup step still on your list: look at the true function of that step, then find a way to convert it to external setup — something you can do while the machine keeps running.

The key discipline in Stage 2 is looking at your current internal setup as if seeing it for the first time, without letting old habits and assumptions stand in the way of change. Three practical techniques make the conversion possible.

Advance preparation of operating conditions. Get parts, tools, and operating conditions ready before you stop the machine for changeover. The classic example is preheating a die mold while the previous lot is still running, instead of waiting until after the machine stops — the mold is already at temperature the moment mounting begins. The same logic applies to pressure, alignment, or any other operating condition the next run needs: whatever can be brought to the right state in advance should be, so the machine never idles waiting for it. The heating, or the pressurising, or the aligning still has to happen somewhere — Stage 2 just moves the question of whether the machine has to wait for it, same as Stage 1 did for transport.

Preconditioning the die mold before the machine stops doesn't remove the heating step — it removes an entire wait step from internal setup, which is where the actual time saving comes from. Source: OEC SMED Training.

Function standardization. Standardize only the functions that are essential to setup — not every part. Look closely at each individual function in the setup, such as clamping, centering, or dimensioning, and decide which of those functions can realistically be standardized across dies or tools. Then find the way to make that function more efficient by replacing the fewest parts possible — the quickest way to replace something is to replace as little as possible, or nothing at all. A press shop running several die sets, each with its own clamp size and bolt pattern, had operators hunting for and hand-fitting matching clamps at every changeover; standardizing only the clamping function — fitting every die with the same clamp height and bolt spacing — meant one common set of clamps fit them all, and clamp search-and-fit time dropped to near zero, while the dies themselves stayed different in every other respect. The same idea shows up in two other forms: centering moved onto a standardized external jig, done before the die reaches the machine rather than on the machine bed after mounting; and dies loaded into standardized cassettes that slide into a common mounting frame, so the frame — not the die — stays fixed to the machine.

Intermediary jigs. Two identical jig plates, used alternately, keep the machine running while the next setup is prepared. While a workpiece or die attached to one jig is being processed, the next workpiece or die is centered and attached to the other, identical jig. When the first workpiece finishes, it's removed from the machine still attached to its jig, and the second jig — already loaded with the next workpiece — is mounted immediately. Centering and attaching never happen on the machine itself; they always happen on the jig that's currently off the machine, as external setup. A press line running several die sets in rotation applied this by building two identical intermediary jig plates: while one die ran on the machine, the next die in the rotation was centered and bolted onto the second jig at a nearby bench, and when a run finished, the jig — die still attached — came off as one unit while the next, already loaded, went straight on. Centering and bolting moved entirely off the machine, and internal setup became a straight jig swap. On a profile milling machine, the same technique took alignment time from minutes of spindle-idle waiting down to a seconds-long plate swap, because both jig plates were built to seat in the exact same position on the machine table.

While Jig A runs on the machine, Jig B is already being centred and loaded off to the side — by the time Jig A finishes, Jig B is ready to mount immediately, and the roles simply swap for the next cycle. Source: OEC SMED Training.

Stage 3: Streamlining All Aspects of the Setup Operation

By the time you reach Stage 3, Stage 1 has separated internal from external setup, and Stage 2 has converted as much of the remaining internal setup to external as the true function of each step allows. Stage 3 is the third and final stage: it improves everything that's left, both internal and external, by looking closely at each operation's function and purpose one more time. Implementing Stage 3 leads, in nearly all cases, to setups within the single-minute range.

External setup improvements at this stage focus on streamlining the storage and transport of parts and tools — addressing tool and die management directly. Three questions are worth asking of every small tool, die, jig, and gauge in the setup: What's the best way to organise these items? How do we keep them maintained in perfect condition and ready for the next operation? How many of these items should we actually keep in stock? Getting those three questions right keeps every future changeover from being slowed down by a search for the right tool, or a tool that turns out not to be ready when it's needed.

Internal setup improvements at this stage come from four practical techniques, applied in order.

Parallel operations. Machines that need operations at both the front and back — large presses, plastic molding machines, die-casting machines — waste real time and movement when a single operator has to walk the full length of the machine repeatedly. Dividing the setup between two people, one at each end, eliminates that walking: work that once took 12 minutes can take about 4, simply by removing the repeated trip back and forth. Safety and reliability matter most when running parallel operations — workers follow procedural charts and signal "go ahead" or "wait" to each other, preferably with a buzzer, whistle, or light, whenever one completes an operation the other depends on.

The machine and the tasks are identical in both cases — the only thing that changes is whether one person walks the full length of it repeatedly, or two people each stay put at their own end. Source: OEC SMED Training.

Functional clamps. A functional clamp is an attachment device that holds objects in place with minimal effort and can be tightened and loosened quickly. Traditional bolts and nuts do the job, but every full turn is wasted motion — a bolt only truly clamps or releases on its very last turn. Functional clamping systems fall into three families: one-turn methods, where a single rotation — a pear-shaped hole, a U-shaped washer, a split-thread bolt — clamps or releases fully; one-motion methods, where a single push, pull, or lever action using cams, wedges, or springs clamps or releases instantly; and interlocking methods, where parts engage directly with each other and need no separate fastener at all. The goal across all three families is the same: hold securely, release instantly.

Eliminating adjustments. Trial runs and adjustments, recall, account for up to 50 percent of traditional setup time — the largest single share of any of the four basic setup steps. Eliminating adjustments reduces this portion of setup time more dramatically than any other single SMED technique. Three practical techniques make it possible. Fixed numerical settings replace trial-and-error adjustment with a pre-set, repeatable position — a dial reading, a digital display, or a marked stop — that any operator can set directly and repeat exactly, without redoing the trial-and-error that established the value in the first place; this works best for settings that recur often and don't change from job to job. Visible center lines and reference planes turn an invisible or implied reference — one an operator would otherwise measure or eyeball fresh at every changeover — into a scribed line, a painted mark, or a machined notch that lets the operator align by sight, with no measuring tool required. And the Least Common Multiple, or LCM, system finds shared positions that serve several different settings at once: if a gauge needs to reach three different bolt-thread pitches — 20mm, 24mm, and 30mm — a single scale can't mark all three cleanly, but the least common multiple of 20, 24, and 30 is 120mm, so marking positions every 120mm gives every one of the three pitches a shared, common setting point.

Three different bolt-thread pitches, one shared set of marks — the LCM system trades three separate scales an operator would have to choose between for a single scale that works for all of them. Source: OEC SMED Training.

Mechanization. Mechanization should be used for fine-tuning, not for dramatic reduction, and it belongs last on this list deliberately. It should only be considered after every attempt has been made to streamline setups using the three techniques above. Powered clamps, automated die changers, and similar equipment can shave further seconds off a setup that has already been separated, converted, and streamlined — but they're expensive, and they can't fix a poorly organised setup on their own. Reach for mechanization last, after parallel operations, functional clamps, and eliminating adjustments have already done the heavy lifting.

Bringing the Three Stages Together

Every changeover improvement in this guide traces back to one of three stages. Stage 1 splits internal from external setup — typically a 30 to 50 percent time cut on its own. Stage 2 moves the remaining internal steps to external through advance preparation, function standardization, and intermediary jigs. Stage 3 refines what's left, in both categories, through parallel operations, functional clamps, eliminating adjustments, and — only as a last step — mechanization. Together, the three stages move a changeover from tens of minutes into the single-minute range, and the techniques apply well beyond die presses — any changeover, in any industry, benefits from the same internal/external distinction and the same three-stage discipline.

None of this is a one-time project with an end date. SMED is a starting point, not a finish line — there's always another changeover on your floor worth running through the same analysis: videotape it, time it, sort every task into internal and external, the same way I've described above. The people doing that changeover every day, the setup technicians and operators, will usually spot the best improvements first, if they're brought into the analysis directly rather than handed a redesign after the fact. If you take one thing from this guide back to your own floor, let it be the first sort: pick the changeover everyone already complains about, and separate what's genuinely internal from what's been done internally out of habit. That first sort, on its own, usually finds the first third of the time you were losing.

Build SMED Capability

Reading through three stages and a dozen techniques gets a team to the whiteboard. Applying them to a real changeover — timing it honestly, sorting the tasks, building the checklist, testing the first converted step — is where the actual minutes come off, and it's best learned on your own equipment, not someone else's case study.

• Start with JIT Support Tools: Building the Foundations of Stability, where SMED sits alongside poka-yoke and TPM as one of three daily disciplines that keep a JIT floor stable

• Continue with the hub article, Mastering the Lean Production System, for the leveled-production and small-batch thinking that SMED makes economically viable

• Continue with Cellular Manufacturing: A Practitioner's Guide to the Physical Transformation for the 5S and visual management discipline that keeps a changeover's tools and dies organised between uses

• Continue with Pull Production: A Practitioner's Guide to Signal and Flow Control for how fast, reliable changeovers make small-lot pull production practical on the floor

• Explore OEC's Lean Thinking Workshop, where SMED timing studies are practiced hands-on against your own changeovers

• Explore OEC's Value Stream Mapping Workshop for how changeover time shows up as a specific, measurable line item once you map the current-state process it sits inside

About the Author

Allan Ung is the Founder and Principal Consultant of Operational Excellence Consulting (OEC), a Singapore-based management training and consulting firm he established in 2009 to help organisations maximise customer value and minimise waste through the disciplined application of Lean management and Design Thinking.

Over more than three decades in operations and quality leadership, Allan has held senior roles at IBM, Microsoft, and Underwriters Laboratories (UL), and spent formative years with Singapore's National Productivity Board, where Cost of Quality and Total Quality Process programmes he led achieved quality-cost reductions of up to 50% for participating organisations.

Allan holds a Bachelor of Engineering (Mechanical) from the National University of Singapore and completed advanced consultancy training in Japan as a Colombo Plan Scholar, studying the Toyota Production System and Japanese quality management practices at their source. He is a Certified Management Consultant (Japan), a Certified Lean Six Sigma Black Belt, and an accredited TPM Instructor.

SMED is a core changeover-reduction module within Allan's Lean Thinking workshop, and its shopfloor application — sizing a real changeover, sorting real tasks into internal and external, building a real checklist — is practiced hands-on within his Value Stream Mapping workshop, delivered to manufacturing and operations teams across sectors including electronics, marine and offshore, healthcare, and process industries. His training presentations and toolkits are used by organisations across Asia, Europe, and North America to build shopfloor capability that outlasts any single consulting engagement.

Allan's guiding philosophy: "The machine doesn't care why it's stopped — only whether the task in front of it genuinely needed the stop at all."

👉 Learn more at: www.oeconsulting.com.sg

Related Articles and Resources

• JIT Support Tools: Building the Foundations of Stability — the parent guide where SMED is introduced alongside poka-yoke and TPM as one of three daily disciplines

• Mastering the Lean Production System — the hub article covering leveled production and the small-batch thinking SMED makes viable

• Cellular Manufacturing: A Practitioner's Guide to the Physical Transformation — where 5S and visual management are covered at full depth

• Pull Production: A Practitioner's Guide to Signal and Flow Control — how fast changeovers make small-lot pull production economically practical

• OEC's Lean Thinking Workshop — hands-on SMED timing studies and changeover analysis

• OEC's Value Stream Mapping Workshop — mapping changeover time as a specific, addressable line item in the current-state process