Tool changeover from 95 to 60 minutes: how an automotive stamping plant handled smaller batches
Lean · 3 min read · 07.10.2026
Client
A sheet-metal stamping plant for the automotive industry, a Tier-2 supplier. 210 employees, production in two shifts. The plant's main capacity is a stamping line with mechanical presses that supplies parts for welding and assembly. Tool changes were governed by the production plan — and for a long time it had no reason to build up small batches.
The project was initiated by the production director. Customers were shortening lead times and requesting more frequent deliveries of smaller quantities, which was impossible to reconcile with large batches. We present the company anonymously; this is a composite case study from several of our projects in stamping plants, not a single identifiable client.
Challenge
A tool change on the main line took an average of 95 minutes: removing the old tool, inserting the new one, adjustment, trial strokes, and quality approval of the first piece. Operational data showed that the fastest shift managed a comparable changeover in 60 minutes. The difference therefore was not in technology but in work organization.
Long changeovers made small batches economically unviable, so planning typically pushed batch sizes to two to three weeks of demand. Work-in-progress inventories covered more than three weeks of demand and tied up resources that the plant could have used elsewhere. Express orders could not be scheduled without interrupting a production run. They were handled through overtime and reshuffling deadlines.
Approach
- Breaking the changeover down into elements. With the foremen, we recorded and analyzed several changeovers into individual steps. Each step was assigned a time and a flag: internal (press stopped) or external (press can keep running). The analysis showed that more than 40 of the original 95 minutes went to searching for tools, transporting material, and repeated adjustment — not to the changeover itself.
- Moving steps outside the press stoppage. Following the SMED method, we created a preparation standard: the tool staged at the changeover point, tools and gauges on a cart next to the press, material and documentation prepared before shutdown. Steps that previously ran during downtime were moved before or after the changeover.
- Speeding up internal steps. We simplified tool clamping: standardized bolts, quick-release clamps where the design allowed, and two people working simultaneously from both sides of the press. We standardized the tools to a common shut height, so the lengthy tightening and adjustment after insertion was eliminated.
- Standard and training for both shifts. We documented the new procedure in a one-page standard with photographs and role assignments. We trained both shifts, including quality representatives, so that first-piece approval would not block the start of production. Every shift member goes through the checklist before a changeover — preparation does not depend on the memory of the most experienced operator.
- Measuring and sustaining the result. The shift records the time of every changeover on a board next to the press. Once a week the foreman reviews the times with planning; if a changeover exceeds 35 minutes, the focus is on finding the cause in the procedure, not finding someone to blame.
Results
The changes relied solely on work organization and modifications to existing tooling. The first changeovers under the new standard took around 40 minutes. After both shifts were trained, the result stabilized.
- Average changeover time fell from 95 to 32 minutes (−66 %).
- Planning reduced batch sizes by 50 %; deadlines are still met even with more frequent tool changes.
- Work-in-progress inventory fell by 33 % within three months.
No new press or new tooling was purchased. Headcount on the line stayed the same. Six months after the project, the standard is holding and changeovers are running below 35 minutes. Smaller batches made it possible to schedule express orders without interrupting a production run — the hall once again serves production, not storage of semi-finished goods.
Changeover times can be cut without major investments, and the freed-up capacity can be used right away. If long setups or growing inventories are troubling you, take a look at our cost reduction service.
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