Lean Manufacturing

Lean names seven classic wastes: overproduction, waiting, transport, overprocessing, inventory, motion and defects. Its tools follow from them: value stream mapping to see where lead time is lost, pull control with kanban instead of producing to a forecast, smaller batches, quick changeovers (SMED), standardized work and continuous improvement (kaizen).

Lean manufacturing in practice

Smaller batches are where lean meets arithmetic. A line runs its products in batches of 2,000 units and changes over 8 times a week at 60 minutes each, so 8 hours a week go to changeovers. Halving the batch to 1,000 units halves the average cycle stock of each product and shortens the wait for the next run, but it doubles changeovers to 16 a week, or 16 hours. If the line is the bottleneck, those extra 8 hours come straight out of plant output. Smaller batches pay off once changeover time has fallen, here to 30 minutes, which keeps the weekly total at 8 hours. That is why SMED comes before batch reduction, not after it.

The second limit is the word inventory. Lean targets stock made ahead of demand and work‑in‑process waiting between operations. Safety stock that covers variability in demand or supplier lead times is a different thing: cutting it without reducing that variability moves the problem into stockouts, expediting or overtime. Lean also assumes fairly level demand (heijunka). Where demand swings with promotions or seasons, the buffer in front of the constraint protects output and needs to be sized, not removed.

Logio maps material flow and tests changes such as batch size, buffer placement or a new layout with dynamic simulation before they reach the shop floor, as part of intralogistics and material flow and production capacity planning projects.

Related terms

• Cycle Stock
• Bottleneck
• Theory of Constraints (TOC)
• Overall Equipment Effectiveness (OEE)
• Just‑in‑Time (JIT)
• Kanban