OEE in Make-to-Order vs. Make-to-stock Production: A Guide to Optimization Strategies

Make-to-order vs. make-to-stock production is a subject that most manufacturers are unaware of. A make-to-stock plant and a make-to-order plant may use the same machines and the same ERP. But the way OEE impacts their performance, production planning and profitability is fundamentally different. Yet the majority of manufacturers apply the same production objectives and improvement methods, whatever their model. This is a mistake. A 75% OEE on a high-variety, low-volume make-to-order line is not the same as a 75% OEE on a dedicated line producing the same item 24 hours a day. This guide details what OEE actually measures in each context, where losses lie, and how to adapt your tracking strategy to your production reality. Understanding this distinction is essential to any credible continuous improvement approach. Why the manufacturing model changes production planning and capacity In make-to-stock production, manufacturing is driven by forecasts and the production schedule. Production runs are long, changeovers are infrequent, and the main objective is to maximize throughput. Here, OEE functions as a pure efficiency indicator: each point gained translates into additional volume to feed warehouses and ensure inventory management. In make-to-order production, manufacturing responds to specific production orders. Production runs are short, changeovers are frequent, and flexibility takes precedence over gross volume. The OEE is therefore an indicator of production capacity to meet deadlines, rather than an indicator of volume. As a direct consequence, the levers for improving OEE are not the same. Optimizing output on a make-to-order line without reducing changeover times means improving a figure without improving actual performance. The way monitoring is organized must reflect this difference. The operational complexity of a make-to-order environment is structurally greater than that of an in-stock environment. More references, more adjustments, more risk of error. Ignoring this reality when setting OEE parameters is like comparing apples and oranges. OEE and resource availability: optimizing make-to-stock production Critical losses, yield rates and quality in long production runs In make-to-stock production, availability losses are enemy number one. Every minute of unplanned downtime represents a number of parts not produced, which should have been added to the stock. Machine breakdowns, raw material delays and preventive maintenance failures are the main causes. The actual uptime is often less than the planned uptime.