Machine Changeover Planning and Setup Time

Make setup time visible

Processing duration is only part of the time an order needs on a resource. A product change can also require cleaning, tooling, adjustment or preparation. Treat these activities as occupied resource time instead of hiding them in an unexplained gap between orders.

Separate two questions: how long does a change take, and which change is actually required? A fixed setup allowance can be enough for a simple process. Where the previous product affects preparation, use a from-product/to-product rule. The transition from A to B does not have to take the same time as B to A.

Example: the same orders, a different sequence

Suppose one machine must process A1, B1 and A2. Each order takes two hours. The machine begins ready for product A. An A-to-A transition takes ten minutes; A-to-B takes 45 minutes; B-to-A takes 60 minutes. Assume all orders and materials are available at the start.

Grouping the A orders saves 50 minutes in this constructed example. The reduction comes from the stated transition rules, not from faster processing. Initial setup is zero only because the starting machine state was explicitly defined as ready for A.

Define rules before optimizing

Record the starting state of each machine and the transitions relevant to your product families. Include a same-family setup when inspection or cleaning is still required. When a setup consumes an employee as well as a machine, validate that both can be available. Never use a blank setup value to mean both zero time and unknown time.

Distinguish preparation that can happen while the machine is running from preparation that stops it. Only the latter necessarily occupies machine capacity. If work can happen in parallel, represent that deliberately; do not assume all setup activities can overlap.

Review the sequence in LiftOrbit

LiftOrbit supports machine setup rules and displays changeovers in the production Gantt. Build an initial plan from a consistent set of orders, resources and constraints. Then inspect the optimized plan and compare its operation sequence and occupied time with the baseline.

Check that setup blocks remain present, that each transition matches the products on either side, and that required materials are available. Rebuild the baseline when the underlying orders change rather than comparing a new workload with an old plan.

Use a rough capacity check first

The capacity calculator accepts a count of setups and an average time per setup. It is useful for a weekly estimate, but it does not choose a sequence or evaluate a transition matrix. For those decisions, model the individual orders and resources in the planner.

For a practical production context, read the ceramic workshop planning example. All timings in this article are illustrative assumptions, not a claim about customer savings or guaranteed optimization performance.