Composites Scheduling Around Autoclave Cure Cycles

Composites manufacturing scheduling falls apart when an autoclave is modeled as hourly capacity, because a cure cycle is one load that occupies the oven for its full run, not a bucket of divisible hours. EDGEBIC by User Solutions books each cure as one load per cycle on a one-per-day resource, pools interchangeable autoclaves into a group, and gates skilled layup by operator qualification, so the cure calendar reflects what the floor physically does. For a shop where the autoclave and the layup crew are both scarce, that honesty is what keeps promises from breaking.

The Cure Cycle Is One Load, Not a Bucket of Hours

An autoclave running a twelve-hour cure is committed for that cycle. It does not run six hours of one load and six hours of the next. A scheduler that treats the autoclave as having "sixteen hours available" on a two-shift day will book two cures into a window only one can occupy, and the second load is late before the first is out.

Mark the autoclave as a one-per-day resource and the scheduler books a whole cycle to one unit for the day. The cure occupies the oven, the next load waits for a free unit or the next day, and the plan reads as a real cure calendar. Several parts that share a cure recipe ride one load and book one autoclave-day together, which is how the equipment actually works. This is the same instance logic explained in how EDGEBIC picks an instance, load balancing versus one per day.

The Load Is the Schedulable Unit

Composites almost always cure several parts in one load. The schedulable unit is the load, not the individual part. Schedule the shared cure as a single job on the one-per-day autoclave and track the constituent parts against it, and the oven books for the full cycle regardless of how many parts ride along.

That framing makes idle cure capacity obvious. A partly full load and a full load both consume one autoclave-day, so when the calendar shows a half-empty Thursday cure, a planner can hold a same-recipe part one more day and combine it into the next load rather than firing a second cycle for a handful of parts. The alternative, a scheduler that hides the load structure, buries that decision. The same load-versus-part arithmetic governs any cure that owns a resource for a fixed stretch, which is why scheduling precast concrete around form beds and cure time reads so familiarly to a composites planner.

Pooling Autoclaves That Are Not Identical

Real shops rarely have perfectly interchangeable ovens. Some autoclaves run recipes others cannot, and some are larger. Group the genuinely interchangeable units into a work center group and keep special-recipe autoclaves as their own work centers.

A load routed to the group is shopped across only the members that can run its recipe, and each member carries its own effective cycle time, so a slower oven books longer for the same load and the plan reflects the real cost of using the older unit. An autoclave qualified for only one recipe stays out of the pool, so a load that needs it is never sent to a unit that cannot cure it. The pooling mechanics are covered in how a work center group shops a pool of machines.

When Layup, Not the Oven, Is the Constraint

In many composites shops the autoclave is not the bottleneck. Skilled hand layup is. A scheduler that only plans the ovens will assume layup finishes on time and cure loads that were never ready.

Model the layup qualification as an operator skill and require it on the layup step, so the scheduler only places layup on a shift with a certified technician present. The cure then plans backward from the layup completion, so an autoclave load is scheduled around when its parts are actually ready rather than around a wishful date. When skilled layup is the true constraint, the plan shows it as the constraint instead of blaming the ovens. The skill model is documented in operator and skill scheduling explained, and the same certification approach used in aerospace operator certifications applies directly.

Keeping Layup and Cure Close Together

Prepreg has out-time. A part laid up and left waiting days for an oven is a scrap risk. Plan the autoclave load from the layup finish rather than from an arbitrary date, so a laid-up part is sequenced close behind its layup rather than stranded. When the cure calendar shows a load slipping past a safe window, that is the signal to combine it into an earlier same-recipe load or add a cycle. The plan makes the gap between layup and cure visible so a planner acts before the material is at risk.

Feeding the Cure Calendar From the Floor

A cure calendar is only as good as the cycle and layup times behind it. Operators log actual start and end on a shop-floor kiosk, so a cure that ran long or a layup that took extra hours is captured as a measured actual rather than an assumption. Those actuals flow back into the same schedule, and a reschedule around a delay never moves a load that already cured, it only re-times the loads still waiting. The workflow is covered in shop-floor actuals tracking.

Composites scheduling shares a lineage with the most demanding aerospace and defense work. The User Solutions and RMDB heritage runs in settings including US Navy availabilities that coordinated tens of thousands of interdependent tasks, and the same finite-capacity discipline that survives that scale is what keeps a cure calendar honest here.

For a related batch application, see heat treat furnace scheduling, for the version where the tool rather than the oven is the finite unit, scheduling boat building around molds, cure time, and launch dates, and for the fundamentals, finite versus infinite capacity scheduling. The industry fit guide maps the rest, and EDGEBIC is the product hub.

Ready to build a real cure calendar? Contact US for a demo and bring one week of autoclave load records.