Dye Lot Sizing: The Machine Sets the Window

Every dye batch is a compromise between the machine's appetite and the order's shape, and the compromise is decided at batching time: how much greige, from which lots, into which vessel. Sized well, batches are cheap and shades behave. Sized carelessly, the dyehouse manufactures its own shade problems and calls them bad luck.

The machine sets the window

Each vessel has a working range: a nominal capacity and a band, roughly 80 to 100 percent of it, where liquor ratio and fabric circulation behave as designed. Underload a jet and the effective ratio climbs, chemistry drifts, and the shade with it; overload and circulation suffers, bringing unlevelness and crease marks. The dye lot quantity calculator does the fit arithmetic: order quantity, machine band, and out falls the batch count and sizes that keep every batch inside its window.

Fewer batches, but honest ones

Batch count is a cost lever: each batch pays its setup, its chemical minimums, its vessel hours. So the pull is always toward fewer, fuller batches. The honest limits are two. Never outside the machine window to save a batch, that trade buys one batch and risks re-dyeing several. And never blend greige lots casually to fill a vessel: greige from different knitting lots or yarn lots can take dye differently, and a batch that mixes them may be internally unlevel in a way no lab dip predicted. Where blending is unavoidable, it should be a recorded decision with the lots named, which is exactly the lot lineage discipline paying off in the wet department.

Batches feed shade bands

However well the dyehouse performs, batch-to-batch variation exists, which is why every batch gets a shade assessment and a band. The batching plan decides how hard that discipline gets tested downstream: one order dyed in three batches has three potential bands to manage at the cutting table; the same order squeezed into two well-sized batches has two. Batch planning is thus quietly a cutting-room decision, the beginning of the vessel-to-lay-table chain.

The planner's version

For planning, batches are the dyehouse's unit of capacity: a vessel-day holds so many batches, and an order's dyeing lead time is its batch count times cycle time, queued behind everything else. Which closes the loop: batch sizing done at order intake, with the calculator, feeds the backward schedule an honest dyeing duration instead of a hopeful one.