Modelling guide
Scrap bins, by-products and recycling into raw material
Rejected units go somewhere on the floor, not into thin air: a bin beside the station that rejects them, emptied every so often.
Built in A field or setting does it directly.
When
Steps leave waste besides the unit (offcuts, sprues). And the material in both comes back, reground or remelted, as raw material for the line.
How
- A step that rejects units has a scrap share (
scrap_probability, see Scrap, yield and OEE). - The bin: a machine with a
scrap_binblock in Hardware (Hardware → Scrap bin):{ "capacity": 15, "empty_every_h": 2 }. Build layout places one beside each station that rejects units, on free floor; without a bin of your own it drafts one, sized to hold what the busiest gets between emptyings. A full bin holds its station until it is emptied (SCRAP_BIN_FULL). - Recycling: on the product that is scrapped,
recycles_to: { "product": "<raw material id>", "qty": 0.35 }(Product table → Recycles to, Recycled qty): what one scrapped unit gives back. Less than went into it is the loss. When the bin is emptied, that much becomes stock of the raw material, issued before new material. - By-products: on the step that leaves waste,
byproduct: { "product": "<product id>", "qty": 0.03 }per unit (Product table → By-product, By-product qty). It goes to the bin beside that station, outside the bin's count of scrapped units, and is recycled with them as the waste product's ownrecycles_tosays. - The results give
summary.scrapBins(received, by-product, peak, emptied, how long stations waited),summary.byproductsandsummary.recycling(recovered, used, new, recycled share).
Check
Housings are moulded from PP granulate (0.4 kg each), trimmed and checked; trimming leaves 0.03 kg of sprue each, and the check rejects 8%. The trim station and the check each get a regrind bin, emptied every two hours; sprue comes back kilo for kilo, a rejected housing as 0.35 kg. About 27 housings are rejected and replaced, every order is still met, and roughly 15 kg of reground granulate replaces new granulate in the moulder.