Industrial engineering formula
Machines needed for each operation to meet a daily target, rounded up per operation and grouped by machine type.
Machines for an operation = daily target × operation SMV / (working minutes × efficiency)
| Symbol | Meaning | Unit |
|---|---|---|
| Q | Daily target | pcs |
| SMV_op | Operation SMV | min |
| T | Working minutes | min |
| η | Planned efficiency | - |
Use it when laying out a line for a new style or checking whether the machine park can support an order.
Target 1,200 pcs per day, 480 minutes, 70% efficiency. Available minutes per machine = 480 × 0.70 = 336.
| Operation | Machine | SMV | Exact | Allocated |
|---|---|---|---|---|
| Shoulder join | Overlock | 0.35 | 1.25 | 2 |
| Side seam | Overlock | 0.70 | 2.50 | 3 |
| Hem | Flatlock | 0.50 | 1.79 | 2 |
Overlock machines: 5. Flatlock: 2. Add spares for breakdowns.
Line balancing spreads the operations of a garment across operators and machines so work flows at the target rate without piles of WIP or idle people. A practical step-by-step method with a worked example, balancing efficiency and common mistakes.
A guide to the industrial sewing machines found on garment lines: lockstitch, overlock, flatlock, chainstitch, bartack, buttonhole, button sew, kansai and automatic units. What each does, where it is used and what to check.