Industrial Garment Production and Work Study
Scope
Production systems, work measurement, line balancing and productivity metrics.
Core rules
- Method study improves the method before time study measures it.
- Standard time = observed time x rating factor + allowances (personal, fatigue, delay).
- SAM (standard allowed minutes) is the standard time per garment operation.
- Efficiency = (output x SAM) / minutes worked x 100.
- Takt time = available production time / customer demand.
- Line balancing: find the bottleneck, equalise work content, control WIP; use 5S, andon, kanban and Kaizen. Pitch time is the line target cycle; excess WIP hides imbalance.
Worked example
A line works 480 minutes and produces 400 pieces; SAM is 0.90 min. Reasoning: earned minutes = 400 x 0.90 = 360; efficiency = 360 / 480 x 100 = 75%. If demand is 500 pieces, takt time = 480 / 500 = 0.96 min per piece, so any operation above 0.96 min is the bottleneck.
Traps
Confusing efficiency with utilisation; forgetting allowances; balancing by number of operators instead of work content; ignoring rework time.