SAM (Standard Allowed Minute), also called SMV (Standard Minute Value), is the time a trained operator needs to complete one operation at a normal pace, including allowances for fatigue and personal needs. Almost every number an industrial engineer uses - targets, efficiency, line balancing, costing - starts from SAM.
Why SAM matters
- Targets: how many pieces a line should make per hour.
- Efficiency: how well the line used its available minutes.
- Costing: labour cost per garment = SAM × cost per minute.
- Planning: how many lines and days an order needs.
The three building blocks
SAM is built from three parts:
| Part | What it means |
|---|---|
| Observed time | The average time you measure with a stopwatch |
| Rating | How fast the operator worked compared with a normal pace (100%) |
| Allowance | Extra time for fatigue, personal needs and small delays |
Formula: Basic time = Observed time × Rating ÷ 100. SAM = Basic time × (1 + Allowance ÷ 100).
Worked example: attaching a pocket
You time an operator for 10 cycles. The average is 30 seconds (0.50 minutes). She works slightly faster than normal, so you rate her at 110%. The factory uses a 15% allowance.
- Basic time = 0.50 × 110 ÷ 100 = 0.55 min
- SAM = 0.55 × 1.15 = 0.633 min
Add the SAM of every operation in the garment and you get the garment SAM. A basic T-shirt is often around 5-8 minutes; a formal shirt may be 18-25 minutes, depending on the design.
Two ways to get SAM
- Time study: measure real operators with a stopwatch, then apply rating and allowance (as above).
- Predetermined time systems such as GSD: build the time from standard motion codes, without depending on one operator's speed. This gives more consistent values across factories.
Common mistakes
- Timing too few cycles. Take at least 10 good cycles and remove abnormal ones.
- Rating every operator at 100%. Rating is a skill; practise with training videos.
- Forgetting machine delays and bundle handling in the allowance.
- Using the buyer's costing SAM as the production target without checking it on the floor.
Tip: Keep one SAM per operation in your operation bulletin and reuse it everywhere, so targets, efficiency and costing all use the same number.