SAM / SMV (Standard Allowed Minutes)

Almost everything a garment factory needs to know reduces to a single number per style: how many minutes of sewing work does this garment contain? Capacity is minutes. Cost is minutes multiplied by a rate. Efficiency is minutes produced divided by minutes attended. Line balance is the distribution of minutes across operators. Get SAM wrong and every one of those is wrong in the same direction, quietly, on every order.

SAM and SMV are used interchangeably in most factories. Both mean: the time an average qualified operator, working at a defined standard pace, needs to complete an operation, plus the allowances that make that time achievable over a full shift rather than for one heroic minute.

How a SAM is built

SAM = basic time x rating, plus allowances.

**Basic time** is the observed cycle time for the operation, established either by time study (stopwatch, many cycles, averaged) or by a predetermined motion system such as GSD, which builds the time from a database of standard human motions — reach, grasp, position, sew — without needing to observe the operation at all. The predetermined approach is the only way to cost a style before it has ever been sewn, which is why it dominates in factories that quote before sampling.

**Rating** adjusts the observation for the pace of the operator being watched. A fast operator observed at 120 percent of standard pace produces an observed time that must be scaled up to represent an average operator. This is where time study becomes judgement rather than measurement, and it is where two engineers can honestly disagree.

**Allowances** are added on top: personal needs, fatigue, and unavoidable machine and process delays. They are a percentage addition, and their size is a factory policy — a fair allowance is one that a competent operator can actually sustain across a shift.

A whole-garment SAM is the sum of its operation SAMs. A basic T-shirt might come to a handful of minutes; a tailored jacket to many times that. The absolute figures vary by construction, machinery and method, and any number quoted without the operation breakdown behind it should be treated as an estimate.

Line balancing: the reason SAM exists

A sewing line is a chain of operations, and its output is set by the slowest one. If shoulder join takes 0.8 minutes and collar attach takes 1.4, then no matter how many shoulder joins the line completes, garments emerge at the pace of collar attach. Every other operator is either waiting or building a pile of work in front of the bottleneck.

Line balancing is the allocation of operations to operators so that each workstation's total assigned SAM is as close as possible to the same figure — the takt time implied by the target output. Where an operation is longer than takt, it is split, or given two operators, or an operator is helped by an assistant. Where several operations are short, they are combined onto one operator.

The measure of a good balance is that the effective station times converge. In the table above they sit within a narrow band, so no station is badly starved and no station is a hard bottleneck. Balance efficiency is conventionally expressed as total SAM divided by (number of workstations x the longest station time). Doing this well is one of the highest-leverage activities in a garment plant, and it is impossible without reliable operation-level SAMs — which is exactly why [shop-floor data capture](/glossary/shop-floor-control) and SAM belong to the same conversation.

Operator and line efficiency

Efficiency = minutes produced / minutes attended.

An operator who attends for 480 minutes and produces 300 garments at an operation SAM of 1.2 minutes has produced 360 standard minutes against 480 attended, giving 75 percent efficiency. The same arithmetic aggregates to the line, and to the factory.

Two things are easy to get wrong here. First, efficiency is only as honest as the SAM: a factory that loosens its SAMs will see efficiency rise without a single extra garment being made, which is why SAMs and efficiency targets must never be negotiated by the same people at the same time. Second, low efficiency on a new style is normal and expected — the learning curve is real, and comparing day one of a new style against week three of the last one is a comparison of two different things.

Why CMT costing lives or dies on SAM

Under a [CMT model](/glossary/cmt-fob) the factory sells labour, and SAM is the quantity being sold. The cost of a garment's sewing is, in essence:

Cost per garment = SAM x (cost per standard minute), where the cost per minute is the fully loaded cost of running a line — wages, supervision, overhead, depreciation, factory cost — divided by the standard minutes that line actually produces.

That denominator is where the trap is. A factory that calculates its cost per minute using *attended* minutes rather than *produced* standard minutes will understate its cost by exactly the amount of its inefficiency. Quote from that number and it will win orders it cannot make money on, and the more of them it wins, the worse the position gets. The cost per minute must be computed against realistic achieved efficiency, not against theoretical capacity.

The same figure drives capacity: a line's output in pieces is its productive minutes divided by the garment SAM, which is why sewing [capacity planning](/glossary/capacity-planning) is always done in minutes and converted to pieces per style.

SAM and piece-rate incentives

Where operators are paid an incentive on output, SAM is the yardstick, and it becomes a number with money attached — which changes its politics entirely. A loose SAM inflates recorded efficiency and pays a bonus for work not done. A tight one demotivates and drives disputes.

Two disciplines keep this honest. SAMs must be set by an industrial engineering function that does not own the efficiency target, and they must be re-studied when the method, machine or attachment changes — because an operation whose SAM was set before a folder was fitted is now paying an incentive for the folder's work rather than the operator's.

Vastra ERP holds SAM at operation and style level, uses it to balance lines and convert line capacity into pieces per style, measures actual operator and line efficiency against it from [shop-floor](/features/shop-floor) scans, and feeds the resulting cost per standard minute into order costing so CMT quotations are built on achieved efficiency rather than theoretical capacity.