V-curve speed survey

Plot nameplate vs. actual speed for every machine on the line. On a balanced line the curve forms a V around the bottleneck — upstream and downstream machines run at 110–130 % of the bottleneck speed to absorb micro-stops. A flat curve means hidden bottlenecks; a reverse V means starvation.

Date

Line

Product / SKU

Reference speed (BN)

Surveyed by

#	Machine / station	Nameplate (u/min)	Measured (u/min)	Ratio vs. BN	Target (% BN)	Observation
1					130 %
2					120 %
3					115 %
4					110 %
5					100 % · BN
6					110 %
7					115 %
8					120 %
9					130 %

Plot · measured speed (% of bottleneck)draw one dot per machine, join with a line

140 %

120 %

100 %

80 %

60 %

Bottleneck · 100 %

M5 · BN

Read the curve

Healthy V — bottleneck at the bottom, others 10–30 % faster, accumulators between them.

Flat line — every machine near 100 %. No buffer → any micro-stop stops the whole line.

Reverse V — bottleneck faster than neighbors. The line is starving / blocking itself.

Action

1. Identify the slowest machine = bottleneck.

2. Check accumulator size upstream and downstream.

3. Don't speed up non-bottlenecks — it adds scrap, not throughput (Goldratt).

4. Re-survey monthly or after every changeover campaign.

Surveyor

Maintenance

Plant manager