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MSL Floor Life Remaining Calculator

Moisture sensitive parts that absorb too much humidity can crack or delaminate in reflow. Teams track exposure time against the MSL floor life printed on the bag. This calculator tells you how much time is left and whether a reel will finish in time.

Your numbers

Floor life at 30 C and 60% RH or less after the bag is opened.

40 hours

Total hours out of dry bag or dry cabinet.

parts
parts per hour

Placements per hour of this part number on the line.

Your results

Floor life remaining
128 hrs
Margin after reel is used
120 hrs
Negative means the reel expires before it is finished.
Floor life consumed
23.8%
Hours to consume the reel
8 hrs
Run time needed to place all remaining parts.
Bake required before use
0
1 means exposure exceeded the limit, so follow J-STD-033 baking and do not place.

Floor life limits apply at 30 C and 60% RH or lower and are printed on the moisture barrier bag. Follow J-STD-033 and the component supplier's label for exposure counting, resets and bake conditions.

Save results:

Floor life remaining vs exposure used

Sweeps Exposure used so far from 0 to 700, holding your other inputs fixed.

Track MSL clocks in your ERP

Optional: discuss lot-level floor life tracking in your ERP.

Optional. The tool and every export work without this. No spam.

How to use it

Pick the MSL from the bag label and enter the hours of exposure already used, counting every time the parts were out of dry storage. Add the parts left on the reel and how many the line places per hour. The calculator shows remaining floor life, the hours needed to finish the reel and the margin between them.

Floor life by MSL

J-STD-020 and J-STD-033 define the levels. MSL 2a allows 4 weeks, MSL 3 allows 168 hours, MSL 4 allows 72 hours, MSL 5 allows 48 hours and MSL 5a allows 24 hours, all at 30 C and 60% RH or below. MSL 6 parts must be baked and used within the time on the label, so they are not covered here.

  • Lower MSL number means more tolerant of humidity
  • Clock starts when the bag is opened
  • Dry cabinets can pause or reset the clock only per J-STD-033 rules

Reading the result

If a reel has 100 hours left and the job needs 8 hours of placement, the margin is large. If the margin is negative, plan to split the reel, return the remainder to dry storage within the allowed time, or schedule a bake. A flag of 1 on the bake output means the part has gone beyond its limit and must be baked before it touches reflow.

Common mistakes

Operators often forget to log time when a reel is removed from the feeder for a changeover. Others assume the line is cooler or drier than 30 C and 60% RH without measuring. Track exposure by reel ID and tie it to the ERP lot so the clock follows the material, not the machine.

Frequently Asked Questions

Does a dry cabinet reset the clock?

Only under the conditions in J-STD-033 for dwell time and humidity, and partly rather than fully in many cases. Do not assume a reset. Follow your documented procedure and the supplier's label.

What happens if floor life is exceeded?

The parts must be baked per J-STD-033 before reflow, with temperature and time that depend on package thickness and MSL. Skipping the bake risks popcorning and hidden cracks.

Are hours counted when parts sit on the line overnight?

Yes, if the reel is out of a dry bag or controlled cabinet, the exposure clock keeps running, regardless of whether the line is producing.

Why is MSL 6 excluded?

MSL 6 has no fixed floor life. The device must be baked before use and reflowed within the time limit on the label, so a generic calculator would mislead.

Netray can add MSL exposure tracking to your ERP lot records so the floor life clock is visible to planners and operators.

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