Why HIC Cards Change Color When the Bag Is Opened: Leaky Bag, Weak Desiccant or Late Reading

An HIC card that changes color as soon as the bag is opened usually points to a punctured moisture barrier bag or a leaky heat seal, too little or already saturated desiccant, bagging in a humid room, or reading the card too late. Read it within the first few minutes; if the 10% dot has changed, PRIMEAG recommends checking J-STD-033 to decide on rebaking.

Eight in the morning at an electronics plant in Vietnam: the storekeeper cuts open the moisture barrier bag holding IC reels for the SMT line. The HIC card inside is already turning pink at the 10% dot, and in some bags up to the 60% dot. The line is waiting: issue the parts or send them for baking?

HIC card changed color: read it correctly before drawing conclusions

Once the card is out of the bag, the dot colors start drifting toward the humidity of the warehouse. Therefore:

• After cutting the bag, take the card out and read it immediately, ideally within a few minutes.
• Compare each dot with the reference color scale printed on the card. The card is most accurate when read at about 23 °C.

General J-STD-033 rule: if the 5% or 10% dot has changed color, the bag has taken up moisture and MSL components must be assessed for rebaking before reflow. For the threshold of each MSL level, check the tables in J-STD-033 and the caution label on the bag. How to calculate floor life is covered in moisture control in the component store and MSL floor life.

Five causes, checked in order

1. Punctured bag or leaky heat seal

Inspect the seal: wrinkles, pinholes or an off-line seal are paths for moisture. Strong vacuum can let component leads pierce the film. Use a correctly sized moisture barrier bag (350×500, 600×400 mm or custom); a bag that has been cut open is single-use only.

2. Too little desiccant, or desiccant already saturated

Desiccant quantity is calculated in “units”, depending on bag area, water vapor transmission rate (WVTR) and storage time. A pack left out for half a day should be treated as saturated. Silica gel desiccant and HIC cards come in sizes from 1 g to 100 g; send your bag size and PRIMEAG will calculate the number of units.

3. Bagging in a humid room, or bagging too slowly

The air trapped in the bag already carries water vapor. Put a dehumidifier in the packing area and heat-seal the bag in one go.

4. HIC card can left open

Cobalt-free 6-dot HIC cards are packed in cans of 125 or 200 cards with a desiccant pack; take cards out quickly and close the lid at once. The highest dot must still show the dry color before the card goes into the bag.

5. Reading the card late

A card left on the table waiting for the inspector will certainly “show humidity”.

Cobalt and cobalt-free cards

Traditional cards use cobalt(II) chloride, blue when dry and pink when humid; this substance is on the REACH SVHC list, so many exporting customers require cobalt-free cards. PRIMEAG’s cobalt-free cards come in two types, blue → pink (HIC-6) and brown → green (HIC-6B), with a 10–60 % or 5–40 % scale to order. The colors differ from the old cards, so train operators to read against the scale printed on the card.

Note: cards and desiccant are delivered within 24–48 hours in Ho Chi Minh City, Binh Duong and Dong Nai; quotes within 30 minutes.

Where to start

• Photograph the seals and cards of the 3 bags that just showed humidity.
• Check the card can, the desiccant carton and the humidity of the packing area.
• Components that need treatment: follow the rebake and repack procedure for MSL components past floor life.

Frequently asked questions

• We read the HIC card half an hour after opening the bag. Can we still trust the result? — You should not. After a few minutes in open air the dots follow the room humidity, not the conditions inside the bag. If the card was read late, treat the bag cautiously as if it had absorbed moisture.
• Cobalt-free HIC cards change to different colors than the old cards. How do we read them correctly? — Cobalt-free cards come in a blue-to-pink type and a brown-to-green type. Always compare each dot with the reference color scale printed on that card, not with what you remember from cobalt cards.
• Can an HIC card that has changed color be reused for the next bag? — No. Every dry pack needs a new card taken from a sealed can, together with dry desiccant and a new, freshly heat-sealed moisture barrier bag.