Dear Hao,
The storage of PCB and materials in process for PCB is addressed in IPC-1601 Printed Board Handling and Storage guidelines.
Here is one section of the document regarding PCB storage.
5 PRINTED BOARD RECEIVING, STORAGE AND ASSEMBLY
5.1 Before Opening Dry packed packages should be inspected to verify there are no tears, punctures, or openings of any kind
that expose the contents. If openings are found, and the HIC indicates that the dry environment of the bag has been compromised
(see 5.3), then the printed boards should be evaluated for excessive moisture content per 5.8. Printed boards may also be visually
inspected for any changes to the final finish that may indicate that solderability has been degraded.
If physical inspection is required, intact bags may be opened for inspection by cutting at the top of the bag near the seal. Time
of exposure to ambient conditions should be controlled to minimize moisture uptake. If bags are opened under factory ambient
conditions (not exceeding 30 °C/60% RH), then either:
a) Place printed boards in dry storage at 10% RH or less within one hour, or
b) Return them to dry packaging (see 4.3.1) within 30 minutes. In this case, the original desiccant and HIC may be reused.
Note: If the 60% spot on the HIC indicates wet, the HIC and desiccant should be replaced.
If ambient conditions of temperature, humidity, or exposure time are exceeded, printed boards should be evaluated for excessive
moisture per 5.8.
I hope this helps some.
Best regards,
Dave
David W. Bergman 大山人
Vice President, International Relations
IPC - Association Connecting Electronics Industries
3000 Lakeside Drive Suite 309S Bannockburn, IL 60015-1249 USA
+1 847-597-2840 tel
+1 847-615-5640 fax
+1 847-867-1388 mobile
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Skype: davidbergmanipc
www.ipc.org
From: TGAsia [mailto:[log in to unmask]] On Behalf Of wuhao
Sent: Thursday, August 18, 2011 4:17 AM
To: TGAsia
Subject: [TGAsia] PCB warehouse condition of temperature and humidity
Dear all :
Does anyone can tell me if have a special standard to define the pcb warehouse condition of temperature and humidity .
Best regards
Hao
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