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Questions on J-STD-033A procedure (Table 4-1)

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CW

#39730

Questions on J-STD-033A procedure (Table 4-1) | 15 February, 2006

Reviewing the J-STD-033A procedure and try to better understand Table 4-1 ...

There are 3 columns for Baking Temperature & recommended Duration ... 1st one is for 125C, then for 90C, then followed by 40C ...

it also specify the environmental condition such as Saturated 30C/85% RH, OR At limit of Floor Life + 72hr @ 30C/60% RH etc. What does those mean??? Can anyone help to explain that to me?? Appreciate it!!!!!

Best Regards, CW

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GS

#39786

Questions on J-STD-033A procedure (Table 4-1) | 17 February, 2006

Hi CW,

mine is not the answer to your questions, but I suggest you to take a look of the latest level of J-STD-033B (October 2005)

The J-STD-033A was from July-2002, and several important points are different from latest level. For instance, in Chapter 4 DRYING the modified tables 4-1, 4-2 and added also table 4-3, it may be it could help to answer your questions.

Best Regards.............GS

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GS

#39787

Questions on J-STD-033A procedure (Table 4-1) | 17 February, 2006

Hi CW,

mine is not the answer to your questions, but I suggest you to take a look of the latest level of J-STD-033B (October 2005)

The J-STD-033A was from July-2002, and several important points are different from latest level.For instance, J-STD-033B in Chapter 4, DRYING : they modified tables 4-1, 4-2 and added also table 4-3, it may be it could help to answer your questions.

Best Regards.............GS

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CW

#39799

Questions on J-STD-033A procedure (Table 4-1) | 18 February, 2006

thanks for the reply GS.

Do you know what does those condition mean? what is saturated 30C/85% RH????

i need to understand this before i could release my procedure and provide training to the operators

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GS

#39801

Questions on J-STD-033A procedure (Table 4-1) | 18 February, 2006

Hi CW, now I'll try with my English to explain:

first of all, on the new J-STD-033B, the voice " Saturated 30C�/85% RH " is not more used on columns of table 4-1.

Instead of that you will find " Exceeding Floor Life by >72h " and " Exceeding Floor Life =<72h " only on all columns of the table 4-1. (User Bake : Floor Life begins continuing at time = 0 after bake)

Any way, both are referred to the environment conditions (ie. worst case max 30�C/85%RH) at which the MSDs have been submitted during their Floor Life once out from MBB or bake, before to be dried or baked off or soldered by Reflow. Hope my interpretation is correct.

I suggest you any way for your procedure and operator training to refer at the new J-STD-033B (Oct/2005) because many changes are included compared to previous level 033A.

Regards............GS

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CW

#41094

Component termination contain silver | 20 April, 2006

hi All, recently i have received some parts with the lead turning black, and i then found out the leads are silver plating, is that going to be a problem? or it is simply a cosmetic issue? pls advise ASAP!! thansk a lot!!

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#41114

Questions on J-STD-033A procedure (Table 4-1) | 21 April, 2006

I struggled with the std too, when trying to justify the need for a desiccant cabinet. according to my interpretation:

1. the components are baked at 125 or 150 dec C within 24 hrs of manufacture (this is MET) and sealed in the MBBs at the component manufacturer before shipping to the customer. the shelf life of the components in the sealed MBB is at least 12 months

2. when the customer opens the MBB, the floor life clock of the component starts. thie floor life varies according to the MSL rating.

For MSL Level 2, 2a and 3 If exposure time 72 hrs, bake according to table 4-1 to RESET the floor life. at this point the shelf life can also be reset if sealed again in a MBB

For MSL Level 4, 5 and 5a If exposure time 72 hrs bake according to table 4-1 to RESET the floor life. at this point the shelf life can also be reset if sealed again in a MBB

J-STD-033B DOES say that a desiccant cabinet capable of maintaining RH level below 5% is equivalent to a MBB. I am not clear on how oprning the cabinet doors would affect the components though (anyone who is patient enough to read till this point hazard a guess on this???)

Hope this clears up your question

Amol

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CW

#44404

Any suggestion on snap on EMI sheilding? | 6 October, 2006

hi All, Anyone use snap on type EMI sheilding before? I would like to provide a DFM to a customer who currently have a EMI shield soldered on the boards, which i found this not quite manufacturing friendly as it block the view for inspection, plus repair is a problem. And there always exist some coplanarity issue where we need to touch up after reflow. I would like to suggest customer using snap on sheild, any recommendation?

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