Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


MS Level 6

davep

#7000

MS Level 6 | 20 June, 2001

What experience does anyone have with a MS level 6 SMT component? I have a part that must go from component baking to reflow within six hours. According to the component mfg, a sealed MS bag w/ desicant is not sufficient protection to increase the six hour time.

reply »

#7003

MS Level 6 | 20 June, 2001

Exposing MS parts longer than the part manufacturer's recommended exposure time opens you up to cracked plastic.

[Ha!!! Did you see that play on words??? "Opens you up to cracked plastic" ... that's GREAT!!! The subtile interplay of word with meaning, YES!!!]

reply »

#7005

MS Level 6 | 20 June, 2001

Dave, if you have a level 6 then you have no other option then to bake it and reflow before it exceeds the specified floor life. For more details check out the joint IPC/JEDEC standard J-STD-033. It can be downloaded for free at http://www.jedec.org.

reply »

Darby

#7008

MS Level 6 | 21 June, 2001

Dave, As one who delights in all manifestations of word play is subtile under the floor or under the roof?

reply »

dason_c

#7016

MS Level 6 | 21 June, 2001

DaveP, I never see the Level 6 component, can you describe what is the package look like, ie high pin count PBGA, component thickness?

DaveF, if we can store the components in the dry environment say below 10%, can we stop the floor life clock after mandatory bake?

Rgds. Dason.

reply »

#7023

MS Level 6 | 21 June, 2001

I doubt it. [Although, I can't say that I understand this as well as I'd like.]

Francois Monette has a good handle on the topic. He has demonstated superior knowledge in this area with postings on the following threads on SMTnet: * Date: January 20, 2001 08:54 PM Subject: Humidity of SMT component storage environment. * Date: December 05, 2000 03:10 PM Subject: Re: Humidity Control and Moisture Sensitivity

reply »

#7024

MS Level 6 | 21 June, 2001

Possibly, let me think through this. I always thought it was the original tile, after you re-tiled. Yeth, that makes it the under the floor one!!!

reply »

davep

#7037

MS Level 6 | 22 June, 2001

The part is a high pin count PBGA with an integrated ceramic heatsink.

What I am trying to understand is how to handle this part in production. It seems as though you would have to have an oven very near your SMT line, pulling a few trays of parts at a time. It becomes even more difficult if your SMT line does not run 24/7. What is the maximum time that you should leave parts in the oven? One good thing, this part is on the second pass of a double reflow assembly.

reply »

dason_c

#7041

MS Level 6 | 22 June, 2001

DaveP, once you shut down the oven, the moisture will start and move into the oven unless you can completely seal the oven after you turn it off. Therefore, keep the components into the oven, don't work. However, if the oven is continously on until you used up all the component, it may caused the oxidation and it mention on J-STD-033 7.2.7.1.

We have dry cabinet and control the temperature/humidity but JEDEC only accept storage conditions for components classified as level 2 through 5a and not level 6????? The only solution is rebake and rebake until you used up.

I doubt is it possible and change the package from PBGA to CCGA/CBGA and you don't have this issue.

Good luck.

Dason

reply »

#7063

MS Level 6 | 25 June, 2001

You�re correct. This is a messy situation.

Do not store components at the bake temperature longer than the time required to dry out the units for use in the reflow. Long storage times at elevated temperatures can cause soldering problems and the antistatic properties of the shipping carriers to deteriorate.

The issues that you mentioned are compounded by component carrier baking issues. Certain carriers can only take a low temperature bake without melting. For high temperature [125�C ] bake, you probably have to remove components from tubes and reels, but can probably leave in waffle packs, and bake, only once.

For high temperature [125�C ] bake; you probably can high temperature bake, only once.

A while ago, someone was pitching on SMTnet a "system" for tracking MSD status.

reply »

 Reflow System

Essemtec Fox Compact Automatic Pick and Place