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Electronic Assemblies Manufactuirng - Bake-out ramp rate

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#79671

Electronic Assemblies Manufactuirng - Bake-out ramp rate | 30 January, 2018

Hi, In our shop we've always baked out PCBs and moisture sensitive parts prior to electronic assembly using a gentle ramp rate of 2 degC/minutes going hot (93degC) and same ramp rate going cold (back to room temp).

We're trying to outsource that process but our subcontractor has an oven constantly set to 85degC and open the door of the oven and place the components in it and close the door. We're worried about thermal shock. We saw a temperature variation of +25degC (room temp) to +65degC in less than 5 seconds when parts are going in this oven already hot. Parts will also be seeing a thermal shock on their way out of the oven from 85C to room temp.

I was looking for directions but couldn't find any standard specifying ramp rate for bake-out.

What is your standard operating procedure as far as bake-out ramp rate?

Any comments would be appreciated!

Thanks!

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#79674

Electronic Assemblies Manufactuirng - Bake-out ramp rate | 30 January, 2018

I used to bake parts before. After I discovered the drying cabinets, that is not a concern anymore. I strongly recommend you to get one of these and try it. It dries them out pretty quick and keeps very low humidity all the time. No heat applied.

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#79699

Electronic Assemblies Manufactuirng - Bake-out ramp rate | 1 February, 2018

I'm guessing you're right that would be one way of doing it. Thanks for your feedback. Best, David

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#79702

Electronic Assemblies Manufactuirng - Bake-out ramp rate | 2 February, 2018

I developed our company's procedure for moisture sensitive devices based on J-STD-033 and I don't recall anything requiring a certain ramp rate. Furthermore baking at 85C will greatly extend the time to reset the clock and it is harder to maintain <5% RH inside the oven the lower you go in temperature (I found this out the hard way).

We have a dry cabinet to store the devices after baking or freshly opened reels. However a dry cabinet will not reset the clock unless the exposure time is <12 hrs AND it it kept in dry storage for at least 5x the exposure time. So if your device was exposed for 8 hours during a shift, it has to stay in the dry cabinet for 40 hours or else the clock is not reset, only paused.

Follow J-STD-033 and use either the 90C or 125C baking time tables and you won't have any concerns.

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#79746

Electronic Assemblies Manufactuirng - Bake-out ramp rate | 9 February, 2018

I completely agree. J-STD-033 spells out the "how to" of baking, quite clearly. You have to bake something for an expensively long time at 80 - 85C in order to properly desiccate your components.

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#79770

Electronic Assemblies Manufactuirng - Bake-out ramp rate | 14 February, 2018

The process of electronic manufacturing services consists of the manufacturing of a lot of complex parts and might consist of a range of services. To get high-quality EMS services, contact Optimatech!

https://www.optimatech.net/electronic-manufacturing-services/

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dwl

#79802

Electronic Assemblies Manufactuirng - Bake-out ramp rate | 15 February, 2018

To the optimatech guy;

If your going to spam the forum I'd at least make sure your URL works.

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#80442

Electronic Assemblies Manufactuirng - Bake-out ramp rate | 21 May, 2018

Thank You for informing me :)

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