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Bridge Defects

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Is a bridge considered a defect, if adjacent pads/component ... - Jun 30, 2023 by calebcSMT

A bridge is a defect. Full stop. If you are working in cont... - Jun 30, 2023 by MagyarT

Doesn't IPC specify bridges are only unacceptable when uncom... - Jun 30, 2023 by calebcSMT

Does the bridge/short defect is consistent? If bridge is not... - Jul 03, 2023 by researchmfg

Hi Researchmfg, If upload picture would be great to interpr... - Jul 03, 2023 by Jalina

Caleb, If the leads were connected via trace, and this woul... - Jul 03, 2023 by MagyarT

Well noted - and makes sense. Though 'technically acceptable... - Jul 03, 2023 by calebcSMT

For this general question, not a consistent bridge but inste... - Jul 03, 2023 by calebcSMT

Calebc, My opioin is different. If the bridge is consistent ... - Jul 04, 2023 by researchmfg

calebcSMT

#89657

Bridge Defects | 30 June, 2023

Is a bridge considered a defect, if adjacent pads/component leads are electrically connected (common) via a trace but said trace is covered in solder mask ?

Essentially, of course bridges are never a target but is rework required/de-bridging required if the two leads OR components are connected on the same track?

Even though solder mask is to prevent flow of solder, since these are indeed connected on the board level, a bridge in that case would become a process indicator correct?

TLDR: if two components lead/pads are connected via trace, this is considered common conductors therefore acceptable as a bridge rather than defect?

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MagyarT

#89658

Bridge Defects | 30 June, 2023

A bridge is a defect. Full stop.

If you are working in contract manufacturing, talk to the customer and get approval from them to accept it. They will not refuse unless there are high risks involved.

If you are building your own products, then have the representation of the bridge in the product drawing/documentation.

Regards, Tom

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calebcSMT

#89659

Bridge Defects | 30 June, 2023

Doesn't IPC specify bridges are only unacceptable when uncommon, therefore if the leads were connected via trace wouldn't this classify them as common therefore acceptable?

Would it be safe to say, at least from a electrical stand point its acceptable?

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researchmfg

#89665

Bridge Defects | 3 July, 2023

Does the bridge/short defect is consistent? If bridge is not consistent then QA guy and customer will think it is a defect even its adjacent pads are electronic connected.

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Jalina

#89666

Bridge Defects | 3 July, 2023

Hi Researchmfg,

If upload picture would be great to interpret this question, anyway,if bridge occur defect should be adjudge NG product,to avoide this issue,firstly,bridge is a PCB defect that happens when solder gets to an area it shouldn't be. You can also prevent solder bridging by minimizing the solder paste volume. Also, components with more lead can prevent the solder from flowing in between the leads.

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MagyarT

#89669

Bridge Defects | 3 July, 2023

Caleb,

If the leads were connected via trace, and this would be accepted by the customer, production documentation must be updated with the deviation.

What people see is a bridge, 95% of them don't look further if the bridge is on a common trace or not.

Regards, Tom

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calebcSMT

#89672

Bridge Defects | 3 July, 2023

Well noted - and makes sense. Though 'technically acceptable' from an electrical/functional stand-point, unless it was called out within documentation/discussed with the customer, it should still be looked at as a defect, since otherwise its very ambiguous and you would not expect inspectors to be looking at every bridge to see if a trace is present... let alone then expect the customer to also not be concern by a bridge not documented.

I suppose I came from the position that rework is always last resort and I find too much over inspection in the industry, along with unneeded rework. So in essence, I was curious if situation where let's say a SOP every once in a while had bridge, could you just simply pass it through inspection to avoid un-needed rework... but it's evident now though you may get away with it; typically as you mentioned customers will see bridges as defects (even if it tests functionally) unless a specific call-out/discussion has been had.

Never assume.

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calebcSMT

#89673

Bridge Defects | 3 July, 2023

For this general question, not a consistent bridge but instead more a question if you had a component that randomly had a bridge, to avoid unneeded rework could you accept it as long as electrical they're common?

But I think as you have mentioned, regardless if it works, it may still be considered a defect without documentation or such.

If it was consistent, it would definitely be a red flag for QA/Process engineer to be taking a look at the cause and resolution.

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researchmfg

#89675

Bridge Defects | 4 July, 2023

Calebc, My opioin is different. If the bridge is consistent then we can treat it as the design made it. If the bridge is not consistent then QA and Process engineer shall take a look since the process is not stable.

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