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defects in pcb manufacturing

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#60196

defects in pcb manufacturing | 27 October, 2009

I work for a CEM. We are having some quality issues with some pcb's that came from China. (I know, big surprise) Can anyone with pcb manufacturing experience look at some pictures I have and give me an opinion as to what could go wrong in the pcb manufacturing process that would cause these "defects" I put defects in quotation marks because our China supplier is trying to tell us these boards meet IPC-A-600 standards. They say it is strictly cosmetic and will not effect the board functionally. Attached is a couple pic's. Any & all help will be greatly appreciated.

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#60203

defects in pcb manufacturing | 27 October, 2009

Top picture: We're not wild about the 'poor registration,' the differing thickness of the solder mask, and the crud all over the board. But, then again, we don't have a basis for rejection. Bottom picture: No basis for rejection

Help us out, what don't you like about these boards?

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#60205

defects in pcb manufacturing | 28 October, 2009

solderresist has a big offset?

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#60207

defects in pcb manufacturing | 28 October, 2009

I don't like these boards for a couple different reasons.

1. They may be fine functionally but they look like crap.

2. What is our customer going to think when we deliver boards that look like this? They will probably wonder the same thing I do... boards that look this bad on the surface how are they under the mask?

Thanks for your comments/opinions.

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#60208

defects in pcb manufacturing | 28 October, 2009

I agree with you. Personally, I would either return them and look for a new supplier or scrap these boards. Unless your customer provided these boards and gave you the go ahead to populate them, they will not be too pleased about the build.

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#60226

defects in pcb manufacturing | 29 October, 2009

The top picture probably won't run. You have black soldermask dramatically misregistered and overlapping what look a lot like fids. Either your machines are going to pitch a fit and not find the fid or they're going to center on the soldermask outline. Neither is going to leave you with acceptable results.

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#60236

defects in pcb manufacturing | 30 October, 2009

Hi, I see a huge solder mask shift on chip comp pads. This would result in mid-chip solder balls or solder beads. Overall, the solder mask workmanship is not acceptable. Mask is on pad.

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#60246

defects in pcb manufacturing | 1 November, 2009

Just my opinion:

Top pic - Solder mask registration WAY too far off, without a doubt I would reject.

Bottom pic - I would worry that there was/is a contamination that caused the poor looking mask. This may be cosmetic only, but unknown. I would reject them. If the PCB fab company will not remake the boards for you then get a new fab company. There are plenty of good ones out there. No need to accept sub-par boards. Your customer will not care to hear excuses if these boards fail during/after assembly.

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#60254

defects in pcb manufacturing | 1 November, 2009

Hello Julie

Yr supplier is saying that these boards meet the requirement of IPC-A-610. I think that you need to check this requirements at least. But, it does dot mean that these are acceptable.

Thanks.

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#60258

defects in pcb manufacturing | 1 November, 2009

Hi Julie,

My opinion is that the top board would not pass IPC, solder mask encroachment on pads.

Second board is what we call Orange peel,this can be caused two way's. 1) the solder mask was not tack dried enough prior to imaging which caused artwork to stick to panel during imaging. 2) these could have been hand screened on a table (Not by a screen coater) and the screen was sticking to the boards do to uneven pressure by the operator.

top board would be easily rejected due to poor registration. Bottom board looks like crap and could be rejected due to uneven solder mask thickness and poor quality control.

I would agree to other comments that if this is typical quality that your are receiving from this shop, I would investigate other suppliers.

My Disclosure:

I am a Direct salesman for a Taiwan board supplier.

Like in the US their are good and bad shops. I would say that 99% of shops in Taiwan & China would not find this product acceptable.

Best Regards, Mike Dupont Active Sales Associates Inc.

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#60260

defects in pcb manufacturing | 2 November, 2009

Base on the top picture condition, seems like the boards condition is a lot with solder splash or solder ball which is per IPC-610 is under reject (under 5.6.2)for class 3 product. While the picture 2 is showing those the solder resist is not melt properly during PWB manufacturing side, that's condition as per IPC-610 also under rejectable for class 3 product, check under clause 10.5.1. Before you decide that condition is better to know what's kind class your manufacturing process been build and adopt.

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#60271

defects in pcb manufacturing | 2 November, 2009

Umar - the boards are not assembled - so Solder splash is not applicable.

Solder resist does not Melt it cures.

As a board supplier I would not want my clients to adapt if they are receiving crap product, I would expect them to leave.

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#60273

defects in pcb manufacturing | 3 November, 2009

Davef, you really make me laugh!!! pretty funny sarcastic way to represent the typical supplier response... If we could have a "The things (Top 10) that you will hear about your PCB supplier"

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#60276

defects in pcb manufacturing | 3 November, 2009

Has anyone ever done a tape test to see if the solder resist pulls away from the PCB? Is this an acceptable method for testing solder resist acceptability?

This is an issue I am experiencing with our PCBs. I am receiving boards with excess solder on the fiducials. I'm sure this is from the HASL process, but is there an IPC spec for the height of the HASL finish on the fids?

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#60288

defects in pcb manufacturing | 3 November, 2009

I think most have summed up the first pictures also is the drillng looking like it is misregistered as well.

Better to do a solvent test to determine resist cure not the old stuff the newer chemicals show under cure problem much better. Try your stencil cleaning solvent if its decent material then it will remove undercured residue's, this is still a big problem to the assembly industry HASL not flat anyway so go to ENIG or similar for flatness and long term reliability cheers greg blt

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#60290

defects in pcb manufacturing | 3 November, 2009

Solder Mask Adhesion Pull Test Tape List IPC-TM-650 Test Method 2.4.28.1, Adhesion, Solder Resist (Mask), Tape Test Method, defines the procedure for determining the adhesion of solder resists (masks) used over melting metals, (such as solder plated and reflowed solder printed boards both prior to and after soldering), nonmelting metals, and printed board substrates. The test method requires a roll of pressure sensitive self-adhesive film tape 1.3 cm [0.5 in] wide exhibiting an adhesive strength of at least 44 N/100 mm [40 oz-force/in] but no more than 66 N/100 mm [60 oz-force/in] as tested per ASTM D3330.  This web page provides a non-comprehensive list of tapes meeting this requirement.   This list is dynamic and IPC recognizes that other applicable tape brands may exist and will be included as IPC is notified.  None of the brands listed below are endorsed by IPC. If you are familiar with another tape brand that meets these requirements, IPC encourages your input.  Please provide your  name, e-mail address, and company name when providing a written e-mail to JohnPerry@ipc.org .  When providing information on an applicable tape brand, please include the company website (if available) in addition to the brand name. Brand Name||Brand Web Site||Adhesive Strength 3M Scotch 600||http://www.3m.com||44 N/100 mm [40 oz-force/in] 3M Scotch 371||http://www.3m.com||44 N/100 mm [40 oz-force/in] 3M Polyester Film Tape 853||http://www.3m.com||52 N/100 mm [48 oz-force/in]

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#60292

defects in pcb manufacturing | 3 November, 2009

Thank you, Manuel

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