Critical Characteristics/Dimensions of PCBAs

[ga2qa23]

Hello All, is there a guide for what is typically considered a critical characteristic/dimension of a Printed Circuit Board Assembly (PCBA)?

I'm used to working in metal parts but now I'm diving into the world of electronics. My company is buying a custom-made PCBA from a board manufacturer vendor, and I have to define critical characteristics/dimensions the print (drawing) of the PCBA, and the vendor will do a 100% verification check of every critical element, so that we don't need to validate their manufacturing process of the custom PCBAs.

I understand that I must perform a risk analysis (ideally a Design FMEA) which will basically calculate my critical characteristics/dimensions, but I find it hard to translate a Design FMEA into individual elements on a PCBA print. I think that any external connector is definitely a critical dimension, and any important functions of the PCBA are critical elements. It would be great if there was a guide out there to help understand this. Thank you!

 

[ECHO]

If you are looking for a guide, IPC is the only thing that comes to mind. Here is a checklist I found online:
https://www.ipc.org/media/3418/download

There are mechanical elements like dimensions, mounting hole locations, clearance and connector locations but I would also spend some time making sure that the board is built true to the gerber files.

I also also think that a product performance test would be value added and if your volume supports it, maybe consider using a bed of nails fixture.

 

[ga2qa23]

That document is incredibly helpful, thank you!

By a "product performance test", do you mean a 100% inspection, where we do a inspection/functional check of every single unit?

 

[ECHO]

Yes sir

 

[QLearning]

Hi All, I'm jumping into this conversation thread and hoping you can help me. We are a contract manufacturer for printed circuit board assemblies. Just recently, we have received assembly drawings from a customer that has critical characteristics called out on the drawing. Which standard says that a "control plan" is required for critical characteristics. Is it in ASME Y14? Thanks!

 

[Miner]

Just recently, we have received assembly drawings from a customer that has critical characteristics called out on the drawing. Which standard says that a "control plan" is required for critical characteristics. Is it in ASME Y14? Thanks!

This is typically required by the automotive industry and is spelled out in the AIAG Advanced Product Quality Planning and Control Plan (APQP) manual. However, many non-automotive customers may also require it. This will usually be spelled out in customer-specific requirements (CSRs), in your contract or in the customer's supplier quality requirements. It's been awhile since I was in automotive, so I'm not sure whether it is mentioned in IATF 16949.

 

[QLearning]

Thank you for your quick response! We are certified to AS9100D, and typically do not see key or critical characteristics called out on the drawing. Our customer stated that because there were critical characteristics called out on the print, we would need to have control plans for each and submit them as part of our AS9102 FAIR package. I'm just wondering where this control plan is a requirement. Customer does not call out IATF 16949. Thanks.

 

[Johnnymo62]

I think whether or not they are required by AS9100D you will need to do the control plan because your customer is asking for it and its on the drawing your company agreed to use.

 

[Miner]

Many people left the automotive industry and went into other industries bringing these APQP concepts with them. Technically, these requirements should have been spelled out in the contract between you and your customer. Whether you push back on this "ask" depends on whether you have the leverage to do so. If you are a small fish in a big pond, you will probably want to comply.

 

[QLearning]

I think whether or not they are required by AS9100D you will need to do the control plan because your customer is asking for it and its on the drawing your company agreed to use.

Johnnymo62 - thanks for your reply. It came up as we were preparing an AS9102 FAIR for the assembly. The customer wanted the control plans to the critical characteristics that were identified on the assembly drawing to be included in our FAIR package. "...your customer is asking for it and its on the drawing your company agreed to use." So, this was the point of my question. We saw the critical characteristics called out on the drawing, but where does it say that for every critical characteristic you need to have a control plan? FYI, we will be preparing control plans from now on, whenever to we see a critical characteristic.