I truly believe that about 99.9% of circuit board fabricators belong firmly in the "I am proud of my boards" category.

My experience over 40 years in working with many, many fabricators leads me to say that. Even for fabricators building boards in Asia, or from any 3rd-world country, worldwide. By the way, that is a very old-fashioned image. There are very few of those left.

If a fabricator did that, they would also cut corners elsewhere with disastrous results leading to the loss of their business, and any fabricator with any major skin in the game knows this.

In addition, the IPC goes to great lengths to help prevent PCB users from being victimized by these types of unscrupulous vendors.

They have both a PCB Fabricators Certification program, as well as many standards such as the PWB provider's audit guideline and other standards that require certified data to show this does not happen.

I would not buy circuit boards from any vendor NOT CERTIFIED to IPC's fabrication program. Period. And I would never think of qualifying a PCB fabricator without auditing them to IPC checklists periodically,  either. 



But guess what? You don't have to take my word for it; do what I do.



On every PWB pallet design, include three redundant vias connected with a single trace on two layers connected to two 0805 pads, one pad on each side of the carrier strips along the sides of the board itself, or else somewhere else on the panel.

Program your pick and place machine to pick and place a chip cap or resistor on every 1st or 10th or 20th or 5000th panel. At random, you can analyze one of these test strips. Inspect them for wetting, or either X-ray or microsection the throwaway carrier for via hole wall thickness, trace roughness, copper foil thickness, run it through XrF for plating thickness, test whatever you are concerned with.



Adding this redundant feature costs little or nothing in fabrication costs, and you get a free "coupon" with every board or panel you receive. Check anytime or everytime. Whatever allows you to sleep at night.

No extra packaging costs to handle coupons separately; its built into every board carrier or panel you get.



Will they rotate their drill bits so the FIFO is always rail/board? Hmm.....the cost of doing that is....nah!

Corner cutting ALWAYS shows up. 

Always.

Odin





-----Original Message-----

From: TechNet <[log in to unmask]> On Behalf Of Dennis Fritz

Sent: Friday, April 12, 2019 11:51 AM

To: [log in to unmask]

Subject: Re: [TN] Board Fabrication - Drilling Coupons



Wow, this is the second time in the last 3 months I have heard the possibility of "gaming the system" by producing coupons with special care, compared to the board quality being shipped.  Where did the idea go - "I want to improve my process and quality all the time, so I will drill sample coupon holes with the last drill hit before going to re-sharpening"?



I guess board quality is going the way of our politics - it's only bad if I get caught, not  "I am proud of my boards".



On Fri, Apr 12, 2019 at 11:36 AM Jack Olson <[log in to unmask]> wrote:



> Is there anything in IPC documentation that prevents the fabricator 

> from drilling all the coupons first (with shiny new drill bits) and 

> then the rest of the boards in the panel?

> Sorry to sound cynical, but it seems like someone would have thought 

> of that already, right?

>





--

Denny Fritz

Consultant

812 584 2687