While secondary drilling prohibitions do apply to drilling of the original holes after plating, they were not intended to apply to rework of the original holes which were drilled as primary (prior to plating) as long as the rework does not result in the hole being out of tolerance, either in hole diameter or location from datum registration point X0, Y0.
Remember, rework means returning the original non-conforming characteristic to meet all applicable requirements.
If they ended up with plating inside pre-drilled holes that is not supposed to be there, how would the fabricator then rework those holes to meet the fabricated print requirements if a strict prohibition of secondary drilling were applied? Does that mean I cannot take a dental pick and lightly scrape away a copper sliver after plating is completed?
I am not talking about increasing the hole size, just using the same size bit (or etchant) to clean out any excess copper.
Just call it touchup.
The limitation of no secondary drilling was intended to prevent mis-registration and exposed inner layer copper and smearing, as you pointed out. But cleaning the extraneous copper from the holes already drilled is not likely to cause any mis-registration at that later step. Per 6012, any copper smear inside the unplated holes is considered a defect condition.
It does not say "Well, maybe a wee widdle bit is OK."
-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Tuesday, June 10, 2014 1:38 PM
To: [log in to unmask]; Stadem, Richard D.
Subject: RE: [TN] Plating in non-plated holes - again
I know I am late chiming in, but how are non-plated through holes not secondary drilling requirements? Your drawing requirement for NPTH would supercede any fabrication specification. Or am I wrong?
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Tuesday, June 10, 2014 11:35 AM
To: [log in to unmask]
Subject: Re: [TN] Plating in non-plated holes - again
Secondary drilling of holes already drilled is not secondary drilling, however. It is rework. Rework of defects that should have been found and fixed in the first place.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Henry Rekers
Sent: Tuesday, June 10, 2014 10:52 AM
To: [log in to unmask]
Subject: Re: [TN] Plating in non-plated holes - again
I'd love to do that, but our specification demands no secondary drilling.
My guess is due to past registration issues.
_____________________________________________________________________________________
Henry Rekers P. Eng | Schneider Electric | Global Supply Chain |
Senior Manufacturing Engineer
Phone: +1-250-652-7100 ext. 7510 | Toll Free: +1-866-466-7627 ext.
7510 | Fax: +1-250-544-2390 |
Email: [log in to unmask] | Site:
www.schneider-electric.com | Address: 2195 Keating Cross Road,
Saanichton, BC, Canada, V8M 2A5
*** Please consider the environment before printing this e-mail
From:
Brian Ellis <[log in to unmask]>
To:
TechNet E-Mail Forum <[log in to unmask]>,
[log in to unmask],
Date:
06/10/2014 08:38 AM
Subject:
Re: [TN] Plating in non-plated holes - again
Drill after ENIG
Brian
On 10.06.2014 18:26, Henry Rekers wrote:
> Hey there technetters. A while back, I sent a message about enig
plating
> contamination in NON-plated holes. I've bounced it back to the board
> shop saying that it is unacceptable, but they claim it is due to 6012
> 3.5.2
> I also think it's unacceptable in the 4552 spec. The design
> documentation clearly states non-plated. It's not plated, just
partially
> plated.
>
> Any advice?
>
> Thanks.
>
_____________________________________________________________________________________
>
>
> Henry Rekers P. Eng | Schneider Electric | Global Supply Chain |
> Senior Manufacturing Engineer
> Phone: +1-250-652-7100 ext. 7510 | Toll Free: +1-866-466-7627 ext.
> 7510 | Fax: +1-250-544-2390 |
> Email: [log in to unmask] | Site:
> www.schneider-electric.com | Address: 2195 Keating Cross Road,
> Saanichton, BC, Canada, V8M 2A5
> *** Please consider the environment before printing this e-mail
>
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