Alain,
That average takes into consideration the thinnest points(from what I
have found). The CMI unit operates on the eddy current principle.
Baaaaack in 1992 I performed a gage R&R on this unit and found it to be
extremely reliable for our process, i.e. 1.2 - 1.5 mils of copper in the
hole. I plan on doing another study on the current unit we use and will
post those interested. Aside from pinning or cross sectioning I've found
this to be most efficient if the instrument being used is reliable,
again for your process.
Rick
GTC
>-----Original Message-----
>From: Alain Savard [SMTP:[log in to unmask]]
>Sent: Friday, March 24, 2000 5:17 AM
>To: [log in to unmask]
>Subject: Re: [TN] Measuring plated thru hole copper
>
>Don't know how to tell you this Franklin, put copper plating in small
>diameter holes (below 0.014") is not the same as in larger holes. In small
>holes, you may get much thicker plating at the surface and near the knee of
>the hole then what you get near the centre of the hole. Back when we had our
>in-house plating shop, way back in '97, I had looked into getting such a
>device and found it unreliable at best. It gives a good approximation, but
>it measures an overall average, not the thinnest points. But technologies
>may have changed since I looked into this.
>
>My 2 cents worth,
>
>Alain Savard, B.Sc.
>Chemical Process Analyst
>CAE Electronics Ltd.
>e-mail: [log in to unmask]
>
>-----Original Message-----
>From: Franklin Asbell
>Subject: Re: [TN] Measuring plated thru hole copper
>
>Are you looking for a device to measure thickness on individual holes? O
>overall through hole plating. The CMI device is very accurate at measuring
>hole wall copper thickness.
>
>Yes, it has hole size limitaitons but it's not the actual hole you are
>measuring, right? You might consider adding a few probe holes around the
>panel, the CMI unit works great in that way.
>
>Franklin
>
>----- Original Message -----
>From: May William D (Dean) CNIN
>Subject: [TN] Measuring plated thru hole copper
>
>> We are looking to buy a hand held unit to measure plated thru hole copper
>> thickness. I know CMI makes one but it can only measure a minimum hole
>size
>> of 35 mils. Are there any other vendors out there that make hand held
>> units.
>>
>> Would appreciate any information.
>>
>> Thanks!
>>
>> Wm. Dean May
>> NSWC Crane
>> Bldg. 38, Code 8086
>> 300 Highway 361
>> Crane, IN 47522
>> 812-854-3073
>
>##############################################################
>TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
>##############################################################
>To subscribe/unsubscribe, send a message to [log in to unmask] with following
>text in
>the body:
>To subscribe: SUBSCRIBE TECHNET <your full name>
>To unsubscribe: SIGNOFF TECHNET
>##############################################################
>Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
>information.
>If you need assistance - contact Keach Sasamori at [log in to unmask] or
>847-509-9700 ext.5315
>##############################################################
##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe: SUBSCRIBE TECHNET <your full name>
To unsubscribe: SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################
|
