Author Topic: Measuring each Layer dimesions  (Read 15794 times)

magarcia9

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Measuring each Layer dimesions
« on: December 21, 2012, 01:26:56 PM »
When a PCB is fabricated  is it normal to ask the PCB magnufacturer that the customer wants to witness the measuring dimension of each layer? For example copper thickness, trace width, and copper pour.

This question was ask by mechanical engineers at my company.

doggg1

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Re: Measuring each Layer dimesions
« Reply #1 on: January 05, 2013, 12:11:01 AM »
Hello,

You can have a cross section of the board sent to you. This is not part of any of your boards, but is actually a part of the extra material which holds the boards together on the, for example 18" by 24" overall panel. It has example layers so you can measure the copper thickness on each layer and prepreg between them. Your board house can get these to you a day or two before the boards show up, or can email you a picture of the cross section if you want it. in 25 years of doing boards, I have never needed them. I inspect the operation before I do business.

db

Glen77354

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Re: Measuring each Layer dimesions
« Reply #2 on: January 06, 2013, 04:39:48 PM »
to: magarcia9

I agree with doggg1.  I've bought boards for 20 years and I want to visit a board house and assess their capabilities before starting business.  Having said that, I might ask them for samples for various purposes - or cut up a couple of the boards received myself to analyse the quality of the process.

n most instances, especially if you don't have the tools, the board house will cut and provide prepared samples to you, with, or without their own data.  There could be a small fee, but for those initial orders, it is worth it to gain the confidence.

Good luck!

ponyboy

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Re: Measuring each Layer dimesions
« Reply #3 on: July 26, 2013, 06:19:25 AM »
Is it possible the customer is asking for a check on the X & Y dimensions of the inner layers - meaning are they all the same size? 
If not, there will be layer to layer misalignment and compromise of the registration.

This is often measured in process by an x-ray drill or similar when adding drill tooling holes.

X-sections are great for showing alignment of the layers at one point and in one dimension only - if you really want to know if the layers line up, you need the in process measurements mentioned above.