Actually, looking at Bill's address, he IS the laminate manufacturer!
oops!
At 08:57 02/09/99 -0700, you wrote:
>The first thing that comes to mind is why don't you let your laminate
supplier do this
>for you? I will assume you have a good reason for doing this your self.
How many high
>are you pressing this package, when I worked at a lamination facility we
did that kind
>of thing 18 panels high in a 48" x 72" format with a large quality of
wedge shape wood
>blocks against the bolsters.
>
>Another little trick is to replace some of your 7628 with unclad laminate
in the
>middle. That way you only need two plies of the prepreg on each side of
the unclad
>against the copper foil. This will reduce the slippage considerably.
>
>Good Luck
>
>Chuck Brummer
>
>Wang, William (Suzhou Laminate) wrote:
>
>> Chuck:
>> I'm sorry that I didn't provide enough information. The slippage
>> happens to 1.5 mm or 1.6 mm double sided laminate during the lamination
>> process (copper foil, 8 ply 7628 prepreg, copper foil, not PCB
>> multilayer lamination). It happens from time to time, sometimes zero
>> percent though we change nothing in our process. We reduce the resin
>> content of 7628 prepreg, the slippage percentage decrease but lead to
>> under-thickness problem.
>>
>> Thanks and best regards
>> William Wang
>> ----------
>> From: Chuck Brummer
>> To: [log in to unmask]
>> Subject: Re: [TN] Copper Clad Laminate Slippage
>> Date: Wednesday, September 01, 1999 10:52PM
>>
>> Let us count the ways, sorry just a little joke. In my last bit of
>> advice I suggested
>> that the problem could be fixed by increasing the resin to glass ratio.
>> But too much
>> resin not enough glass can make your package slip. When was the last
>> time you checked
>> your press for parallelism? You might be pushing the package to one
>> side or corner.
>> If your gel time is off the prepreg can get very slippery. How many
>> layers? Are your
>> making a multilayer that has little "C" stage core and very much
>> prepreg. Do you need
>> to block the load. When we last used vacuum assisted lamination I made
>> some aluminum
>> frames to assure the load was centered and resisted slippage because we
>> use some
>> conformals that can cause slippage when the stack was higher. When we
>> do not use the
>> vacuum assist we reduce the stack height.
>>
>> Dan Brandler, where are you? You should probably have some insight for
>> this guy.
>>
>> Chuck Brummer
>> [log in to unmask]
>>
>> Wang, William (Suzhou Laminate) wrote:
>>
>> > I'm a greenhand of copper clad laminate, can anyone tell me why
>> > copper clad laminate could slip during press and how to prevent from
>> > slippage? (We use vacuum assisted hydraulic press)
>> >
>> > Thanks and best regards
>> > William Wang
>> >
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