Our current end point req'ts on thickness tolerance are:
        Substrate to Substrate Board Thickness


         <<...OLE_Obj...>> 

                                Board (substrate to substrate) thickness
tolerance
                Designed t              Tolerance	
                * 50 mil (1.3 mm)       ±12% - not to exceed 20 mils (0.5mm)

                < 50 mil (1.3 mm)       ±20%	
 


Regards,
Robert J. Russell
e-mail: [log in to unmask]
Tel: 609-639-3173, Fax: 609-639-3197

Mailing  Address                                   Shipping Address
Lucent Technologies, Bell Labs           Lucent Technologies 
Room # 5-3082                                         Room#5-3082
P.O.Box: 900                                             Route 569, Carter
Road                            
Princeton, NJ 08542-0900                       Hopewell, NJ 08525


> ----------
> From:         Barnett, Richard[SMTP:[log in to unmask]]
> Reply To:     Combined Forum of D-33a and 7-31a Subcommittees;Barnett,
> Richard
> Sent:         Friday, September 22, 2000 2:44 PM
> To:   [log in to unmask]
> Subject:      Re: [IPC-600-6012] End Product Requirements for Board
> Thickness T olerances
> 
> Folks,
> I can't see the applicability of this requirement, when overall board
> thickness is a variable based on system level design and integration. If
> we
> are seeking default tolerances, then these should be applied to the "raw"
> materials (glass, weave, cores, copper...etc). The board thickness will be
> a
> function of all these combined, but the applicability of a default
> tolerance
> for overall thickness on end-product just doesn't seem to fit.
> 
> Rich Barnett
> Corporate Component Procurement,
> PCA Technology Engineering
> Compaq Computer Corporation
> 
> -----Original Message-----
> From: Rene Martinez [mailto:[log in to unmask]]
> Sent: Friday, September 22, 2000 9:12 AM
> To: [log in to unmask]
> Subject: Re: [IPC-600-6012] End Product Requirements for Board Thickness
> Tolerances
> 
> 
> I also think a default is in order.  Especially because the designers need
> to know the limitations of how tight of a tolerance can be called out when
> you add inherent tolerances of copper,laminate, plating, etc.
> 
> -----Original Message-----
> From: Jih Yuan [mailto:[log in to unmask]]
> Sent: Friday, September 22, 2000 5:47 AM
> To: [log in to unmask]
> Subject: Re: [IPC-600-6012] End Product Requirements for Board Thickness
> Tolerances
> 
> 
> John, From an OEM perspective, I think it's always good to have a default
> value. That's what the industry standard is about.  Jih
> 
> -----Original Message-----
> From: IPC-600-6012 Mail Forum [mailto:[log in to unmask]]On Behalf Of
> John Perry
> Sent: Wednesday, September 20, 2000 5:37 PM
> To: [log in to unmask]
> Subject: [IPC-600-6012] End Product Requirements for Board Thickness
> Tolerances
> 
> 
> Hello Everyone,
> 
> IPCWorks 2000 has come and gone.  Ready for Expo in Anaheim?  Sheez, are
> you
> kidding?
> 
> As participants in the IPC-6012 and IPC-A-600 groups, many of you have
> also
> been involved with the IPC-2220 design series, and many of you may recall
> the ancient IPC-D-300G Printed Board Dimensions and Tolerances document.
> This old dinosaur was recently replaced by the IPC-2615, thankfully
> without
> the outdated end-product requirements such as bow and twist and annular
> ring, all of which have been updated through the years where they belong -
> in the design and performance specs.
> 
> One, however, hasn't been transferred to the appropriate requirements
> documents, and I wanted to make sure that it was an intentional exclusion.
> IPC-D-300G used to provide tolerances for board thicknesses.  We don't
> have
> any applicable tolerances for this in any of the other spec.  Sure,
> IPC-4101
> does provide tolerances for laminate materials (Table 7) , and IPC-6012
> and
> IPC-A-600 provide thicknesses for foil plus plating (under review now as
> we
> speak!), but did we intentional avoid the transfer of nominal thickness
> tolerances for finished rigid boards to the design and performance series
> of
> documents that we currently use for boards?  Should we point people to the
> use of IPC-4101 in conjunction with the IPC-6012?  As always, your input
> is
> much appreciated.
> 
> Best Regards,
> 
> 
> 
> John Perry
> Technical Project Manager
> IPC
> 2215 Sanders Road
> Northbrook, Il 60062
> 1-847-790-5318 (P)
> 1-847-509-9798 (F)
> [log in to unmask]
>