IPC-4101 allows you to specify laminate thickness in three ways. Classes A,B,C are the unclad laminate thickness measured mechanically (micrometer). Class D is measured via microsection. Classes K,L,M are measured mechanically over the cladding. The differences between A,B,C are for different thickness tolerances Class C is the tightest). The same holds for K,L,M. > ---------- > From: John Denton[SMTP:[log in to unmask]] > Reply To: TechNet E-Mail Forum.;John Denton > Sent: Thursday, August 13, 1998 8:54 AM > To: [log in to unmask] > Subject: Re: [TN] PCB substrate thickness > > Ian Squires wrote: > > > > Help, > > Looking at substrate thickness on PWB > > if i specify 2oz copper 1.6 mm would the substrate be the same size, > thicker or thinner than 1oz copper 1.6 mm. > > > > Many thanks for any speedy replies (one of those urgent ones where > the boss man is standing over me). > > > > Regards > > Ian Squires > > Senior Production Engineer > > ------------------------------------------------------- > > > > Graseby Dynamics Ltd > > A Smiths Industries Company > > Park Avenue, Bushey, Watford, Herts, WD2 2BW > > Web Site: www.gradyn.co.uk > > Phone: 01923-228566 xt 295 > > Fax: 01923-221361 > > E-mail: [log in to unmask] > > > > Registered in England no. 480992 > > Registered office: > > 765 Finchley Road, London, NW11 8DS > > ------------------------------------------------------- > > > > ################################################################ > > TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" > section for additional information. > > For technical support contact Hugo Scaramuzza at [log in to unmask] or > 847-509-9700 ext.312 > > ################################################################ > > HELLO IAN, > > IF YOU ARE SPEAKING IN GENERAL TERMS ABOUT COMMONLY ORDERED > MATERIAL, THAN MY EXPERIENCE HAS BEEN THAT THE WAY PEOPLE REFER TO > MATERIAL DEPENDS ON IF IT IS A DOUBLE-SIDED BOARD OR CORE LAMINATE > THAT > WILL BE USED TO BUILD A MULTILAYER. (ALL EX. BELOW ARE IN INCHES). > > IF IT DOUBLE-SIDED: STANDARD .062 1/1 MATERIAL WOULD HAVE A LAMINATE > THICKNESS OF .0592 WITH A .0014 COPPER THICKNESS ON THE TOP AND > BOTTOM. > IF YOU SPEC .062 2/2, STANDARD LAMINATE THICKNESS IS .0564 WITH .0028 > THICK COPPER ON TOP AND BOTTOM. OVERALL THICKNESS REMAINS AT .062. > > IF IT IS CORE MAT'L FOR MULTILAYER: LET'S SAY 2 .014 CORES ARE BEING > USED ON A 6 LYR WITH A FINISHED OVERALL THICKNESS OF .062 AFTER > LAMINATION. IF YOU REFER TO .014 1/1 THAN THE LAMINATE THICKNESS IS > ..014 WITH AN OVERALL THICKNESS OVER COPPER OF .0168. IF YOU REFER TO > ..014 2/2 THAN ONCE AGAIN LAMINATE THICKNESS IS .014 BUT OVERALL > THICKNESS IS NOW .0196. > > OF COURSE WHEN YOU GO TO ORDER MATERIAL FROM A VENDOR, THEY DON'T > NECESSARILY KNOW IF YOU ARE BUILDING A M/L OR NOT. THE GOOD NEWS IS > THAT THERE IS A VERY CLEAR CONCISE WAY OF CALLING OUT WHAT THICKNESS > OF > LAMINATE YOU WANT AND WHAT COPPER WEIGHT YOU WOULD LIKE (AS WELL AS > THICKNESS TOLERANCES, PITS AND DENTS CLASSIFICATION AND WARP & TWIST > ALLOWANCES, IF CRITICAL) IN MIL SPEC 13949 (WHICH IPC IS CURRENTLY > CHANGING (HAS ALREADY CHANGED?). PERHAPS SOMEONE THERE CAN BRING YOU > UP > TO SPEED ON THE NEW SPEC IF IT HAS NOT ALREADY BEEN COVERED IN THIS > FORUM. > > JOHN DENTON > OMNI PWB > > I'M SURE THE IPC PEOPLE CAN GIVE YOU THE NEW SPEC NUMBER AND > > ################################################################ > TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" > section for additional information. > For technical support contact Hugo Scaramuzza at [log in to unmask] or > 847-509-9700 ext.312 > ################################################################ > ################################################################ TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################