Hi Ramakrishnan, Over the years I typically see these bakes during PCB fabrication at 105C or 125C. I also typically see much shorter bake times after electroless and after oxide (typically 1 hour or less). Typically I have not seen bakes after lamination or on incoming material (assuming they have been properly packaged and stored). The key air bake is prior to HASL. Depending on material and design, these can be 4 hours or even longer (typically at 125C). For solder float coupons, I have seen anywhere from 105C to 190C with bake times anywhere from 1 hour (190C) to 24 hours depending on the materials in the stack up and the need for fast results. Joel Joel S. Peiffer 3M Electronic Solutions Division 3M Center, Building 201-1E-21 St. Paul, MN 55144 Tel: (651) 575-1464 Cell: (612) 327-1983 Fax: (651) 737-4601 [log in to unmask] From: Paul Reid <[log in to unmask]> To: <[log in to unmask]> Date: 10/24/2013 11:02 AM Subject: Re: [TN] PCB BAKING DURING FABRICATION Sent by: TechNet <[log in to unmask]> Hi Ramakrishnan, I think that your bake temperature of 140°C is too high for a DICY cured material. I'd drop the temperature to 105°C. I'd drop the bake after lamination and possibly the bake after electroless if you can dry them without oxidation. Sincerely, Paul Reid Program Coordinator PWB Interconnect Solutions Inc. 235 Stafford Rd., West, Unit 103 Nepean, Ontario Canada, K2H 9C1 613 596 4244 ext. 229 Skype paul_reid_pwb [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Ramakrishnan Saravanan Sent: October 24, 2013 11:43 AM To: [log in to unmask] Subject: [TN] PCB BAKING DURING FABRICATION We are using 170 deg C IPC 4101/24 material for making hi reliability PCBs. The PCB coupons are subjected to 6X Solder Dip to access PTH integrity & laminate integrity. 5X R/W also carried out. to achieve this initial laminates(cores) are baked at 140 deg C for 4 hours. after blak OXIDE baked at 140 deg C for 4 hours after MLB pressing baked at 140 deg C for 4 hours after electroless copper plating baked at 140 deg C for 4 hours prior to HASL baked at 140 deg C for 4 hours a total of 20 hours at 140 deg C baked during fabrication. after PCB fabrication. the coupon is separated from PCB and the coupon is baked for 12 hours at 120 deg C. The coupon is subjected to 6X solder dip & 5x R/W simulation. My doubts are Q1. These extra long hours of baking will deteriorate the chemical & mechanical properties of the laminates ? if so , what are the properties are getting affected. The material dicy cured FR4. Q2. Whether Test coupon results will reflect the quality of PCBs ?. R.Saravanan ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________