Hi, Jonathan, Your temperatures seem very high and your 180 C duration is long compared with what I'm used to using - what sort of boards and what sort of solder are you using? What components are failing? More details, please. Have you made sure that the maximum case temperature of any of your components (especially the failing ones) is not being exceeded? Have you also made sure that, if any of the components are moisture sensitive, they are either within their moisture exposure limits or have been baked out prior to assembly and soldering? If you're sure everything else is OK and all that you're left with is the reflow cool-down rate, I would go for about 4 C per minute. Pete Duncan Jonathan A Noquil <Jonathan.A.Noquil@FAIRCHIL To: [log in to unmask] DSEMI.COM> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) Sent by: TechNet Subject: Re: [TN] Cooling Rates <[log in to unmask]> 06/28/01 07:40 PM Please respond to "TechNet E-Mail Forum."; Please respond to Jonathan.A.Noquil Hello Guys, What is the best cooling down rate in a reflow oven? Does anybody have experience on what maximum cooling down rate that will not result in Silicon cracking? We have some silicon cracking (Chips) and we are still evaluating if fast cool down can cause this problem. My Profile is: Pre-heat: 150 C Soak: 250 C Reflow 1: 290 C Reflow 2: 290 C Time of Reflow: 180 secs Thank you very much in advance for your ideas tomorrow --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------