Formula = weight of component in grams/total pad mating area in square inches The resulting grams per sq. in. must be less than or equal to 30. This formula came by way of Phil Zarrow from his article on Reflow Soldering of Through-Hole Components (Journal of SMT, Oct. 1999.) Bob Robert Barr Manufacturing Engineering Formation, Inc. Voice: 856-234-5020 x3035 Fax: 856-234-6679 -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Stephen Brown Sent: Monday, July 23, 2001 11:02 AM To: [log in to unmask] Subject: [TN] Component Mass / Pad Geometries Question? There is a formula somewhere which I can use to calculate the maximum allowable mass of a component in relation to the pad lands. Basically I want to make sure our designers do not put components on the underside of the PCB which are going to fall off during doublesided reflow. I would like to point out that this is a design for manufacturability question, not an attack on the tentative grasp on reality some card designers have. Steve. ---------------------------------------------------------------------------- ----- 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 ---------------------------------------------------------------------------------