Chris, I passed on this the first time because I wasn't sure if you were asking a design question or an assembly acceptance question. Assuming assembly acceptance (or design, for that matter), the issue is any requirement for minimum electrical clearance. Minimum electrical clearance is defined in IPC-2221 Table 6-1 and is dependant on voltage characteristics. While IPC-A-610B doesn't specifically state the obvious for chip component minimum electrical spacing, one of the "overhang" requirements for Gull Wing Leads (Fig 10-43) does address "All classes shall not violate minimum conductor spacing . . .". Several other areas in IPC-A-610B also refer to terminations not violating minimum electrical clearance. IPC-A-610 is in revision, and if you feel specific criteria relating to this is important for surface mount components also, I invite you to submit a comment on IPC-A-610B Chapter 10 Surface Mount Assemblies to add a note to the lead-in paragraph or each specific section that component lead or termination area overhang shall not violate minimum electrical clearance. --------------------------------------------------------------------------------------------------------------- IPC HAS A NEW PHONE SYSTEM!! EXTENSIONS HAVE CHANGED!! Be sure to listen to the prompt for new directions. IPC/SMTA Electronics Assembly Expo Technical Committee Meetings, Conference, Exhibits Providence RI October 24-29 More info at http://www.ipc.org Jack Crawford, IPC Project Manager - Assembly 2215 Sanders Road, Northbrook IL 60062-6135 [log in to unmask] NEW DIRECT NUMBER 847-790-5393 fax 847-509-9798 >>> Chris Ball <[log in to unmask]> 10/13/98 03:57PM >>> Ok then, can anyone enlighten me slowly? Lemme rephrase it a bit.... 1206 resistor pads are 1.8 wide. The body is 1.8 max wide. IPC-A-610B, class 2 says it's acceptable as long as you have 50% overlap of widths... so it can move .9 either side... so that's a box 3.6 wide that is ok... right so far? So if two 1206 resistors are side by side, 3.6 apart, and each part is shifted worst case, they touch. Is that an acceptable condition per IPC-A-610B, class 2? Or does it mean the parts have to be spaced further than 3.6 in order to insure that your board is manufacturable per IPC-A-610B, class 2? Or does anything mean anything anymore? C'mon y'all....Jo-Ann?... Gary?... Abdulrahman?... Thank you in advance for all your help ;-) -Chris- ################################################################ DesignerCouncil 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 DesignerCouncil <your full name> To unsubscribe: SIGNOFF DesignerCouncil ################################################################ 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 ################################################################ ################################################################ DesignerCouncil 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 DesignerCouncil <your full name> To unsubscribe: SIGNOFF DesignerCouncil ################################################################ 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 ################################################################