Few glue suppliers will have info on tensile, but they will have for shear. Try asking for that instead or look it up on the data sheet. As a very rough approximation tensile will 85 -90 % of shear, but be careful when setting up tests that you don't inadvertently test for peel as the numbers you get will be deceptively low. Some of the adhesive suppliers have a handy torque tester like device, you set this at say 90% of the theoretical number and this allows you to test non destructively on real boards. As Steve said they will be small numbers, [if you assume a typical SMT adhesive has a shear strength of say 2000 psi you can work out a pretty good estimate of the likely real number from your dot size.] The shear force on a component from the solder wave is actually quite small and most adhesives will exceed this. If you are getting drop outs I personally would suggest you might want to look in to your glue handling procedures. Be on the look out for having two: the one that's written down and the one that actually goes on. A goodly proportion of adhesive problems are finger problems/handling related, most probable one is material going out of time Mike Original Message ----- From: Stephen R. Gregory <[log in to unmask]> To: <[log in to unmask]> Sent: Thursday, June 15, 2000 12:40 AM Subject: Re: [TN] Pull Test for Glue Process > In a message dated 06/14/2000 5:48:48 PM Central Daylight Time, > [log in to unmask] writes: > > > Fellow tech netters, > > > > I am trying to setup some pull test specs for our expoxy > > process, we currently using a DEK screen printer and a FUJI FGL2 to > > dispense glue. Does any one know what are the pull test (in pounds) for the > > different components (example 0805, 1206, Tantalums, etc)?. I have found > > that the only way of knowing if a populated board with glue is going to > > withstand the handling is by having a pull test as a process measurement. > > Any ideas? > > > > Thanks > > > > > > Jorge Rodriguez > > Process Engineer > > Conexant Systems > > Hi Jorge! > > I'm going to offer my opinions, but they are only that. My opinion of > quantifying the force it takes to separate a component from the epoxy bond is > a little over the top, you could be spending your time doing better things... > > The epoxy used to bond components for wave solder has very little strength to > withstand rough handling in the process, and that's where I would concentrate > my efforts if it were me. People need to understand that the boards that have > epoxied components on the bottomside need to be handled very carefully. The > epoxy is only supposed to hold the components on enough to be waved...they > can't be handled in the same way as boards that have soldered components on > them. Of course it's not a good idea to be banging on soldered components > either, but you catch my drift... > > I've been through similar situations. The boards come off of wave missing > bottomside components, and the first thing that has been pointed at was; "you > didn't cure the epoxy good enough..." or; "you didn't put enough epoxy > down..." But they have a hard time arguing with me when you can look and see > that the epoxy that was deposited is still on the board and has the imprint > of the component is still in the epoxy...it was obvious that the component > was there and got knocked off... > > Epoxy cure is simple...I set 150-degrees C. across all zones in my oven and > set the belt speed to make sure it sees that temp for at least a minute and a > half...simple. > > When a lot of people hear the word epoxy, they think that it's the same two > ton strength stuff that you use to repair your broken chair leg with, but > it's not. People need to learn to handle boards very carefully with epoxied > bottomside components.... > > My two cents... > > -Steve Gregory- > > ############################################################## > TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional > information. > If you need assistance - 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 1.8c ############################################################## 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 web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################