Jerry, Thanks for your FIRST sentence, opinion. We use x-ray and as far as troubleshooting and improving our process it has been one of the best investments made. Rick Howieson General Technology Corp. >-----Original Message----- >From: Jerry Cupples [SMTP:[log in to unmask]] >Sent: Tuesday, May 30, 2000 4:12 PM >To: [log in to unmask] >Subject: Re: [TN] To X-ray or Not to X-ray. > >At 02:53 PM 5/30/00 -0600, you wrote: > >>Help, >> >>My company is asking for information leading to the possible purchase of an >>X-ray machine for BGA s. >> >>We are placing some with metal tops such as the ALTERA. ANY info on who, >>what, where, etc. etc. etc. >> >>Would be kindly appreciated. > >I have an opinion here, and it's just an opinion... > >Buying an X-Ray machine "for BGA's" is pretty common, as of course you can't >"see" the joints much otherwise. > >But you wouldn't buy an X-Ray machine just to check your lungs every 6 >months, would you? Not even if you were doing it for every employee, you >wouldn't. > >My brother is a radiologist. He can look at images which look like clouds, >and pick out the "Roentgen signs" that indicate disease and abnormalities. >When I look at them, they look like clouds. It took him years of internship >and residency to develop the skill analyze the images, plus a photographic >knowledge of human anatomy achieved along the way. He needs to know what >every section of a body SHOULD look like, and indicators for many >abnormalities in males, females, adults, juveniles. > >If you do buy one, you should plan to dedicate a technician who will learn >how to operate the equipment, process the images, and interpret what is found >- and the time and cost of this manpower is probably greater than the cost of >the equipment. You can expect it to be a long process to get much useful >information. There are many types of packages, and they are mounted on >different boards with different pads. This will change every six months or so >with some regularity. > >Some people think the process of interpreting the image ought to be simple, >like looking at the x-ray of a broken arm, and seeing the crack, and saying, >"yes, it's broken". The reality is that you see cloudy images and have to >adjust the contrast and use a lot of your training and experience to >determine what the image means. > >Having an X-Ray machine just to find shorts on BGA's after soldering is >overkill. What you may want is the ability to make judgements about the >amount of solder, the voids, and the wetting. This requires laminography, >sophisticated image processing, a trained technician, and then you have >indications which can be used to make logical inferences, not necessarily >clear cut process measurements. (I've seen my brother arguing with other >radiologists about the meaning of images, and he wrote a chapter in one of >the medical texts...)Your mileage may vary, etc. > > >cheers, > > >Jerry Cupples >Interphase Corporation ><html> >At 02:53 PM 5/30/00 -0600, you wrote:<br> ><br> ><blockquote type=cite cite><font face="arial" size=2>Help, <br> ></font><br> ><font face="arial" size=2>My company is asking for information leading to >the possible purchase of an X-ray machine for BGA s.<br> ></font><br> ><font face="arial" size=2>We are placing some with metal tops such as the >ALTERA. ANY info on who, what, where, etc. etc. etc.<br> ></font><br> ><font face="arial" size=2>Would be kindly appreciated.<br> ></font></blockquote><font face="arial" size=2><br> ></font>I have an opinion here, and it's just an opinion...<br> ><br> >Buying an X-Ray machine "for BGA's" is pretty common, as of >course you can't "see" the joints much otherwise.<br> ><br> >But you wouldn't buy an X-Ray machine just to check your lungs every 6 >months, would you? Not even if you were doing it for every employee, you >wouldn't.<br> ><br> >My brother is a radiologist. He can look at images which look like >clouds, and pick out the "Roentgen signs" that indicate disease >and abnormalities. When I look at them, they look like clouds. It took >him years of internship and residency to develop the skill analyze the >images, plus a photographic knowledge of human anatomy achieved along the >way. He needs to know what every section of a body SHOULD look like, and >indicators for many abnormalities in males, females, adults, >juveniles.<br> ><br> >If you do buy one, you should plan to dedicate a technician who will >learn how to operate the equipment, process the images, and interpret >what is found - and the time and cost of this manpower is probably >greater than the cost of the equipment. You can expect it to be a long >process to get much useful information. There are many types of packages, >and they are mounted on different boards with different pads. This will >change every six months or so with some regularity.<br> ><br> >Some people think the process of interpreting the image ought to be >simple, like looking at the x-ray of a broken arm, and seeing the crack, >and saying, "yes, it's broken". The reality is that you see >cloudy images and have to adjust the contrast and use a lot of your >training and experience to determine what the image means.<br> ><br> >Having an X-Ray machine just to find shorts on BGA's after soldering is >overkill. What you may want is the ability to make judgements about the >amount of solder, the voids, and the wetting. This requires laminography, >sophisticated image processing, a trained technician, and then you have >indications which can be used to make logical inferences, not necessarily >clear cut process measurements. (I've seen my brother arguing with other >radiologists about the meaning of images, and he wrote a chapter in one >of the medical texts...)Your mileage may vary, etc.<br> ><br> ><br> >cheers,<br> ><br> ><br> >Jerry Cupples<br> >Interphase Corporation</html> > ############################################################## 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 ##############################################################