Hi Bill, used to work with an airknife system years ago. The original intent of the product was to remove any solder which had not adhered to the basis material and to also remove excessive solder if it was webbed between component leads i.e solder shorts. If the solder had not wetted to the pads or was webbed between the component leads, then the molten metal would have little or no adhesive forces to the product to secure the molten solder to the joint and it would be removed by the air flow of the hot air knife. One of the advantages of the air knife at that time was the thought that it could inspect the solder joints as they were being created. By removing any excess solder from the solder joints, one could determine whether or not the intermetallic had been created. The intermetallic compound creates an adhesive force between the molten tin and the basis copper material and the air knife should not be able to remove this material. I know that if the angle of the air knife is set incorrectly or the pressure is too high, then any and all solder can be blown off any surface. So assuming the angle and pressures are set correctly the results should be solder joints that are created with just the correct amount of solder. This is the type of solder joint which has wetted to the base material, leads and boards, and any excess solder has been removed from the joint. What should the joint look like? You mention insufficient solder? This is a true catch all phrase in the industry. Provided the solder joints look meet the requirements set forth, for example IPC-A-610, then you should have no problem. If the process is blowing out the solder from the PTH then take a look at the pressure and air flow of the system to verify its correctness. Hope this helps, if not call me at 1 800 643-7822 or reach me offline at [log in to unmask] and we can talk about it some more. Regards, Leo Lambert -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Bill Raymond Sent: Wednesday, February 13, 2002 1:32 PM To: [log in to unmask] Subject: [TN] Inspecting Wavesoldered bottom-side SMD joints Hi all, I'm using a wave solder system with a hot air knife... the knife reduces solder shorts just fine, however, the inspectors are finding "more" insufficient solder joints. I've read articles _somewhere_, that when using a hot air knife system, the joints will tend to look different and that inspectors will need to be retrained as to what to look for. Can anyone point me to a source of information?? Thanks, Bill... ---------------------------------------------------------------------------- ----- 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 e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest 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 e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest 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 ---------------------------------------------------------------------------------