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| Subject: A welcoming note... | |
Author: Peter Thornton [ Edit | View ] |
Date Posted: 08:36:44 01/31/04 Sat Welcome to a new World forum for all involved in soldering as part of electronics assembly. Being web based, the forum is openat any time 24/7 from anywhere, world wide. It is entirely free to read any of the posts. Please feel free to browse, and I hope you gain useful free information! Should you wish to post YOUR question, you will need a write password; this is available form t_eeco@hotmail.com on the receipt of a subscription to cover our administration costs. How much you wish to send is entirely up to you! Recognised experts, engineers and others who are willling to contribute will be issued free write passwords. Contact t_eeco@hotmail.com for initial application. Thanks, and happy soldering!! REMEMBER - LEAD FREE COMETH... [ Post a Reply to This Message ] |
| Subject: Lead free soldering mods... | |
Author: Peter Thornton [ Edit | View ] |
Date Posted: 08:46:30 01/31/04 Sat Research is presently underway at the Equipment Engineering Co. to discover if some coatings would be suitable, viable and reliable to enable existing solder pots to be used for lead free alloys. Initial tests on silicon carbide, silicon nitride and amorphous vitrified silicon are presently undergoing accelerated strees testing at 500deg.C in a nitrogen cover gas mini solder pot. The temperature at 500deg.C causes the tin in the alloys to be extremely aggressive; any weakness in the coating will be seen in hours rather than months. Various alloys are under consideration, as are various contamiants to see if the prescence of minute amounts of lead (i.e. from 60/40 plated component leads, for instance). The results will be posted here as soon as definitive answes are available. Watch this space!! [ Post a Reply to This Message ] |
| Subject: Pre-heater temperatures now closed loop... | |
Author: Peter Thornton [ Edit | View ] |
Date Posted: 08:55:17 01/31/04 Sat The simple timed / temperature setting of preheaters in a soldering operation has been up to now a trial and error process, involving conveyor speeds, heater drive power, board configuration, &c., and hours with a profiler system to keep the process in check. Using advanced infra red pyrometry technology, the Equipment Engineering Company developed a simple, cheap, accurate and reliable method of "closed loop" controlling ANY preheater: any component can be monitored to eliminate any possibility of a more susceptable component becoming overheated before the main board has reached a suitable temperature. The pyrometers can detect poorly performing heater stations, occluded cover glass, damaged filaments, out of spec. long wavelength heaters. The system can be configured to flag a warning, and after a programmable number of errors, stop up a machine to prevent scrap or out of spec. product. Full information and prices from OPTL, England, who are the sole agents. [ Post a Reply to This Message ] |
| Subject: Inerting a solder wave... from the inside | |
Author: Peter Thornton [ Edit | View ] |
Date Posted: 09:42:08 01/31/04 Sat To run an inert atmosphere in a wave soldering machine usually involves large volumes of nitrogen, the cheapest oxygen excluding gas available in bulk. This is either used overall in the tunnel style machine, with rudimentary air locks at entrance /exit, or complicated cover shrouds over and around the solder pot... where the real action takes place. To address the huge engineering costs of a tunnel machine, or increase the ineffectual "cover and shroud" method, the Equipment Engineering Co. has developed a method of inerting an existing atmospheric wave (turbulent OR laminar flow) which gets the nitrogen just where it's needed: right up around the joint as it's being soldered on the fly. And what's more, the method uses a tiny fraction of the gas volumes normally associated with inerting... try a few litres per minute for total cover, not cubic metres per hour!! The system will run on existing 60/40 or lead free machines of ANY type, to pot temperatures of 450deg.C. It is fully automatic, cheap, simple and reliable. And patented. Full information can be obtained from www.OPTL.co.uk anytime, who are the sole agents. [ Post a Reply to This Message ] |
| Subject: Painted on coatings given a 12 month guarantee? | |
Author: Peter Thornton [ Edit | View ] |
Date Posted: 15:54:38 02/02/04 Mon I have first hand news of a company in England offering a lead free treatment, guaranteed for 12 months, to enable ANY solder pot to run lead free at any temperature. When I stopped laughing I was told the factory offering this service was inundated with customer's pots to be treated. I ask simple questions. Having had a few years' experience in surface coatings, gleaned from silicon wafer epitaxy reactors, ion implanter wafer holders and such, I know that something as reactive as tin at 260 deg.C is one hell of a soluent. And a "paint on coating" even with a guarantee isn't worth the paper it's written on. 1) Does this coating affect joint reliability by introducing ionic components causing long term corrosion... remember purple plague...? 2) Does this coating work at extended temperatures... >260C? Or do you have to keep temperatures very low, with bad wetting and pull through to top side? 3) Can a painted on coating (2um thick at best, in the weakest place) cope with the abrasion of the force pumped solder... remember, it contains dross and other oxide products, all very abrasive? 4) Does the 'paint on' coating work on pump shafts, where the continuous rotating / friction dross oxygen enrichment occurs? 5) Ask if the guarantee covers consequential liability. If you don't discover a flaw in the painted on coating before you send out boards, you have made joints with metallic contamination... and you won't know until the failures come flooding back in, too late to make amends? 6) You must make your own decision. If you can take a risk, chance your output quality on a cheap, paint on coating, ok: do it. I will take a metalurgically proven, time tested, quality assured solution: if you regard quality as a first issue, you should do the same. Trust silicon carbide / nitride. Silicon wafer epitaxy susceptors run this coating day in, day out in an atmosphere of HCl / Hydrogen (an extremely reducing & corrosive mixture) at 1250 deg.C with no problems... talk to a wafer fab. process engineer in Epitaxy / Diffusion if you don't believe me. email t_eeco@hotmail.com for more information. [ Post a Reply to This Message ] |