There you are, you're finally coming out with some concrete information. To answer your questions, I am making a few assumption. First Q: I don't think you can set a freq border where you leave the wave solder pot all the time, or leave it on and off. This indecision is a lot depend on your process req's, the condition of solder pot, maintenance, and features of your wavesoldering machine. One option is to collect a certain number of boards to be waved and wave them all at once after a few setup/check. This is a lot better option then leaving the solder pot on or on/off. Only the conveyor and preheaters are remained on. Minor preventive maintenance (removing dross, checking flux concentration) should be performed every shift usually prior to running boards thru the machine. Major maintenance such as removing/cleaning/reassembling of front/back plates, nozzle assy, pump and vane of solderpot and a chemical analysis of solder should be performed monthly or 3 months or 6 months etc depending upon the freq of solderpot usage. A few indication of poorly maintained pot: freak-out noisy from pump rotation, unsoldered joints, dirts on the bottom side of boards, reduction of a flow solder height (cracking up the pump to maintain a same height) and obvioiusly a heavy layer of dross on the solder surface. Also if a freq adjustment of flow solder pot indicate a large amount of dross formation. All this shows the pump takes dross with molten solder thru flow ducks and pump it out thru the nozzle. Therefore, the regular removal of dross in the pot is a very important. 2nd Q: Adjust your flow solder height so that it is a little bit higher than the highest point of bottom side of board. This also depends on how stable is the flowing solder and whether stiffeners are used to keep boards from bowing down (remember Tg of FR4 is about 130'c and pot temp is usally btw 240-260'c). Sometimes, dirt on the top section of flowing solder are not usually gets removed when the wave is turn on first time. This is mainly because solder does not get flowed down smoothly thru front and back plates. This can be usually fixed by adjusting down front or back side plate or increasing the pump speed. Run a dummy board prior to running a board. This allows you to check the wave height, and remove dirt on the solder, and make an initial push for a smooth solder flow. From my experience, I didn't like to use the sensor on/off function. The setting can be turned off from the machine parameter setup (not by covering with a piece of tape). Usually first board after the wave is turned on, gets screwed up and 2nd. 3rd... are excellent as long as it is not turned off and on again. This is why in my opinion it is best to collect boards and run the wave all at once (as per the First Q) To be or Not be on. If on, creates too much dross, if on/off by itself, first board gets screwed. 3rd Q: You are asking one million dollar question here. Yes, it is not unusal not to do touch-up after wave. This also depends upon your process, solderbility of boards and components, solderpot contamination and whatever... If you do 5 board touch-up out of 100, say I consider that's pretty good. 4th Q: Flux should be dried prior to hitting the wave. If wet, it creates all kinds of defects as per previous e-mail responses. It is just like a frying a chicken wing in a oily bath. Can you image eating a ton of fatty oil with the fried chicken? Ohh.. I hate that. Same thing for greasy pizza's. Most flux mfg recommends 100'c to 120'c on the component of board. 5th Q: No excuses. You pick one typical board that go thru the wave a lot, and perform the temp profile to check preheat temp's on the component side of board. Adjust one variable at a time. Once it is good, you keep that as the master profile. For other boards, you adjust only one variable ( rec changing the conveyor speed only) to get an acceptable result. Fix the solderpot temp at 250'c or more/less and a board wetting time in the solderbath at 1 to 3 sec. I seldom change the wave profile unless it is big&heavy, thicker board (0.092&up), thinner board (0.032) or too small. 6th Q: It is outrageous. I totally and wholeheartedly agree with you. Boards should only go thru wave once and should produce acceptable result. You said boards supplied by your customer are fluxed (instead of tin/lead finish). That reminds me of rosin-based OSP that was used 20/30 years ago as a protective coating from oxidation. I believe this is the sole responsibility of your customer to supply you solderable boards. For this board, try increasing a board wetting time in the solder bath. It might work or might not. 7th Q: Use nylon spacers to elevate LED's. Contact Bivar, mfg of nylon spacers for electronic components. Tel: 714-951-8808, Fax: 714-951-3974 (it is in Irvine CA, USA) Regards Matthew Park NII Norsat International Inc. ****** Now, to get to my main point, that's right, you are responsible for getting this thing started. I got a few nasty, private and confidential messages. Thanks for those people out there who inflated and used political correctness from my technet messages. The arrest and trial of production supervisor is in order for the willful disobedience of process laws and tempering machine settings. The place where I am, production mgr and assembly people are too eager to pass a buck around and ending up on my desk. Of couse, I meant process-related laws. My guess was right, the responsibility of tackling this wavesoldering problem is squarely up to you, Mr Chee. >>> Hew How Chee <[log in to unmask]> February 20, 1998 9:44 pm >>> Hello all again, (for those who is just curious of who is who : the supervisor and the technician , read the end of the mail) I have read through the numerous responeses and will be looking into the problem very soon. But first, I'll be glad if anyone can provide me with more data. 1) From the feedbacks, some switched on the wave all the time during the wave soldering process and some mentioned the sensor is there to be used. Can anyone provide me the typical frequency between boards (going over the solder wave) and turning the wave on all the time and also the frequency when intermittent wave should be used. On my side, the frequency is about 3-5 boards per minute. What is the maintenance frequency of the wave solder machine also ?. 2) It is known also that the (at my place) boards coming out from the wave machine can sometimes have the corner sides not soldered (the rest is OK). This I belief is due to wave height and conveyor height. Comments ? (The wave is always on). Did anybody face problem with wave height if the wave is switched on and off ? 3) People tell me also that manual solder touch up is necessary after wave soldering. What is the typical percentage of acceptable boards (no need manual touch up) after going wave soldering ?. I want to check whether we are doing too many touch ups. 4) As for the flux, I'll be checking with the supplier. If I remembered correctly, they called it SP-42. Ring any bells ?. Whether the flux should be dry or wet when the board reaches the wave, most of the responses favours dried flux. (At my place, I am having wet flux when the board reaches the wave, this might explain why quite a number of the boards have blowholes). As for the preheat and flux activation temperature, contacting the supplier should solve the problem. 5) Determining the temperature profile for each board might not be the solution for us,maybe it is possible to have a general preheat settings or some formulas to relate the preheat setting with the conveyor speed and PCB profile?. Over at my side, there is only one wave solder machine and I suspose that you need the wave machine to get the temperature profile , this would sacrifice productivity. 6) My production supervisor also encountered PCB boards supplied by customer that had to go through the wave machine twice. On the first time pass, insufficient solder resulted. On the second time, soldering is much more acceptable. The PCB is not tinned but are fluxed. I felt it is ridiculous for a PCB to go through the wave machine twice. This might be due to the preheat temperature that is set too low. (95-100 degree C). Any comments ? The diameter of the pads on the board might be too big compared to the hole diameter. (I read something relating the pad size and acceptability of soldering. IPC standards also, I think, has recommendedations for pad to hole size ratio.). Or is it another "not enough heat for flux activation problem" ? 7) Has anyone face rejects (of LEDs) when 3mm round LED is mounted directly to the board (its body touching the PCB) and is wave soldered. I know that this violates the manufacturer's temperature rating but is thare anyway to solder the LEDs beside manual soldering ? (even manual soldering might violate the temperature specs.). There is no room on the leads for heatsinking as the body is touching the PCB. Hope someone can help. How Chee Malaysia Note : I will not be able to see all your mail from Mon to Fri since I have Net acess only on Sat. Who is Who ?? ============= p.s. : For those who are curious who is who. The maintenance technician is not under the production supervisor and all of us reports to the Operational Manager and NO roses are given. Over here, we are treated equally. I apologized to all since I started this but I did get some laugh out of it. (some entertainment compared to the routine techical things). > > At 11:23 AM 2/14/98 +0800, you wrote: > >Hello, > > > >Can anybody please help or advice. > > > >I am trying to settle a dispute between my company's production > >supervisor and the maintenance technician on the wave soldering > >machine. > > > >1) The maintenance technician insisted that the wave should be switched > >on and off between boards to prevent/lessen "damage" to the wave > >creation mechanism. > >(The wave can be switched on and off automatically by a sensor on the > >conveyor). My production supervisor think otherwise. She covered the > >sensor so that the wave would not be off.(She says the sensor can > >miss a board) So, who is right ? > > > >2) My production supervisor sets the preheat to about 95 degree C so > >that > >the flux would not dry up when the PCB board reaches the wave and to > >increase > >solderability.(but this created a lotof residue on the solder > >bath,according to maintenance). > >My maintenance technician says the temperature should be about 120 > >degree C > >so that it dry up the flux before the board reaches the wave. The reason > >is so that > >not much residue is created. Who is right again ?? > > > >Thanks in advance. > > > >How Chee > >Malaysia > > > >################################################################ > >TechNet 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 TechNet <your full name> > >To unsubscribe: SIGNOFF TechNet > >################################################################ > >Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional > information. > >For the technical support contact Dmitriy Sklyar at [log in to unmask] or > 847-509-9700 ext.311 > >################################################################ > > > > > > ################################################################ TechNet 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 TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################ ################################################################ TechNet 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 TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################