Flux sprayer set up

Charlie: There's a lot of background setting-up fluxers (including sprayers) in the archives. Chris Shea wrote a paper that's in the library (or where ever SMTnet stores stuff like that) that is pretty good. Good luck. Dave F

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Charlie:

As far as setting up a spray fluxer.. Are you spraying no-clean, voc free, water soluble? What you would want to do is to run a blank pcb through the fluxer and pop it out before the preheaters. Visually inspect for variations in uniformity. It should be readily apparent. I believe I sent you a defect chart a few months ago.

As to the amount of flux.. this will be dependent upon the type of flux and how tight your process is... the chart should help with that.. Remember Preheat is the biggest bang for your time. Please feel free to contact me if I can be of further assistance. Vince Whipple

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Hi!Charlie, 1.Are you retrofitting your spray fluxer in your wave soldering machine? If you are, please ensure that you have a air knife just before the preheater!Fluxe fumes tends to accumulate and that could be dangerous if your air exhaust is not funtioning well.Aminimum of 600cfm is required. 2.fumes tends to accumulates in the inner part of the air extractor and after sometimes it will drip back,not only on boards but all over the machines. 3.If you are using a drum type of spray fluxer,you will face a lot of problem,therefore, go for a single head with ID of 1mm,this will ensure no clogging.As for most of customers,I recomend them a Venturing system with simple PLC pneumatic control with PCB present sensor (to sense PCB length and whent o activate spray)and encoding sensor to sense PCB width(just in case you have different board width running) 4.Flux amount spray-there must be a flowmeter to control the amount of flux to be spray,by means of m=how many liters per hour. 5.Flux spray strength-nozzle must be in the distance of 3cm to 5cm from boards-this is to ensure no over spraying or too much air pressure is applied which might lifts the components and spray all over the place. 6.Nozzle spray width- preferably from 40mm to 60mm full cone shape.This allows you to cover quickly more area and the sprayer must be run on a rodless cylinder guide with froward and backward motion.and it is speed controllable. 6.Enough flux sprayed-for that you will have to try and adjust since I do not know what type of fluxes you are using.But here is what I did with some of my customers,based on solids content of less than 4%,we use 2.5liters/hour flowmeter adjsustment. For water soluble, we use lesser spray since the acid number is stronger. 7.General cleaning of spray box and daily purging of nozzle is require.Purge the nozzle with the flux thinner-that is the best! 8.A weekly inspection of all moving parts and tubings is advised. Thank you and Merry Christmas Vincent Chen Malaysia

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