Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


oven resin from adhesives

#21128

oven resin from adhesives | 13 August, 2002

I am currently running several SMT lines that are placing components onto dispensed adhesive (Heraeus PD 944). My problem is that we have always had an issue with a resin type liquid �condensing� on the inside of our oven chimney and then running back down onto the oven. I always ensure the oven profile is correct (slightly above 150 for around 2 minutes) and have checked the exhaust flow rate, which is also adequate. What is causing this and can it be prevented? If not, does anyone have a good idea on how to clean out a 3 meter length of chimney?

reply »

mick

#21143

oven resin from adhesives | 13 August, 2002

The residues are from the flux, not adhesive. Do you have flux management system in oven? You also need to check the flux type = can you use low solids. The effect is the same as steam in bathroom - it is cooling affects in exhaust and flux reforming from vapor state by condensing in stacks

reply »

#21150

oven resin from adhesives | 13 August, 2002

We don�t use this glue. What does Heraeus say about your condensate? [I'm With the previous poster. Your condensate sounds like goop from NC flux not glue.]

How to clean out a 3 meter length of chimney? Depends on your tolerance for pain * Take it and a handful of quarters down to the coin operated car wash and got to it. * Buy a new tube.

Consider adding a piece of flex tubing between your machine and your exhaust pipe. * Start you exhaust pipe, maybe a foot or so above your machine, doesn�t have to be lined-up. * Connect the machine and the exhaust with flex pipe that is so long that it touches the floor.

Consider checking with your reflow oven supplier to be sure your flux trap is working properly.

reply »

#21153

oven resin from adhesives | 14 August, 2002

I hated no-clean for that reason. Yea, the boards are pretty clean and in many cases don't need cleaning but it's not worth it when you consider what it does to your ovens in my opinion. Do water soluable fluxes cause the same havoc in a re-flow?

reply »

#21154

oven resin from adhesives | 14 August, 2002

Thanks for the replys'. So are you saying that SMD adhesive contains a flux agent?, because at this point in the process the boards have no solder on them at all, it's all done at a solder bath after the chips have been bonded.

reply »

#21155

oven resin from adhesives | 14 August, 2002

No. Since most glues don't don't give-up many solids, we're [at least I am] speculating that you are using the same oven for both reflow and glue cure and that the 'slime oozin' out from your TV set' [FZ 'Overnight Sensation']. Ooops, no the slime coming from your vent pipe is an artifact of the nc flux you are using and not from the glue.

reply »

#21158

oven resin from adhesives | 14 August, 2002

no, the oven is only used for curing adhesive and has never been used for reflow!!. I have always assumed that it has been the solvents in the glue that have evaporated off and then cooled again.

reply »

#21160

oven resin from adhesives | 14 August, 2002

Wow. We've never seen that.

You make a reasonable assumption. Since your PD944 is fairly widely used, what does Heraeus say?

reply »

#21162

oven resin from adhesives | 14 August, 2002

Is your exhaust duct connected to a reflow oven that is used for flux? The condensate may be carring over from another oven that shares the same duct.

reply »

#21163

oven resin from adhesives | 14 August, 2002

uuumm, we have four lines in this particular part of the factory all used for curing glue only. our other reflow lines are in another section of the factory with seperate ducts. These lines are however next door to the solder baths.....I will have to check to see if the extraction systems are interconnected...fingers crossed. I'll let you know

reply »

#21218

oven resin from adhesives | 19 August, 2002

No. My ovens are vented on a seperate system. Any other ideas.

reply »

FRANKY

#21219

oven resin from adhesives | 19 August, 2002

I'm not found this problem with adhesive but found in NC flux , Then you should get some residue and analyse it by SEM and EDX for specify the actual source ( flux or adhesive ? ) , if it 's from adhesive , sometime your supplier must join this problem

reply »

blnorman

#21224

oven resin from adhesives | 19 August, 2002

I agree with analysis. You'll never accurately find the source until you determine exactly what the "goo" is. We have this problem, but like previous posters, the goo is flux residue. We do use the ovens for both reflow and adhesive cure. The adhesive may be 100% solids, but during cure something is volatilized. Get an analysis, if you can run an FTIR of the residue.

reply »

Hioki Flying Probe Tester

SMT in-printer dispensing