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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Curing of Glue for SMT Components

Raeto Zryd

#3810

Curing of Glue for SMT Components | 14 June, 2000

Hi there,

I intend to mount some smt components on the soldering side of the PCB and solder via wave soldering equipment. We do not have a reflow oven to cure the glue. Does anybody have a suggestion what small heat cure equipment or system can be used to do the job before soldering.

Thank You Raeto

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Dreamsniper

#3811

Re: Curing of Glue for SMT Components | 15 June, 2000

Hi Raeto,

1. You do not have reflow oven. This means that you are not running Surface Mount Technology in your shop floor...am I correct? Why do you plan to have SMD's under your PCB's ? Can't you replace them with their PTH counter part and have them place on the topside of the board. This will save your company some costs in equipment capital. 2. How are you going to place glue on your component? Manually? do you have adhesive dispensing equipment? or a printer so you can screen print the adhesives?

I think the best option is to manually hand solder them if they are not that many...this is just an advise...there might be some guys there who can help you through...

Good Luck !

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DL

#3812

Re: Curing of Glue for SMT Components | 16 June, 2000

Does the manufacturer of your glue suggest a curing temp? If so and if ya dare..seems to me you do, you could use an oven something like a bakers oven. We use HI Temp ovens to cure epox, glue and stuff like that. Sounds to me like it's time for a new REV. :)

DL

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#3813

Re: Curing of Glue for SMT Components | 17 June, 2000

Contact the adhesive manufacturer, or their website. Most adhesive suppliers offer two cure options - one with a belt oven profile and one with a box oven profile. The belt oven is usually a ramp and plateau of 120-150C for approx 2 minutes. The box oven recipe will give set temp and time in the oven.

In the earlier days of SMT, it was fairly common to rack boards and cure the adhesive in a box oven. Bottomside discretes were the first step in getting into SMT for many assemblers, and they didn't have print-paste-reflow lines. Obviously this practice is not as common these days, so box profiles may no longer be included on the adhesive's data sheets. But they are available.

One word of advice - and this is majorly important - get an adhesive with a high green strength. Green strength is the holding power of the adhesive when it is uncured. If you are curing with a box oven, your assemblies will see lots of handling before the epoxy is cured. A high green strength material will help to keep the parts from skewing off their pads during handling.

Good luck.

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K.T

#3814

Re: Curing of Glue for SMT Components | 21 June, 2000

If u don't have any box oven either, why don't u just use your wave. Turn the fluxer and the solder pot off and run it through your preheaters.

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