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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


High Temp Solder Application

#2523

High Temp Solder Application | 7 November, 2000

My company manufactures a board for a heavy duty automotive application. One of the through hole parts on the board dissipates enough heat that it requires high temp solder. Does anyone know of or have experience with a high quality selective soldering process for mass production??

Thanks in advance John

reply »

jackofalltrades

#2524

Re: High Temp Solder Application | 8 November, 2000

We are currently evaluating a "selective soldering machine" from Ersa. We have been using it for about a month or so now and have found it to be very useful on "difficult to wave solder spots", but it is not as fast as a wave soldering machine. It might worth your time to investigated this type of machine. It can be programed for any dwell at any location, any spot on the board is programed on a case by case basis, in other words this is a very versitile machine, but not high quantity (faster than hand soldering).

reply »

#2525

Re: High Temp Solder Application | 8 November, 2000

There are several very good threads from a couple of years ago on selective soldering and solder fountain machines in the SMTnet Archives.

reply »


DL

#2526

Re: High Temp Solder Application | 9 November, 2000

John,

Ahhhh the possibilities. Have you considered the dissipative properties of available substrates? A ceramic (excellent heat dissipation) based substrate could be a possibility for future designs. Maybe there are surface mount parts out there for ya. as a note: The amt. of heat it takes to reflow some high temp pastes can be damaging to other components.

reply »

#2527

Re: High Temp Solder Application | 9 November, 2000

Luckily for me, if the part were soldered and on the board prior to any processing, I will still be able to build it. I am currently experimenting with screen printing a high temp paste, hand inserting the part (even Chad hasn't come up with an economical way to automate it) and then reflowing it at high temperature prior to any other processing. In my process, the other parts would not see anything out of the usual. The melting temperature of the high temp solder should prevent it from reflowing during our wave soldering process. That's the idea anyway. That way I could protect the other components. Has anyone seen a similar approach taken?? Depending upon the labor involved to hand solder the parts (which is currently the proposed solution), I should be able to justify the equipment.

What ceramic board materials are available as I am not familiar with them?? What is the relative material cost to FR 4??

Any further advice would be greatly appreciated, John

reply »

#2528

Re: High Temp Solder Application | 10 November, 2000

I can�t imagine a high trace count, high via count ceramic board matching-up on price with a FR4 board. http://www.coorstek.com/coorstek/coorstek.asp?menu=literature&reference=literature.asp

But that�s not really the issue, is it? The issue is the reliability of your FR4 boards, because if the leads of a through hole part on the board dissipates enough heat to require high temp solder, then that portion of the board is sitting way above tg for extended periods of time, regardless of the type of solder you are using to attach the component to the board.

Sure, you can beat the component from unsoldering itself from heat dissipation with high temp solder, but that doesn�t keep the board from melting.

reply »


DL

#2529

Re: High Temp Solder Application | 10 November, 2000

John, for more on ceramic circuitry go here http://www.zecal.com/what.html

This might help DL

reply »

andy

#2530

Re: High Temp Solder Application | 15 November, 2000

John , I had some experience of selective solder in a high throughput environment and though the quality of s/s was good , the throughput was not . So if throughput is an issue , forget it . I would go with the hand-solder option , although as has been pointed out , you are going to have to carefully determine what effect this has on the damage to the surrounding FR4 . Also keep a close eye on the quality of the hand solder job when using high temp solder . This will be affected by a need for greater numbers ! ...

Good luck ,

Andy .

reply »

PCB X-Ray Inspection

PCB contract manufacturer