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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Paul Wareham

#10201

Reflow oven for solder side components?? | 11 August, 1999

We are using a mixed technology process with mostly through-hole parts plus some SMT IC's on the component side and some passive SMT parts on the solder side. We do not have a proper wave soldering machine for doing solder side SMT (double wave or omega wave generator). We've recently acquired a reflow oven and we are wondering if we can do a process as follows: place and reflow solder component side SMT, place and wave solder through hole, place and reflow solder the solder side SMT. Basically, can we reflow solder SMT parts on a board that already filled with a bunch of through-hole parts?

Any other process ideas in the absence of SMT wave solder capability?

Regards,

Paul

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JohnW

#10202

Re: Reflow oven for solder side components?? | 11 August, 1999

| We are using a mixed technology process with mostly through-hole parts plus some SMT IC's on the component side and some passive SMT parts on the solder side. We do not have a proper wave soldering machine for doing solder side SMT (double wave or omega wave generator). We've recently acquired a reflow oven and we are wondering if we can do a process as follows: place and reflow solder component side SMT, place and wave solder through hole, place and reflow solder the solder side SMT. Basically, can we reflow solder SMT parts on a board that already filled with a bunch of through-hole parts? | | Any other process ideas in the absence of SMT wave solder capability? | | Regards, | | Paul | Paul,

I guess it really depend's on how heavily populated the card is with PTH stuff and where the lead's are compared to the bottomside parts. My choice would be a doublesided reflow doing the bottomside 1st i.e. all the passives cos they are less likely to drop off the do the tops with the active stuff then the PTH.

JohnW

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Doug Philbrick

#10203

Re: Reflow oven for solder side components?? | 11 August, 1999

| We are using a mixed technology process with mostly through-hole parts plus some SMT IC's on the component side and some passive SMT parts on the solder side. We do not have a proper wave soldering machine for doing solder side SMT (double wave or omega wave generator). We've recently acquired a reflow oven and we are wondering if we can do a process as follows: place and reflow solder component side SMT, place and wave solder through hole, place and reflow solder the solder side SMT. Basically, can we reflow solder SMT parts on a board that already filled with a bunch of through-hole parts? | | Any other process ideas in the absence of SMT wave solder capability? | | Regards, | | Paul |

First off how do you intend on getting paste on the second side with PTH parts already installed. It could only be with a dispencer as far as I know. Second, you add a lot of mass for the reflow process and your temps might be too high for PTH parts! Two possibilities. Paste the top, flip the board and glue the parts on, stuff your PTH and wave solder with what you have. You might be surprised at the results with a single wave. Passives aren't tough to wave. Even if you have some touch up it probably won't be much. If that won't float your boat have selective solder pallets made and do a double sided reflow then stuff your PTH and the pallets will mask off your SMT and you will only wave your PTH.

Good luck

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Kris Harris

#10204

Re: Reflow oven for solder side components?? | 12 August, 1999

| We are using a mixed technology process with mostly through-hole parts plus some SMT IC's on the component side and some passive SMT parts on the solder side. We do not have a proper wave soldering machine for doing solder side SMT (double wave or omega wave generator). We've recently acquired a reflow oven and we are wondering if we can do a process as follows: place and reflow solder component side SMT, place and wave solder through hole, place and reflow solder the solder side SMT. Basically, can we reflow solder SMT parts on a board that already filled with a bunch of through-hole parts? | | Any other process ideas in the absence of SMT wave solder capability? | | Regards, | | Paul | Paul,

Something that we do when surface mount epoxy is not an option is to use solder preforms. Use these on your through hole components when reflowing the top side. Though they are very hand intensive, they will get you around your not having a wave solder problem. They work very well, if your willing to spend the time it takes to install them.

Good Luck,

Kris

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Brian Conner

#10205

Re: Reflow oven for solder side components?? | 13 August, 1999

| We are using a mixed technology process with mostly through-hole parts plus some SMT IC's on the component side and some passive SMT parts on the solder side. We do not have a proper wave soldering machine for doing solder side SMT (double wave or omega wave generator). We've recently acquired a reflow oven and we are wondering if we can do a process as follows: place and reflow solder component side SMT, place and wave solder through hole, place and reflow solder the solder side SMT. Basically, can we reflow solder SMT parts on a board that already filled with a bunch of through-hole parts? | | Any other process ideas in the absence of SMT wave solder capability? | | Regards, | | Paul |

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Brian Conner

#10206

Re: Reflow oven for solder side components?? | 13 August, 1999

| | We are using a mixed technology process with mostly through-hole parts plus some SMT IC's on the component side and some passive SMT parts on the solder side. We do not have a proper wave soldering machine for doing solder side SMT (double wave or omega wave generator). We've recently acquired a reflow oven and we are wondering if we can do a process as follows: place and reflow solder component side SMT, place and wave solder through hole, place and reflow solder the solder side SMT. Basically, can we reflow solder SMT parts on a board that already filled with a bunch of through-hole parts? | | | | Any other process ideas in the absence of SMT wave solder capability? | | | | Regards, | | | | Paul | | | |

Paul,

One possibility would be to screen solder paste on the bottom side, then Epoxy, place components, and reflow the bottom side.

Topside....normal procedure.

Wave, normal procedure.

So your 3 steps would look like this: Bottom Side: Solder paste/epoxy/placement/reflow Top Side: Solder paste/placement/reflow Assembly: Placement/wave

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Boca

#10207

Re: Reflow oven for solder side components?? | 13 August, 1999

| | We are using a mixed technology process with mostly through-hole parts plus some SMT IC's on the component side and some passive SMT parts on the solder side. We do not have a proper wave soldering machine for doing solder side SMT (double wave or omega wave generator). We've recently acquired a reflow oven and we are wondering if we can do a process as follows: place and reflow solder component side SMT, place and wave solder through hole, place and reflow solder the solder side SMT. Basically, can we reflow solder SMT parts on a board that already filled with a bunch of through-hole parts? | | | | Any other process ideas in the absence of SMT wave solder capability? | | | | Regards, | | | | Paul | | |

| First off how do you intend on getting paste on the second side with PTH parts already installed. It could only be with a dispencer as far as I know. Second, you add a lot of mass for the reflow process and your temps might be too high for PTH parts! | Two possibilities. Paste the top, flip the board and glue the parts on, stuff your PTH and wave solder with what you have. You might be surprised at the results with a single wave. Passives aren't tough to wave. Even if you have some touch up it probably won't be much. If that won't float your boat have selective solder pallets made and do a double sided reflow then stuff your PTH and the pallets will mask off your SMT and you will only wave your PTH. | | Good luck | | Doug's right, if you're carefull with SM layout, that is, orientation, spacing and the like, SM solders fine with a single wave.

Moon Man presented another option in answer to me on another thread, double sided reflow, then cover the bottom side SM with solder mask, then wave solder TH. Depends on your volumes and equipment for dispensing mask. I'm going to give it a try when I get a chance.

Hope it help, Boca

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Reflow Oven