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Vapor (vapour) Phase?

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#55069

Vapor (vapour) Phase? | 14 June, 2008

Is anyone out there using vapor phase soldering techniques? 1. I'm wondering what results you are getting? 2. How are you controlling the thermal profiles (specifically ramp rates and TAL)? 3. What fluid type are you using? Who is the mfg?

Thanks,

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#55071

Vapor (vapour) Phase? | 15 June, 2008

Hi,

We used it previously a few years ago, and I think I posted some comments on it here in the forum in the past you might want to search out.

It's a weird process, because it solders incredibly, and I mean it's incredible. There is no oxygen, so the solder really flows up the joint, and you can solder incredibly large objects right next to small devices, and it equals out due to the process itself.

However the big problem we had was we just kept getting tomb-stoning, and no matter what we did we just could not get rid if to. We tried all kinds of stencil designs' and it just kept happening. As our volume increased and our company grew, it became the main cause of faults in production, and a good convection oven overcame this issue. It was really bad with smaller 0402 components.

Once we replaced VP with convection, we never used the VP again, because of the problems, so we sold the VP oven. We sold the oven, and the guy who purchased it was soldering power supplies that hard thermally large components next to small components, so they liked it.

Also, the fluid is expensive, and you really need to get a good oven with built in cooling and automatic timing, so you can use it in production. If you don't have this then its really only good for prototypes.

However if I was starting out again, I would use a pasta cooker with some vapor phase fluid in it, because it's such as low cost soldering method, that's going to solder well for prototypes. The pasta cooker worked well, so i would use it again for that if i had no money.

Good luck!

Grant

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#55077

Vapor (vapour) Phase? | 16 June, 2008

We are using VP on all of our lead free assemblies. 1. We are getting great, very repeatable results. 2. The profiles were created during the implementation of the equipment and we only change 3 parameters for each assembly processed. Heater power, heat time and dwell time above liquidus. 3. Fluid is Galden LS-230, mfg is Solvay-Solexis

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#55080

Vapor (vapour) Phase? | 16 June, 2008

Hi,

How has it worked for you with small parts such as 0402, and are you using these size parts, and getting any tomb-stoning problems?

We used lead paster with our vapor phase, while lead free should have less surface tension, so I have always wondered if lead free helped eliminate the kinds of tomb-stoning problems we had.

Grant

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#55082

Vapor (vapour) Phase? | 17 June, 2008

We've had very few tombstone problems but all were fixed by reducing the apertures of the affected components.

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#55086

Vapor (vapour) Phase? | 17 June, 2008

We are also using Vapor phase for our process. We currently have 6 profiles that we have established. 3 for Leaded and 3 for Leadfree. We have set-up our profiles depending on the mass of the board. We do have some tombstoning depending on several variables in the oven. vapor fluid level is a big hitter. The number of boards that are being run on the carrier etc. Overall it does a good job for us especially BGA's.

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#55093

Vapor (vapour) Phase? | 18 June, 2008

We have evaluated vapour phase in the past and was very impressed on how simple and easy it was to use and control. Gods send when being pushed in an audit because so little can be changed and will work within the chemistry within the unit. I so wanted this to work well to justify using it for lead-free but it failed on an issue important to us. By the very nature of the chemistry of the unit the PCB assembly is lowered into the vapour and the vapour gives up its heat and condenses onto the solder paste and has a �washing� effect on the solder paste and washes some of the solder spheres from the paste onto the PCB. If you have gold contact pads and gold fingers on the PCB, these become contaminated which to us was not acceptable. The PCB is a lot dirtier than with a convection oven. Some of the paste manufacturers were making pastes to combat this but had to return the vapour phase unit before I had a chance to try them properly. On the tomb-stoning issue I find a modified inverted homeplate design works well, more like a squared arch. This was used to combat mid-chip solder balls which did the job well but also had a side effect of clearing all of our tomb-stoning!

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#55098

Vapor (vapour) Phase? | 18 June, 2008

We actually found the opposite to be true. Boards processed in VP are much cleaner than those processed in our air-only convection oven. We tested 5 lead free solder pastes upon implementation and found that the type of paste does affect the number of solder balls. 3 of the 5 pastes we tested worked great though.

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#55117

Vapor (vapour) Phase? | 18 June, 2008

Woo10,

If you need assistance with profiling in the vapor phase environment, I am with KIC Thermal and we have been working with vapor phase equipment manufactures developing processes and profilers for use in the vapor phase reflow applications.

Please feel free to call if you need assistance.

Mike

770-355-6156

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