Ovens
Re: Ovens
The oven is ok. When you get about the cheapest there is that does the job, the value for money is usually good. 
In a way, all heat is infrared, but really, there are just regular iron heating elements. Works for me. I don't do very many boards in a typical year and those are prototypes, so I'm going to check the function of the board thoroughly anyway, so I would catch any bad joints (so far, none that I can blame the oven for). The main issue is the smell. I don't really know if it is the oven or the paste, but I run it under a regular kitchen overhead hood with a tube out of window.
> does it have enough power to solder a board with ground planes?
I've only done smallish boards but yes, it does. The controller is the key component here. When the controller makes the oven go through a proper pre-heating phase, the whole board gets hot, so the internal layers don't matter that much.
In a way, all heat is infrared, but really, there are just regular iron heating elements. Works for me. I don't do very many boards in a typical year and those are prototypes, so I'm going to check the function of the board thoroughly anyway, so I would catch any bad joints (so far, none that I can blame the oven for). The main issue is the smell. I don't really know if it is the oven or the paste, but I run it under a regular kitchen overhead hood with a tube out of window. > does it have enough power to solder a board with ground planes?
I've only done smallish boards but yes, it does. The controller is the key component here. When the controller makes the oven go through a proper pre-heating phase, the whole board gets hot, so the internal layers don't matter that much.
Re: Ovens
http://www.amazon.com/Panasonic-NB-G110 ... B008C9UFDI
best reflow toaster. just set to max temp, wait for reflow, count to 10, turn off and open door. only one bga error (due to placement) in years of using this toaster. I only use for prototyping, but works great.
best reflow toaster. just set to max temp, wait for reflow, count to 10, turn off and open door. only one bga error (due to placement) in years of using this toaster. I only use for prototyping, but works great.
Re: Ovens
Hi Dan,
I also use a modified "kitchen" oven for reflow soldering with good results. Mine has a small vent inside the oven chamber and I believe that this contributes to a more even head spread than direct IR alone.
Similar to Juku's experience, potentially dangerous fumes are the biggest problem with this approach but I would assume the same applies to "cheap" commercial reflow ovens. For now, I simply use the oven outside my house, but I am also working on a ventilation system which will extract the fumes.
While "manual control" with a thermometer and stopwatch works, the process is neither very accurate nor repeatable in my humble opinion.
Thus I built some custom electronics for temperature measurement + heating regulation to meet temperature profiles as defined by solder paste and component manufacturers. Basically it is a microcontroller, display and some buttons, thermocouple interface and solid state relais to turn heating elements on and off.
From my experience, three factors are critical for the heating profile:
1. ramp time and gradient (from ambient to liquidus) must meet solder paste requirements, so that flux is activated at the right time and solder really "flows" into place later
2. temperature must then rise above the melting point of the solder paste, obviously higher with lead free solder (about 217°C for most pastes). Time above this liquidus temperature must be long enough but not too long (~ 10 seconds).
3. maximum temperature must not exceed the max temp rating for your components, probably < 230°C
Last factor turned out to be the hardest to meet. Due to temperature overshoot you might simply destroy sensitive components such as quartz, electrolytic caps or ICs during reflow phase.
I found I had to insulate the oven and add additional heating elements to achieve a compliant profiles.
Also, the brand and type of solder paste had a great influence on results. I currently use this paste:
http://www.beta-estore.com/rkuk/order_p ... .html?p=18
While I built the temperature regulation from scratch, I found a few commercial options that look promising. If I did it again, I might give that a try instead. Greatly reduces effort - depending on your oven you might just need to add addtional heating power and / or insulation but control is really the complex task.
Beta has a "external" controller which basically turns oven on and off based on temperature measurment and some "training data".
They are at version 3 but the previous model is still available and cheaper - looking at the features I would say it does the job.
http://www.beta-estore.com/rkuk/order_p ... html?p=613
http://www.beta-estore.com/rkuk/order_p ... wg=1&p=242
If you are interested in building / modifying your own oven, the following controller might be an interesting alternative - if you don't mind importing it from the US:
www.zallus.com/product/zallus-oven-kit/
If you try either of these, I would be interested to hear about your results.
I also use a modified "kitchen" oven for reflow soldering with good results. Mine has a small vent inside the oven chamber and I believe that this contributes to a more even head spread than direct IR alone.
Similar to Juku's experience, potentially dangerous fumes are the biggest problem with this approach but I would assume the same applies to "cheap" commercial reflow ovens. For now, I simply use the oven outside my house, but I am also working on a ventilation system which will extract the fumes.
While "manual control" with a thermometer and stopwatch works, the process is neither very accurate nor repeatable in my humble opinion.
Thus I built some custom electronics for temperature measurement + heating regulation to meet temperature profiles as defined by solder paste and component manufacturers. Basically it is a microcontroller, display and some buttons, thermocouple interface and solid state relais to turn heating elements on and off.
From my experience, three factors are critical for the heating profile:
1. ramp time and gradient (from ambient to liquidus) must meet solder paste requirements, so that flux is activated at the right time and solder really "flows" into place later
2. temperature must then rise above the melting point of the solder paste, obviously higher with lead free solder (about 217°C for most pastes). Time above this liquidus temperature must be long enough but not too long (~ 10 seconds).
3. maximum temperature must not exceed the max temp rating for your components, probably < 230°C
Last factor turned out to be the hardest to meet. Due to temperature overshoot you might simply destroy sensitive components such as quartz, electrolytic caps or ICs during reflow phase.
I found I had to insulate the oven and add additional heating elements to achieve a compliant profiles.
Also, the brand and type of solder paste had a great influence on results. I currently use this paste:
http://www.beta-estore.com/rkuk/order_p ... .html?p=18
While I built the temperature regulation from scratch, I found a few commercial options that look promising. If I did it again, I might give that a try instead. Greatly reduces effort - depending on your oven you might just need to add addtional heating power and / or insulation but control is really the complex task.
Beta has a "external" controller which basically turns oven on and off based on temperature measurment and some "training data".
They are at version 3 but the previous model is still available and cheaper - looking at the features I would say it does the job.
http://www.beta-estore.com/rkuk/order_p ... html?p=613
http://www.beta-estore.com/rkuk/order_p ... wg=1&p=242
If you are interested in building / modifying your own oven, the following controller might be an interesting alternative - if you don't mind importing it from the US:
www.zallus.com/product/zallus-oven-kit/
If you try either of these, I would be interested to hear about your results.
Re: Ovens
I have the Beta kit. My experiences can be read here: http://dangerousprototypes.com/forum/vi ... f=2&t=4471
Re: Ovens
thanks for the detailed reply, Juku! Much appreciated.
I got lucky and picked up a V2 controller, second hand, rather cheaply. I've experimented and used it with a basic IR toaster oven, with a bit mixed results, but it's only the start. so far I've only done a few prototype boards, so I'll see as I go further into things.
greetings from Belgium
D
I got lucky and picked up a V2 controller, second hand, rather cheaply. I've experimented and used it with a basic IR toaster oven, with a bit mixed results, but it's only the start. so far I've only done a few prototype boards, so I'll see as I go further into things.
greetings from Belgium
D
Re: Ovens
reasonably priced vapor phase oven:
http://imdes.de/
Short demo video from the mfg:
http://imdes.de/condens_dl/condens_dl_p ... -micro.mp4
Seems to be a small company but still as long as it works ...
This is handy for small packages (BGA,qfn) etc and diy lead free soldering.
http://imdes.de/
Short demo video from the mfg:
http://imdes.de/condens_dl/condens_dl_p ... -micro.mp4
Seems to be a small company but still as long as it works ...
This is handy for small packages (BGA,qfn) etc and diy lead free soldering.
Re: Ovens
Any experiences with chinese ovens like T962? It costs around 200$ (smaller version with 180x235 mm working space) and with some fixes (http://www.instructables.com/id/T962A-S ... n-FixHack/) it could be quite useful. Anybody has it, I am thinking of ordering one ...
Regards,
Gregor
Regards,
Gregor