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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Blow holes on radial parts solder joints

#5874

Blow holes on radial parts solder joints | 5 April, 2001

On mixed technology PCBs, we find numerous blow holes on the solder joints of radial parts (electrolytics, LEDs, etc). The solution that works so far is to cut the leads very long in the radial inserter so that the part is kinda loose and the air in the hole can evacuate from the top of the PCB when passing in the wave.

Can something be done to the wave to eliminate these blow holes, because inserting these radial parts too loose creates other problem in the radial inserter...

reply »


CAL

#5877

Blow holes on radial parts solder joints | 5 April, 2001

Do the parts sit directly on the PCB? Typical 2.0 mm Max is desired for the component to be off the PCB. Are stand-offs an option? The long lead wiggles as it passes through the wave and thus agitating the air out.Does your wave a "dancer" option?

Cal

reply »

#5884

Blow holes on radial parts solder joints | 5 April, 2001

As a band-aid, consider running your chip wave when soldering these boards [Similar to Cals "dance with me babe" suggestion.]

If the problem is as broad based as you say and the radial components have a tight fit, consider increasing the holes by a drill size. Having said that, this radial part tight fit / hole size thing makes me feel uneasy, because the radials we use have a huge diversity of wire diameter, shape, and hole size fit. Cal makes a good point about stand-off height, but that also makes me feel queasy for a similar reason.

Are you holding out on us? ;-)

reply »

#5887

Blow holes on radial parts solder joints | 6 April, 2001

Thanks for the tips. I'll have to check with the designers if they can accomodate the height if I was to use parts with stand-off. The bigger holes was already suggested, but they don't want to change them until a new revision on the product comes out...

reply »

#5888

Blow holes on radial parts solder joints | 6 April, 2001

Thanks for the tips. I'll have to check with the designers if they can accomodate the height if I was to use parts with stand-off. The bigger holes was already suggested, but they don't want to change them until a new revision on the product comes out...

reply »

Boca

#5895

Blow holes on radial parts solder joints | 6 April, 2001

We had the same problem years ago when we started using a radial inserter. The inserter would dutyfully insert and clinch the leads. The problem in our case was the component body sealing to the fab, especially on electrolytics caps with a film jacket. 1. The standoff idea suggested would work. 2. I would be careful about opening the hole sizes, it could cause poor lead to hole ratios for insertion and solder joint integrity. 3. Can you spec components which don't seal to the fab as well? 4. You could try a slower conveyor speed on the wave solder machine, that would increase the time over the wave and give the flux / air under the components time to expand / escape before leaving the wave. This may reduce but probably not eliminate your problems. It's not a great solution because it can easily get you into trouble on other issues.

Boca

reply »

#5896

Blow holes on radial parts solder joints | 6 April, 2001

We build a mixed tech [eg, QFP, SMT fly shit, DIP] board where we can't clinch the DIP. So we set the clinch and cut on the DIP to just barely clinch, leaving the leads very perpendicular to the board.

I wonder if you could do something similar with the radials to leave "more hole" visiable to the wave, as a solution to this problem?

reply »

Used PCB Equipment - ECM

PCB machines