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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Rob Williams

#15964

turbulent wave restrictions | 7 May, 1998

I am running a board that is .062" thick and has components that over hang the edge of the board by .090". I have bottom side smt components (chip caps and resistors only) and use the turbulent wave to help solder the components. The problem I am having is that in order for the turbulent wave to work properly, I sometimes get solder on the over hanging components. If I turn the turbulent wave down, I will get solder skips on the bottom side. I have tried using a titanium stiffener but there is no room to clip the stiffener on the board securely. I suggested putting a breakaway on the edge to compensate for the rise in the turbulent wave, but I am getting negative feedback from design and purchasing. Before trying to justify ordering pallets, is there anything else I can try? I want to try not to add any additional labor to the cost.

reply »

DARRYL SCHLOSSER

#15969

Re: turbulent wave restrictions | 7 May, 1998

| I am running a board that is .062" thick and has components that over hang the edge of the board by .090". I have bottom side smt components (chip caps and resistors only) and use the turbulent wave to help solder the components. The problem I am having is that in order for the turbulent wave to work properly, I sometimes get solder on the over hanging components. If I turn the turbulent wave down, I will get solder skips on the bottom side. I have tried using a titanium stiffener but there is no room to clip the stiffener on the board securely. I suggested putting a breakaway on the edge to compensate for the rise in the turbulent wave, but I am getting negative feedback from design and purchasing. Before trying to justify ordering pallets, is there anything else I can try? I want to try not to add any additional labor to the cost. ROB, FOR A QUICK SOLUTION CUT A SECTION OF BARE BOARD THE SAME WIDTH AS THE BOARD THAT YOU ARE TRYING TO SOLDER AND BUT IT UP TO THE REAR OF THE BOARD ON THE CONVEYER. THIS WILL WORK FOR LOW VOLUME APPLICATIONS. FOR A HIGH VOLUME SOLUTION A PALLET IS THE BEST IF YOU CANNOT DESIGN A BREAKAWAY ON THE REAR OF THE BOARD.

reply »

Chrys

#15968

Re: turbulent wave restrictions | 7 May, 1998

| I am running a board that is .062" thick and has components that over hang the edge of the board by .090". I have bottom side smt components (chip caps and resistors only) and use the turbulent wave to help solder the components. The problem I am having is that in order for the turbulent wave to work properly, I sometimes get solder on the over hanging components. If I turn the turbulent wave down, I will get solder skips on the bottom side. I have tried using a titanium stiffener but there is no room to clip the stiffener on the board securely. I suggested putting a breakaway on the edge to compensate for the rise in the turbulent wave, but I am getting negative feedback from design and purchasing. Before trying to justify ordering pallets, is there anything else I can try? I want to try not to add any additional labor to the cost. I know you don't want to add labor to the board, so you've got a tradeoff depending on the volume you're running. How about masking the bottom of the parts with solder masking tape or peelable solder mask? Lots of people like 3M make the tape, and chemical companies like Kester make the dispensable, peelable mask. If you're running through a wash cycle, there's water soluble varieties that you don't have to peel off. I know this adds a small amount of labor, but it's probably the same amount you'd commit by palletizing and de-palletizing.

reply »

D.Lange

#15966

Re: turbulent wave restrictions | 7 May, 1998

| I am running a board that is .062" thick and has components that over hang the edge of the board by .090". I have bottom side smt components (chip caps and resistors only) and use the turbulent wave to help solder the components. The problem I am having is that in order for the turbulent wave to work properly, I sometimes get solder on the over hanging components. If I turn the turbulent wave down, I will get solder skips on the bottom side. I have tried using a titanium stiffener but there is no room to clip the stiffener on the board securely. I suggested putting a breakaway on the edge to compensate for the rise in the turbulent wave, but I am getting negative feedback from design and purchasing. Before trying to justify ordering pallets, is there anything else I can try? I want to try not to add any additional labor to the cost. Rob, I use board shunts. They do nothing for stiffening but they work well for masking connectors. They are hi-temp rubber with slot cut in them to slip on (.062 or more or less) and they can be cut out with razor knife to conform to local components. Remove material as you wish. Pop it on when loading and pop it off when soldered. I cut two or three so that I can keep that many in tunnel at same time. Wave operator can install them as he checks components. They are dirt cheap (I'm still working with samples), pop on and pop off, and you dont have to worry about Kapton or solder masking. Contact Ron @ JC Supply 10130 Talley Lane Houston TX,77041 1-800-660-8891 Part #5820-byb and 5812-byb YOU WILL LIKE IT!

reply »

Steve Gregory

#15965

Re: turbulent wave restrictions | 8 May, 1998

| I am running a board that is .062" thick and has components that over hang the edge of the board by .090". I have bottom side smt components (chip caps and resistors only) and use the turbulent wave to help solder the components. The problem I am having is that in order for the turbulent wave to work properly, I sometimes get solder on the over hanging components. If I turn the turbulent wave down, I will get solder skips on the bottom side. I have tried using a titanium stiffener but there is no room to clip the stiffener on the board securely. I suggested putting a breakaway on the edge to compensate for the rise in the turbulent wave, but I am getting negative feedback from design and purchasing. Before trying to justify ordering pallets, is there anything else I can try? I want to try not to add any additional labor to the cost. Rob, It really shouldn't be a major deal for you to justify fixtures, unless of course you only build a few of these boards at a time. I used to only go out and get fixtures if the board was really odd shaped or had something about it that absolutely required a fixture in order to wave it. But, I found that if the only thing you use the fixtures for is to provide a means to mask the areas on the board that you would normally cover with a liquid mask or tape, using a fixture for that justifies the cost. If you think about the labor and time it takes to apply tape or liquid masking, let it cure before stuffing the PTH, and then having to remove it after wave, a fixture eliminates all that...that in itself justifys the cost of the fixture. -Steve Gregory-

reply »

Bob Willis

#15967

Re: turbulent wave restrictions | 9 May, 1998

All the comments that have been made a great but I do have to say that much of the problem comes back to the design engineers not designing for manufacture. Centre board supports would have sorted the problem without jigs.

| | I am running a board that is .062" thick and has components that over hang the edge of the board by .090". I have bottom side smt components (chip caps and resistors only) and use the turbulent wave to help solder the components. The problem I am having is that in order for the turbulent wave to work properly, I sometimes get solder on the over hanging components. If I turn the turbulent wave down, I will get solder skips on the bottom side. I have tried using a titanium stiffener but there is no room to clip the stiffener on the board securely. I suggested putting a breakaway on the edge to compensate for the rise in the turbulent wave, but I am getting negative feedback from design and purchasing. Before trying to justify ordering pallets, is there anything else I can try? I want to try not to add any additional labor to the cost. | Rob, | I use board shunts. They do nothing for stiffening but they work well for masking connectors. They are hi-temp rubber with slot cut in them to slip on (.062 or more or less) and they can be cut out with razor knife to conform to local components. Remove material as you wish. Pop it on when loading and pop it off when soldered. I cut two or three so that I can keep that many in tunnel at same time. Wave operator can install them as he checks components. They are dirt cheap (I'm still working with samples), pop on and pop off, and you dont have to worry about Kapton or solder masking. Contact Ron @ | JC Supply | 10130 Talley Lane | Houston TX,77041 | 1-800-660-8891 | Part #5820-byb | and | 5812-byb | YOU WILL LIKE IT!

reply »

3D SPI

Rework Training Materials