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Tombstoning of chip capacitors

#9953

Tombstoning of chip capacitors | 24 August, 1999

Could use a little help here. Can anyone clarify to me the cause and fix of chip caps/resistors tombstoning following reflow? Any help would be appreciated. Thanks.

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#9954

Re: Tombstoning of chip capacitors | 24 August, 1999

| Could use a little help here. Can anyone clarify to me the cause and fix of chip caps/resistors tombstoning following reflow? | | Any help would be appreciated. Thanks. | Most common reason is uneven heating where one side of the component achieves liquidus before the other. The surface tension of the molten solder then pulls the component upright like a good soldier. Could be uneven heat distribution in your oven, shadowing by another component, large copper area or no heat reliefs on one side, non center placement( or just a bad placement), contamination or other solderability problems on one side. good luck John Thorup

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Scott Davies

#9955

Re: Tombstoning of chip capacitors | 25 August, 1999

| | Could use a little help here. Can anyone clarify to me the cause and fix of chip caps/resistors tombstoning following reflow? | | | | Any help would be appreciated. Thanks. | | | Most common reason is uneven heating where one side of the component achieves liquidus before the other. The surface tension of the molten solder then pulls the component upright like a good soldier. Could be uneven heat distribution in your oven, shadowing by another component, large copper area or no heat reliefs on one side, non center placement( or just a bad placement), contamination or other solderability problems on one side. good luck | John Thorup | | Tombstoning problems used to be a lot more common before the advent of the latest solder pastes, so it may be worth getting your solder paste supplier involved to help you develop a solution. It may be that you are not using the best available paste for your particular application.

Regards Scott

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Larry

#9956

Re: Tombstoning of chip capacitors | 25 August, 1999

| | | Could use a little help here. Can anyone clarify to me the cause and fix of chip caps/resistors tombstoning following reflow? | | | | | | Any help would be appreciated. Thanks. | | | | | Most common reason is uneven heating where one side of the component achieves liquidus before the other. The surface tension of the molten solder then pulls the component upright like a good soldier. Could be uneven heat distribution in your oven, shadowing by another component, large copper area or no heat reliefs on one side, non center placement( or just a bad placement), contamination or other solderability problems on one side. good luck | | John Thorup | | | | | Tombstoning problems used to be a lot more common before the advent of the latest solder pastes, so it may be worth getting your solder paste supplier involved to help you develop a solution. It may be that you are not using the best available paste for your particular application. | | Regards | Scott |

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Larry

#9957

Re: Tombstoning of chip capacitors | 25 August, 1999

| | | | Could use a little help here. Can anyone clarify to me the cause and fix of chip caps/resistors tombstoning following reflow? | | | | | | | | Any help would be appreciated. Thanks. | | | | | | | Most common reason is uneven heating where one side of the component achieves liquidus before the other. The surface tension of the molten solder then pulls the component upright like a good soldier. Could be uneven heat distribution in your oven, shadowing by another component, large copper area or no heat reliefs on one side, non center placement( or just a bad placement), contamination or other solderability problems on one side. good luck | | | John Thorup | | | | | | | | Tombstoning problems used to be a lot more common before the advent of the latest solder pastes, so it may be worth getting your solder paste supplier involved to help you develop a solution. It may be that you are not using the best available paste for your particular application. | | | | Regards | | Scott | | | | Gary I had the same problem awhile back, tried everything with reflow. Ended up the operator was using old dry paste! So don't forget the basics

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JohnW

#9958

Re: Tombstoning of chip capacitors | 25 August, 1999

| | | | | Could use a little help here. Can anyone clarify to me the cause and fix of chip caps/resistors tombstoning following reflow? | | | | | | | | | | Any help would be appreciated. Thanks. | | | | | | | | | Most common reason is uneven heating where one side of the component achieves liquidus before the other. The surface tension of the molten solder then pulls the component upright like a good soldier. Could be uneven heat distribution in your oven, shadowing by another component, large copper area or no heat reliefs on one side, non center placement( or just a bad placement), contamination or other solderability problems on one side. good luck | | | | John Thorup | | | | | | | | | | | Tombstoning problems used to be a lot more common before the advent of the latest solder pastes, so it may be worth getting your solder paste supplier involved to help you develop a solution. It may be that you are not using the best available paste for your particular application. | | | | | | Regards | | | Scott | | | | | | | | Gary | I had the same problem awhile back, tried everything with reflow. Ended up the operator was using old dry paste! So don't forget the basics | Gary,

Another reason for Tombstones is poor PCB design. I'm thinking Pad design here, if your pad's are too big compared to both width and height of the component you will get tombstonning.

JohnW

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Dave

#9959

Re: Tombstoning of chip capacitors | 25 August, 1999

| | | | | | Could use a little help here. Can anyone clarify to me the cause and fix of chip caps/resistors tombstoning following reflow? | | | | | | | | | | | | Any help would be appreciated. Thanks. | | | | | | | | | | | Most common reason is uneven heating where one side of the component achieves liquidus before the other. The surface tension of the molten solder then pulls the component upright like a good soldier. Could be uneven heat distribution in your oven, shadowing by another component, large copper area or no heat reliefs on one side, non center placement( or just a bad placement), contamination or other solderability problems on one side. good luck | | | | | John Thorup | | | | | | | | | | | | | | Tombstoning problems used to be a lot more common before the advent of the latest solder pastes, so it may be worth getting your solder paste supplier involved to help you develop a solution. It may be that you are not using the best available paste for your particular application. | | | | | | | | Regards | | | | Scott | | | | | | | | | | | | Gary | | I had the same problem awhile back, tried everything with reflow. Ended up the operator was using old dry paste! So don't forget the basics | | | Gary, | | Another reason for Tombstones is poor PCB design. I'm thinking Pad design here, if your pad's are too big compared to both width and height of the component you will get tombstonning. | | JohnW | Gary, I would suggest you look at the stencil apertures before going after the reflow profile. Is this a problem that just started? Whats changed? A small change in the stencil could make a big difference.

Dave

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Jason Tomlinson

#9960

Re: Tombstoning of chip capacitors | 25 August, 1999

| | | | | | Could use a little help here. Can anyone clarify to me the cause and fix of chip caps/resistors tombstoning following reflow? | | | | | | | | | | | | Any help would be appreciated. Thanks. | | | | | | | | | | | Most common reason is uneven heating where one side of the component achieves liquidus before the other. The surface tension of the molten solder then pulls the component upright like a good soldier. Could be uneven heat distribution in your oven, shadowing by another component, large copper area or no heat reliefs on one side, non center placement( or just a bad placement), contamination or other solderability problems on one side. good luck | | | | | John Thorup | | | | | | | | | | | | | | Tombstoning problems used to be a lot more common before the advent of the latest solder pastes, so it may be worth getting your solder paste supplier involved to help you develop a solution. It may be that you are not using the best available paste for your particular application. | | | | | | | | Regards | | | | Scott | | | | | | | | | | | | Gary | | I had the same problem awhile back, tried everything with reflow. Ended up the operator was using old dry paste! So don't forget the basics | | | Gary, | | Another reason for Tombstones is poor PCB design. I'm thinking Pad design here, if your pad's are too big compared to both width and height of the component you will get tombstonning. | | JohnW | If your pads are too far apart you could see a lot tombstones as well.

JT

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