63/37 vs 65/35 solder

We are currently using a 65/35 solder for our wave process but are considering switching to a 63/37 for a substantial cost savings. No one here seems to know why we everused a 65/35 formulation in the first place. I understand 63/37 to be pretty much an industry standard. Any comments on a down side to 63/37 (before we change over) would be appreciated. Thanks Bill Bannister

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| We are currently using a 65/35 solder for our wave process but are considering switching to a 63/37 for a substantial cost savings. No one here seems to know why we everused a 65/35 formulation in the first place. | I understand 63/37 to be pretty much an industry standard. | Any comments on a down side to 63/37 (before we change over) would be appreciated. | Thanks | Bill Bannister | The main attributes of this alloy are a higher liquidus temperature ( 475F vs 361F) and that it is not eutectic I.E. it has a plastic state on cooldown rather than going from liquid to solid. If you don't need the higher temperature for your products the 63/37 makes sense. If the non-eutectic attribute is not a problem in your process, it seems to me that you could just start buying 63/37 and, as you replenish you pot, gradually change rather than dumping. Have your pot analyzed and monitor its progress to 63/37 and adjust the pot temp down as appropriate to the alloy to avoid excess dross generation, etc. Comments from anyone? John Thorup

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| | We are currently using a 65/35 solder for our wave process but are considering switching to a 63/37 for a substantial cost savings. No one here seems to know why we everused a 65/35 formulation in the first place. | | I understand 63/37 to be pretty much an industry standard. | | Any comments on a down side to 63/37 (before we change over) would be appreciated. | | Thanks | | Bill Bannister | | | The main attributes of this alloy are a higher liquidus temperature ( 475F vs 361F) and that it is not eutectic I.E. it has a plastic state on cooldown rather than going from liquid to solid. If you don't need the higher temperature for your products the 63/37 makes sense. If the non-eutectic attribute is not a problem in your process, it seems to me that you could just start buying 63/37 and, as you replenish you pot, gradually change rather than dumping. Have your pot analyzed and monitor its progress to 63/37 and adjust the pot temp down as appropriate to the alloy to avoid excess dross generation, etc. Comments from anyone? | John Thorup | Thanks John for the response. The eutectic aspects of the 63/37 alone may be worth the switch from 65/35. Maybe less bridging. Also we don't have any requiement for high temp solder. Our solder pot is currently set for 500F. Sure would be nice to lower that a bit. Any hints on a target temp using the 63/37? Thanks Bill Bannister

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| | | We are currently using a 65/35 solder for our wave process but are considering switching to a 63/37 for a substantial cost savings. No one here seems to know why we everused a 65/35 formulation in the first place. | | | I understand 63/37 to be pretty much an industry standard. | | | Any comments on a down side to 63/37 (before we change over) would be appreciated. | | | Thanks | | | Bill Bannister | | | | | The main attributes of this alloy are a higher liquidus temperature ( 475F vs 361F) and that it is not eutectic I.E. it has a plastic state on cooldown rather than going from liquid to solid. If you don't need the higher temperature for your products the 63/37 makes sense. If the non-eutectic attribute is not a problem in your process, it seems to me that you could just start buying 63/37 and, as you replenish you pot, gradually change rather than dumping. Have your pot analyzed and monitor its progress to 63/37 and adjust the pot temp down as appropriate to the alloy to avoid excess dross generation, etc. Comments from anyone? | | John Thorup | | | Thanks John for the response. The eutectic aspects of the 63/37 alone may be worth the switch from 65/35. Maybe less bridging. Also we don't have any requiement for high temp solder. Our solder pot is currently set for 500F. Sure would be nice to lower that a bit. Any hints on a target temp using the 63/37? | Thanks | Bill Bannister | | Bill,

we run 63/37 in all our wave machines, std pot temp is 240 degrees C and we have no real problems with bridging or stuff but then that's as much to do with the design as the solder. You should also be able to lower your preheat's I would think so there's another cost saving ( all be it a really small one)

JohnW

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| | | | We are currently using a 65/35 solder for our wave process but are considering switching to a 63/37 for a substantial cost savings. No one here seems to know why we everused a 65/35 formulation in the first place. | | | | I understand 63/37 to be pretty much an industry standard. | | | | Any comments on a down side to 63/37 (before we change over) would be appreciated. | | | | Thanks | | | | Bill Bannister | | | | | | | The main attributes of this alloy are a higher liquidus temperature ( 475F vs 361F) and that it is not eutectic I.E. it has a plastic state on cooldown rather than going from liquid to solid. If you don't need the higher temperature for your products the 63/37 makes sense. If the non-eutectic attribute is not a problem in your process, it seems to me that you could just start buying 63/37 and, as you replenish you pot, gradually change rather than dumping. Have your pot analyzed and monitor its progress to 63/37 and adjust the pot temp down as appropriate to the alloy to avoid excess dross generation, etc. Comments from anyone? | | | John Thorup | | | | | Thanks John for the response. The eutectic aspects of the 63/37 alone may be worth the switch from 65/35. Maybe less bridging. Also we don't have any requiement for high temp solder. Our solder pot is currently set for 500F. Sure would be nice to lower that a bit. Any hints on a target temp using the 63/37? | | Thanks | | Bill Bannister | | | | Bill, | | we run 63/37 in all our wave machines, std pot temp is 240 degrees C and we have no real problems with bridging or stuff but then that's as much to do with the design as the solder. You should also be able to lower your preheat's I would think so there's another cost saving ( all be it a really small one) | | JohnW | We run at 470F (243C). Like JohnW I doubt that you will see a noticable improvement in bridging unless lower preheat temps allow more flux to be present when the board hits the wave. The main improvement will be fewer disturbed (cold) joints caused by movement or vibration while in the plastic zone. If you are having defect problems you could try Alpha's 16 step experiment (16 Boards To A Better Process). Good Luck. John Thorup

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| We are currently using a 65/35 solder for our wave process but are considering switching to a 63/37 for a substantial cost savings. No one here seems to know why we everused a 65/35 formulation in the first place. | I understand 63/37 to be pretty much an industry standard. | Any comments on a down side to 63/37 (before we change over) would be appreciated. | Thanks | Bill Bannister | So Bill, why not 60/40?? Dave F

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| | | We are currently using a 65/35 solder for our wave process but are considering switching to a 63/37 for a substantial cost savings. No one here seems to know why we everused a 65/35 formulation in the first place. | | | I understand 63/37 to be pretty much an industry standard. | | | Any comments on a down side to 63/37 (before we change over) would be appreciated. | | | Thanks | | | Bill Bannister | | | | | The main attributes of this alloy are a higher liquidus temperature ( 475F vs 361F) and that it is not eutectic I.E. it has a plastic state on cooldown rather than going from liquid to solid. If you don't need the higher temperature for your products the 63/37 makes sense. If the non-eutectic attribute is not a problem in your process, it seems to me that you could just start buying 63/37 and, as you replenish you pot, gradually change rather than dumping. Have your pot analyzed and monitor its progress to 63/37 and adjust the pot temp down as appropriate to the alloy to avoid excess dross generation, etc. Comments from anyone? | | John Thorup | | | Thanks John for the response. The eutectic aspects of the 63/37 alone may be worth the switch from 65/35. Maybe less bridging. Also we don't have any requiement for high temp solder. Our solder pot is currently set for 500F. Sure would be nice to lower that a bit. Any hints on a target temp using the 63/37? | Thanks | Bill Bannister | | Bill, If you run enough volume over the pot the proportion of tin will naturally reduce, more tin is lost in dedrossing compared to lead. Just let nature take its course and monitor with solder analysis, and add 63/37 per someone else's suggestion.

The pot temperature we use is 490F.

Boca

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