MODELS:
Using Lead Free Solder
Pb Solder |
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The above symbol indicates Lead (Pb) Free solder was |
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used during the construction of PWBs. Only Lead |
| • Poor | ||||
Free solder should be used when servicing these |
| • Higher temperatures can cause flux spattering. | ||||
PWBs. |
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| • Soldering iron tip life is shortened. | |||
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| • Dull finish solder joints (not shiny) can appear to be | |||
Solder must be compatible with that used by the |
| a “cold” solder joint. |
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manufacturer. Leaded solder can not be used on | In general a tip temperature of 700° F will usually provide | |||||
PWBs manufactured with | ||||||
ishi standard for service requires the use of | good results. |
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Copper |
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through the Parts Department. |
| Displays used to indicate | ||||
Order part number: PB FREE SOLDER |
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| PCBs will be marked, indicating the level of | |||||
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Lead Free solder has a higher melting point, and does | struction. Table 1 defines the levels by phase and shows | |||||
not “wet” as well as leaded solder. This means it does | the different symbols that will be displayed on the PCB. | |||||
not adhere as readily to the solder iron tip, and the | Additionally, a PCB constructed using | |||||
surface to be soldered. To counteract this, the flux | be simply marked LFS. |
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used is more corrosive. |
| When possible, the indication will be placed close to the | ||||
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The following cautions must be taken when using Pb | part number that is screened onto the PCB (not the part | |||||
Free solder. |
| label). Figure 1 is an example of a PCB showing the | ||||
• Higher temperatures can cause the PWB to | display and its location. |
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warp, detaching surface mount |
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| Short Display (When the | |||
components. |
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Phase | Definition | Display | area is too small) |
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• Higher temperatures may | Solder | Pb S | ||||
cause thermal damage to | Pb | |||||
components. |
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•Higher temperatures can cause
plastics, such as connectors, | Solder, PCB surface |
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relays, LEDs electrolytic |
| finishing and component | Pb | Joints | Pb | J |
| lead plating is | |||||
capacitors, etc. to melt or |
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| Components may have |
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warp. |
| internal Pb. |
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• Higher temperatures can cause | Solder, PCB surface |
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surface oxidation resulting in |
| finishing and components | Pb | PCA | Pb | P |
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poor solder |
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| free) |
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| Table 1: |
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Display |
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Figure 2: Pb-Free display on PWB
PAGE 45