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84 SMT007 MAGAZINE I JANUARY 2019 areas reached at least 246°C which is within the recommended range of 25–45° above the melting point of the solder. Group 3 SIR Results All locations with and without components passed the acceptance criteria. The data in Figure 8 shows that at no time did the resis- tance measurement dip below the 1.0e8 ohms of resistance. This indicates that in a normal field service environment without excessive available atmospheric moisture, the product should not fail when voltage is applied. Thermal Profile Group 4 The final group was processed at a peak temperature of 260°C to determine what, if any, effect additional thermal energy has in relation to cleanliness and SIR performance. The preheat and cooling ramp are still within the recommended limits (Figure 9). Group 4 IC Results The additional thermal energy did not signifi- cantly reduce the level of ionics beyond the peak temperature of 250°C. Adding thermal energy can actually be detrimental and induce damage Figure 7: Group 3 thermal profile. Table 3: IC results for Group 3.