The quantity of the tin paste affects the soldering quality of MELF resistors dramatically and obviously!
Following
are the soldering status of same batch melf resistors at one reflow machine.
The 1st 2 pictures with very bad soldering quality due to too less tin paste so no tin
could climb to can and only the bottom of the caps were soldered. Some caps
turned dark due to no new tin climb to the caps during the high temperature
reflow period so the caps were oxidized.
The 3rd one shows the perfect soldering quality just by adding the tin paste quantity. The
tin climbed to the caps and surrounded the almost half part of the caps that
makes perfect soldering!
Thunder Precision Resistors have been make precision MELF resistors from 2000 for honorable customer ENEL and are experienced expert to keep the caps of the melf resistors in perfect solder ability and provide soldering solution for all our users concern soldering problem, including our honorable customer FLUKE.