Soldering temperatures

Which is the suggested soldering temperature in lead free processes? Our experience shows that 90% of solder joints using JBC tools can be performed successfully at 350ºC or less, in any case it is not recommended to exceed 370ºC.

Why is it possible to solder at lower using a JBC tool? It is possible because the tip has an extremely fast thermal response.

On a conventional iron’s tip there is a strong drop in temperature while the tip is transferring the heat to the board. If the thermal response is slow, the tip does not have the time to recover the temperature, especially if a series of solder joint is performed. This is the reason why the operator is used to select a higher temperature, resulting in short tip life and PCB / component damage.

Which are the advantages of soldering at lower temperature?

- The tips last much longer because of reduced oxidation. This improves the 'wettability' of the tip and therefore also the heat transfer efficiency.

- The flux does not burn directly on the tip, but is activated while soldering. In this way, the tip does not turn dark so quickly and its wettability is better.

- The risk of damaging components and pcb through excessive heat transfer is minimised.

- The process quality is optimized because there are less rework issues and scraps.

Which is the suggested sleep temperature? The factory setting of 220ºC is adecuate for most situations. At this temperature oxidation is lowered to a minimum and ramp up to work temperature, when the tool is taken out of it's stand, will be completed in about a second.

Which is the best system to clean the tips?

It depends on maintenance issues and on the technology of the soldering system. A wet sponge is an efficient system if it is kept clean and damp (not swamped), it is changed periodically and deionised water is used. The tip's temperature partially decreases during the contact with the wet sponge, but this could be a disadvantage only with older generations of soldering systems, where the iron does not have a very fast thermal response and it takes several seconds to recover the working temperature. The cleaning wire (brass) is an alternative to the sponge. It needs less maintenance and does not decrease the temperature of the tip, that's why some handsoldering producers with low thermal response prefer it. On the other hand, it releases some material residues which may fall on the PCBs if the holder is not protected. The stand of the brass should be heavy in order not to move during its use, otherwise the operator will need also the other hand to hold it. The metal brush is a more aggressive way to clean the tip, but if used gently cleans well the tip with minimal damage. The tip tinner / cleaner is a chemical method to clean and retin the tip at the same time. It should be used when above methods fail and a very active cleaning method is needed. There is also a new sand cleaning method from JBC: the tip must be entered inside a protected sand deposit and turned it around. This method is advisable when all else fails.