Lead-free is mandatory but ever since the earlier introduction of lead-free solder paste there has been the question of how advanced a reflow oven should be.

Kaisertech, supplier of the Dima range of ovens, says the success of a reflow oven is not measured by size or the amount of heating zones but by the ability to create every possible reflow profile. A simple calculation will help to explain what is needed. For most lead-free reflow profiles the board needs about three to five minutes in the process chambers.

For manufacturers that produce only small batches of boards the speed of the conveyor is not really important.

If the oven runs at 20cm per minute a tunnel length maximum of 100cm (20cm x 5min) is required, or if the oven runs at 40cm per minute a tunnel length maximum of 200cm (40cm x 5min) is required.

The number of zones needed is a similar story.

High throughput ovens are using several zones, but in practice these zones are set at the same temperature.

Dividing one long zone into several smaller zones makes it easier to keep the temperature uniform over a longer distance.

In theory only three zones plus one cooling zone are required (ramp-soak-peak), but in practice it is easier to create an ideal profile when adding one extra heating zone.

Both the Dima Breeze and Solano ovens have been developed to provide powerful convection heating irrespective of the size and mass of the components.

Additionally an unlimited variation of temperature profiles is achieved by tunnel designs that include four top four bottom heating zones.

Forced hot air heating maintains consistent edge-to-edge temperatures, regardless of component size or density.

To eliminate the possibility of damage caused by static both have as standard equipment an air ioniser in the cool down zone.