3 - Assembly of electronic circuits

The manual dispensing unit can deposit solder paste dots onto the pads on the PCB. The amount of the deposited solder paste can be adjusted by setting the dispensing time and pressure. The volume will also depends on the inner diameter of the dispensing needle. The manual pick-and-place system has a movable placement head, which can reach the component feeders and the pads on the surface of the PCB. The vacuum in the head is automatically switched on when the head gets in contact with the components; and switches off after the placement of the component.

It can be used as a workstation for wide variety of flip chip applications, based on a simple but very precise principle for the optical facedown alignment of the chip:

• with this, the operator is able to see the alignment of the footprint and the component bumps/pads
• moving the precision table, the operator positions the PWB footprint exactly underneath the component
• if the two pictures are in total overlapping, the positioning is complete

The Fineplacer is used to place very fine pitch components which the automatic pick and place machine can not position perfectly. Another function of the Fineplacer is chip bonding:

• the substrate is placed onto the heating element, as a base and heated up to the desired temperature
• the bare flip chips are picked up by the nozzle (for soldering, the nozzles have PTFE insulators not to conduct heat away)
• the nozzle is not released, until the chip bonding or soldering is done
• heating is stopped, nozzle is released