SMT placement equipment

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Internal details of a four head, gantry style pick-and-place SMT machine

Feed mechanism used to load components into a pick-and-place machine

SMT (surface-mount technology) component placement systems are robotic machines which are used to place surface-mount devices (SMDs) onto a printed circuit board (PCB). They are used for high speed, high precision placing of broad range of electronic components, like capacitors, resistors, integrated circuits onto the PCBs which are in turn used in computers, telecommunications equipment, consumer electronic goods, industrial equipment, medical instruments, automotive systems, military systems and aerospace engineering.

The systems, also commonly called 'pick and place' machines, normally use pneumatic suction nozzles, attached to a plotter-like device to allow the nozzle head to be accurately manipulated in three dimensions, and each nozzle can be rotated around its own axis.

Surface-mount components are placed along the front (and often back) faces of the machine. Smaller components (such as resistors and capacitors) are supplied on tape, the tape reels being loaded onto 'feeders', mounted to the machine. Larger ICs are often supplied arranged on sticks or trays, which are stacked in a compartment on the machine for this purpose.

Through the middle of the machine there is a conveyor belt, along which unpopulated PCBs travel, and a PCB clamp in the centre of the machine. The PCB is clamped, and the nozzles pick up individual components from the feeders/trays, rotate them to the correct orientation and place them on the appropriate pads on the PCB with a great deal of precision. More sophisticated machines can optically inspect components on picking, to ensure that the correct component has been picked, that it has been picked successfully and that it is in the correct rotational orientation. The components may be temporarily adhered to the PCB using the wet solder paste itself, or by using small blobs of a separate adhesive, applied by a glue dispensing machine.