The component placement machine, also known as the pick and place machine, is one of the most important pieces of
equipment for surface mount assembly. Apart from the fact that it constitutes about 50% of the total capital
investment, the throughput of the manufacturing line is primarily determined by the pick and place machine [5]. There
are three different types of placement machines used in PCB assembly. The construction and working of these are
discussed briefly in the following paragraphs.
Multi headed component placement machines are the most widely used. These are also referred to as gantry style
placement machines. The machine has a moving arm which carries the placement heads on it. The board comes in on
a conveyer and is held in place, on the table, during the time the placement operation is being carried out. The
machine has a feeder magazine onto which the components to be placed on the board are loaded and a tool changer
where different nozzles are stored, since not all components can be placed with the same nozzle. Different size nozzles
are needed, depending on the size of the component being placed.
The multi headed machines are again classified into two types. The first type has the board fixed and the head
moving in the x-y-z directions to pick up the components from the feeders and place them on the board and
traversing to the tool changer to change the nozzle as and when the need arises. This is shown in Figure 1. The
second type of machine has the board moving in the x-y direction and the feeder magazine moving in any one
direction, mostly x. The head is not fixed, but its movement is restricted. It travels to a fixed pickup location to pick up
a component and back to a fixed placement position. That is the reason why a moving board and feeder magazine are
required.
The second type of placement machine is the high speed ship shooter (HSCS) also known as turret type placement
machines. It uses a rotating turret to hold the placement mechanism, which consists of multiple heads. The turret
rotates from a fixed pickup location to a placement location. Since the pickup location is fixed, a moving feeder
magazine is essential. Also the board has to be moving to facilitate proper placement. As the turret carries multiple
heads, the tool change time encountered in the multi headed machines is eliminated and this makes the placement
operation much faster. One of the disadvantages with this type of machine is the fact that it cannot be used for
placing high mass components, because of the moving board.
The third type of placement machine is the robotic arm placement machine. In this type of machine, the boards are in
continuous motion on the conveyer with robotic arms mounted along the conveyer with component feeders located
along the conveyer. The movement of board on the conveyer and the motion of the robotic arms has to be
synchronized to accomplish the correct placement of components.
The machine considered for this research is a multi-headed placement machine with a fixed board and moving head. It
is a dual headed machine. Each of the heads can use a variety of nozzles for placement of different sized components.
The heads move to the feeder magazine to pick up at most two components, and move back to the board to place the
components on to the board, simultaneously or sequentially, without having to go back to the feeder magazine, thus
reducing the placement time. The machine has laser as well as vision centering capability [6].