Whether it is a fully automatic or a manual , whether it is a high-speed or a medium-low speed , their overall structure has similarities. The structure of the placement machine can be divided into: frame, PCB transmission mechanism and support table, XY and Z /θ servo positioning system, optical recognition system, placement head, feeder, sensor and computer operation software. The accuracy of the placement machine is its positioning accuracy and repeatability. Grandseed will to share with you.

The structure and characteristics

1.Transmission mechanism and support table

The role of the conveying mechanism is to send the PCB that needs to be placed to a predetermined locations, and then send it to the next process after the placement is completed. The transmission mechanism is an ultra-thin belt conveyor system placed on the track. Usually the belt is placed on the edge of the track, the belt is divided into A, B, and C3 sections, and the PCB clamping mechanism is provided in the transfer area of Zone B. Infrared sensors are installed in Zone A and C. More advanced machines are also equipped with barcode readers. , It can identify the entry and exit of PCB and record the number of PCB. 

2.XY and Z / θ servo positioning system

(Functional XY positioning system is the key mechanism of the placement machine and the main index for evalsuating the accuracy of the placement machine. It includes XY transmission mechanism and XY servo system. It has two common working methods: one is to support the placement head, that is, the placement head is installed on the X rail, and the X rail moves in the Y direction to realize the whole process of placement in the X and Y directions. This type of structure is in the general type It is more common in the placement machine (universal machine); the other is to support the PCB carrier platform and realize the PCB movement in the X and Y directions. This type of structure is common in the placement machine (turret type) of the tower rotating head In this type of high-speed machine, the placement head only rotates, and the placement process is completed by the horizontal movement of the feeder and the movement of the PCB load plane. The above-mentioned XY positioning system belongs to a movable guide rail structure.

3.Optical recognition system

(After the pick-up head picks up the components, the CCD camera images the components and converts them into digital image signals. The geometric dimensions and geometric centers of the components are analyzed by the computer and compared with the data in the control program to calculate the nozzle center and the element. The errors of ΔX, ΔY and Δθ at the center of the device, and timely feedback to the control system for correction to ensure that the component pins and PCB pads coincide.

4.SMD head

(The placement head is a key component of the placement machine. After picking up the components, it can automatically correct the position under the control of the correction system, and accurately place the components in the specified position. The development of the placement head is a sign of the advancement of the placement machine. The placement head has evolved from the early single-head and mechanical centering to the multi-head optical centering. The following are the types of placement heads.

5. Feeder

(The function of the feeder is to provide the chip components SMC / SMD to the placement head according to a certain rule and order, so as to accurately and conveniently pick up. It occupies a large number and position in the placement machine. Arrange an important part of the placement process. With the increase of the placement speed and accuracy requirements, the design and installation of feeders in recent years have received more and more attention. According to the different SMC / SMD packaging, the feeder usually has several kinds of tape (Tape), tube (Stick), disc (Waffle) and bulk materials.

6.Sensor

(The placement machine is equipped with a variety of sensors, such as pressure sensors, negative pressure sensors and position sensors. As the placement machine becomes more intelligent, it can perform component electrical performance checks and monitor the normal operation of the machine at all times. The more sensors used, the higher the level of intelligence of the placement machine.