In the SMT production line, the placement machine is a device that accurately places the surface mount components on the PCB by moving the mounting heads. Its overall structure is divided into three major parts. The main part is the placement head. From the concept of electric loading robots, the placement head of the placement machine is an intelligent robot that can pick up components as required and precisely Place it on the preset PCB board.
When the vacuum negative pressure is generated, the suction nozzle directly touches the parts of the SMT component. The size of the suction nozzle hole and the shape of the SMT component have a very practical nozzle for each placement machine. For the placement machine to adapt to the placement of different components, it is also equipped with a device that automatically replaces the suction nozzle. There is also an elastic compensating buffer mechanism between the suction nozzle and the suction pipe to ensure the protection of the chip components in the picking process and improve the component mounting rate.
SMT pneumatic solenoid valve:
The micro pneumatic electromagnet of the mounting head is another important component on the mounting head. It manages functions such as movement, pick and place, etc. With the development of the mounting machine, the integrated solenoid valve group has also developed considerably. Some individual solenoid valve thicknesses Only 10-18 mm. And the electromagnet drive power is small, the drive level of the general circuit can be directly driven.
The various mechanisms of the patch head can work together to install a variety of sensors to effectively coordinate the working status of the patch. When the patch function is decided, the overall structure design of the patch head becomes the key to the placement machine. The patch head is a high-speed motion component. To improve the accuracy, it must reduce its weight and volume, so design a structure to achieve full functionality. Patch head is also the design focus of the patch.
Pick-up machine components pick and place:
The pick-up element is a vacuum sucker which sucks the components. It has a simple structure and is easy to maintain. In the pick-and-place operation, the pick-up nozzle must be pick and place faster and smoother as it moves in the Z direction. The early Z-direction movement of the suction nozzle was accomplished using a micro-cylinder. In the last decade of use, the cylinder was found to be susceptible to wear, with a short life and high noise levels. At present, many new models have adopted a new type of electromechanical transmission rod instead of Z-axis, which can control the Z-axis movement state and greatly improve the overall performance of the Z-direction movement.
Mounter component positioning:
The component positioning system of the patch head is an important part of the patch quality, and it is also a difficult technique to study the patch technology. When the component is attached to the component, the component is in a stable floating state. The early technology used mechanical claws for passive positioning, thus solving the problem of component positioning of early placement machines. However, it was actually a mechanical method. Various errors in mechanical manufacturing directly reflected the quality of component positioning, especially the improvement of the patch speed. At the time, the mechanical noise, the wear of the parts, and the longevity of precision all limit the advancement of the mechanical positioning claws.
In recent years, sampling systems for vision systems, servos, computer image processing, etc. have changed the use of machinery alone to solve positioning problems. Instead, it uses a non-contact infrared, laser alignment system and automatically corrects deviations during movement.
SMT component rotation:
When the suction head suction device is moved and positioned, most of the components perform a quantitative rotary motion (q angle). Firstly, the axis of the installation axis of the component on the correction plate and the axis of the component during the movement (q′ angle) is the first. Solve the angle difference (q" angle) of the component on the feeder and the pad axis of the PCB board q=q'+q". The mechanism for correcting the angular misalignment of component mountings has long been controlled by an open-loop stepper motor and operated by a small synchronous belt. Nowadays, the novel placement machine has been replaced by some special micro-motors, which greatly improves the performance of the mechanism. In order to increase the placement speed of the placement machine, a multi-nozzle combination is adopted in the placement head, and its operating procedures are precisely controlled by a computer.