SMT Machine for PCB Assembly Process
What is SMT machine
SMT machines are also known as SMT Machines used to automate the assembly process of the printed circuit board (PCB). The task is to pick the electronic components and place them on the empty circuited PCB board.
During the assembly process of the PCB board, the most important key factor is to get the components placed at the right place with an accuracy of 0.05mm. These factors can only be achieved by using a high-tech SMT machine.
Working Process of SMT machine
At first, the PCB board gets loaded from the PCB loader and the Solder Paste Printer applies the solder paste to the surface of the PCB board. Now the PCB board is ready for the pick and place process.
After solder paste is applied the conveyor passes the PCB board into the SMT machine for the placement of components on the PCB board. The machine has a fixed width and length adjustment according to the size of the PCB board. The PCB board gets locked by the SMT machine.
Adjustment of Mark Points
Every SMT machine needs to scan the mark points first. Normally there are two mark points on a PCB board.
Accurate scanning of mark points confirms the position of the PCB board. The head moves to mark1 and the camera scans the mark point and saves it by taking the picture of mark1 likewise the head moves to mark2 and the camera scans the second mark2 saves the picture in the database.
Now the SMT machine or SMT machine has successfully obtained the exact position of the PCB board. It’s the time of scanning the mounting pointing.
Scanning of Points for Mounting Process
The linear camera scans each mounting point of the PCB board by taking the pictures and saves them into the database when scanning of the component is done the machine is ready for the picking of the components.
Picking of components
Each component is picked simultaneously from the electronic feeder. To pick up the right component the head comes to the feeder and picks up the electronic component with the help of the installed nozzle in front of the spindle.
There are multiple spindles in a machine’s head ranging from 4 to 10. Spindles are installed with different nozzles according to the component size.
Placement of Components
When the picking of the components is done there is a turn to place the components on the surface of the PCB board. Firstly each component is scanned by the flying camera and the nozzle adjusts the right dimension of the component after that the component will be placed on the surface of the PCB board.
After the placement of the suitable components, the PCB board is ready for the soldering process. The conveyor unlocks the PCB board and passes it to the soldering section.
The hardware of the SMT machine
The SMT machine contains one of the complex hardware parts. Major hardware parts include the guiding rails, servo motors, linear cameras, conveyor system, electronic system.
diagram of SMTmachine
The hardware of the SMT machine
Y-axis guiding rails are used to roll the head in the y-direction.
The Y-axis guiding rail has a servo motor installed on the front side with a ball screw which helps to move the head on the Y-axis.
The Head is placed on the X-axis with the rails attached
Head moves on the top of the X-axis
Feeder is installed
Cutting Blades are installed under the machine they are used to cut the feeder’s tape during the production process.
The computer is installed with self-made software for the high processing of machine
The conveyor is an important part of the SMT machine. The PCB drives on the surface of the conveyor.
The conveyor adjustment system allows adjusting the width of the conveyor according to the size of the PCB board.
The SMT machine lifts up the bottom surface. To get the PCB fixed in the conveyor.
An IC tray plate is installed to pick up the IC components while mounting.
A linear camera is used to scan the component after picking it up from the feeder base.
Head of SMT machine
The Head of the SMT machine is designed to scan, pick and place the component at a certain angle on the surface of the PCB board. The head is provided with certain air pressure. During mounting the head generates the vacuum to pick up the components and release the air pressure to place the components.
The right side R axis motor is used to rotate the first four spindles into a 180-degree. direction.
The left side R axis motor is used to rotate the last four spindles into a 180-degree direction for the right placement of the tiny chips.
There is a flying camera attached in the center of the head of the SMT Machine which scans the chip while picking from the feeder.
The air pressure is provided into the head to pick up and reread the components.
Air pressure of SMT machine
The smt machine is provided with an external air pressure source between 0.5 Mpa to 0.7 Mpa.
PCB Passing Process
The PCB board comes inside of the SMT Machine, gets mounted, and passes out from the other end of the conveyor.
Passing of the PCB board from one side.
The PCB board gets locked by the barrier for the stable mounting of components.
Mark camera move to the feeder to pick up the components
Nozzle picks up the component with the help of a marked camera.
A linear Camera installed in between the feeder scans the attached components and adjusts the placing point of the component.
After adjustment is done head moves to the mounting area and the SMT machine starts mounting the components.
After mounting, the PCB board goes out from the second end of the machine.