TECHNICAL ARTICLE

Introduction of 6 common sensors of placement machine

Views:365Update time:2022-10-22

                               Introduction to the 6 common sensors of the placement machine, remember to collect it


Many people have great doubts about the different sensors in the placement machine. What is the difference between different sensors? What is the role of these sensors? Why do some placement machines only have one sensor, and some have multiple sensors? Next, XLin Industry will introduce the role of common placement machine sensors.


We all know that the placement machine is the core equipment for SMT processing and production. It is a composite of many technologies such as machinery, optics, and computer systems. At present, the main placement machines are imported from foreign brands, such as Siemens (ASM), Panasonic , Fuji, Samsung, Yamaha, etc., a placement machine can range from hundreds of thousands to millions, and the value of the product can be reflected from the price. There are many types of sensors in the placement machine, and different sensors are responsible for different Work, such as pressure sensors, image sensors, etc., these sensors are constantly monitoring the operation status of the placement machine. The more sensors, the stronger the machine performance and the more intelligent it is.

西门子TX系列贴片机

Siemens TX series placement machine


1) Pressure sensor

The pressure system of the placement machine includes the working pressure of various cylinders and vacuum generators. These generators have certain requirements for air pressure. When the pressure is lower than the specified pressure of the equipment, the machine cannot operate normally. The pressure sensor has been monitoring the change of pressure. Once the machine is abnormal, it will alarm in time to remind the operator to deal with it in time.


2) Negative pressure sensor

The suction nozzle on the patch head sucks the components by negative pressure, which is composed of a negative pressure generator and a vacuum sensor. When the negative pressure is not enough, the components will not be able to be absorbed. When the feeder has no components or the components are stuck on the feeder and cannot be absorbed, the suction nozzle will not be able to absorb the components. The occurrence of these situations will affect the normal operation of the machine. Work. The negative pressure sensor monitors the changes of negative pressure all the time. When there is a situation where it cannot absorb or absorb components, it can alarm in time, reminding the operator to replace the feeder in time or check whether the suction nozzle and negative pressure hose are blocked.


3) Position sensor

The transmission positioning of the PCB includes the counting of the PCB, the real-time monitoring of the placement head and the worktable, and the movement of the auxiliary mechanism, etc., all of which have strict requirements on the position, and these positions are required to be realized by various forms of position sensors. On the front track, there are generally 2 sensors. The sensor at the entrance of the PCB mainly detects whether the PCB is imported. Once the PCB is detected, the conveyor belt on the front track will run. If there is a PCB waiting or being pasted on the middle track The PCB at the entrance will run to the second sensor position of the front track and stop running. After waiting for the PCB on the middle track to be exported, it will be transferred to the middle track to prepare for placement.


If there is a PCB waiting at the second sensor position of the front track, even if the sensor at the entrance of the PCB detects that there is a PCB, the conveyor belt on the front track will stop running and be in a waiting state. The sensor on the middle track mainly detects whether there is a PCB waiting to be mounted. If a PCB is detected, the placement program will run quickly, and the components will be mounted to various positions on the PCB according to the instructions.


After the components on the PCB are assembled, they are quickly imported to the back-end rail, and the conveyor belt on the back-end rail will run to export the mounted PCB to the next process. If the PCB is blocked at the exit of the rear rail, the PCB will not be exported even if the PCB on the middle rail is placed.


During the placement process of the placement machine, the placement head moves at high speed along the X-axis and the y-axis. In order to prevent the placement head from hitting the cantilever of the machine, there are 2 limit positions in the X-axis and y-axis directions of the placement machine. Sensor, once the placement head reaches the limit sensor, the machine will stop running immediately. It can be seen that the limit sensor mainly protects the patch head.


4) Image sensor

The real-time display of the working status of the placement machine mainly uses a CCD image sensor, which can collect various required image signals, including the position of the PCB and the size of the components, and through computer analysis and processing, so that the placement head can complete the adjustment and placement. Work.


5) Laser sensor

Lasers are now widely used in placement machines, which can help determine the coplanarity of device pins. When the device under test runs to the monitoring position of the laser sensor, the beam emitted by the laser irradiates the IC pin and is reflected to the laser reader. If the reflected beam is the same as the emitted beam, the coplanarity of the device is qualified; when When they are not the same, the device will make the emitted light beam longer due to the deformation of the pins, and the laser sensor will recognize that the pins of the device are defective. In the same way, the laser sensor can also identify the height of the device, which can shorten the production lead time.


6) SMD head pressure sensor

With the improvement of the speed and accuracy of the placement head, the intelligent requirements for the placement of the components on the PCB are getting higher and higher. This is the so-called "z-axis soft landing" function, which uses the pressure sensor and servo The load characteristics of the motor are realized. When the components are placed on the PCB, they will be vibrated at the moment, and the vibration force can be transmitted to the control system in time, and then fed back to the placement head through the control of the control system, so as to realize the z-axis soft landing function. When the patch head with this function is working, it feels smooth and light. If you observe further, the depth of the solder paste immersed when the components are mounted on the PCB is roughly the same, which is good for preventing the tombstone and dislocation during subsequent soldering. Welding defects such as flyers are also very beneficial.

图片2

Siemens placement machine placement head


The sensor is a kind of inspection equipment that can sense the detected information content, and can convert the sensed information content into electronic signals or other required data output according to a certain regularity, so as to achieve the transmission of information content. , settlement, storage, presentation, recording and manipulation.


The characteristics of the sensor include: miniaturization, intelligence, intelligent system, multi-purpose, specialization, and digitization. It is the main stage to complete automatic identification and intelligent control. The emergence and development trend of sensors have allowed objects to have touch, taste buds and tactile sensations, making objects more and more alive. The above is the introduction of XLin Industrial on the six common sensors of the placement machine. I believe that through this article, everyone has a further understanding of the sensors of the placement machine. If you have any other doubts, welcome to consult. 

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