At present, LED lighting products, environmental protection and energy saving, cost-effective features have been accepted by the market, while governments have introduced policies, phasing out incandescent, LED in the promotion of indoor lighting applications, LED light industry will become a solution to energy and the environment The term synonyms, LED lighting market rapid development. This rapid development will inevitably involve the LED placement machine, LED production equipment, the rapid development of the field.
First, SMT and placement machine
Surface mount technology (SMT), can also be called surface assembly technology, surface mount technology and patch welding technology. It is a board-level electronic assembly technology that mounts surface-mounted components (SMDs) onto printed circuit boards (PCBs). At present, advanced electronic products, especially in computer and communications electronics, has been widely used surface mount technology.
1.1 Advantages of SMT
SMT is with the development of the electronics industry was born, with the electronic technology, information technology, computer application technology development and development. The rapid spread of SMT benefits from its advantages.
1) components assembly density, electronic products, small size, light weight.
2) easy to achieve automation, improve production efficiency.
3) high reliability. Automated production technology ensures reliable connection of each solder joint, and because the surface assembly components (SMD) is leadless or short lead, and firmly mounted on the PCB surface, so its high reliability, seismic capacity Strong.
4) High frequency characteristics are good. Surface Assembling Components (SMD) No pin or segment pins, not only reduces the impact of the distribution characteristics, but also on the PCB surface welding solid, greatly reducing the parasitic capacitance and parasitic inductance between the lead, so to a large extent Reduce the electromagnetic interference and radio frequency interference, improve the high-frequency characteristics.
5) reduce costs. SMT PCB wiring density increases, reduce the number of holes, the area becomes smaller, with the function of the PCB layer to reduce the PCB manufacturing costs are reduced. Leadless or short lead SMC / SMD saves lead material, omitting thread cutting, bending process, reducing equipment, manpower costs. Increased frequency characteristics reduce RF commissioning costs. Electronic product volume reduction, weight reduction, reducing the cost of the machine. Welding reliability is good, making the cost of rework reduced.
1.2 SMT basic process
(1) SMT is a system engineering technology
(2) a typical SMT production line
1) to form a SMT production line must have three important equipment: printing press dispenser, placement machine, reflow furnace wave soldering machine, which wave soldering this process, with the development of surface mount technology, especially Bottom Lead IC Package BGA QFN a large number of applications, its role becomes more and more inadequate, so the current mainstream or reflow this process.
2) Whether it is for large machine manufacturers or medium-sized machine manufacturers, the classic can recommend SMT production line generally consists of two placement machine, a high-speed placement machine (chip components placement machine) 1 high-precision placement machine ( IC component placement machine), so that their duties, is conducive to the entire SMT production line to play the highest production efficiency. But now the situation is changing, a lot of placement machine manufacturers introduced a multi-function placement machine, making the SMT production line only by a patch machine composition possible. 1 multi-function placement machine to maintain a high patch speed in the case, you can complete all the components of the placement, reducing investment, by small and medium enterprises, Academy of Sciences of all ages.
1.3 The simplest placement machine model
The most basic placement machine consists of rack, circuit board clamping mechanism, feeder (not shown in the figure), patch head, nozzle and X, Y, Z axis, which Z axis in addition to Z can move , And can also be rotated in the θ direction (so as to adjust the rotation angle of the component from the pad).
1.4 LED placement machine
On behalf of the LED placement machine is a surface mount technology (SMT) placement machine in a, with the development of LED technology, the traditional SMT placement machine has been unable to meet the LED industry production needs, LED placement machine It came into being.
LED placement machine is designed specifically for the LED industry, custom SMT placement equipment, used to achieve large quantities of LED circuit board assembly. Equipment requires accuracy is not high, but requires fast speed. LED special placement machine to reduce the cost of patch equipment, and improve production efficiency. At present, many types of LED placement machine, but whether it is automatic high-speed placement machine or manual low-speed placement machine, their overall layout is similar.
Automatic LED placement machine is a computer control, collectors electrical as one of the high-precision automation equipment, by the rack, PCB transmission and bearing organization, drive and servo positioning system, placement head, feeder, optical identification System, sensor and computer control system, which through the suction - displacement - positioning - placement and some other functions, completed the SMD quickly and accurately mounted to the PCB board.
1.5 LED placement machine and the difference between the traditional placement machine
LED placement machine mainly to meet the 3014,2835,3528 and 5050,5630,5730 lamp beads placement accuracy requirements. Relative to the traditional placement machine processing accuracy, LED placement machine requirements are relatively low. But the LED placement machine is more focused on the performance, that is, the stability of the machine running, speed, operability, size requirements, so the requirements of the LED placement machine must have the following design ideas and hard requirements.
1) intelligent means more mature to use to the LED special placement machine, all kinds of excellent performance of the sensor can be implemented in the operation of the full collection of data to the computer disposal to protect the stability of the entire placement process and reliability. At the same time and other equipment, according to the scientific methods and technical specifications, regular LED placement machine maintenance, such as the machine and the circuit board surface dirt cleaning and washing, can effectively prevent the dust and dirt caused by poor internal heat dissipation, Causing overheating burnout devices. LED placement machine has a good stability in order to maximize efficiency for enterprises to produce benefits and reduce production costs.
2) LED placement machine speed must be fast, the minimum 18 000 points / h above the placement speed.
3) easy to learn and user-friendly operation method can greatly shorten the training time, and in the production process to reduce misuse, improve production efficiency and product quality.
4) LED placement machine can be mounted at least 1 200 mm length of the PCB, because a large part of the LED is to replace the traditional light pipe lighting, so the length will greatly exceed the traditional PCB size. In addition to these, in order to ensure that a single LED light board without color, requiring the placement of the entire batch of LED lights for the same color temperature BIN (BIN generally represents the LED lamp beads of some parameters range, different range can be used in different Number, said these parameters include voltage, color temperature, brightness, etc., so there will be voltage BIN, color temperature BIN, brightness BIN this argument, you can use BIN on behalf of the product model).
1.6 China LED placement machine technology development
As a fourth generation of light source of the huge market potential, coupled with the strong support of government policy, the domestic LED lighting industry is almost leapfrog development. From the early LED display hot, to the current transition to LED commercial lighting, interior lighting, outdoor lighting, lighting engineering, LED products from a single hot products, the transition to the field of LED applications and popularization.
LED development led to the relevant equipment industry hot, reflow, wave soldering, printing presses, LED placement machine, LED packaging equipment, the momentum of rapid development. At present, most of the domestic LED equipment can be mounted 1.2 m light board of the small placement machine, basically use the platform movement structure, combined with double swing arm movement, to achieve LED placement. Track LED placement machine in the country less. This is the next step, many enterprises in the development of a direction.
At present, the domestic LED placement machine technology is still in a primary stage. Developed products, can only meet the early needs of some small and medium enterprises. China is an electronics manufacturing power, need different grades of domestic LED placement machine. It must be based on the actual situation preferred models, reduce the difficulty of domestic LED placement machine development, rapid access to the electronic equipment industry.
Second, LED placement machine the most critical technology
2.1 precision machine photoelectric integration technology
In the process of LED placement machine, this technology reflects: the placement of the head through the precise mechanical movement of the components from the feeder to pick out and through the calibration body, the accurate and rapid installation of components to the PCB board The
2.2 visual technology
Take non-stop fast shooting positioning technology, to achieve optical image capture positioning, flight alignment.
2.3 magnetic levitation technology
Can solve the high speed and patch precision motion control technology Magnetic levitation linear motor drive applications, improved the original servo rotary motor screw screws exist low speed, noise shortcomings. Linear motor applications are magnetic levitation technology, no friction when moving, no resistance, high speed, long service life.
2.4 efficient intelligent software technology
With the composition and structure of the placement machine increasingly complex and diversified, the importance of placement machine software technology is more and more reflected. Efficient real-time multi-task parallel processing operating system, intelligent placement process optimization, automatic diagnostic technology is bound to greatly improve the efficiency of production and product quality.
2.5 modular and system integration technology
The purpose of modular and system integration technology is to propose optimized and improved solutions for the three basic requirements of speed, accuracy and flexibility of LED placement machines. Flexible modular technology emphasizes the portability, interoperability, scalability and configurability of the device, providing a reconfigurable and openability of the device control platform to control requirements, enabling simple and efficient construction and completion of specific requirements Surface mount equipment to improve assembly productivity.
2.6 Motor uses lightweight design concept
Can significantly reduce the weight of the machine part of the movement, which makes the operation of the machine when the power consumption is also significantly reduced to only 1/4 of the ordinary placement machine consumption, power consumption up to 1/4 of the ordinary placement machine; LED placement machine The placement accuracy is not demanding, but requires faster. At present, the domestic professional for the LED placement machine, there are several to do, according to the speed can be divided into four different, six, eight equipment, you can refer to Taimu Rui LED640, LED660 V and LED680 V several LED special stickers The actual understanding of the machine. The middle of that number represents the number of patch head number. The higher the number, the higher the speed. LED placement machine mainstream applications should be able to mount a large area of the PCB board, to meet the requirements of the online, so as to ensure the speed.
Third, LED placement machine development trend
LED placement machine in the manufacturing process plays a very important role in contemporary mainstream electronic assembly technology production equipment in the largest investment, the most technologically advanced, SMT production line production capacity and production efficiency of the largest equipment. In fact, the most failures, the speed bottleneck is largely from the patch of this process, so the development of placement machine equipment is the most compelling. Currently has the number and advanced level of placement machines, has become a business, regional or national electronic manufacturing capacity of the key signs. Here the development trend of the current placement machine described below.
3.1 LED placement machine is moving towards higher precision
Mounter accuracy refers to the placement machine X, Y-axis navigation movement of the mechanical precision and Z-axis rotation accuracy. Mounter using sophisticated mechanical and electrical integration technology to control the mechanical movement of the components from the feeder to capture and through the calibration mechanism after the precision and reliable placement to the circuit board. In order to produce products with higher performance, the first major challenge is to improve the placement accuracy of the placement machine. The following from the LED process began to say with a more accurate LED placement machine may be the future of LED production of the revolutionary impact.
In the ordinary LED packaging technology, the chip electrode with the support of the pin is generally connected through the gold wire to achieve the way, but the golden wire break has been one of the common causes of failure. LED lighting applications in the gold line is the cause of dead lights and light failure of such a common problem of the culprit. Dead lights can be divided into two cases, one is completely not bright, the other is hot state is not cold or bright, or flashing. The main reason for the absence of electrical circuit is open circuit, the reason is because the gold wire Weld or poor contact.
With the introduction of flip-chip welding technology, the two can be connected through a more stable metal bumps to connect, save costs and greatly improve the reliability and cooling capacity. LED has a long life and other advantages, with the flip-chip technology than the traditional use of gold wire interconnect packaging technology to play the advantages of LED, LED flip-chip welding technology to achieve a single chip and multi-chip module without gold Solid crystal plastic packaging, with high brightness, high light efficiency, high reliability, low thermal resistance, good color consistency and many other advantages.
LED non-gold line package that the industry commonly known as "no package" "free package." This process is the use of flip chip and circuit board direct SMT paste, the SMD package process omitted, directly flip the chip with SMT method to fit on the circuit board or carrier, because the chip area is much smaller than the SMD device, so This process requires a very sophisticated design.
The future of LED placement machine to improve the accuracy of the basic conditions, the direct use of flip-chip package without the process, which will be a small revolution LED process, you can save a lot of packaging costs, and greatly improve the production costs and shorten the production cycle, Making LED products really high performance and low price to enter the general lighting market. The LED placement machine directly to the LED process, great potential to become the future trend of technology.
3.2 LED placement machine is developing in the direction of high efficiency
One of the most important features of today's society is competition. It is this competition that inspires people to explore innovation; it is this competition that promotes the ever-changing development of science and technology. Driven by the LED lighting market in full swing, LED placement machine's efficient work must become the core competitiveness of the embodiment. High efficiency is to improve production efficiency, reduce working hours, increase production capacity, and create economic benefits. On the basis of the current efficiency of the main methods are: to strengthen the LED placement machine automation performance and improve the equipment structure and work mode.
3.2.1 to strengthen the LED placement machine automation performance
The development and perfection of information science and technology today has greatly promoted the level of automation, such as automatic control, automatic adjustment, automatic compensation, automatic identification and so on to self-learning, self-organization, self-maintenance, self-repair and other higher level of automation become possible. At the same time for the placement of this automated CNC equipment, the efficiency of software programming to improve the efficiency of equipment is also essential to develop a more powerful software function system.