With the rapid development of surface mount technology, the application of SMT in China’s electronic assembly industry is more and more extensive. Facing numerous models

How to select the mounting machine is still a complex and difficult work. Several key technical issues should be paid attention to when selecting the mounting machine.

Mounter type

At present, mounters can be roughly divided into four types: boom type, composite type, rotary table type and large parallel system. Different types of mounters

There are advantages and disadvantages, usually depending on the requirements of the application or process on the system, and there is also a certain balance between its speed and accuracy.

Boom type machines have good flexibility and accuracy, and are suitable for most components. High precision machines are generally of this type, but their speed

It cannot be compared with composite, turntable and large parallel systems. However, the component arrangement is increasingly concentrated on active components, such as those with leads

The installation accuracy of QFP and BGA array elements is crucial for high output. Composite, rotary and large parallel systems are generally not applicable

Install on this type of element. The boom type machines are divided into single arm type and multi arm type. The single arm type is the earliest developed and still used today

Multi function mounter. The multi arm mounter developed on the basis of single arm can double the working efficiency, such as YV112 of YAMAHA

There are two boom mounting heads with 12 nozzles, which can install two circuit boards at the same time.

The compound machine is developed from the boom type machine. It combines the characteristics of the turntable type and the boom type. A turntable is installed on the boom, like

Simens’ Siplace80S series mounter has two turntables with 12 suction nozzles. Because compound machines can increase the number of booms

It has higher speed and greater flexibility, so its development prospect is promising. For example, Simens’s latest HS50 machine has four

The mounting speed can reach 50000 pieces per hour.

As the pickup element and mounting action of the rotary table type machine are carried out at the same time, the mounting speed is greatly improved. The high-speed mounting machine with this structure

It is most widely used in China, with high speed and stable performance. For example, the mounting speed of Panasonic’s MSH3 machine can reach

0.075 seconds/tablet. However, due to the mechanical structure of this machine, its mounting speed has reached a limit value, and it is impossible to increase significantly.

The large parallel system consists of a series of small independent assembly machines. Each has a lead screw positioning system manipulator, and the manipulator has a camera and

Install the head. Each mounting head picks up elements from several belt feeders, and can install multiple circuit boards in multiple partitions. These boards pass through

The machine periodically changes the angle alignment position. For example, PHILIPS FCM machine has 16 mounting heads, achieving a mounting speed of 0.0375 seconds/piece,

However, for each mounting head, the mounting speed is about 0.6 seconds/piece, which is still possible to be greatly improved.

Composite, turntable and large parallel systems belong to high-speed installation systems, which are generally used for the installation of small piece elements. Rotary table machines are also

It is called “Chip shooter” because it is usually used to assemble chip resistors and capacitors. In addition, the secondary machines have high-speed “ejection”

Ability. Because the required accuracy of passive components, i.e. “chips” and other lead components is not high, the chip shooter assembly can achieve high productivity. high speed

Since the structure of the machine is much more complex than that of the ordinary boom type machine, the price is also much higher. This should be taken into account when selecting equipment.

The test shows that the installation accuracy of the boom type machine is good, and the installation speed is 5000-20000 elements per hour (cph). Compound and rotary table

The assembly speed of type A machine is relatively high, generally 200000-50000 per hour. Large parallel systems can be assembled quickly, up to an hour

50000-100000.

vision system

The machine vision system is the second factor that significantly affects the installation of components. The machine needs to know the exact location of the circuit board and determine the components and boards

The precision of automatic assembly can only be guaranteed by the position of. Jialichuang Laser Steel Mesh

Imaging is accomplished using a video system. The video system is generally divided into top view, bottom view, head or laser alignment, visual position or camera

Depending on the type.

(1) The overhead camera searches for the target (called the reference) on the circuit board, so that the circuit board can be placed in the correct position before assembly;

(2) The overhead camera is used to detect elements at a fixed position. Generally, CCD technology is used. Before installation, the elements must be moved over the camera

For video processing. It looks like it takes a little time. However, since the mounting head must be moved to the feeder collecting element, if

The camera is arranged between the picking position (from the feeding position) and the installation position (on the board), so that the video acquisition and processing can be carried out during the movement of the installation head

At the same time, so as to shorten the installation time;

(3) The head camera is directly installed on the chip head, and the line sensor technology is generally used

In the process of completing the detection of components, this technology is also known as? quot; Flight alignment technology “, which can greatly improve the mounting efficiency; (4) Laser alignment

It refers to generating a moderate light beam from the light source to irradiate on the element to measure the impact of the element projection. This method can measure the size of components

, shape and deviation of suction nozzle central axis.

However, for components with pins, such as SOIC, QFPHE and BGA, the camera of the third dimension is required for detection. So the alignment of each component

It takes a few more seconds. Obviously, this will have a great impact on the speed of the whole mounter system. In the case of three components

In the formula (CCD, line sensor, laser), the CCD technology is the best, and the current CCD hardware performance has a considerable level. In CCD hardware

In terms of development, we have developed “Back Lighting” and “Front lighting” technologies, as well as programmable

Lighting control to better meet the mounting needs of various components.

Feeding

The boom type machine can support a variety of different types of feeders, such as belt type, disk type, bulk type, tube type, etc. This is related to high-speed installation

In contrast, the latter can only use bulk or belt feeders. When installing many large ICs, such as QFP and BGA, boom type

The machine is the only choice. In addition to the mounting accuracy, it is also an important reason that the high-speed machine does not support the disk feeder. Jialichuang Laser Steel Mesh

In general, the manufacturer should consider the universality of the feeder on his machine, but sometimes the manufacturer will also design the feeding for a specific machine

This limits the use of the feeder on other machines. Special machines not only cause a large number of feeders to be idle, but also require space

Store them.

flexibility

Due to the increasingly fierce competition of electronic products and the increasing uncertainty of production, it is necessary to frequently adjust the output of products or arrange the transfer of products

Therefore, the placement machine is required to have good flexibility to adapt to the ever-changing manufacturing

Environment, which is often referred to as flexible manufacturing system (FMS). For example, the placement machine of Universal Instruments of America has mutual functions from dispensing to placement

In other words, only the dispensing component and the patch component need to be exchanged. This kind of equipment is suitable for processing enterprises with multi tasks, multi-purpose and short production cycle. machine

Flexibility is a shutdown factor that we should consider when purchasing equipment.