Preface

 

 

 

Placement flexibility is the most eye-catching trend in placement technology in recent years. Almost all newly launched placement machines emphasize their flexibility. There is no new assembly plant or production line that does not consider flexibility as a factor in equipment selection and configuration. Important principle, it can be said that placement flexibility is the basic characteristic and key inspection indicator of modern placement machines.

 

 

 

1. The trend of flexibility is irreversible

 

 

 

Flexible mounting originated from flexible manufacturing. It is a new manufacturing concept and trend that began in the 1990s. This trend is especially obvious in the manufacturing of electronic information products. One style of product produces millions and tens of millions. The orders most favored by manufacturers are getting fewer and fewer. The good days of assembling the same PCBA in a production line for several months are gone forever. It has become commonplace to change products in a few days. This situation has increasingly become an irreversible trend in the new century, prompting electronic manufacturers to change their concepts and assembly models. The one with the greatest impact is the placement machine. The most obvious market signal is that the once-famous production line configuration of high-speed machines and multi-function machines suitable for mass production has been left out, while flexible combined platform models have become the new favorite of the market.

 

 

 

In fact, this change is an inevitable trend in the development of human social civilization. With the rapid development of the world economy and the great abundance of material products, people have higher and higher requirements for the humanization and personalization of various products. The same products will inevitably be ignored. On the other hand, with the rapid development of manufacturing, especially electronic manufacturing, at a certain period, limited market demand and unlimited manufacturing capabilities will inevitably create conflicts. Only by continuously launching innovative products can product manufacturers survive and develop in the fierce competition. This This driving force promotes product upgrading faster and faster, and it is a natural result that flexible electronic assembly has become a trend. In electronic assembly, what is most in need of flexibility is placement technology.

 

 

 

2. The meaning of mounting flexibility

 

 

 

Placement flexibility is also called placement elasticity and flexibility.

 

 

 

In the SMT industry, although people are already familiar with placement flexibility, what exactly is placement flexibility? What are the standards for flexible placement machines? Placement accuracy, placement speed and placement capability can all be quantified into specific data. Can placement flexibility be quantified?

 

 

 

Obviously, flexibility, unlike precision and speed, cannot be accurately quantified. Flexibility is similar to characteristics such as advancement and innovation. It is just a conceptual, dynamic, and relative description of equipment characteristics.

 

 

 

Starting from the actual requirements of production, placement flexibility should include the following aspects.

 

 

 

(1) Ability to adapt to different PCBA products

 

This is the basic requirement for machine flexibility. "Adaptation" here means that one SMT machine model can handle a variety of products, rather than the traditional combination of high-speed machines and multi-function machines.

 

 

 

Different PCBA products may use PCBs of different types, different sizes, different thicknesses, different materials, and different surface coatings. Therefore, the requirements for the PCB transfer, clamping, support, and benchmark identification capabilities of the placement machine are different. At the same time, they may There are different requirements for patch mode, detection method and mounting force. Flexible placement machines should be able to adapt to the variables of these different PCBs without requiring users to change models.

 

 

 

Different PCBA products contain different components. In any single board, the number and proportion of chip components, the types of small chip components (0201 and 01005), the size, type and pitch of CSP, large and complex IC packages such as QFP and CCGA, and connectors, and special shapes The type, size and surface properties of components all place different requirements on the placement capabilities of the placement machine. Flexible chip placement machines should be able to adapt to changes in these different components without requiring users to change models or make additional investments.

 

 

 

(2) Able to balance accuracy and speed

 

This is also a basic requirement for machine flexibility. Usually, among the characteristics of the placement machine, there are mutually restrictive contradictions between flexibility and speed, flexibility and accuracy, and speed and accuracy. Placement flexibility often comes at the expense of speed. Improving accuracy cannot be achieved without losing speed. Enhancing flexibility and improving accuracy are not mutually exclusive. However, modern assembly technology is to challenge these contradictions, requiring both precision and speed to be taken into account in the process of flexibility, so that the three can go hand in hand, achieve dynamic balance, and achieve optimal coordination.

 

 

 

What is gratifying is that due to the continuous innovation of modern technology and the development of equipment manufacturing technology, the above-mentioned contradictions are gradually being resolved, and to a certain extent, high-precision and high-speed flexible chip placement machines can be realized.

 

 

 

(3) Rapid production conversion

 

The basic purpose of flexibility is to achieve high-efficiency production of small batches and multiple varieties, so there are relatively high requirements for the fastest production changeover and setup time. At present, rapid conversion is mainly achieved through flexible configuration of parts systems that can be quickly replaced and advanced open, high-efficiency placement machine software systems that can be programmed offline. The theoretical conversion time of the newly launched placement machines has been shortened to 30 to 15 minutes. Of course, it is the same as the theoretical placement speed. The data given by these equipment suppliers are only for comparison and reference.

 

 

 

(4) Ability to upgrade

 

This is also a requirement for improving machine flexibility. As an enterprise production investment, placement equipment is an inevitable requirement to maximize benefits. However, in today's ever-changing market, an investment company is required to accurately estimate the future product direction and type. Obviously, not every company has the ability. Therefore, the placement machine is required to be flexible in the following situations.

 

• When there is a major change in production scale (usually expansion of production capacity), the ability to adapt to new requirements by adding modules or replacing parts rather than repurchasing equipment. For example, the simplest configuration is a 3-arch placement machine with 6 placement heads, with a placement speed of 30,000 cph. By adding modules, the output can be gradually expanded in increments of 5,000 cph.

• When the product category changes significantly, it can adapt to new product placement requirements by adding modules or replacing some parts. For example, a newly launched placement machine can mount 30mm × 30mm IC packages, and can be expanded to a 50mm × 50mm placement range by configuring a special placement head.

• When new technologies emerge in the manufacturing of placement machine equipment, they can be upgraded at a lower cost.

 

 

3. Ways to achieve flexibility of placement machines

 

 

 

Currently, the newly launched flexible patch machines achieve flexibility mainly through equipment structure combination and component replacement.

 

 

 

1. Flexibility of the placement machine structure

 

 

 

(1) Arch type and rotating type composite

 

This flexibility consideration is the idea of "optimized combination", which integrates the multi-function and high precision of the arch type placement machine and the high speed advantages of the rotary type placement machine into one placement machine, that is, on the arch It is equipped with a vertically rotating multi-nozzle placement head, ranging from a single arch single head, a single arch double head to a double arch, and a 4-arch multi-head structural combination. At the same time, these placement heads can be customized according to the type of components to be mounted. There are different changes, using technologies such as rapid replacement of placement heads to achieve flexible functions. For details, please pay attention to the SMT Engineer Home official account and follow-up explanations.

 

 

 

(2) Modular platform structure module

 

The platform adopts a building block structure and uses a series of small individual placement units to form a highly flexible placement platform. Each unit has its own mechanical transmission and positioning system, equipped with cameras and placement heads. Each placement unit has a certain number of feeders to mount a part of the PCB. The PCB moves within the machine at a set speed. In addition, multiple placement units jointly complete the placement tasks. This method is similar to a traditional manual assembly line. Each person assembles some components of the circuit board at a fixed position, and the circuit boards are assembled sequentially on the conveyor belt.

 

 

 

There are several modes to specifically implement the modular platform structure, as shown in the figure below.

 

 

 

 

 

① Structure of sub-machine [see picture (a) above]:

 

It consists of a control host and several functional modules. The functional modules are designed according to the mounting requirements of different types of components, and can mount various components with different accuracy and speed. By configuring different numbers of functional modules for the control host, users can flexibly adjust the production capacity of the placement machine and improve equipment utilization. This form is the first modular placement machine launched by various manufacturers, and it is also the mainstream modular placement machine on the market.

 

② Modular structure [see picture (b) above]:

 

Modular placement machines are modular placement machines that have entered the market in recent years. This type of placement machine breaks through the modularization model of functional components and extends the modular design to the entire placement platform. The placement machine is in the form of a module. To design, each patch module itself is an independent and complete small patch machine system. Different patch modules can be connected and combined through common interfaces (including mechanical and electrical) and installed on the same modular base. , and realize distributed control through the main control system, forming a highly flexible placement system. This structure is a flexible structure that is currently favored by manufacturers and has great development potential.

 

③ Cell machine structure [see picture (c) above]:

 

The difference between the cell machine structure and the modular structure is that each "cell" machine is an independent small placement machine including a machine base. The cell machines are connected through a unified interface to achieve production capacity and placement. Any combination of types. The basic point of this kind of flexibility is "breaking it into parts", which is another way of thinking about flexibility. Currently, there are relatively few manufacturers and models that provide this kind of product.

 

 

 

2. Flexibility of placement head

 

 

 

The placement head is a key component of the placement machine and the key to achieving flexibility. The latest placement heads can be used to mount a variety of components and have adaptive functions. The more flexible and precise placement heads can shorten conversion time and adapt to high-speed and changing production needs.

 

 

 

The following are the main technologies used in flexible placement heads:

 

• Automatically adapt to changes in component thickness and size;

• Automatically adapt to feeder changes;

• The placement head movement adopts a patented linear motor, which is stable in a short time and ensures placement speed;

• A variety of automatically replaceable nozzle sets;

• Learning function of special cameras and automatic feeders for picking and positioning small components 0201 and 01005;

• Use a special quick-switching valve to speed up the vacuum device when picking up components and placing them;

• Two cameras with optimal field of view and resolution, respectively used for components of different sizes and requirements, combined with high-speed image recognition software and appropriate high-speed data transmission technology to achieve high-speed and high-precision image processing;

• The modular spindle can be quickly replaced and maintained offline to ensure that the machine does not interrupt production.

 

 

3. Intelligent feeding system

 

 

 

A significant element of achieving true flexibility is making the feed system “intelligent” so that it can support rapid set-up and line changeovers. Faster, lighter and more intelligent feeder solutions are required.

 

• Miniaturization and lightweight: These are the functions that today’s truly intelligent feeders should have. The figure below shows a miniaturized and lightweight feeder;

 

 

 

 

• Fast: It loads in seconds, clamps the tape and stores it anywhere.

• Automatic identification: When the feeder equipped with tape is inserted into any slot, the machine software can automatically identify whether there are components in the feeder and the location of the components, without the need to program the pickup position; An alarm will sound when the amount of components in the feeder is less than the setting.

• Dedicated barcode system: enables tracking of components and data cataloging, such as batch ID and quantity; barcodes can be scanned during the loading and unloading process, eliminating the need for manual operations, so setup and line change are faster.

• Simplification of feeders: The simpler the feeders and the fewer types, the less likely problems will occur, the requirements for maintenance will be less, and it is easy to achieve the efficient mode of "assembly and disassembly".

 

 

4. ‘Flexibility of other parts

 

 

 

① PCB conveying system - has the ability to handle veneers of any shape and size, can automatically measure the thickness of veneers, and facilitates automatic line change between veneers of different sizes.

 

② PCB support mechanism that can be quickly set up and adjusted.

 

③ Machine automatic detection and correction function.