0201 electronic component mounting process from difficult to conventional 


Although it is generally considered to be a relatively recent development, printed circuit boards (PCBs) have been available since the early 1950s. Since then, they have become smaller, lighter and more The demand for fast electronic products has been driving the development of electronic components, PCB and assembly equipment technology towards SMT.
The earliest general acceptance of SMT occurred in the early 1980s, when machines such as Dynapert MPS-500 and FUJI CP-2 entered the market. At that time, 1206 (3216) resistors and capacitors were the most popular placement components. However, in a year or two, 1206 gave way to 0805 (2125) as the most common component packaging for SMT placement.
During this period, both machines and components evolved rapidly. As the machines became faster and more flexible, the 0603 (1608) components began to develop. At this time, many assembly machine manufacturers went back to research open (R&D, research and Development) A laboratory that re-evaluates the technology used to accommodate these newer, smaller components. Higher resolution cameras and smaller vacuum nozzles are among the variations that these components bring to the assembly equipment.
The emergence of 0402 (1608) packaging has created further challenges in all aspects of PCB assembly. In terms of machine development, vacuum nozzles have become smaller and more fragile. New emphasis has been placed on the components of the feeder. It acts as a unit for improvement, sending parts more accurately for the machine.
With the advent of 0402 components, process challenges have increased to those that need to be addressed for successful component placement. Solder paste printing has become even more critical - stencil thickness and solder paste mesh are Increasingly important process considerations. The technology required for this placement also involves important new costs.
The combination of these factors has led to the slowest adoption of a new form of packaging in the history of the electronics industry. In total, nearly five years, 0402 packaging has been widely accepted in the industry - and many assembly plants are never posted today. Pack a 0402 piece.
Now, it has entered 0201.
Over the past year and a half, 0201 placement has been a key topic of discussion throughout the industry. Due to the size, weight and power consumption requirements, many OEM board assemblers need to incorporate even smaller components and technologies into their CM, contract manufacturer must also have new technology to keep the assembly process up-to-date and provide customers with a complete range of services. For machine builders, the challenge is to develop a dynamic technological change. In the times, it is more resistant to obsolete assembly equipment.

0201 placement challenge
The placement of the 0201 component is more challenging than the component intervention in the front. The main reason is that the 0201 package is approximately one-third the corresponding 0402 size.
The previously accepted machine placement accuracy immediately became a limitation of the introduction of the 0201. In addition, the traditional industrial tapeding specification allows for too much movement for reliable 0201 placement, and the process control level must be increased to Make 0201 placement a production reality.
Although these obstacles are very large, they are far from insurmountable. Of course, they need all the determination, because the technology necessary for the 0201 placement requires a lot of money and top management's promise of research and development (R&D).

The key to reliable 0201 placement
At FUJI, the aggressive R&D program has produced the ability to make all circuit assembly machines compatible with 0201 at 100% speed, with a minimum suction reliability of 99.90%, a target suction reliability of 99.95%, and minimal placement reliability. At 99.99%. At the outset, every aspect of the design was evaluated for its ability to be a complete 0201 solution, and the combination of single elements of closely related machine component parameters proved to be critical to success. These parameters included :

Figure 1 Component Feeder Workbench. The R&D program concludes that the ability to precisely position the carriage table - and make minimal adjustments to compensate for the inaccuracy of the tape - is the component's high reliability At 99.95% of the key factors.
In order to achieve this, the feeder table must be precision machined to ensure repeatable positioning of the individual feeders, and a dual-track linear moving guide is used in combination with a high-resolution semi-closed loop servo system. This design allows for very Small adjustment - based on the result of the suction accuracy judged by the vision system. This ensures that the component is as close as possible to the center.
Component feeders. Feeders must be manufactured to extremely tight tolerances to ensure repeatability of the suction position, regardless of component height and a large number of possible component positions. The mechanism used to position and lock the feeder in position must be durable. And precision, but also to be user-friendly. In addition, the material used to make the feeder must be high-strength and light-weight to allow ergonomic operation while ensuring precise, repeatable delivery of the carrier tape. .
Feeder drive sprocket. The drive sprocket plays a key role in the ability of the machine to position the component tape. The shape, taper and length of the drive sprocket teeth significantly affect the ability of the feeder to position the tape. Other factors have also been investigated. Research, such as the diameter of the drive sprocket and the number of contact between the belt and the sprocket. The changes made to the basic sprocket design improve the positioning accuracy. The earlier design increases the X direction by 20% and the Y direction by 50%. .
Figure 2. Suction head. After properly feeding the component, the next step is to draw the component onto the vacuum nozzle and bring it to the board. The vacuum nozzle needs to be compliant to absorb the components in the suction and placement. The impact during the period compensates for small changes in solder paste height and reduces the risk of component breakage. For these reasons, the nozzle must be able to move within its fixture.
Material selection, material hardness, machining tolerances, and thermal characteristics must all be understood to construct a reliable suction head. The nozzle must move freely within its holder without sacrificing accuracy (Figure 1).
Nozzle shaft assembly. The nozzle shaft is also a key design element - by maintaining the entire nozzle and shaft assembly directly aligned, eliminating overdrive. Overpressure is due to the up and down movement of the placement head. It is caused by the inertia generated. If the nozzle and the shaft are not in a straight line, there will be a little whip - or overpressure. The overpressure causes the change of the positioning accuracy, which is determined by the speed of movement, the weight of the nozzle and the weight of the component. By eliminating overpressure, direct alignment reduces the number of negative factors associated with component pick-and-place placement (Figure 2).
Figure 3 nozzle design. The change in nozzle design is an important factor in allowing the 0201 component to be received. To draw a 0.6x0.3 mm component, the nozzle must have an outer diameter of no more than 0.40 mm. The thin nozzle shaft is fragile but must maintain precision to maintain high suction reliability. The change from linear axis to tapered design increases nozzle strength and allows the nozzle to resist bending (Figure 3).
Matrix structure. All machines generate vibration during operation. The base frame design is a key first step to reduce the speed and motion effects of vibration and harmonic resonance. Vibration and harmonic resonance through the use of cast iron base frames and state-of-the-art structural techniques. Can be reduced to a controllable level within the machine so that negative effects can be dealt with.
Up to standard
With all six key factors, the obstacles to reliable 0201 placement have been eliminated. As a result, R&D's focus has shifted to newer, smaller components, and 0201 is no longer considered a leading edge component packaging technology.
For 0201 component placement, the accepted process window is approximately 75 μm X and 75 μm Y at 3 .. To achieve 6 贴 placement reliability, X and Y tolerances must be reduced to 50 μm. The latest high-speed placement The device has a rating of 66μm and the actual standard deviation is approximately 35~45μm. As the 0201 component becomes more widely used and the manufacturing process becomes tighter, improved accuracy can be achieved.
The difference in component size between suppliers poses a challenge to 0201 feeding and placement. Bulk feeding is being opened and should be available in 2001.
Although the machine now has this capability, only a small percentage of users will be ready to take the 0201 placement in the next 12 to 24 months. This is similar to the ball grid array (BGA) and the 0402 component. Introduced, in the assembly environment, the machine's ability is ahead of the process state.

Challenge of SMT industy
While the placement of 0201 components is now a standard feature of new placement equipment, additional work is needed to improve the overall end-user process. At machine builders, component suppliers, circuit board manufacturers, formwork factories, and solder pastes. The relationship between manufacturers needs to be strengthened to form a more seamless development process. The end result will be a unified understanding of the process and a better working relationship that will benefit end users, especially through Make new production technologies faster and