Joy Technology Co.,Limited

SMT 0201 assembly from difficulty to conventional placement process



0201 placement challenge
The placement of the 0201 component is more challenging than its previous component intervention, mainly due to the fact that the 0201 package is about one-third of the corresponding 0402 size.the original acceptable machine placement accuracy has immediately become a limiting factor in the introduction of the 0201. In addition, the traditional industrial taping specifications allow too much movement for reliable 0201 mounts, and process control levels must also be increased So that the 0201 placement becomes a production reality.Although these obstacles are very large, but they are far from being insurmountable.Of course, they need all the determination, because the 0201 placement of the necessary technology to obtain a lot of money and the highest management of the study Development (R & D) promise.

Reliable 0201 placement key
SMT equipment manufacturers have been able to make all the circuit assembly machine to 100% speed compatible with the ability of 0201, the minimum draw reliability of 99.90%, the target of the reliability of 99.95%, and the lowest placement reliability of 99.99%. At the outset, each aspect of the design has been evaluated for its ability to complete a complete 0201 program, as well as a single element of the closely related machine component parameters that proves to be critical to achieving success.

These parameters include:
Component Feeder Workbench.
The R & D program concludes that the ability to precisely locate the carriage table
And making minimal adjustments to compensate for the inaccuracy of the tape - is a key factor in achieving the reliability of the component above 99.95%. To achieve this, the feeder table must be machined to ensure a single feed Repeatable positioning of the device and the use of a two-track linearly movable guide in conjunction with a high-resolution semi-closed loop servo system which allows for a small adjustment - based on the accuracy of the absorption accuracy determined by the visual system. Close to the center.

Component feeder.
The feeder must be made to achieve extremely tight tolerances to ensure that the suction position is maintained repeatable, regardless of element height and a large number of possible changes in the position of the component. The mechanism used to position and position the feeder in position must be durable and precise In order to maintain user friendliness, the materials used to make the feeder must be of high strength and light weight to allow for ergonomic operation while ensuring the precise and repeatable delivery of the carrier tape.

The drive sprocket drives the sprocket to play a key role in the capacity of the machine positioning element. The shape, taper and length of the drive sprocket wheel significantly affect the ability of the feeder to orient the tape. Other factors are also investigated Such as the diameter of the drive sprocket and the number of contacts with the sprocket, etc. The change in the basic sprocket design improves the positioning accuracy, the earlier design increases by 20% in the X direction, 50% in the Y direction, The

Absorb the head.
After the feeder element is properly fed, the next step is to draw the element on the vacuum nozzle and take it onto the circuit board. The vacuum nozzle needs to be adapted to absorb the impact during the draw and mount element, The slight change in the height of the solder paste and the risk of rupture of the element. For these reasons, the nozzle must be able to move within its fixture. Material selection, material hardness, machining tolerances and thermal characteristics must be understood to construct a reliable The nozzle must be free to move within its holder without sacrificing accuracy.

Suction nozzle assembly.
The nozzleshaft is also a key design element - by overriding the entire nozzle and shaft assembly, eliminating the overdrive phenomenon due to the inertia of the top and bottom of the mounting head If the nozzle and the shaft are not in a straight line, they produce a little jitter (whip) - or overpressure. Overvoltage causes a change in positioning accuracy, which depends on the speed of movement, the weight of the nozzle and the weight of the component. By eliminating overpressure, To reduce the number of negative factors associated with component picking and placement.

Nozzle design.
The change in nozzle design is a very important factor in allowing the inclusion of the 0201 element. In order to draw 0.6x0.3 mm of the element, the nozzle must have an outer diameter of no more than 0.40mm. This forms a long and thin nozzle , Bending is fragile but also must be kept in order to maintain the high reliability of the drawing. The change from the linear axis to the tapered design increases the nozzle strength and allows the nozzle to resist bending.

Base structure.
All the machines are vibrating during operation. The base frame design is the first step in reducing the speed and motion effects of vibration and harmonic resonance. By using cast iron base frames and art-level structure techniques, vibration and harmonic resonance can be achieved in the machine To a manageable level, so that negative effects can be met.

Up to standard
Through all six key factors, reliable 0201 placement barriers have been eliminated.Therefore, 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 current process window is about 0.075mm X and 0.075mm Y at 3 Sigma. In order to achieve 6 Sigma mount reliability, the tolerance of X and Y must be reduced to 0.050mm. High-speed placement equipment has a rating of 0.066mm, the actual standard deviation of about 0.035 ~ 0.045mm. With 0201 components become more widely used and manufacturing process tight, can achieve improved accuracy.