SMT patch proofing requirements for the placement machine
- 2020-08-17-

Requirements for placement machine in SMT placement proofing

In SMT patch proofing, the placement process is completed by a special placement machine-placement machine. The placement machine, also known as the "placement machine", is a special machine that replaces manual placement. The basic placement machine is composed of a frame, a circuit board clamping mechanism, a feeder placement head, a suction nozzle, and X, Y, and Z axes.The basic requirements of SMT patch proofing for the placement machine can be summarized in three sentences: one is to paste accurately, the other is to paste well, and the third is to paste quickly.

1.Paste it accurately. Sticking properly includes the following two meanings. ①The components are correct: The type, model, nominal value and polarity of the components at each assembly position are required to comply with the requirements of the product assembly drawing and schedule, and the wrong position cannot be pasted. ②Position accuracy: The ends or leads of the components and the target graphics should be aligned and centered as far as possible in position and angle. At present, the centering target of SMT patch proofing, in addition to the traditional land pattern on the PCB, there is also a way to target the actual printed solder paste pattern.

2. Post well. Posting well includes the following three meanings. ①No damage to components: during picking and placement of SMT patch proofing placement machine, due to feeder, components, printed board errors and Z axis control failures, etc., components may be damaged, leading to placement Invalidate. ②The pressure (the height of the patch) is appropriate; the pressure (height) of the patch should be appropriate, the pressure of the patch is too small, the solder ends or pins of the components are floating on the surface of the solder paste, and the solder paste cannot stick to the components. It is easy to move the position when the chip is too large, and the solder paste is squeezed out too much, which is easy to cause the solder paste to stick, and it is easy to cause bridging during reflow; too much pressure can even damage the components. ③Guarantee placement rate: due to unreasonable adjustment of SMT patch proofing placement machine parameters, poor component placement performance, and feeder and suction nozzle failures, components will fall during the placement process. This phenomenon is called " "Dropping" or "throwing". In actual production, the "mounting rate" is used to measure. When the mounting rate is lower than a predetermined level, the reason must be checked.

3. Post fast. Usually there are tens to thousands of components on a circuit board, and these components are pasted one by one. SMT patch proofing speed is the basic requirement of production efficiency (capacity). The placement speed mainly depends on the speed of the placement machine, but also closely related to the optimization of the placement process, the application and management of the equipment.