Operation of SMT high speed mounter

In a sense, SMT technology has become a pillar of SMT and an important symbol of the in-depth development. SMT mounter is the core and key equipment in the assembly line of SMT products. The advanced degree of SMT processing mounter fundamentally determines the two requirements of the mounter process: mounting accuracy and mounter rate.

First of all, the function of PCB transmission device is to send the PCB that needs to be placed to the predetermined position, and then send it to the next process after the placement is completed. The transmission device is an ultra-thin belt line transmission system placed on the track. The belt line is usually divided into A, B and C sections. The transmission part of B section is equipped with PCB clamping device, and there are infrared sensors in A and C sections. More advanced machines also come with barcode recognition devices that can set up the entry and delivery of PCBS and record the number of PCBS, as shown below.

PCB Transmission device

During mount operation, the circuit board must be fixed. This splint prevents the circuit board from moving without interfering with the available mount area. On some devices, the splint can automatically feed a new circuit board into the machine and send the circuit board full of components to the next step. The driving device is divided into integral guide and movable guide according to the type of mounter.

(1) integral guide rail. In this kind of mounter, the entry, placement and delivery of the PCB are always on the guide rail. When the PCB is sent to the guide rail and advances to section B, the PCB table has a backward motion and encounters the back limit block, so the PCB stops running. At the same time, the top block with locating pin under the PCB goes up to push the pin into the process hole of the PCB, and the clamping device on section B clamps the PCB. The locating pin is shown below.

PCB positioning pin

Under the PCB, there is a support board with an array of round holes. When the PCB enters section B, a proper number of support rods can be installed on the board according to the PCB structure. As the table moves up, the support bar holds the PCB at the horizontal position, so that the PCB will not be pressed down and the placement precision will not be affected.

If no process holes are reserved for PCB in advance, the position of PCB can be confirmed by an optical identification system. At this point, the locating pin on the locating block can be removed. When the PCB is in place, the positioning of PCB can be completed by the front and rear limiting bit blocks of PCB and clamping device together.

(2) movable guide rail. In another kind of high-speed mounter, the guide rail of section B is fixed relative to sections A and C, while the guide rail of section A and C can rise and fall. When PCB is sent to guide rail A from the printing press, guide rail A is in A high position and connected with the guide rail of the printing press: when PCB runs to B, guide rail A sinks to the same horizontal plane as guide rail B. PCB is moved from section A to section B and is clamped by section B. When PCB placement is completed, it will be sent to the guide rail of section C, which will be moved up from the low position (the same level as section B) to the same level as the guide rail of the equipment in the next process, and PCB will be sent from section C to the guide rail of different types in the next process with different structures, which mainly depends on the overall structure of the mounter.