Once the Solder Pasting is done and properly inspected, comes the turn of Component Placement. Each component is removed from its packing using a vacuum or gripper nozzle, checked by the vision system and placed in the desired location. This is an automated system done at a very high speed. The technology used for this phase depends highly on the types and design of the PCB being manufactured.
But to achieve a reliable and repeatable process, one must be considerate of certain aspects, these are:
Type of data available: One must be mindful while selecting the software for designing the PCB. They must possess the ability to output various types of data. The most commonly used are the Gerber data and the ‘CAD’ data. They are standard electronics industry file formats and are best for generating placement programs. They are used to communicate design information to PCB manufacturers
PCB design: How a PCB is designed and panelized is important for the component placement process. Here are some considerations:
Panel size: The machines have a specified maximum and minimum size for the panels they can process. Ensure your panel fits within the estimated size.
Handling strips: It is important to penalize the PCB as mostly the components are placed too close to the edge and for the convenience of the PCB handling mechanism within the various machines.
Fiducial marks: Simple shapes are placed within the track layer of the PCB, called the Fiducial marks. They help in avoiding any confusion of aspects and enable accurate positioning of all the components on the design board.
Component size and position: The components might vary in size, therefore using program optimizing software, one must ensure that the smaller components are placed before the larger ones to avoid any disturbance.
Nozzles: Nozzles are used to hold the component securely between the picking and placement steps. Based on the component surface, the type of nozzle is chosen. It is very important to pick the correct type of nozzle and ensure no problems with the nozzle for accurate and consistent placement.
Vision system: The machine’s vision system checks every component to ensure that all the programmed part dimensions match, checks for any damages and programs each component with the correct tolerance parameters.
PCB support: The material used to make PCBs must be of adequate thickness to ensure proper support. Any inconsistency can challenge the component placement process. If it is not well supported, the placement pressure will lead it to deflect.
How components are supplied: Common ways of supplying components are by using tape/reel, tubes and trays. Larger quantities don’t possess much concern as they can be directly loaded onto the machine but when in smaller quantities, they cannot be directly loaded onto the machine but rather need to be hand placed or put into a different packaging that might raise a quality concern.
As you can see, the component placement process might sound easy but is quite tedious and the above-stated aspects need to be taken care of to maintain consistency and ensure repeatable results.