We’re now talking about BGA-packaged components with 4,000 or so leads or balls, 0.3mm pin pitch and below, highly component populated automatic test equipment PCBs, and ever shrinking conventional PCBs and small flex circuits for Internet of Things (IoT) and wearables.
That tells you that component placement on these PCBs at the pick and place assembly stage is more critical today than ever before.
Considering that PCBs continue to shrink in size and increase in complexity, placement demands a well-disciplined list of checks, being ever watchful of mixing in damaged components, and verifying pad sizes with respective components.
Take a look at our article inCircuits Assembly Magazine to get the full low down on the key steps to follow to assure your project achieves proper component placement.
In the meantime, here are some tips and hints to follow to get a better grasp of correct proper placement.
- Find out about the first check at the SMT stage, Fig. 1. It’s a feeder component check QC performs so that each component is identified on the tape and reel or trays and is matched with the BOM.
- Understand that not all pick and place machines handle the wide range of component sizes. Sometimes custom feeders must be ordered for accurate placement.
- First article inspection performs a QC check after the first article board goes through placement from the pick and place machine but before going through the reflow oven.
- Be careful about “consigned components” OEMs provide at times. These devices are cut from the tape and reel and provided to production as an exact number of components. It’s best to have components in a tape and reel package for accurate PCB placement.
- As an OEM, avoid salvaging components from dead boards and provided to your EMS Provider for your projects.
- Sometimes BGA pad designs with pads of different sizes pose placement issues. It’s a good idea to maintain close connections with your EMS Provider so that the OEM customer can be alerted to poorly designed PCBs or questionable fab houses.
It’s best for the OEM to closely work with his EMS Provider who has in-house design and assembly and close ties to a highly reputable fab house. This way, the OEM is assured that assembly and design teams frequently interact to iron out an assortment of placement concerns. Therefore, to have successful and accurate placement, PCB designers must closely interact with assembly and process engineers to assure the right type components are used and placed on the PCBs.