|Air-knife PCB cleaning system. |
Foreign material, dust, lint, foreign object damage (FOD) — whatever you call it — when it's on your circuit boards, it's never a good thing. For engineering managers tasked with reducing waste and increasing quality, there are many ways to eliminate foreign material in your processes. Unfortunately, many of these methods have some shortcomings. That's why Simplimatic Automation has developed a better way to clean circuit boards.
One standard way to reduce or eliminate defects is to ensure that the application of solder paste happens on a clean, dry PCB. Foreign material between the stencil and circuit board can cause a high volume condition during printing, leading to components not seating correctly.
Good inspection processes and equipment also can prevent the damage to the company's reputation that results from bad product getting out the door. Better yet, defect elimination in the assembly process of printed circuit boards has obvious benefits for the bottom line, impacting efficiency, scrap and yield loss, as well as customer satisfaction. By improving processes during assembly, you can minimize the costs associated with scrapping all the defective products your inspection systems will hopefully uncover.
Historically, tacky roller systems are the most common method of board cleaning. In this method, product is conveyed under a roller that has a tacky surface that adheres to the foreign material, lifting it from the board. This method has its shortcomings. Failure to monitor the roller can lead to foreign material being reapplied to subsequent boards or the adhesion of the roller material itself to the board. Tacky roller systems also don't work on populated boards.
Simplimatic Automation worked with one of its largest OEM customers to develop a better way to clean boards and address these shortcomings. This new solution is based on blowing debris off the board and removing it from the environment. This is accomplished by passing the board between air knives while turning over the air in the blow-off chamber, removing it to a clean room-rated vacuum cleaner. The air knives come equipped with ionizer bars to eliminate the buildup of static electricity. Sensors on the vacuum line, ionizer and air supply all ensure the safety of the product by preventing product transfer if any of these three systems are off-line for any reason.
Not So Tacky
Results have been outstanding. In head-to-head analysis against tacky roller systems, the Simplimatic Board Cleaner yielded better results. In the first month, we saw improvement from a baseline of 843 PPM to 190 PPM. We have since added further enhancements to allow increasing air flow, which continues to improve upon initial results.
Cleaning bare boards at the start of the SMT process is an excellent beginning, but other operations can generate foreign material, making board cleaning a necessity. Secondary operations that require screwing on connectors generate foreign material, for example, and the air knife-based system is still very effective at removing foreign material where other solutions come up short. This is because the air knife makes no physical contact with the PCB or components, and air flow can be regulated for gentle or aggressive cleaning as required.
Every engineering manager would agree that foreign material on your circuit boards has a negative impact on your product quality and the efficiency of your processes. The good news is, the new Simplimatic Board Cleaner gives you an effective new way to clean circuit boards with better results than standard cleaning methods.
Contact: Simplimatic Automation, 78 Corporate Way, Evington, VA 24550 800-294-2003 Web: http://www.simplimatic.com