 |
|
CASE STUDY: OPTIMA FLUXING SYSTEM |
|
Lead-Free Wave Soldering:
Measuring Through-Hole Penetration with Optima Fluxing System |
|
Lead-free solder alloys do not "spread out" and fill the plated-through holes of circuit boards as well as lead bearing alloys. As the industry moves toward lead-free soldering, applications are more dependent upon good flux chemistry and a robust fluxing system able to deliver flux into all plated-through holes of a circuit board. The Optima Fluxing System is able to deliver 100% flux through-hole penetration, regardless of circuit board width, thickness, plated-through hole diameter or the type of flux chemistry to be used. |
|
USI recently teamed up with a leading EMS provider to study the performance of the Optima Fluxing System, measuring its ability to uniformly apply no-clean, VOC-free flux across the three-dimensional surfaces of large, thick circuit boards. A circuit board test vehicle* was designed, measuring 22" wide, 16" long, 0.165" thick and containing three banks of plated-through holes of 0.060", 0.040" and 0.020" in diameter.
Test Procedure:
Blue pH paper (which turns yellow when it comes in contact with VOC free flux) was sandwiched between the test vehicle* and a cover and sent into the Optima Fluxing System. Synchronized to the speed of the conveyor, the Optima system began a series of spray strokes at the leading edge of the test vehicle and repeated these strokes until the test vehicle passed completely over the spray station |
Test Vehicle - 22" Wide, 16" Long, 0.165" Thick
|
|
The flux application was controlled by three machine parameters:
1. Flux flow rate (rate at which flux flows to the spray head)
2. Traverse speed (speed at which the spray head traverses under the test
vehicle)
3. Spray pattern pitch (how much overlap was allowed between spray strokes)
|
pH Paper on Test Vehicle to
show Through-Hole Penetration |
|
Once the Optima system control parameters were adjusted for optimum performance, sixty observations were taken to prove machine repeatability. The yellow dots on the pH paper illustrate 100% flux through-hole penetration of the more than 15,000 plated-through holes of the test vehicle.
|
|
Conclusion:
Careful study of each square inch of the pH paper shows that the Optima Fluxing System uniformly applied flux into each of the more than 15,000 plated-through holes of the test vehicle. Ultra-Spray Technology, (a maintenance free nozzle less technology) synchronization to the conveyor, and exact speed and position control of the Smart Motion actuator system to traverse the spray head were the key components that allowed the Optima system to run all sixty observations without loss of control over the process. Unlike nozzle fluxing and jetting technology systems that clog during production, USI fluxing systems run 24/7 without process variation. |
* This method for measuring flux deposition is covered by U.S. patent number 6,321,591 B1
assigned to Electronic Controls Design, Inc.
| |
|
