|
|
|
|
|
|
|
|
Oscillating Nozzles for Improved Cleaning
Production Floor |
|
Authored By:Eric Becker Speedline Technologies Camdenton, Missouri USA TranscriptImplementation of lead-free soldering technology has created new interest in high performance cleaning of printed circuit assemblies. Many studies have been commissioned regarding removal of flux residues from tight spaces; the effect of impact force on penetration; capillary action versus surface tension; and optimization of the pressure/flow balance in the wash module. Little attention, however, has been paid to the prewash section of an inline cleaner. The prewash is a key functional process in successful cleaning during which chemical reactions are initiated, PCA temperature is raised, and gross contaminants are flushed from the board. To address certain cleaning challenges, oscillating nozzle technology has been developed. These nozzles move the fluid stream back and forth providing a more effective spray pattern in terms of coverage and impingement. In any inline cleaning application, the prewash is the first module to start the cleaning process. This should be the most important starting point for the application setup. The prewash is defined by the type of process and the facilities feeding the machine. The type of nozzle used in the prewash should be determined by testing and application development. To achieve great cleaning results, the process needs a great start. This paper reviews the impact of oscillating nozzle technology during the cleaning process. SummaryImplementation of lead-free soldering technology has created new interest in high performance cleaning of printed circuit assemblies (PCAs). Many studies have been commissioned regarding removal of flux residues from tight spaces; the effect of impact force on penetration; capillary action versus surface tension; and optimization of the pressure/flow balance in the wash module. Little attention, however, has been paid to the prewash section of an inline cleaner. The prewash is a key functional process in successful cleaning during which chemical reactions are initiated, PCA temperature is raised, and gross contaminants are flushed from the board. Traditionally, fan-type nozzles have been used in the prewash. The small droplets produced by fan nozzles are indeed effective at wetting open surface areas. However, since mass is a critical component of both force (mass x acceleration) and kinetic energy (1/2mass x velocity2), they produce inherently low impact force due to their small size. This limits the ability of fan nozzles to break apart residue and to distribute wash chemistry beneath components on the board surface after initial impact. To address these issues, oscillating nozzle technology has been developed. These nozzles move the fluid stream back and forth providing a more effective spray pattern in terms of both coverage and impingement. The larger droplet size has more mass and increased impact force, enabling the nozzle to achieve better results at lower pressure with reduced water usage. ConclusionsIn any inline cleaning application, the prewash is the first module to start the cleaning process. This should be the most important starting point for the application setup. The prewash is defined by the type of process and the facilities feeding the machine. The type of nozzle used in the prewash should be determined by testing and application development. To achieve great cleaning results, the process needs a great start. Do not overlook the prewash module when setting up and running a cleaning application. Utilizing our new nozzle technology can significantly improve production rates and reduce operating costs. Initially Published in the IPC Proceedings |
|
Comments
|
|
|
|
|
|
|
|
|