Hi Folks, just wondering if anyone else agrees that Rheometric pumps do not work and are more trouble than they're worth. They do not circulate the solder paste properly. The only solder paste that is processed on a FIFO basis is the material directly under the supply points which means "dead spots" in the middle and the edges. Doesn't matter which solder paste you use, if you leave it in that environment for days without being used, then it's going to deteriorate.
On top of that, the number of parameters you need to control mean the process window is very small. With squeegees, assuming a sound mechanical setup, you just need to worry about force and speed. Rheopump has speed, force, pressure, PID and they all have a big impact on each other.
My opinon is based on 4yrs of hardship trying to get a stable process with this technology. We're now cleaning out the pumps every week which completely eliminates the argument that Rheopumps reduce waste drastically.
All opinion/suggestions welcome.