Inline Washers

James,

Have you considered going to a No-clean process? BGA's can be difficult to impossible to clean using an aqueous process. The water just won't penetrate under the entire BGA and efficiantly remove your flux residues. The tighter the pitch, and smaller the balls, the less ability the water has of penetrating past the the first few rows. The way I understand it is the surface tension and water droplet size cannot penetrate into the very confined spaces under your uBGA. There are a number of very good no-clean solder pastes. Most of these pastes can drop into your process a lot easier than specifying, and purchasing a new inline washer, with it's associated water treatment and DI systems.

Alan

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We use an Aqueous Technologies Millennium III closed loop system. The footprint is no more than 12-13 feet. We wash water soluble solder paste residue with excellent results however, due to the nature of our solid solder deposit process, we are washing bare boards, no components in the way. Obviously this is easier than washing boards with components mounted. We do not use any additives in our system other than the occasional de-foamer.

The filters produce DI water and when the water in the machine gets dirty we just pump it into an evaporator out back and re-fill it. Simple set up.

Good luck,

mk

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Cookson Electronics Equipment- Electrovert AquaStorm 200 highly recommended options: Checkmate Conveyor Hurricane Jets in Wash and Rinse 4 Additional Top Spray Bars in Wash *Closed Loop Filtration System for Wash *Positive Displacement Chemical Metering System ChemicalIsolation Level 3 Aqua-Loop closed loop filtration system for Rinse TorridZone Dryer if you desire a "test ready" product out of the cleaner, otherwise go for SCAT option in Dryer 1 & CAT option for Dryer 2.

*- if cleaning no-clean

This configuration cleans no-clean flux residue from under devices with 3mil gap at a conveyor speed of 1.5 ft./min.

for info, go to http://www.cooksonee.com

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Definitly evaluate the TD washer smt 324 / 318. I have two units and they have been fantastic from a maintenance point of view.

Small, quiet and easy to maintain.

I am in the middle of cleaning capability and ionic contamination testing as we speak. So, I can not comment on its cleaning capability.

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James,

I am not a cleaning technician. My company buys and sells mostly used capital equipment. I can tell you from a service point of view, Technical Devices is the most highly recommended of the companies you are considering. They are always available to me for setting up their used machines and giving support to our customers who are always pleased with their cleaning results.

Check out their cleaner at: http://www.technicaldev.com/cleaners.html

Check out their customer service at: http://www.technicaldev.com/customerfeedback.html

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I would like to thank everyone for their input, it has been very helpful.

James

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James,

I've done some extensive studies cleaning BGA's while I was employeed by one the companies you are considering. In an attempt to avoid being commercial I will use general statments to address your question(s).

The key to cleaning underneath BGA's is efficient penetration and then effective water displacement. A combination of spray nozzle configuration, pressure, flow, water quality, temperature and dwell time will generate excellent cleanliness results.

The pre-wash and initial wash section should include a high flow, atomizing spray configuration. The smaller water droplets and high flow rates will cause the water droplets to penetrated into the center of the BGA ball pattern. High pressure, high impingement force nozzle (jet) should be applied to displace the water from within the center of the BGA. The water from the pre-wash will solubilize the flux and the high velocity jet will displace the flux entrapped water.

Note: The speed of the belt will control the dwell time in the wash section. Obviously the slower the belt the more time the wash section will have to remove the flux residue.

Water quality, temperature, and pressure are contribute the efficiency of the cleaning process. Older cleaning systems were not designed to clean underneath SMT components and therefore do a terrible job.

I would recommend a system with a 10 HP pump in the wash section with appropriately designed spray nozzles. Keep in mind pump horse power ratings do not translate into effective cleaning results. The key to effective BGA penetration is not big pumps, but an efficient methods of delivering kinetic energy to the center of the BGA.

Good luck!

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