1. Determine exact volume (capacity of wash tank) L x H x W divided by 231in² = Gallon capacity + the additional capacity of the plumbing
   lines and the pump(s).
   
2. Then add X amount of water (as in example below).
3. Then add Y amount of chemistry to the water to desired operating % (as in example below).
   EXAMPLE: If wash tank has a 50 gallon total capacity; the correct procedure to make a 10% wash solution is add (X = 45 gallons) of
   water then add (Y = 5) gallons of chemistry. (Not 50 gallons of water, then adding 5 gallons of chemistry). This would be a 9% . This miscalculation may also over--flow the wash section tank. A true 10% solution is 1 part chemical to 9 parts water.
4. Use a 100ml graduated cylinder: add 10ml chemistry to the cylinder.
5. Add 90ml of water to the 10ml of chemistry.
6. Cover top of cylinder and shake to mix thoroughly.
7. Use a Refractometer to take a sample of this 10% mixture and determine °Brix.
8. Write down °Brix reading.
9. Repeat 1.g twice and average the three readings.
10. Turn on unit to thoroughly mix the 10% wash tank solution (Steps 1.b & 1.c)
11. Take a 100ml sample of this wash tank solution.
12. Use the refractometer to compare the result of Step 1.k to the result(s) of Step 1.i.
13. The reading(s) should match + or - .2 °Brix. The wash tank solution should now be a 10% solution.
    

Note: If Refractometer test samples are in excess of 100°F you may fog lens and prism and get a hazy unclear reading.

During the cleaning process there are a number of factors that contribute to the loss and sometimes an increase* in the concentration of wash
solution chemistry. The higher the cfm that is being generated by the exhaust ducting, the higher the loss of the solution. The exhaust loss can
be reduced by the following:

1. Install an adjustable dampener at the base of the vertical ducting that is attached to the cleaning unit's top/manifold.
2. Install the riser at a 45° angle to the ceiling ducting versus a straight 90° angle.
3. Install 1 or 2 extra sets of (chemically resistant) curtains at the loading entrance of the cleaning unit's conveyor.
4. Install a chiller (condensing coils) in the exhaust ducting.

*Some water based chemical solutions will lose more water than their chemical compounds.

The efficiency of a air-knife(s) or squeegee(s) drag-out control system is the greatest contributor to loss or conservation of the wash solution.
Drag-out is the wash solution that is carried out either on the assembly, it's fixture or the conveyor system itself.  Drag-out is going to be the
same percentage of chemistry that is in the wash solution tank. If the wash tank solution is a 10% mixture the drag-out will be the same
10% solution. The following are reasons for increased drag-out:

• If the product being cleaned has tight spaces underneath attached components, has connector sockets, terminated holes or has arrayed attached components.
• If there is not an air-knife or blow-off system as the product exits the wash solution section.
• If the air-knives or blow-off systems are improperly angled or placed.
• If the wash solution has excessive foaming; the foam might reach the height of the wash tank's exit porthole (opening for the conveyor)
  or top of the tank and may be carried into the following process tanks. The assembly/part itself as well  as the conveyors chain/belt will
  transport the foam downstream.

1. Pre-determine the tank capacity for the wash tank, and wet isolation section.
2. First "dam" the wet isolation section and primary rinse section. To "dam" means that there will be no solution going to drain from the
   wet isolation or water going to drain from the primary rinse. This means there will be no incoming water with the exception of the
   wet isolation section. Most wet isolation sections are fed off an external water source. The normal number of spray bars in a wet
   isolation section are 1 upper and lower bar: each containing Six - 0.25 gpm spray nozzles. The equation for the introduced volume of
   water for five minutes of processing would be 12 nozzles x 0.25 gpm = 3.0 gpm of incoming water x 5 minutes =15.0 gallons. Most wet
   isolation sections are a minimum of 25 gallon holding capacity; therefore, in five minutes there should be no danger of overfill.
3. Fill the wash section with water only and shut off incoming make-up water, pre-mixed solution lines or chemical injection lines.
   (Make sure drain is closed).
4. Make sure the wet isolation is empty and the drain closed.
5. Make sure the primary rinse is only going to recirculate on itself with no water going to drain or water coming in.
6. Make sure the primary rinse is at least 2 gallons lower then the overflow level.
7. Make a water level and volumetric measurement of the primary rinse.
8. Turn off or completely dampen exhaust ducting.
9. Set conveyor speed and spray pressures to standard processing settings.
10. Do not heat any of the tanks, run this test at ambient temperatures.
11. Collect scrap assemblies/parts or panels that are representative of actual production sizes.
12. Collect enough scrap assemblies/parts or panels to be able to take the first scrap piece off the exit and to be able to reload this piece
    (at the entrance) immediately after placing the last scrap piece on to the loading entrance. Keeping continuous product on the conveyor
    will give a more accurate indication of processing drag-out percentage(s).
13. Start the test and run for 5 minutes. (The test should be able to run at least this long unless; the drag-out is extremely high and the wet isolation section is very small).
14. After processing for 5 minutes, turn off the cleaning unit and take measurements of the increase of water that has collected in the wet
    isolation tank and/or the primary rinse. Also take a measurement of the wash tank section, which should show a loss.
15. Use the measurements made in 3.n and compare to 3.a to 3.g) to determine volume loss or gain. You can then extrapolate
    the measurement differences per hour, shift, day etc.
16. Repeat above test, this time with chemistry, temperature, all exhaust ducting in normal operation modes.
17. Compare the readings from the first "ambient" test to the second "heated" test. There can now be a determination made of what
    proportion temperature and cfm contribute to chemistry loss versus the "cold tests" volume loss due to true drag-out.
18. A conductivity meter may be utilized to test the efficiency of your wet isolation by checking the resistivity of deionized water in your
    primary rinse tank. If the losses and/or gains are substantial enough, a refractometer may be used to make these loss or gain
    measurements.
19. If test results between the "ambient" test and the "heated" test are substantially higher, try dampening the exhaust ducting cfm and try
    utilizing the below techniques in 4.

Note: Keep detailed notes on all tests and measurements.

If the desired cleaning can be achieved without high p.s.i. there are several benefits:

Higher p.s.i. and finer nozzle apetures contribute to the spray "atomizing", allowing it to be drawn up the ducting more easily. Lower pressures
with larger aperture nozzles can decrease this type of loss. This methodology is High Volume Low Pressure (HVLP). Larger flooding type nozzles placed at the wash entrance and wash section exit will decrease the high-pressure sideways deflections that may contribute to higher drag-out. Setting
the first upper and lower spray bars (wash tank entrance) nozzles at 4 and 2 o'clock positions (respectively) and the last upper and lower spray
bar(s) (wash tank exit) at the 8 and 10 o'clock position (respectively); accomplishes two purposes: controls the sideways spray deflection,
reducing drag-out and gives two different spray angles for cleaning.

Note: Process conveyor speeds rarely decrease to accommodate more chemical contact time. Therefore, if the chemistry being used provides cleaning by a chemical reaction; it would be beneficial to increase the gpm of the nozzles. Higher gpm may offset higher conveyor speeds in mimimal length wash sessions. The more chemical flow the assembly/part is subjected to; the better the cleaning results.

After completing the above tests, there will now be determined differences in the amount of loss from the"heated" chemistry and cfm versus ambient drag-out from the
cleaning unit, as well as the capacity of all the process tanks. Without this information, the below will be "guesstimates" and will not allow for solid process control parameters.

Each of the following methodologies will be explained as it pertains to process control in the cleaning of flux from electronic assemblies/parts with Enviro Gold #816/18.54A:

pH can be the simplest way to measure the effectiveness of an #816 wash solution. The monoethanolamine (MEA) is an alkaline material.  At a 10% solution in de-ionized water
the solution will give a second digit reading of 11.40 to 11.50 on a pH Meter. Calibration, temperature and differences in the brands of the Meters account for the spreads in readings.

Calibrating your pH meter is very important in obtaining proper starting data points.

The MEA is the only alkaline material in the product. It is the material that causes the saponification of the acid in the flux to take place. As the MEA in the #816 neutralizes more
and more flux acid the pH of the MEA begins to drop. This drop can correlate with reduced cleanliness. The correlation can be done in real time by having an in-house Ionic Tester,
such as an Omegameter, IonoGraph or Zero-Ion unit. As the cleaning becomes diminished,the ionic count in micrograms (of conductive salt equivalency per square inch) will increase.

To maintain a proper cleaning pH, X amount of chemistry must be introduced with or in the make up water/solution. This make-up is needed to keep the wash tank from going into fluid
depravation. However, eventually the tank will need to be drained and totally fresh product will need to be introduced. This is due to the flux and its byproduct acting as a buffering
system that will inhibit the pH of the solution from being raised back up to an optimum process cleaning range.

Note 1): Removing and cleaning filters, checking for spray nozzle blockages and removing pieces of tape or components after draining is highly recommended.

Note 2}: Always let pH test sample cool to ambient before taking reading.

Methodology that volumetrically determines the concentration of a desired substance in a solution. This is accomplished by adding a standard neutralizing solution of known volume and strength until the reaction is completed. This reaction is usually indicated by the change of color of the indicator solution. Hydrochloric Acid can be used as the standard solution for titrating the Enviro Gold #816. Methyl Red should be used as the indicator solution.

Hand held digital titrators do work, but tend to be inconsistant. Accurate titrating is difficult to do on the process floor. A bench mounted burrette is more consistant. The problem is; if there  is a lab on site, it may be busy or far from the production floor which will inhibit getting real time data. Note: Always let test sample cool to ambient before making a titration.

Optical device for measuring the index of refraction of a material. Clean water that is devoid of any contaminant/loading will give a reading of 0 degrees Brix at 20°C. As you add the #816 chemistry to the water the °Brix reading will increase. At a true 10% concentration of the #816 chemistry the °Brix will read 7.4, + or - .2°Brix. As the wash solution loads from the flux the
°Brix will also increase.

With the use of an in-house Ionic tester, the increased density of the wash solution can be linked to diminished cleaning effectiveness. This is very hard to do because there will be a loss of more water from the solution than chemistry from the solution. The chemistry will become more concentrated and it is hard to distinguish the true flux loading percentage from the #816's own concentration increase. That higher proportion of water loss from the wash solution is the X factor. That X factor makes the Refractometer fairly ineffective at monitoring the wash solution in a moderate to high cfm cleaning unit.

The only way a refractometer can be used to gauge the effectiveness of a bath is if the
wash solution is run to an endpoint and never has any make-up solution added to the tank.
The tank would also need to be somewhat enclosed with very low cfm being ducted from it
so the water loss would be at a minimum. The Refractometer cannot give accurate readings when variables are introduced to the process and solution.

Depending on the through-put and what contaminant is being cleaned in the process, wash
tank solution samples can be taken at intervals. These samples should be 4 ounces and
poured into clear glass bottles. As the wash solution changes to a denser brown or
yellowish color it can be a fair indicator of the wash solution's cleaning strength. This
coloration change is also dependant on the amount of water or chemistry that is added.
If this methodolgy is used, an Ionic-tester will be needed to validate that the coloration
change is indicative of a reduced cleaning effectiveness.

If the vast majority of the product being cleaned has the same type flux or contaminant,
a piece or surface area tracking log may work. Since contract manufacturing has such a
high product size mix, total surface area may be more suitable than a assembly/part count
log. You first need to run the chemistry to a known end-point. Example: at X amount of assemblies/parts or at X amount of surface area that has been cleaned, the chemistry is no longer in the safety margin of a pre-determined cleanliness acceptance levels, the chemistry will
be drained and replaced with fresh product. The count or "area washed" measurements will start out again from zero. This can work effectively if the variables are minimal. (See example below in Time:)

Time means keeping track of the number of hours and days the chemistry has had product processed through it. If production numbers are fairly consistant, generic examples could be:

Examples from the above production numbers:

1. If the chemistry was filled and fresh on Monday and the pre-determined time
   endpoint is at 24 hours ,the chemistry would then need to be changed be near the
   end of Thursday's production.
2. If the chemistry was filled and fresh on Monday and the pre-determined assembly/
   part count endpoint is 3,500 the chemistry would then need to be changed near the
   end of Wednesday's production.
3. If the chemistry was filled and fresh on Monday and the pre-determined assembly/
   part surface area endpoint is 350,000 in² , the chemistry would then need to be
   changed near the end of Friday's production.

Note: Always leave a (minimum of 5 percent) to a 10 percent lower endpoint figure. This
will enable the cleaning process to have a built in safety margin for error.