Guest Editorial -For Plateworld.com

 Don Baudrand, Don Baudrand Consulting,   e-mail:donwb@tscnet.com


 

Cost savings and conservation in plating processes

Conserving chemicals

Everyone wants to save money. How many of the items listed below do you practice?

Careful selection of the suggested ideas should be done. They may not apply to your situation. Hopefully there is at least one idea you can use to your advantage to reduce water use, reduce waist treatment costs, improve quality and save money.

  1. Allow drain time over the plating tank when lifting the rack or barrel of parts. 5 to10 seconds before rinsing can save valuable Plating solution. Longer times are even more helpful. But be careful that the plated parts do not dry.
  2. In conjunction with no.1 above, a drain pan at the exit area of the tank is an additional plus. Be sure it slopes back into the plating tank.
  3. In addition to dwell time and drain pan, a fog rinse provides even more conservation and prevents drying. The fog spray can lengthen the dwell dime over the tank and add make up water in a small amount. It acts as the first rinse resulting in conservation of water in the following rinse stations. Fog spray is a good idea even if drying is not a problem.
  4. Counter flow rinse tanks are another great way to conserve water and do a better job of rinsing. A two tank system will save up to 50% of the water compared to a single tank, and a three counter flow rinse system can save up to, or in excess of 90% of the water use compared to one rinse station.
  5. Spray rinses are a very good way to rinse and conserve water. Most racked items for plating can be effectively rinsed by spray. Some parts may require an immersion rinse in addition to a spray to help remove chemicals entrapped in holes or capillaries. Or areas that a spray cannot hit well enough. Counter flow spray rinsing is possible with the right plumbing system.
  6. Drag out tanks using little or no make up water added has been used effectively for conservation of plating and processing solutions. But be aware that dilute solutions may change pH and precipitate particulate matter or react in dilute conditions such that when added back to the plating solution may be harmful. Be sure to check this idea. Once you use a drag-out tank, it is suggested that the rack or barrel of parts be submerged in this tank prior to entering the plating or processing solution so that there is a drag in of the plating or processing materials.
  7. Agitation of rinse tanks can be helpful. Air agitation is often used. Be sure that the air source is a low-pressure oil-less blower and not from an air compressor. Most air compressors have vaporized oil in the air stream. Vaporized oil will go through oil filters into your tank. Note: Turn of the air before the rack or barrel enters the tank to take advantage of the surface flow rinsing to the over flow compartment. The surface flow to the weir can rinse most of the plating or processing solution if the rack or barrel is lowered very slowly into the rinse tank
  8. The negatives of installing counter flow rinse tanks are the cost of additional tanks; floor space and possibly longer time flow through the process.
  9. Devices that control water are available such as conductivity controllers that work by measuring the conductance of the water. They are set to turn on the water flow when a specific conductance is registered due to the presence of conductive materials such as the plating or processing solutions. The water is turned off when the conductance is again lowered to the set point.
  10. Timer controls can be effective by turning the water flow off when the tank is not in use.
  11. Flow restriction devices that limit the water flow into the tank. This good for constant production. The level of allowed rinse tank contamination must be determined first then the flow restrictive device is set to maintain a constant flow.
  12. It is possible in some instances to operate the processing or plating solution at a lower concentration thus lowering the drag out amount.
  13. Continuous filtration of processing and plating solutions is a good idea. Filtering provides agitation and sparkers with or without eductors. Eductors increase the flow velocity
  14. Multi purpose rinse tanks are used to conserve space. But are potential causes of problems when reactions take place or when unwanted other processing or plating solution are contaminated by the combination rinse that still have chemicals in it.
  15. For barrel plating it is necessary to maintain the holes by drilling back to the proper size. Parts and media can peen the inside portion of the holes closing them from slightly to completely closed. The cost savings in less drag out far offsets the cost of maintenance.
  16. Good rack maintenance is important in protecting plating solutions for drag in of processing solution entrapped in crack rack coating, split rack tip coverings. These defects in rack coatings contribute to drag out losses and higher waste treatment costs. It is very difficult to rinse small cracks and capillaries.

I wish you all good plating and good profits.

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