jack

Topic: drag in and solution levels.

Not sure if this is the right section to post this question, so please feel free to move it to the right section.

Is there a way to reduce drag in ?

The problem is this, after 2-3 days our tank levels rise and we need to lower it back down.

At the present time we pump the solution's in drums and have them taken away by an environmental company so we don't overload our waste water system.

A few solutions that we came up with and wanted your input;

1- Have the barrel hang time raised over rinse tanks to reduce drag-in

2-Have the barrel hang time reduced over plating and preparation tanks reduced to maintain levels with drag out.

Are these viable options ? 




jimtrottier

Re: drag in and solution levels.

Jack,  Not knowing what your process is or your system it is hard to determine an answer to your question.  I have deduced that it is a barrel line, do you have reverse flow rinse tanks?  Your idea of extended time over the tank you are coming out of is a good idea as long as it is not an extreamly hot tank that could cause a dry on situation on the parts.  Another option is an up barrel rotation that can cut time to the next tank to just a few seconds. 

   I don't know what your waste treatment situation is but you should also see if there is a way you could handle the excess in house, it would also be cheaper in the long run than to have a handler to take it off premisis.

    Jim

DustinGebhardt

Re: drag in and solution levels.

Solution growth due to drag-in can also be reduced by adjusting the relative surface tensions of the 2 baths.  If you are dragging solution from Bath A to Bath B and Bath B is growing in volume, you can add a surfactant Bath A which can help it shed solution quicker.  You can also reduce the surface tension of Bath B to help increase the carry-out from that bath.  Just try to keep the surface tension of Bath A lower than that of Bath B and you should rarely have a solution growth problem.


And as Jim has already said, adding or increasing up barrel rotation will help reduce the carry-over of solution. 

-Dustin Gebhardt,
CEF
Plating Engineer
Danaher Tool Group
Gastonia, NC

jack

Re: drag in and solution levels.

Sorry for the lack of information guys.


Yes it is a barrel line and the tanks that have a solution growth are the tin tank and the cyanide copper tank.

Before entering the copper solution the barrel does a double reverse rinse.

Before entering the tin the barrel does a double reverse rinse and a neutralization.

So basically;


1- keep the surface tension lower by adding surfactants (are there any risk of contamination with surfactants ?)

2-Rotation

DustinGebhardt

Re: drag in and solution levels.

When choosing a surfactant, be sure to check with your chemical vendor for a compatible type.  Many times, whatever surfactant you are using in the plating bath is the same kind you can use in the rinse tanks prior to the bath.

-Dustin Gebhardt,
CEF
Plating Engineer
Danaher Tool Group
Gastonia, NC