Consistent Colors

Question:

How can I get consistent colors in my chromate conversion process? My customer seems to think that the color should be the same each time I do a lot of parts. I disagree with him but I do not want to lose this customer. Any suggestions? R. S.

Answer:

The answer to your question is fairly simple. You have to set up standards and then you have to adhere to these standards. The first step is to meet with your customer and determine the range of color that will be acceptable to him. This can be done by showing him samples of finished parts with different shades of color and having him select those that are acceptable.

The second step is a little bit more difficult but critical. You will have to determine the standards that will give you the required color range. Such factors as pH, chemical composition of the bath, immersion time, bath temperature, rinsing procedure, and drying temperature will be factors. You may also find that the actual zinc plating will have to be controlled as well. Parameters that have to be controlled in the zinc plating step are chemical composition and rinsing procedures.

The last step is to implement procedures that will maintain these conditions. This may be the most difficult part of the process. However, I should point out that in today’s competitive environment this is the only way to operate.