Hi guys, I'm having an issue with colorant (I think) and was hoping someone could point me in the right direction. I've been working with pre-colored ABS resin but the body of the formed components reveals white streaks. I pre-heated and dried the ABS resin at 194 degrees F for 4 hours.
Crystallization Sounds like crystallization in the ABS from cold work. I assume the part is vacuum formed. The ABS will crystallize when cold worked and this may result from the preheat before vacuum forming. Higher temp preheat will reduce the crystallization, but may result in improper forming or integrity of the part. Heating the part after forming may eliminate the white, but also may likely slump the part. And acetone fusing after the forming may also remove the white streaks, but may result in unacceptable part appearance. I often use an acetone dip followed by drying in dehumidified air, but crispness of detail can suffer and over-acetoning can also lead to part geometry slump. The only other time I have seen white streaks is if I perform an acetone fusing after forming and get moisture condensation and resulting moisture hazing.
Hmm, this does sound like a sticky situation. I'm going to give the acetone dip a shot followed by dehumidified drying and hope for the best. Thanks, JPFalt!
While looking for more information, I came across a pretty thorough PDF on color consistency for injection molding in case anyone else hits the same problem I have.
