The phenomenon of color streaking is characterized by localized changes in the color of a molded component or by streaking.
| Appearance |
 |
 |
| Characteristics |
Variation from the original color |
A streaking pattern in a molded product |
| Cause |
This type of problem is principally caused by poor thermal stability of the coloring agent. Furthermore, it occurs more easily in locations such as welds, ribs, and the like which are likely to induce shear flow. |
- Poor distribution of coloring agent.
- leaning effect of plastic deposited within the molding machine (or cylinder).
|
| Countermeasures |
- Switch to a coloring agent with good thermal stability.
- In terms of molding conditions, it is desirable for the plastic and die temperature to be high, and for the speed of flow to be low (i.e., hot-slow molding).
|
- Improve the quality of distribution during compounding.
- Fully clean the inside of the cylinders.(We recommend our own UMG Clean™ for this purpose.)
- Check the screw head, back-flow prevention rings, and other similar items for defects.
- Change the molding machine.
|
| Appearance |
|
| Characteristics |
Variation from the original color |
| Cause |
This type of problem is principally caused by poor thermal stability of the coloring agent. Furthermore, it occurs more easily in locations such as welds, ribs, and the like which are likely to induce shear flow. |
| Countermeasures |
- Switch to a coloring agent with good thermal stability.
- In terms of molding conditions, it is desirable for the plastic and die temperature to be high, and for the speed of flow to be low (i.e., hot-slow molding).
|
| Appearance |
|
| Characteristics |
A streaking pattern in a molded product |
| Cause |
- Poor distribution of coloring agent.
- leaning effect of plastic deposited within the molding machine (or cylinder).
|
| Countermeasures |
- Improve the quality of distribution during compounding.
- Fully clean the inside of the cylinders.(We recommend our own UMG Clean™ for this purpose.)
- Check the screw head, back-flow prevention rings, and other similar items for defects.
- Change the molding machine.
|
