Troubleshooting: polymer degradation

When using wrong parameters when processing a material on the Filament Maker it will result in the degradation of the polymer.

Polymer degradation is the change in the properties of a polymer under the influence of environmental factors such as heat, oxygen, light, or chemicals. When a polymer degrades, the “chains are broken open,” resulting in the properties of the polymer changing. Two of the properties that can change are the melting temperature or that the material won’t melt. A material not melting can cause the flow to get obstructed or clogged. These parts that get clogged can often only be removed by extruding a special purging material or by removing the entire screw in the worst-case scenario.

1. Polymer thermal degradation

Heat is one of the factors that can result in a material degrading. The first way heat can cause polymer degradation is when a polymer gets heated above its degradation temperature. You can recognize this when the output changes color; you can see this change in the figure 1.

Figure 1: Degraded polymer compared to the non degraded polymer

Besides color, the material also releases gases, which you should not breathe in. The heater’s temperature should be decreased to prevent material degradation from occurring during the extrusion process. You can also increase the screw speed; this way, the polymer has less time in the barrel, resulting in a lower temperature.

2. Material degredation

Another possible cause of material degradation is contamination. For example, suppose the polymer you’d like to extrude with has another polymer contaminating it. In that case, the difference in degradation temperature can mean that your polymer will start degrading as soon as you begin processing it. We recommended that you check to ensure your polymer isn’t contaminated and the filament maker purged well.

3. Chart with causes and actions

Figure 2 shows a summary of the possible causes and the corrective actions that should be taken when a polymer is degrading.

Figure 2: Summary of potential causes and corrective actions that for abnormal smoke production.