Modified General ABS Plastic

Modified ABS plastic has a decomposition temperature of over 270°C; however, due to the influence of time and other process conditions, the resin often starts to change color around 250°C. If producing light-colored, glossy products below 20°C, and if a shutdown of 15 minutes or more is required, the barrel temperature should be first reduced to 120°C.

Modified Flame Retardant ABS Plastic

During startup or shutdown processes, modified flame-retardant grade ABS plastic requires cleaning the barrel (using general grade ABS) before processing to prevent the flame retardant from decomposing. For shutdowns lasting 15 minutes or more, it is necessary to lower the barrel temperature to below 100℃ and empty the barrel of material before shutting down. Subsequently, clean the barrel with general grade ABS before stopping the machine.

All standard and modified fire-resistant ABS plastics require slightly lower barrel temperatures, and special attention must be paid to the stability of the front section barrel temperature and nozzle temperature; otherwise, it will cause poor appearance.

Modified PC Plastic

To enhance the melt activity of modified PC plastic, it should be achieved by raising the injection temperature rather than increasing the injection pressure. At around 300°C, the plastic remains largely unreacted when held in the barrel for an extended period. However, when the temperature exceeds 340°C, PC begins to decompose, resulting in a darker product color and defects such as silver streaks, dark bands, black spots, and bubbles on the surface. Concurrently, the physical and mechanical properties of the product also significantly degrade.

When starting up, if the material stored in the barrel is a resin with a lower molding temperature and poor thermal stability, such as PVC or POM, it is not advisable to use PC to clean the barrel or to increase the barrel temperature. Instead, the barrel should be cleaned at a low temperature using resins with better thermal stability, such as PE or PS. Then, raise the barrel temperature to the PC processing temperature, clean the barrel again with PC recycled material, and remove the other resins before processing with new material.

Requests for shutdowns of 20 minutes or more require the barrel temperature to be reduced below 160℃ to prevent material degradation and discoloration due to extended downtime.

Modified POM Plastic

It is advisable to use lower molding temperatures and shorter molding cycles as much as possible. The molding temperature for modified POM plastic should generally not exceed 200°C, while homopolymer should not exceed 220°C; at these temperatures, material decomposition can occur within minutes. Avoid prolonged stays in the barrel at temperatures above 190°C, as this can also lead to material decomposition. When starting up, first turn on the nozzle heating power supply to preheat the nozzle, and then switch on the barrel heating power supply.

Prior to processing modified POM plastic, if there is material in the barrel at a temperature exceeding the POM processing temperature, the barrel must be cleaned with other resins such as PE. Once the temperature drops below the POM processing temperature, clean the barrel with PE again, then add POM for molding and processing operations.

During the molding process, if a strong pungent formaldehyde odor is detected and the product exhibits yellow-brown streaks, it indicates that the material has overheated and degraded (high moisture content can also cause this, but the streaks are fainter). At this point, the material inside the barrel should be immediately evacuated using the air-injection method, and the barrel should be cleaned with PE. After the temperature has returned to normal (or the material has dried), proceed with the processing.