Processing Machinery
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ABS brittle cracking——unreasonable temperature parameters
Fenómeno do problema
The product is generally brittle, and it is significantly improved or worsened after adjusting the barrel temperature, strongly related to the temperature setting.
Análise das causas
If the barrel/nozzle temperature is too low, ABS is under-plasticized, the fluidity is poor, the filling internal stress is large, and the product is brittle; if the temperature is too high (especially when the regrind ratio is high), degradation is accelerated, also brittle——both too low and too high temperature cause brittle cracking.
Solução
①Control the barrel temperature at 200~240℃ and the nozzle at 210~250℃ according to the ABS grade (general grade/heat-resistant grade); ②when the material is easy to degrade (much regrind), appropriately lower the rear section temperature of the barrel and shorten the residence time; ③use the melt state to judge whether the plasticizing is in place; ④avoid adjusting the machine based on a single temperature point.
Conclusão principal
ABS temperature is a 'double-edged sword': too low causes under-plasticization brittleness, too high causes degradation brittleness; set the range according to the grade, adjust the rear section according to the regrind, and judge by the melt state rather than the displayed temperature, only then can the true process window be found.
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