Processing Machinery
6 visualizações
Weld line cracking of PP thin-wall parts
Fenómeno do problema
Stress concentrates at the weld line of thin-wall parts, and they crack along the weld line after being subjected to external force.
Análise das causas
The molecular chains are not fully fused where multiple melt fronts converge; thin-wall parts have fast filling speed and more obvious front cooling, so the weld line strength problem is amplified.; during on-site investigation, verify item by item according to this mechanism to avoid blindly adjusting the machine based only on experience
Solução
①Reduce the number of gates or change the gate position to relocate the weld line; ②increase the melt and mold temperatures; ③increase the injection speed in the convergence area; ④set vents and overflow wells at the confluence.
Conclusão principal
Thin-wall part weld lines should be kept away from stress-bearing areas by design means; process temperature and speed increases can only partially improve strength.; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence
Isto foi útil?
0 pessoas acharam isto útil
Obrigado pelo seu comentário!