Splay marks, silver streaks, and flow marks are common surface defects primarily caused by unstable melt temperature and inconsistent viscosity, both directly regulated by thermocouples. Leading hot runner brands including Husky, Mold-Masters, Yudo, and Incoe emphasize that precise temperature control eliminates the root cause of these defects. Fluctuating heating leads to uneven flow, trapped gas, and inconsistent melt behavior, resulting in visible surface imperfections that ruin part appearance.
Advanced thermocouple technologies for surface quality include ultra-fast response, minimal overshoot, low signal drift, and near-gate sensing positioning. These ensure melt remains at a consistent, optimal temperature for smooth flow. Premium sensors maintain stable viscosity to prevent turbulent filling and moisture expansion that causes splay.
Surface defect reduction is critical for consumer goods, automotive interiors, medical devices, electronics, and transparent parts where appearance directly determines product value.
Common causes of splay include thermocouple lag, temperature overshoot, drift, and poor thermal contact. Using high-performance hot runner thermocouples significantly reduces surface defects and lowers scrap rates.
