For broader context, compare this topic with ontwerp van spuitgietmatrijzen<\/a>en supplier sourcing guide<\/a>.<\/p>\n Flow marks are visible surface imperfections on injection molded parts that appear as wavy lines, ripple patterns, or bands of slightly different color or gloss. They form when the advancing melt front cools unevenly against the mold wall, creating a wrinkled or folded skin that gets frozen into the final part surface. In our factory, flow marks rank among the top three cosmetic defects that cause part rejections\u2014particularly for consumer-facing products where surface appearance is critical.<\/p>\n While flow marks rarely affect part structural integrity, they make products look unfinished and unprofessional. For automotive interior panels, consumer electronics housings, and medical device enclosures, even minor flow marks can trigger quality rejections that delay production timelines and increase costs. Understanding the root cause\u2014the interaction between melt front velocity, temperature, and mold surface\u2014is the first step toward eliminating this defect. The good news: in most cases, flow marks can be resolved entirely through process parameter adjustments without any mold modifications.<\/p>\n Melt temperature is the single most influential process parameter for flow marks. When the melt temperature is too low, the plastic skin solidifies prematurely against the mold wall, creating drag and wrinkle patterns as the still-flowing core pushes the solidified skin forward. We\u2019ve found that a 10\u201320\u00b0C increase in melt temperature eliminates flow marks in roughly 50% of cases without any other changes.<\/p>\n We always increase temperature in 5\u00b0C increments and evaluate 10 shots at each level. Going too high risks material degradation, yellowing, or increased zinkvlekken<\/a> due to lower melt viscosity during packing.<\/p>\n\n
![\"Defecten](\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/02\/800x457_insert_6.jpg\")
How Does Melt Temperature Affect Flow Mark Formation?<\/h2>\n
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\n \nMateriaal<\/th>\n Standard Melt Temp (\u00b0C)<\/th>\n Recommended Temp to Reduce Flow Marks (\u00b0C)<\/th>\n Maximum Safe Temp (\u00b0C)<\/th>\n<\/tr>\n<\/thead>\n \n ABS<\/td>\n 220\u2013240<\/td>\n 240\u2013260<\/td>\n 270<\/td>\n<\/tr>\n \n PC<\/td>\n 280\u2013300<\/td>\n 300\u2013320<\/td>\n 330<\/td>\n<\/tr>\n \n PP<\/td>\n 200\u2013230<\/td>\n 230\u2013250<\/td>\n 270<\/td>\n<\/tr>\n \n PMMA<\/td>\n 220\u2013240<\/td>\n 240\u2013260<\/td>\n 270<\/td>\n<\/tr>\n \n PA6<\/td>\n 240\u2013260<\/td>\n 260\u2013280<\/td>\n 290<\/td>\n<\/tr>\n \n POM<\/td>\n 190\u2013210<\/td>\n 200\u2013215<\/td>\n 220<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n