November 2023
Dr. Ing. Simon Wurzbacher & Dr. Ing. Julian Schild
Targeted Control of the Pin Opening Speed:
"Bright Prospects"
Surface blemishes in the form of differences in gloss level are typical defects on flat, sequentially filled parts.
With Synflow technology, parts quality can be ensured easily and in a reproducible manner.
There are many causes for surface defects on injection-molded flat parts. In addition to the influence of the tool – particularly the cavity surface or the temperature control, it is often the selected injection molding parameters that can lead to surface defects. The severity of such defects depends considerably on the properties of the plastic, i.e., due to additives or basic polymer or their mixing ratio in the case of blends.
Hesitation lines are visible defect lines that can often appear as gloss changes or blush on the part surface. These hesitation lines that appear in the form of a gloss level difference on the part surface crosswise to the flow direction are caused by local pressure fluctuations during sequential filling through valve gate nozzles.