The distance between the cooling channel and the mold cavity can be increased to make the temperature at the cavity surface more uniform.
This also increases the temperature rise at the surface of the cavity during injection. Which has positive consequences for the distortion, the mechanical properties of the parts and, to a limited degree, mold filling.
The smaller the spacing, the more rapidly heat is removed and the shorter the cycle, but the resulting cavity surface temperature variations can lead to part quality problems. As a general design guideline, cooling channels should be placed about 2–2.5 times the channel diameter from the cavity. The following diagrams show the more even mold surface temperature obtained with correctly positioned cooling lines.