Weld or knit Lines

Weld or knit Lines

Visible lines formed on the surface of the moulding, usually located between gate points or downstream of apertures or other obstacles.

Weld lines are formed when separate melt fronts travelling in different directions meet and can be visible and or reduce the part strength.

Solution:

         1. Increase the injection speed.

         2. Increase the hold pressure.

         3. Increase the melt temperature.

         4. Optimise hold pressure switch over point.

         5. Ensure adequate venting in the region of the weld line.

         6. Increase the mould temperature.

         7. Investigate moving the gate point.

         8. Change master-batch check compatibility.