How much will strength (tensile) decrease at a knit line in unfilled, mineral reinforced and glass?
In general, the knit line strength will be equal (or close) to the base (neat) resin. Thus, glass-filled nylon will have a similar knit line strength as an unfilled nylon. The actual weld quality will vary with flow length, flow front speed, tool temperature which affects the temperature of the melt, etc.. Nylon has very good weld line strength and will generally retain most of its strength (closer to level of an unreinforced material for glass-reinforced grades). Polyesters retain a lower level of strength in the weld line area.
