Hi All..I am having a great nightmare in solving flow lines on this product.It is a 4 cavity mold, 4 speakers. I always get the flow line ( Seems to be a cold flow line when cooling) on the cavities of the right side of the mold.
Ant help...You love and appreciate.

Take care
Wellington Correa

Any chance these speaker cones have a metallic colorant? I used to mold some speaker cones that were colored metallic silver. No matter what we did to the process we experienced intermittent dark lines that looked like flowlines in the direction of flow. The color supplier told me that these lines happen because the metal flakes line up sideways and look dark - and that there was nothing that could be done about it. Without seeing the flowlines you are describing, that is the best guess I can give.

Is there any way you can send or post a picture of the part? Try to show as much of it as possible especially the gating layout. If there is a runner get a photo with the runner still attached. Also, a photo of the hot half of the mold may prove helpful.

Photos as stated above would be great. I would also suggest to run a short shot pocess, in that you only change amount of material going into mold by position/shot size. This is first accomplished by dropping packing/hold pressure to 0.
If using a profile on injection than figure out where those changes are in finished part, you may be surprised.
In many of these cases I have found where the parts are acutally windowing, thus creating a gas trap and weld line.

I agree with the comments above, the more information the better. A photo of the part that shows the cold flow line and a mold layout with the runners would help a great deal to diagnose your problem.

My assessment is the same, can't discern much here without seeing the tool layout and a fill series of parts. Vent placement/size/number is also critical.

As above , it is better for analyze with mold flow .
You can try to put thin stick paper (0.08mm thick or so)on the likely airtrip area, just to know if the venting can help ,if ok, adjust the injection parameter also. It depends on sevral:gate postion, venting, part design, mold temperature,etc..