A weld line on plastic parts can cause structural problems and/or be visually unacceptable.
A weld line is created when two or more flow paths meet during the filling process. Weld lines can be caused by material flowing around holes or part inserts, multiple injection gates, or variable wall thicknesses - where different localized fill rates can cause separate flow fronts. If the different flow fronts have cooled before meeting, they will not interfuse well and can cause a weakness in the molded part. A line, notch and/or color change can appear. This is undesirable in highly visual areas of the part.
It may not be possible to remove weld lines from the part. Changing the injection location, modifying local part thickness, changing the selected material, and/or modifying processing parameters could move the location or minimize visual impact of the weld line.
The weld line element examines the way the molten plastic will fill the metal injection mold and highlights where weld lines will be formed.
To view the weld line contribution to the indicator value, click . The Alerts icon on the same panel will define any weld line alerts.
Weld line alerts
panel will display a sub-menu. The sub-menu items are outlined below: - Weld Lines
- Click this option to view weld lines on the part.
- Show non-uniform thickness regions
- Displays areas of non-uniform thickness on the part.
- Molten plastic will preferentially flow through thick sections of the part. Variations in part thickness can cause different flow front speeds and potentially subsequent weld lines when these flow fronts rejoin.
- Injection location toolbar
- This toolbar enables the addition, relocation or removal of injection locations. Injection locations are the positions where molten plastic enters the metal injection mold. Injection locations have a major impact on the subsequent location of weld lines.
- Animation toolbar
- This enables the user to view the filling animation. Understanding how the part is filled can assist in understanding how to adjust or where to add injection locations.
Weld line visualization
Any weld lines that appear on the part can viewed. Click on . Click on the Weld Lines option in the Information pop-up tab.
Weld lines appear on the part as red areas where the flow fronts meet.