How to improve weld lines?

weld line

Table of Contents

Preventing this is all about high-level design. I will discuss some molding defects that may occur in the injection molding process and how to repair and avoid them. Design defects we will discuss weld lines.

Explanation: in fact, the weld line is more like a plane than a line that meets each other as the molten plastic flows from two different parts of the mold.

weld line

Cause: When the molten plastic is partially solidified, it is caused by the insufficient combination of two or more flow fronts.

Remedial measures:

1. You can raise the temperature of the mold or molten plastic.

2. You can increase the injection speed.

3. The design of the flow pattern can be adjusted to a single source stream.

4. Change to plastic with less viscosity or with lower melting temperature.

Hey! I’m Jerry — a hands-on mold & CNC guy who’s spent years turning ideas into real, tangible products. From tight-tolerance molds to complex machining projects, I’ve seen (and solved) a bit of everything.

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We will contact you within 1 working day, please pay attention to the email with the suffix “@cavitymold.com”. 

or email direct:jerry@cavitymold.com