You’ve designed your part, created the tooling, and are ready to begin the plastic injection molding process. But then, there is a change of plans. Rather than using ABS plastic, you will now be making the parts out of nylon. No problem. Just have some nylon shipped to the manufacturer and you’re good to go, right?
What’s known in the plastic injection molding business as “gate blush” or simply “blush” is a cloudy or hazy discoloration of the plastic on a finished part. It is most often found near gate locations, where material enters the part. Not only is the defect in color and gloss visually unappealing, the plastic in that area can be weaker than in the rest of the part. Needless to say, it’s an issue that needs to be corrected as soon as it is discovered.
In plastic injection molding, the “gate” is the opening in a mold through which the molten plastic is forced into the cavity, the tooling representation of your part. The type of gate (which I’ve blogged about previously) and its location are critical. In fact, it’s no exaggeration to say that gate location can make or break a part. The type and placement of the gate can affect many aspects of a project including:
In plastic injection molding, one of the most important aspects of the mold design is how and where it is gated. The “gate” is the opening in a mold through which the molten plastic is injected into the final part. It is the boundary between part and scrap. The location, size, and shape of the gate can have a significant effect on everything from the structural integrity to the visual appearance of a finished piece.