Thin to thicker walled parts and components that are predominantly hollow and have a uniform, symmetrical shape is typically produced through the process of blow molding.
Companies offering custom blow molding are able to complete production of plastic bottles, containers, and parts in all shapes and sizes to meet the needs of Original Equipment Manufacturers. However, it is essential to consider the process, the desired end result and the engineering specifics of the design to customize the process and provide a durable, long-lasting final product.
There are different options in custom blow molding that can be considered to create the hollow interior cavity. The choice of the process will be determined by the specifics of the design as well as the end use requirements.
One of the most common blow molding processes used in the medical device manufacturing process is injection blow molding. In this application, the liquid polymer is injected into a cavity that contains a core element.
When this is cool the exterior mold is removed and, through the core pin that is still inserted, air is forced into the cavity, pushing out from the inside. When the interior is cooled the pin is removed, and the device is perfectly shaped on both the interior and the exterior.
In this process, the melted plastic is pressed into a hollow tube that is inserted into a mold. Air is blown into the center of the interior tube with the liquid plastic, this takes just fractions of a second, which then coats the interior of the mold uniformly while leaving the center hollow.
For more complex shapes where there are different internal hollows, an injection stretch option in custom blow molding may be required. While this is often a two-stage process is can create more complex shapes while remaining fast and very cost effective.