Producing Hollow Parts…

A molder in China just sent this unique question about producing hollow parts…

We are a molder in China and our customer asked us to prototype a decorative hollow part for a consumer application. What is the best method to do this?
My Response
In the prototype phase, the quickest, and least expensive way to do this is using either rotational molding or blow molding.
Rotational Molding: The material clamped within a mold, it is rotated about multiple axis while it is heated to melt the material and cover the circumference of the interior. The mold is then cooled and the part is eventually removed. This process is very slow, but is great for very low production prototypes.
Extrusion Blow Molding: This process uses an extruded, tube shaped, parison which is clamped within the mold and blown to size using pressurized air. The mold is more expensive than a rotational mold, but you are able to manufacture many more parts than with rotational molding.
You can learn more about Extrusion Blow Mlding with our blow molding series of training:
Additional Thoughts
You can also produce the part using injection molding along with an assembly process such as ultrasonic welding… but this seems far too expensive for a prototype of a basic decorative consumer part.

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