Basic knowledge and design principles of Unscrewing Moulds

Unscrewing injection moulds are an important part of mould design and are used to manufacture unscrewing parts. Let us learn about the basic knowledge and design principles of injection mold unscrewing.

Threaded products are usually divided into Inside Unscrewing Moulds and Outside Unscrewing Molds:

Inside Unscrewing Mould: usually used for products with low precision requirements, using Huff molding.

Inside Unscrewing Precision Mould

Outside Unscrewing Mold: outside unscrewing is divided into two types: non-rotating demoulding and rotating demoulding.

Outside Unscrewing Injection Mould

Non-rotational demoulding

Forced demoulding: Suitable for products with simple mold structure and low precision requirements. Dethreading through the elasticity of the plastic, usually used for tough plastics (e.g. polyethylene, polypropylene).
Manual demoulding: Demolding the threaded core together with the product requires multiple threaded cores, which is labor intensive and has low production efficiency.

Demolding of spliced unscrewing cores: suitable for products with intermittent internal threads, but it is prone to edge separation and the thread accuracy is not high.

Rotary demoulding: After the threaded product is formed, it undergoes relative rotational movement with the threaded core in the mold to achieve demolding.

The shape or end face needs to have anti-rotation patterns or patterns, otherwise it will be difficult to demould.