Analysis of Plastic Bottle Cap Thread

Update:29 Sep 2021

One, rotating deep thread
1. During the injection molding process, there is a rotating equipment system in the mold. This action can effectively maintain the integrity of the cap screw. Therefore, the thread shape of the bottle cap can be effectively manipulated, and the bottle cap wall will not be skewed when the thread of the upper bottle shin is rotated.
2. In the process of capping the bottle cap, the plastic bottle cap can be converted into a straight force when rotating the upper bottle shin thread to tighten the bottle cushion against the bottle shin.
3. Because the screw thread of the rotating tooth cannot effectively restrain the cap gasket from falling off, the screw cap should be glued and posted when the gasket is added.
4. Rotating deep thread has the following defects:

A. This type of thread needs to add multiple pads, which is not ideal.
B. The screw cap restricts the planning of the bottle cap (for example, a bottle cap with a blocked screw thread cannot be rotated in the mold). Of course, the screw cap mold is more messy in planning, and the cost is more expensive in production.
C. There is no restriction on the selection of raw materials when making deep-threaded bottle caps.
TWO, ​​strong off-shallow thread
1. During the injection molding process, the bottle cap can be easily demolded from the mold without the need for mold rotation. Obviously, when planning the screw thread of the bottle cap, the thread must be shallow in order to allow the "strong release" during the injection molding process, and there must be a moderate thread enough to cover the screw thread on the bottle shin perfectly.
2. The strong threaded cap can be posted without adding glue when adding the liner, and the liner can be effectively restrained by the thread so that the cap gasket illustration is not easy to fall off.
3. When you want to add multiple layers of liners to the cap or make a variety of possible plans for the cap (such as the type of bottle cap with blocked thread), forced threading is the first choice.
4. Forced release screw caps restrict raw materials during the injection molding process, during which polyethylene and polypropylene materials are popular choices.