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Factors to affect Plastic TE(Tamper Evident) Cap dimension analysis?In injection moulding and continuous compression moulding
- Dec 12, 2018 -

  Factors to affect Plastic TE(Tamper Evident) Cap dimension analysis?In injection moulding and continuous compression moulding


In brief:Hereby introduce the two technologies of Plastic TE(Tamper Evident) Cap used in water and beverage. It can be taken as the referable instruction of cap dimension adjustment in actual production, as well as plastic cap mould design. 

In bottle water and beverage field, there are two main technologies to make plastic TE caps: compression moulding and injection moulding, with their merits and weakness. Traditional bottle cap injection moulding technology applies to various shapes of bottle caps,while compression moulding is good at energy consumption, and flexible mold maintenance. However, for either injection or compression,to realize good sealing, open and other performance, accuracy in dimension is significant.

1. Plastic cap injection moulding

1.1 Bottle cap injection moulding technology

Through some experiment and analysis, experts figure out that, with the increase of bottle cap weight, volume is getting bigger, thus larger in dimension. In the procedure above,bottle cap density remains the same.

1.2 Cooling Time:

Whether from intuitive analysis or the experiment data,with cap’s cooling time in the mould, cap temperature decreases obviously and linearly. Nevertheless,cap’s cooling after demoulding, also exists the same phenomenon, only need more time with the same temperature decline. It means within the same time,cooling efficiency in mould is better than the cooling after demoulding.

1.3 Resin Temperature

With the resin temperature rises, in the same cooling time, the final caps we get is in higher temperature. After demolding and nature cooling, according to Expansion and Contraction principle, cap’s dimension is getting smaller. Resin temperature related Injection parameters are extruder and mould temperature.

2. Continuous compression moulding technology process

Compression moulding process is by melting resin in extrusion,and cutting melted material as quantity pellets by scraper after material going extrusion head. Then drop the pellets into the mould cavity, through moulding,cooling and demoulding in a cycle. The procedure of bottle cap compression moulding machine mainly includes extrusion, material cutting, material drop,moulding, cooling and demoulding.

2.1 Cooling Time

In continuous compression moulding, cooling time is adjusted by compression moulding machine's rotate speed,(that's capacity). The lower capacity, the longer cooling time, and we get the bottle caps in lower temperature. After expansion and contraction,cap  is bigger in dimension.

2.2 Resin Temperature

With the raise of resin temperature, within the same cooling time, the higher temperature we get, after expansion and contraction, the cap is in smaller dimension.

2.3 Mould Temperature

The higher mold set temperature, within the same cooling time, the worse bottle caps cooling in the mould. The higher temperature we get, after expansion and contraction, the cap is in smaller dimension.


2.4 Bottle cap weight

After experts’ considerable experience, it shows, with the increase of cap weight, the final cap’s temperature also ascends,which makes smaller cap dimension. In theoretical analysis, bottle cap weight raise would get bigger caps.

Therefore, the weight affection of cap weight, depends on how much weight rises, and the level of temperature change, since this two factors would offset with each other.


3.Other factors

Besides the above technology and machine parameter, other factors also make influence to bottle cap dimension, such as masterbatch, additive(like necleating agent), material character, mould performance( thermal conductivity),etc.

In actual production, masterbatch also have a big effect to cap’s dimension. Compared with non-color caps, in the same production technology, for example, orange cap is smaller, while golden and green cap is bigger in dimension. However, the function of necleating agent is to speed up crystallization, rises density, then getting smaller volume and smaller dimension.


In conclusion:

Plastic Temper Evident cap is widely used around the world,well,technology R&D of a bottle cap moulding machine manufacturer is significant. At present, in China, domestic high-precision, high-efficiency, and long-lifetime cap moulding machine and moulds mainly depend on imported machinery.


Jeepine dedicates in bottle Cap Compression Moulding Machine (CCM) and Compression Cap Mould, gathering a innovative R&D team led by academicians.

At present, with the aggressive R&D, Jeepine have become the leading enterprise of Chinese premium and high-efficiency Cap compression Molding Machine. Pursue high quality and remain the competitive technology are in bottle cap compression moulding machine are our invariable mission.