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  • Writer's pictureJPT Cores

Explainer: Postal tube end cap manufacture & plastic moulding.


When it comes to manufacturing Postal tubes, packing tubes or transit tubes recyclable plastic end caps go together hand in hand to secure products within and these are formed using a technique called plastic moulding.


Plastic moulding is the process used to shape and mould the end cap itself, not only for the use of end caps but within many sectors including medical, automotive, container manufacture and many more. This process is performed by placing a heated liquid polymer within the desired mould to form the space or product required, LDPE or low-density polyethylene being the most common for end plugs.


LDPE has great advantages within the Cardboard tube and postal tube industry as it fulfils the requirements needed to work with all our Transit packaging tubes and capped cores alike. LDPE is lightweight very tough but also very flexible. It has a natural wax coating appearance is also a very low cost to produce with an excellent chemical resistance. LDPE can also be manufactured in different colours, with the White being most common for Mailing tubes.


There are many different techniques used to achieve the finished product you require and in the case of cardboard tubes, postal tubes and any form of capped tube we are looking for a flexible but secure fixing.


Transit packaging tubes
Postal tubes with fitted end caps

Plastic moulding has been around since the 1800’s and has taken many forms and has evolved a huge degree over this time. The very first injection moulding machine was patented by the two American bothers Isaiah and inventor John Wesley Hyatt in 1872. The industry grow quickly during the 1940’s due to the 2nd World War, as there became a huge demand for mass produced and inexpensive products to be produced.


There are many different types of plastic moulding and the most common methods are rotational moulding, injection moulding, extrusion moulding, compression moulding, blow moulding and thermoforming.


The common mis-conception with plastic is the recycling of the material used. LDPE however is not a single use plastic and can be recycled to a lower grade product. The LDPE pellets themselves may come from a recycled source, therefore LDPE is one of the more safer cleaner plastics to use. Recycled it can take many new forms like composite flooring, Bubble wrap, plastic bags and moulded items such as bins and both indoor and outdoor furniture.


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