Innovative design requirements of plastic packaging provide a new direction for injection moulds

China is a big country of packaging manufacturing and consumption in the world, and the proportion of plastic packaging in the total output value of the packaging industry has exceeded 30%, becoming a new force in the packaging industry and playing an irreplaceable role in food, beverage, daily necessities and industrial and agricultural production in various fields. Plastic packaging industry packaging products, packaging materials steady growth, packaging new materials, new processes, new technology, new products continue to emerge. Plastic packaging is an important part of the plastic industry, we should increase the innovation of the plastic packaging industry research and development, reflect the industrial policy of plastic packaging materials, focus on the development of product fields and technical fields, development direction, etc..

Product lightweight design

A large part of the cost of packaging products lies in raw materials. Assuming that the cost of other production factors cannot be reduced, reducing the use of raw materials can effectively save production costs. Therefore, die and mould enterprises have the obligation to help customers reduce costs and maximize production capacity and benefits through reasonable realization.

Taking a bottle cap as an example, we have successfully reduced the weight of 3025 bottle cap to less than 1.8g, 2925 bottle cap to 1.2g and 38mm water cap to less than 2g through thinning the wall thickness of the cap, subtle adjustment of the shape of the buckle, and repeated verification on the mold.

Innovative design requirements of plastic packaging provide a new direction for injection moulds

Shorten product forming cycle

Under the basic premise of ensuring product appearance, size and function, shorter molding cycle is always the goal that the mold factory diligently pursues. The main ideas of shortening the product forming cycle are as follows:

According to the shape of parts and products, design the arrangement of mold waterway reasonably to ensure the uniformity of cooling of each mold cavity.

As close as possible to the shape of the product, design the cooling waterway of the die kernel (with the shape cooling). If necessary, use 3D printing technology to make the die kernel to ensure the full and fast cooling of the product.

Reasonable selection of die kernel materials to ensure rapid cooling of parts. The part of the top surface of the part that contacts with the product is usually the hot runner into the glue position; The design of the die kernel is in the form of inserts, and it is made of special materials, so that the cooling effect is better and the stability of the size of the product is improved.

Design of adjustable product thickness

For a tear of the structure of the product, such as seasoning bottle caps, xylitol chewing gum lifted the lid, and so on, the wall thickness of the tear in itself is very thin, function requirement and high (both want to consider consumers feel and strength of tear, want to consider the sealing performance of tear ring itself again, too thin could damage cap sealing, too thick will probably affect consumer experience). This kind of FMCG production is huge, high requirements for the life of the mold, generally require millions or even tens of millions of molds. Mold in the process of production have inevitable natural wear and tear, tear function to keep TAB products consistently, we specially developed innovative cavities design, can adapt to the injection factory in the process of production according to the cavities of the natural wear to adjust mould kernel level, so as to realize to adjust the thickness of the product, to ensure product quality stable and reliable.

Intelligent mold design

Reducing labor costs is a major means to reduce costs in modern enterprises, so it is particularly important to reduce the post-processing of injection products. For example, through the mold structure with the manipulator for the product of in-mold cover, in-mold folding, in-mold labeling, in-mold ring cutting and other unmanned operation, continuous production, this is the inevitable trend of the development of modern enterprises. Here the author focuses on introducing the most widely used in-mold flanging and in-mold closing technology in food and beverage, pharmaceutical packaging and daily chemical industries:

In-mold folding: the previous products with this kind of reflexed edge structure, after coming out of the mold, the bending edge becomes a horn opening. It needs to be folded by special bending machine or manual tooling, which is low in efficiency and high in cost. After optimizing the mold design structure, the in-mold folding is realized after the product is ejected from the mold, and there is no need for subsequent auxiliary procedures. It has the advantages of high efficiency, low cost, increased safety and in-mold disassembly.

Closing the cap in the mold: by adding a combined cap manipulator outside the mold, it can complete the automatic closing action of clamshell products. The mechanism is simple and stable, which greatly improves the automation level, saves manpower and improves the economic benefits.