Efficiency in the Purging Process for Thin Wall Packaging Manufacturing

The manufacturing of thin wall packaging products is a highly attractive market. However, the technical process is characterised by multiple challenges. These include highly complex moulds with many cavities, extremely low part weight, high volume production and the necessity of numerous, sometimes radical, colour changes. In particular, the purging process becomes complex. How do plastics companies deal with the issues involved? 

Thin wall packaging products are an increasingly important thermoplastic (TP) market. Just think of, e.g. vegetable bags, packaging for cosmetics such as eye drop dispensers or an accelerating number of health care products. According to market research institute Mordor Intelligence, the thin wall packaging market was valued at USD 38.58 billion in 2020 and is expected to reach USD 55.92 billion by 2026. However, manufacturing is characterised by highly complex moulds with extremely low part weight, high volume production and the necessity of colour changes.

Due to low viscosity, among other things, one of the challenges in the purging process in thin wall applications is efficiency: Manufacturers are looking for on-the-fly solutions that prevent downtime. Further goals are for an easy and quick procedure and scrap reduction. Cleaning hot runners poses an extraordinary difficulty: Purging these effectively is only possible by moulding parts.

Ultra Purge 1001 for on-the-fly purging

A cutting-edge solution for the purging process while manufacturing thin wall packaging products is Ultra Purge ™ 1001 by Chem-Trend. This ready-to-use purging compound is designed to clean high-viscosity polyolefins and is suitable for injection moulding machines. It even allows on-the-fly purge with hot runners during operation. Consequently, Chem-Trend can help manufacturers reduce downtime and scrap by 50 per cent by using the product.

Ultra Purge ™ 1001 consists of high-quality thermoplastic polymers and highly efficient cleaning additives. All the formulation components comply with EU Regulation No. 10/2011 and US-American legislation (21 CFR) for food contact materials. The benefits in a nutshell:

  • Recommended for thin wall packaging materials made of polyolefins
  • Rapid cleaning effect
  • Easy to use
Case study: Use of Ultra Purge 1001

An example of how it works: A global manufacturer of thin wall packaging products, making medical eye drops dispensers, faced severe problems resulting from radical colour changes from black to whitish transparent virgin resin colour leading. This usually resulted in high scrap rates and more than 2 hours of downtime during changeover times that the shift leaders could only execute. Their injection moulding process was subject to 50-80 colour changes per month, entailing 3-4 cleanings per week, each lasting between 120-140 minutes. Among other thin wall products, they produced medical eye drop dispenser caps – each cap weighing less than 1 gram of polypropylene injected via a hot runner into a mould with 32 cavities. That mould produced caps from black masterbatch and natural virgin resin.

With the customer, Chem-Trend was able to identify the best suitable food-approved purge compound that allowed for a simple purge process any operator could run on their own, which also resulted in a reduction of scrap rates due to black streaks.

After thoroughly analysing the whole process, our Ultra Purge™ experts introduced a purging process in which any operator could complete 40% faster than before, resulting in a considerable reduction of scrap parts by 35%.

Ultra Purge™ 1001 was determined to be the purge compound of choice to work with this type of equipment and materials optimally. Screw, barrel and hot runner were purged with the food-approved purge compound by producing parts after only a few minutes of soaking.

Learn more about the Chem-Trend purging compounds for food & healthcare applications.

Read more from Chem-Trend here.

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