Scrap Removal Methods During the Rotary Die-Cutting Process

Reducing the amount of waste produced during the manufacturing process not only promotes sustainability but also helps you save a significant amount of money. In case you are finding it difficult to reduce the amount of waste generated, you can also manage it by applying a few simple techniques.

In case you decide to carry on with your usual routine, you will incur heavy losses in the long term. For instance, improper scrap removal not only increases the post-production costs but can also result in an inaccurate final product and can damage the die-cutting equipment. Manual scrap removal, on the other hand, also increases the overall cost as unnecessary labor expenses get added into the equation, compromising the bottom line.

Furthermore, manual scrap removal negates the advantages of using the rotary die-cutting process, especially when there are tons of efficient scrap removal methods available.

Scrap removal tools like spring plungers, rubbers, stripping pins, etc. are used widely to efficiently remove scraps without compromising the advantages of the die-cutting process. To understand how these tools work, you would first need a clear idea about the scrap removal process.

What is the Scrap Removal Process?

No matter the shape you are cutting using the rotary die, some waste will always be generated. Scrap removal is, therefore, the process of disposing of these scraps and slugs produced during the die-cutting process. Add-on elements like stripping pins are attached to the die-cutting machine to efficiently dispose of any scrap that is generated during the process.

5 Scrap Removal Methods for the Die-Cutting Process:

The easiest way to remove scraps is to use the tools that have been specifically designed for removing slugs from the moving web. While there are many tools available in the market for this function, it is important to match the right tool with the right process.

Here five scrap removal methods have been discussed in detail to help you determine the process that suits your needs the best.

  • Foam/Rubber/Neoprene Inserts

This scrap removal process helps you to avoid slug buildup as you insert the materials inside the cavity of the rotary die. Liquid silicone products, foam, neoprene, and rubber can be used in this process. While using rubber or neoprene inserts to remove scraps is an inexpensive process, the effect is limited and can be insufficient. The inserts do prevent slug buildup, but may not at the end separate the slug from the part completely.

  • Spring Plungers

This is a cost-effective way of removing scraps and slugs without requiring any kind of press modification. The spring plunger is inserted into the rotary die to make sure that the slugs do not get stuck to the cavity. This tool works best with rigid materials, and applying additional under-web vacuum ensures efficient slug removal and collection. This process is comparatively cheap and the tools can be easily replaced on-site.

  • Stripping Pins

Stripping pins are sharp pins that are mounted on the anvil so that they can pierce the slug and transport it to the comb system. The comb system would then remove the waste generated from the anvil.

Stripping pins are considered one of the most efficient ways of removing scraps and slugs. They work best when used at high speed. These pin systems are known to remove scrapes from the outside matrix as well. Stripping pins are widely used in the commercial manufacturing process and are known for their ability to offer 100 percent control and removal of slugs. These pins are replaceable and removable when damaged or worn out.

  • Sacrificial Liner

The sacrificial liner is a low stack, adhesive-lined stripping tape that takes away the web waste that is generated during the process. The liner is inserted into the machine from under the anvil with the adhesive-lined side facing upwards towards the web. When the dies are cut, the waste produced will get stuck to the liner and will be carried away. Once the waste gets stuck to the sacrificial liner, it is pulled down to rewind along with the waste. This process is mostly used to remove scrap that is too small to be disposed of using other scrap removal methods.

Sacrificial liners not only eliminate the scraps but also ensure that the slugs stay stuck within the liner. The liner can be efficiently used on multi-level cutting dies, avoiding metal-to-metal cutting. Using sacrificial liners will help you avoid additional tooling costs and equipment modification.

  • Pulse Air

This method of scrap removal forces a single burst of air through the cavity, timed with the tool rotation aimed at a specific point in the die’s rotation. Applying this method to remove scraps results in reduced air consumption as the die receives bursts of air only when required and not always.

While the pulse air scrap removal process is comparatively more expensive than the standard air ejection process, the former is far more efficient for removing scraps than the latter. The pulse air method is also less noisy than the standard air ejection method.

Conclusion

The key to efficient scrap removal is to match the right technique with the right job. Once you make use of any of the above-mentioned tools like stripping pins, you will benefit from efficient scrap removal, which will in turn help you create a clean and accurate end product.