Laser Slitting

Laser slitting is an advanced manufacturing process that uses a focused laser beam to cut or slit materials with high precision. This technique is used with Nestech laser slitters, where clean edges and minimal material distortion are essential. Unlike traditional mechanical slitting methods, laser slitting offers greater flexibility, faster setup times, and the ability to handle complex patterns or delicate materials without physical contact.

This is an example of the Nestech laser slitting a thermoformed lid to produce a tamper-evident feature. 

This lid was later ultrasonically welded to a filled container. The distinct pull tab feature allows an effortless opening of the product. There is a hinged feature that keeps the lid in an upright position while in use.

The laser has a 3-dimensional, aimed beam. Round, oval, or rectangular shapes are all possible. This would not be possible with a fixed blade. Bridge and slit widths can also be changed throughout the cutting cycle in real time.

Laser slitting for injection molded closures has been pioneered by Nestech. Although the speeds are slower than conventional knife slitting, the benefits include the ability to quickly change the cutting parameters without changing physical tooling. This is a perfect choice for smaller runs and prototyping new designs.

Conventional Closure Slitting

The most common blade shape is curved. The caps roll around the perimeter of the knife in a spindle, and the tamper band is produced. 

The knives are made from hardened tool steel, wire EDM to precisely cut the slots, and fine ground to an exact angle. Normally, these knives are not heated.

Recently, there has been a new requirement in some countries to produce a slit closure with tamper evident features where the cap stays tethered to the bottle. This is relatively simple, where a secondary knife is installed to produce a hinged feature.

Some slitting is done in the mold. This results in increased mold costs and maintenance. There are many tiny parts that extend and retract every time molten plastic is injected into the mold cavity. Any changes to bridge or slit widths require extensive retooling and testing. Slitting, done as a post-molding operation, reduces mold costs and downtime. Changes in a Nestech slitter require only a blade change at minimal cost and are done in a few minutes.