Ultrasonic cutting

Which materials can be cut using ultrasound?

Ultrasonic cutting is particularly popular in the food industry. Products like cakes, confectionery bars, cheese, vanilla slices and wraps are ideal for ultrasonic cutting, as the process does not cause any deformation or damage to the product. The consistency of the food product does not affect the precision of the cut; cut products can be fresh, frozen, crumbly, creamy or composed of different layers or components.

Technical textiles, non-wovens and fabrics can also be efficiently cut using ultrasound, as the oscillating blade performs a dual function – not only cutting the material, but also sealing the edges at the same time.

The technology cuts easily through thick or elastic materials like plastics or rubber – such as window seals and even car tyres during manufacture – because the oscillating blade glides through the rubber with minimal pressure, thanks to the low levels of surface friction. The material melts along the adjoining surface, enabling the blade to glide effortlessly with virtually no resistance.

How does ultrasonic cutting work?

Like ultrasonic welding, ultrasonic cutting technology relies on a sonotrode. In cutting applications, this sonotrode is known as a cutting sonotrode, because it has a sharp blade. This ultrasonic blade is as sharp as a kitchen knife, but the cutting process itself works on an entirely different principle. With a kitchen knife, pressure and surface friction are what cuts through the food. However, materials like rubber can’t be cut in this way.

With ultrasonic cutting, the oscillating motion and the melting of the material allow the ultrasonic blade to glide almost effortlessly through the product. The oscillating ultrasonic blade faces virtually no resistance from the product, so food products do not become deformed and the blade doesn’t get stuck in rubber. Textiles with a thermoplastic component only require minimal cutting pressure, thanks to the melted cut surfaces and low levels of friction.

The material is melted solely by the energy transmitted by the ultrasound. This is an enormous advantage in food cutting applications, as it means that the technology can be used to produce clean cuts in delicate and temperature-sensitive products like cheese or cakes.

Ultrasonic food product cutting is a completely clean technology as any residues left on the blade are shaken off by the oscillating motion during the cutting process. The blade will not get stuck and remains clean at all times.

What requirements can I meet with ultrasonic cutting technology?

• The ultrasonic blade produces smooth, reproducible cuts in all kinds of applications – from cutting films made of PE, PP or PVC to slicing cheese or portioning vanilla slices.
• Whether your product is a cream cake or a plastic component, ultrasonic cutting won’t cause deformation.
• Ultrasonic cutting is ideal for temperature-sensitive materials, as the cold ultrasonic blade won’t cause any heat damage. Chocolate bars might melt in your hands – but they’ll remain intact during ultrasonic cutting.
• With ultrasonic technology, the cycle times for cutting food products, textiles and plastics are exceptionally short. Fast, continuous cutting is also easy to achieve.
• Because of the way ultrasonic cutting works, the technique seals the edges of technical textiles, non-wovens and fabrics while simultaneously creating a clean and precise cut edge, eliminating the risk of fraying.
• The maintenance intervals for cleaning ultrasonic blades are very long. Materials don’t stick to the blade like they would on a kitchen knife; the oscillating motion shakes off any residues during the cutting process, significantly reducing downtime for blade and surface cleaning.
• The technological principle of ultrasonic cutting makes textile cutting a clean and easy process, with minimal levels of dust.

How is ultrasonic cutting integrated into the production process?

The ultrasonic cutting components can be fitted in automated production lines and in special machines.

Cutting food products using ultrasound:

When cutting food products using ultrasound, the production line may be designed for intermittent or continuous cutting.

Intermittent cutting

Intermittent cutting is ideal for applications such as portioning cheese, cakes or bread. The cutting sonotrode uses a vertical stroke movement to cut the product into equal slices or pieces. The ultrasonic components are integrated into the cutting system.

Continuous cutting

For horizontal cutting movements that make a vertical cut through the product, continuous ultrasonic cutting is used. The ultrasonic blade is installed in a fixed position and the product moves towards the blade on a conveyor belt, for example. The cutting sonotrode glides precisely through the product with virtually no resistance to produce a horizontal cut.

Ultrasonic cutting of technical textiles, non-wovens and fabrics:

The key advantage when using ultrasound to cut textiles, non-wovens and fabrics is that the technology melts and seals the edges while making the cut, which also helps to minimise dust.

Unlike in food product cutting, which relies solely on automated solutions, fabrics are sometimes also cut manually if automated cutting is not feasible in a specific application.

Continuous cutting

Textiles on rolls can be cut in a continuous ultrasonic cutting process. The rolls are cut and simultaneously sealed by a cutting sonotrode on a continuous automated line. The speed of the process varies depending on the fabric type and the basic material. We show the principle in this video.

Contour cutting

The process for contour cutting non-wovens and fabrics works in a similar way to punching. The cut is made by the punching stroke and the contour is defined in advance. The cutting blade is either a specially designed sonotrode, which cuts the product on a flat mount with each stroke…

… or the cut is made by a flat sonotrode, which is fitted with a “punching blade” tailored to the shape of the mount that holds the product. This process can be used to achieve almost any contour. Typical applications for this type of ultrasonic cutting include hygiene mask and filter mask production.

Flexible cutting

In flexible ultrasonic cutting, the goal is not to achieve pre-defined shapes or cuts, but to remove excess fabric in a single clean-up step. This step is often carried out manually, but it is also well-suited to automation. For flexible cutting, the covered component is fixed in place and the ultrasonic blade glides around the plastic part. Alternatively, the blade is fixed in place and the edge of the component to be cleaned up is guided past the cutting sonotrode.

A typical application for flexible cutting is to trim excess fabric from covered plastic parts in the automotive sector – A-B-C pillars are a common example.

Benefits - Food:

No deformation
The ultrasonic blade glides through the food product with minimal pressure, preventing deformation and enabling you to cut even the most sensitive food products into thin slices with maximum precision.

Minimal heat transfer to product
The cutting sonotrode does not heat up during the cutting process. This is of particular importance when working with temperature-sensitive foods, as minimal heat is transferred and the process is gentle on the product.

No product residues on the blade
Even when cutting sticky food products, the ultrasonic motion ensures that the blade stays clean. Downtime to clean the blade is reduced to a minimum, system availability is increased and costs are reduced.

Save food: Minimal production waste
Ultrasonic technology is incredibly precise and each step is easily reproducible – which enables you to reduce production waste to a minimum. The fact that the cutting blade remains clean also helps to reduce food waste during the production process.

Benefits - Textiles and plastics/rubber:

A fast process with virtually no resistance
Ultrasonic cutting is a fast technology: the blade glides through the material quickly and effortlessly with only minimal pressure. The basic principles of ultrasonic technology – oscillation and plastification – ensure very low material resistance, which enables you to cut through tough materials like rubber with ease.

Precise and clean
Ultrasonic cuts are highly reproducible, precise and clean. The ultrasonic blades and cut edges do not get dirty and the process generates virtually no dust.

High-speed/high-frequency cutting
Ultrasonic cutting is a fast process: depending on the material and your requirements, speeds of up to 120 cuts per minute can be achieved for products like textile labels, or 25 metres per minute in continuous cutting applications.

Cut and seal edges in a single step – without fraying
Technical textiles, non-wovens and fabrics can be cut and sealed in a single step. The ultrasound technology gently melts the edges to prevent fraying. This process not only minimises dust, but also saves time and money by eliminating the need for any further edge processing.

Cut and join in a single step
With ultrasonic technology, you can cut and weld two separate adjoining layers in a single step. The ultrasound gently melts the fabric to permanently join the two components.

Frequently asked questions about ultrasonic cutting