Over the years, different types of lasers have established themselves thanks to their versatility. Apart from technical differences in construction, the particularity of each laser lies in the propagation medium used to emit energy and the resulting wavelength.

The most common are gas lasers (such as the CO2 laser), semiconductor lasers, fibre optic lasers and solid-state lasers. Depending on the medium used, the laser generates a beam at a different wavelength. The lasers manufactured so far cover the entire electromagnetic spectrum.

Why the laser wavelength is key

The wavelength is crucial in determining the possible uses of a laser. From it depends the kind of interactions between the laser and the material. Each material responds differently to a certain wavelength. Some materials, like acrylic, can absorb in the near IR or be transparent in the far IR. The optimum balance is achieved when most of the energy generated by the laser is absorbed by the material, allowing efficient processing.

Based on what we have said, it is impossible to establish an optimal wavelength. The choice depends on the characteristics of the material to be processed.

However, it is possible to give general indications. It has been demonstrated that some lasers have a wavelength which makes them suitable for a wide range of applications.

The wavelength of CO2 laser

The CO2 laser in particular has a wavelength of 10.6 micrometres, which is in the far-infrared region. This length is absorbed very well by all materials containing carbon. Wood, paper, plastic polymers, organic materials, natural and synthetic fabrics respond perfectly to CO2 laser radiation.

What’s your need?

Certainly, of all lasers, the carbon dioxide laser has proved to have the greatest versatility and has therefore established itself as the main choice for the laser processing of materials. Contact us for more information!

Laser kiss cutting (or kiss die cut) consists in removing the superficial portion of a sheet of material according to a specific cutting path.

Unlike normal laser cutting, laser kiss cutting does not go through all the material but remains on the surface layer.

Due to this characteristic, kiss cutting is mainly used in the paper converting and textile industries.

Laser kiss cutting is used when the superficial layer of a material made up of two attached sheets must be cut.

Laser die cutting of labels is an example of one of the most common applications of kiss cutting. The laser cuts out the surface layer into the shape of the adhesive to facilitate its removal from the support layer.

Laser kiss cutting can also be applied to the field of fabric decoration.

Kiss cutting for digital converting

Digital converting or laser converting is used to perform paper converting processes that would be difficult or impossible to achieve with conventional mechanical methods.

Laser kiss cutting is a typical digital converting application that, as previously mentioned, is particularly used in the production of adhesive labels.

This technique makes production particularly efficient and advantageous, since the costs and time required to set up the machine are eliminated.

In this sector, the materials most used for kiss cutting are:

• paper and derivatives
• polyester
• plastic film
• adhesive tape

Kiss cutting for the textile sector

In the textile industry, laser kiss cutting and laser cutting are used to decorate both semi-finished fabrics and finished garments. In the latter case, laser kiss cutting is very useful for creating personalized decorations.

This technique makes it possible to create different effects such as embroideries, appliqués and labels of various types.

Generally speaking, in this family of applications, two pieces of fabric are sewn together.

Laser kiss cutting then cuts out a shape on the surface layer of the fabric. The upper shape is then removed making the underlying drawing visible.

Kiss cutting is applied mainly on the following textile materials:

• synthetic fabrics in general, in particular polyester and polyethylene
• natural fabrics, especially cotton

The advantages of laser kiss cutting

The kiss cutting technique is not a modern discovery related to laser technology but dates back to traditional printing techniques.

Compared to these mechanical cutting methods based on blades and dies, laser kiss cutting offers several advantages:

• the cutting path can be very complex, making detailed and precise cuts
• the possibilities for customization are innumerable even within the same production cycle
• it can be performed on a large number of materials without interrupting production
• cutting tools don’t get worn during production which therefore eliminates the need for maintenance
• speed, productivity and processing quality are at their maximum
• edges are clean cut and defined and do not need further finishing

The industries of laser kiss cutting

As we have seen, laser kiss cutting is mainly used in the digital converting and textile decoration sectors.

Examples of laser kiss cutting

Which laser systems are suitable for laser kiss cutting

Each laser kiss cutting application must be tailor made for each customer’s needs. In the label industry, a system consisting of a CO₂ laser source and a scanning head is generally used.

The laser source

For the manufacturing of labels, high power isn’t necessary: most applications can be done with a laser source below 500W.

Keep in mind though that the power is directly proportional to the production speed. It is therefore sometimes necessary to resort to higher power because of production needs.

A small clarification on the source’s wavelength: El.En. has developed a CO₂ laser source specially designed for label manufacturing, the RF333P, with a wavelength of 10.2 micrometers.

This wavelength is ideal for polypropylene (PP), of which is made the surface layer of most labels is made. This source is a variant of the Self Refilling series, which are the most suitable for paper labels.

The scanning heads

The scanning head always works in combination with a laser source. Its function is to move the laser beam on the work surface and keep it focused. To do this work the source uses mirrors mounted on galvo motors and a focusing lens on the Z axis.

El.En. produced a scanning head for CO₂ lasers called GioScan. The machine is available in two models:

• GioScan 1735, capable of operating on a surface between 135×135 mm and 800×800 mm
• GioScan 1770HR, capable of operating on a maximum area of ​​2300×2300 mm

A laser system for each laser application

Laser kiss cutting applications are numerous and ultimately depend on the material and production needs.

The advantage of laser technology is that it is possible to create custom applications.

For over 35 years El.En. has produced laser systems for industrial applications.

If you have a production idea in mind that requires laser kiss cutting,

Laser micro-perforation of plastic bags for fresh products

The CO2 laser has been on the market for many decades. Over the years it has proven to be a sturdy tool, capable of providing thousands of hours of processing without having to be serviced or replaced.

Unlike for mechanical production equipment, one of the biggest advantages of laser processing is low maintenance.

Mechanical tools operate by contact between parts and rely on moving mechanisms. The friction generated during machine operation makes wear and tear on this production equipment a pressing problem. Periodically, production has to be stopped in order to carry out the necessary maintenance operations, which increases the costs of operation and processing. The die sector is but one example of an industrial process that suffers from this problem. In this type of application, the dies have to be replaced periodically to guarantee the quality of the cut.

Laser, on the other hand, is a non-contact process. The entire laser system is based on the production and transmission of electronic pulses and the generation of polarised light beams. There are no moving parts or friction and therefore no direct impact on the lifetime of the laser source.

However, this does not mean that laser sources are maintenance-free. Laser sources also wear out, albeit much more slowly. This is why they need regular maintenance.

In the case of CO2 laser sources, the main problem is the rarefaction of the gas inside the laser tube. Year after year, the gas mixture is normally depleted, resulting in around a 1-2% emitted power decrease per year. This causes a gradual deterioration of the processing and a consequent decrease in efficiency.

The only solution to this problem is to periodically regenerate the laser source. However, this is a costly and time-consuming operation that usually involves stopping the production line, resulting in a negative impact on productivity.

El.En. has created a series of laser sources based on Self-Refilling technology to overcome this very problem. These sources, called Never Ending Power, avoid the regeneration of the source thanks to the use of a cylinder that contains the propagation medium. This cylinder can easily be replaced without causing any delays and guarantees the same process parameters and power over time.

This innovative recharging technology now makes it possible to have a laser source that always functions at maximum power. The laser beam’s quality will consistently remain at its highest level and the lifespan of the laser source will practically be infinite. Contact us for more information!

The laser scanning heads are a fundamental component of the galvo systems for laser cutting and marking. These devices deflect the laser beam coming from the source and move it along the X and Y axes according to the operation required.

The components of a galvo head for laser

A scanning head is made of different components.

Galvo mirrors

Mirrors mounted on galvanometric rotary motors deflect the laser beam. These motors transform electrical voltage into angular movement.

The mirrors, mounted perpendicularly on the engines, move the laser beam along the X and Y axes according to the input received from the motor.

The big advantage of these devices is that they can reach a very high acceleration and speed of movement.

The size of the mirror depends on the laser beam. As the diameter and the power of the beam increase so must the diameter of the mirror. The same size in turn influences the acceleration and speed of the engine’s angular movement. The smaller mirrors reach higher accelerations than the larger mirrors.

In the range of El.En.’s products there are galvanometric mirrors for different applications. Find out more about our complete 2-axis CO₂ laser galvanometer mirror line on our website.

Z-linear optics

Galvo mirrors are not the only components of a scanning head. The z-linear lens, which focuses the laser on the work surface, has an important role to play too.

To focus the laser beam and get it to work optimally, the focal length of the lens must vary based on the distance between the scanning head and the point it needs to reach on the surface.

The z-linear lens changes the focal length in real time and maintains the laser beam in focus regardless of its distance from the workpiece.

The control software

The control software makes sure that all the moving parts of the scanning head stay coordinated.

It transforms a vector file (the place where the work to be performed is described), into a path for the laser beam. The control software makes the galvo head and the laser source work together to achieve the desired result.

What processing can be performed with a laser galvo head?

As previously mentioned, the laser galvo heads are mainly used for cutting and laser marking.

Laser galvo cutting

Galvo heads make it possible to reach high processing speeds for cutting applications. Galvo heads are perfect for the processing of thin materials such as paper, cardboard and plastic film.

The head can cut out any shape quickly.

Some of the industries that benefit most from the use of galvanometric motors are the adhesive label sector that use kiss-cutting applications and the packaging industry that uses galvo-laser applications to make products with advanced features.

Galvo laser marking

The main marking applications include the marking of various types of alphanumeric codes, such as barcodes and QR codes, and the engraving of ornamental motifs for decoration.

Laser marking can be performed on different materials such as thermoplastic polymers, wood, fabrics, leather, metals, glass.

In the case of transparent materials it is also possible to perform the impression of three-dimensional figures inside the object.

The advantages of laser galvo heads

Laser applications get many advantages from the use of galvo heads:

• Speed ​​- The galvanometric motors reach very high angular speeds. This means that the laser beam moves over the surface of the workpiece with speeds reaching tens of centimeters per second. Thanks to this the productivity of a laser galvo system is very high.
• Integration – Precisely because of this characteristic, galvo laser systems are suitable for integration into larger production flows. A laser galvo system consisting of a scanning head and a laser source performs best when inserted into automated processes. Furthermore, it is compact enough to be easily added to pre-existing systems, giving it an important upgrade without major changes.
• Quality – The laser galvo systems guarantee high quality and detailed results. In marking applications, the scanning head gives the possibility to create a wide range of effects, including the reproduction of a photograph on a surface.

One device, many tools

Scanning heads are a key tool in laser material processing applications. They transform a single beam of polarized light into an instrument with many applications.

To choose the scanning head that is most compatible with the application you need, request the help of an expert. Get in touch with us: our team at El.En. will be happy to help you find the most suitable laser scanning head for your applications.

Laser cleaning is the process of using lasers to remove dirt, debris or contaminants from the surface of an object. It is a process that lends itself to a variety of industrial and non-industrial applications. From cleaning thermoforming moulds to restoring monuments, there is no area where laser cleaning cannot be successfully applied.

In this article, we explain what the laser cleaning process consists of, the principle on which it is based and why it has an advantage over conventional cleaning methods.

Conventional cleaning methods

In the field of industrial production, the maintenance of production tools is essential, particularly in those areas where the quality of production depends on it. In the plastic thermoforming sector, for example, it is essential to always have clean moulds in order to obtain high quality parts. Rust, dust and material residues are among the most common types of dirt that need to be periodically removed.

However, cleaning operations are very costly in terms of resources. The actual performance depends on the type of maintenance required. But in general we can say that cleaning methods are based on the use of chemical or mechanical methods.

In the first case, cleaning is entrusted to solvents, detergents or other chemical compounds that degrade the material to be removed and facilitate its removal. In the second case, systems such as sandblasting or ultrasonic cleaning are used.

These cleaning methods have major disadvantages. They are very polluting because of their use of chemical products and require operators to take special safety precautions.

In addition, physical contact often causes damage to the workpiece which, in the long run, ends up being damaged by the cleaning operations.

Laser cleaning has established itself precisely because it has the advantage of overcoming the main drawbacks of traditional cleaning methods.

Laser cleaning and its advantages

Laser cleaning consists of irradiating the surface of a material in such a way as to remove the surface layer. The technique is based on ablation. The beam concentrated on the material breaks the molecular bonds of the material that needs to be removed. The material evaporates instantaneously with virtually no residue left behind.

Unlike conventional methods, there are no solvents or other additional chemical substances used in laser cleaning, and since it is a non-contact process, there is no abrasion that could damage the workpiece, as the surface dirt is removed without attacking the underlying material.

It is precisely this protection of the material that makes the laser so attractive. The laser allows you to operate selectively on a given material. The laser only removes materials that are absorbed by its wavelength. In addition, each material has different properties and needs a different amount of energy to be removed. This makes it possible to work on materials very precisely, to calibrate the laser extremely selectively so as not to damage the underlying material.

Flexibility, high controllability of the medium and speed are the characteristics that make laser cleaning an extremely effective tool.

The fashion industry is always looking for new ideas and new technology to make them possible. Laser has become an incredible tool for stylist and designers, enabling them bring even the most technically difficult ideas to light. The pioneer designers who made the first use of laser, often went on to become famous in the fashion world.

It is a known fact that originality takes the win in fashion.

Laser technology has changed the way fashion is designed and produced. Now, like most other sectors, textile manufacturers can use the techniques of digital production: fast prototyping, small scale productions, and the possibility to produce on demand.

When some processes could only be made by an experienced artisan, with laser cutting, they can now be made almost instantaneously and in a perfectly uniform and precise way.

Laser cutting for textiles in fashion

There are many materials used in fashion, most of which can be cut by laser. Though fabric is still the most popular material, acrylic polymers (used for fashion accessories and shoe making) is also commonly used by the fashion industry.

Here is a list of the most common materials that can be cut by laser:

• fabric of natural or plant origin
• wool
• cotton
• linen
• synthetic fabric
• polyester
• nylon
• elastan
• fabric of animal origin
• leather
• silk
• acrylic plastic
• PMMA
• wood
• lace and crochet
• thin metal decorations

The process

The laser beam is concentrated on a specific area of the material until it provoques immediate evaporation. This process, called sublimation, is instantaneous and produces precise and clean cuts.

Other effects can be obtained by varying the laser’s speed. Indeed, laser cutting isn’t the only possible operation. By using the same laser, one can obtain marking effects for decoration.

The process is contactless so there is no risk of leaving unwanted traces on the material. This is particularly advantageous for delicate materials such as silk. This characteristic makes it possible to decrease or even eliminate wear and accidental damage during production, guaranteeing a better end product for sales.

The right technology to use

CO2 laser is by far the most popular in the fashion industry. It is powerful and versatile, and its wavelength is compatible with all the materials used in this field.

A laser system optimized for fabric cutting includes a CO2 laser source and a scanning head. Both are controlled by a software that manages their parameters according to the intended result.

The laser source’s job is to generate a laser beam. The types of laser power available range from low power CO2 lasers like El.En.’s RF88, to high power ones like El.En.’s Blade RF888. The choice of laser power will depend on what kind of production system the CO2 laser is inserted in: the higher the power, the faster the production will be.

The scanning head’s job is to concentrate the laser on the surface and move it along the desired path.

The software is the ‘brain’ of the system: it translates the information contained in vector file produced by the designer in impulses for the scanning head and laser source.

The main advantage of such a system is that it can be completely automated: it can be integrated in pre-existing productive systems or take part in a system made especially for laser cutting.

Do you want a tailor-made application?

As previously explained, laser technology has a wide range of applications. The best way to know which application is right for you, and find the ideal configuration, is to talk to an expert. Send us an email to explain your requirements and we will find the best solution for you.

What if producers and distributors of fruit and vegetables stop using sticky labels? It’s not phantasy but reality: with laser food labeling, labels can be written directly on the skin of a product by removing the superficial layers of the skin itself. An innovation beneficial for the environment and for the consumer. In this article we describe you this processing technique and we present you a case study where we describe how we created an automatic laser system for the labeling of apples. If you already know what natural branding is, you can jump to the case study.

First priority: reducing waste

Recent years have seen the development of a greater sensibility towards the environmental impact of the production processes. Manufacturers are trying to streamline the use of resources and materials, switching to greener ways of producing goods.

For the packaging sector this meant an overall reduction of the materials composing the packaging products: paperboard boxes, rolls of wrapping paper and plastic films are being supplanted by their biodegradable equivalents or they are simply being discarded.

Quite revealing of this trend is what happened to the most simple and traditional packaging product: labels.

CO2 laser labeling? That’s natural branding!

The phenomenon has been called “natural branding” and it especially concerns the packaging of fresh fruits and vegetables. Simply put, natural branding is to replace plain physical labels, sticked on the surface of fresh fruit and vegetables, with “natural” labels, obtained through laser marking.

This is only one of the many applications of CO2 lasers, a technology that demonstrates, again, to be a green process. In fact, producing a mark directly on the skin of produces results in reducing the consumption of materials such as paper and plastic and thus in a smaller environmental footprint of the packaging process. A CO2 laser let you engrave to engrave a lot of information: traceability codes, logo and brand of the producer, expiration dates. All this pieces of information were usually printed on traditional labels that were sticked on the surface of produces.

This laser labeling system is very advantageous for the whole packaging process and for the environment as well: a smaller energy consumption, the reduction of potentially polluting materials, a higher speed of execution. A perfect tool for all the manufacturers aiming at a greener production process.

But how can a CO2 laser engrave the surface of fresh fruit and vegetables?

Laser marking of food

Laser labeling of food is a special application of CO2 laser marking. In a previous article we have assessed the efficiency of laser marking on organic materials such as wood or leather. Even food can be marked without difficulty.

Broadly speaking, the process of laser marking relies on the high energy density delivered by a laser on the surface of a workpiece. It is that process that produces the desired marking on the surface.

An ordinary laser marking system is composed of three parts: a scanning head, a low power CO2 laser source and a computer equipped with the control software.

The scanning head contains three components: two galvo motors with two beryllium mirrors mounted on them; one linear actuator that dynamically adapt the focal length of a lens. The goal of this device is to deflect the laser beam and keep it always focused on the surface of the workpiece. Thanks to the laser scanning head the laser beam can be delivered on the entire surface of the workpiece.

Both the CO2 laser source and the scanning head are controlled by a software that, fed with the correct parameters, achieves the marking process of the desired design. In this way it is possible to control the speed, the position and the power of the laser beam, making it possible to obtain all types of images, logos, codes and markings.

A laser marking system can be adapted to many situations and it can be integrated in existing lines without effort.

The process of labeling trough CO2 laser marking is applicable to any sort of fruits and vegetables. Nevertheless, the best results are obtained with fruit and vegetables having a wooden or thin skin e.g. tomatoes, apples, grapefruits, walnuts, chestnuts, coconuts, pumpkins etc. In this sector it is possible to mark pieces of information such as produce traceability codes, expiration dates, logos of the producer and other personalized information.

The benefits obtained through natural branding are manifold:

• Small amount of energy consumption: the CO2 laser systems employs very small amounts of energy to do the job, resulting in a reduction of costs.
• No consumption of plastic, paper or glue: in CO2 laser labeling of food, labels are directly engraved on the surface of the product. Therefore the environmental footprint can be reduced to a minimum.
• Cleanliness: with CO2 laser marking, the products don’t come into contact with chemical substances like glue. Hence the wholesomeness of the produce is enhanced.
• Higher productivity: the laser marking process is very fast. Although the processing speed depends on the complexity of the information that must be engraved, in most situations the processing time ranges from fraction of seconds, for simple codes to a few seconds, for complex geometries.

At this stage it should be clear why laser labeling of fresh produces is also known as natural branding. It should also be clear how laser labeling is suitable for producers of organic or biological produces and, in general, for all the companies interested in improving their environmental footprint.

A case study: marking traceability codes on apples

Let’s see now how a CO2 laser labeling system has been applied to a line of selection and sorting of fresh produces, in this case apples.

This system was composed by a laser scanning head, a low power CO2 laser source with a wavelength of 10.6 micrometers and a computer with the software that controlled the entire process. The marking system was designed for the integration in the existing machine and was engineered to achieve laser marking of apples on the fly.

That means that the system was able to determine the position and the speed of each apple passing on the moving belt, thus synchronizing the behaviour of the laser beam with the position of the apples on the belt.

The system proved to be extremely fast: it could mark 6 apples per seconds. As we said this speed it’s not fixed but depends on the complexity of the results that need to be achieved.

The energy consumption of this system was of the lowest: the laser source in this applications consumed only 0,3 kW. Although it was designed for apples, this configurations of a laser labeling system can be extended to any typology of fresh fruit and vegetables and seamlessly integrated in existing production lines.

A safe process that doesn’t affect the quality of produces

Laser labeling is a safe process. The marking only affects the most superficial layer of the skin of fresh produces; all the organoleptic properties of the food are respected. They are not modified in taste, color or smell. And the shelf life remains the same: some papers have also highlighted that laser marking never reduce the quality of produces.

The laser labeling of fresh products is an application yet to be explored. The possibilities are wide and let companies greatly improve their environmental footprint.