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.

Corrugated cardboard, also known as corrugated fiberbord or simply cardboard, is the most widely used packaging material. Its low production cost, great mechanical properties and an overall good strength make it perfect to manufacture cardboard boxes of all kind and shape.

Generally, corrugated cardboard is manufactured by a mechanical processes. Tools such as blades, die boards or routers are used to create the profile the overall shape and to score the lines along which the folds will we made.

Mechanical processes are solid and reliable and have a long history. Yet they also have some major drawbacks:

• lack of flexibility toward changes
• limited range of admitted tolerances
• high risk of producing unwanted damage to the material
• generation of waste under the form of trimmings or dust
  

Plus, all mechanical manufacturing processes involve contact, meaning that the tools have to physically touch the surface of the material to achieve the desired transformation.

Laser technologies can overcome all those drawbacks. Laser cutters can cut shapes at high speeds and with higher degree of precision. Let’s give a general overview of the process.

Cutting cardboard with laser

The main advantages of CO2 laser fabrication derive from the fact that laser technologies are a non-contact process.

A single laser laser beam can easily engrave, cut or drill a panel of corrugated cardboard. Thanks to the properties of cardboard, the results are great. The interaction between the laser beam and the material puts in place a sublimation process: it basically means that the laser beam makes the material evaporate, achieving a precise cut.

This is a key feature of laser material processing. First of all it allows great processing speed: all things being equal, a laser cutting system is many times faster than a die-cutting machine.

A laser can achieve the same operations at a speed of thousand of meters per minute. This without compromising the quality of the cut, which always remains excellent.

Another advantage of laser material processing is its flexibility. With traditional machining process, you cannot easily change the cutting geometry.

Changing the cutting shape comes with a cost: it means changing the cutting tool. A manufacturer can hardly start a new productionrun unless it guarantees a return on the investment.

With laser material processing, changing a cutting geometry is way easier. It’s just a matter of minutes and only requires the time to load the drawing of the new geometry in the control software.

Also, a laser works like a multitool. Cutting and engraving can be accomplished with the same tool. A single laser source can perform both operations. Laser engraving is especially useful in the packaging industry, where codes of all kind need to be stamped on the packaging itself in order to comply with regulations or for logistical reasons.

This means that a CO2 laser cutting machine can conveniently process a batch of 5000 or 100.000 pieces cardboard panels of different shape.

Laser technologies can help a packaging produce meet the needs for custom products with small number of pieces. They also make possible the rapid prototyping approach for new packaging products.

A third advantage of laser technologies for cardboard manufacturing is that they don’t produce almost any waste. Laser processing is very clean: cuts and other processes are achieved without producing any scrapes, dust or other waste product, allowing for green production and better work environment.

The lack of those waste products means that the cuts obtained are of the best quality: a CO2 laser produces cuts with smooth and compact surfaces. Unlike mechanical fabrication, it does not affect the fibers of cardboard and paper: therefore the material structure remains untouched, resulting in a reduced possibilities of damaging the material.

Mechanical methods are subject to wear. The use of worn out tools reduce the quality of the product: that’s why the tools have to be periodically replaced or repaired. Those operations slow down the production process resulting, increasing the production costs. On the opposite, a laser will always be a sharp cutting tool, thus always allowing the best quality of the process.

So can you laser cut cardboard?

The answer is yes, you can. And you should. Laser technologies are the perfect tool for cutting and engraving corrugated cardboard. The laser is a fast, flexible and green tool. It allows a manufacturer to satisfy all the requests of customers: a characteristic that is essential for a company operating in the economy dominated by the paradigm of the long tail. Customers are now looking for a different approach, where the priority is given to tailor made products and respect for the environment.

A new approach requires new tools, more flexible and accurate. The tools that let manufacturers control their costs without sacrificing quality the quality are the tools of the future.

Basically, an industry based on mechanical machining was typical of an era and for a market where manufacturers marketed their products and customers were obliged to pick from what the market had to offer.

Contact us

Do you need to cut or engrave cardboard at an industrial scale and you think that laser could be a good option? Contact us: we have a long experience in designing and manufacturing a wide range of laser systems for cutting and engraving corrugated cardboard.

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.

Governments and organizations are constantly seeking solutions to make identification documents secure and tamper-proof. Cost-effective productions are key because in most cases security requirements combine with the need to maintain low costs.

Until not so long ago, all identification documents were made of cheap and readily available materials such as paper or cardboard. The document’s information was printed in ink or handwritten. Of course, not just any paper was used. In order to guarantee the originality of the document and combat counterfeiting, the paper was made using special treatments. Holograms, watermarks, or drawings were applied to the paper to make it as difficult as possible to falsify.

However, these products were not 100% safe since they could still at times be forged. Both the types of paper and the inks could be modified in such a way as to deceive even the most expert eye. This is the reason why the search for forgery-proof solutions has never ceased.

One of the solutions found was the laser marking of documents. The application consists of marking information directly on the material using the laser beam. The interaction between the laser and the material changes the surface layer causing a transformation that produces a mark. This mark is therefore not applied to the material but is an integral part of it. This technique guarantees that any successive modification to the document would result in irreparable damage that would highlight the counterfeit.

Laser marking can be used both on security paper – and on paper in general – but also on new-generation plastic identity documents.

Various objects such as ID cards, passports, credit cards, passes, or even hospital wristbands can be made using laser marking.

Given their identification function, these documents must have very precise functional characteristics:

• the sign must be indelible and resistant to wear and tear.
• the document must be difficult to forge or tamper with.
• there can’t be any defects
• all documents must be identical

The marking process makes it possible to meet all these requirements and therefore satisfy the most stringent international safety requirements. The marking becomes an integral part of the material and cannot be removed. It is virtually impossible to forge a laser marked document unless you use the same tools and materials as the original document.

The laser marking process, like all laser processes, is computer controlled and therefore has a high repeatability and accuracy index. Once the process has been defined, the possibility of error is 0, and machining operations are carried out repeatedly with the same level of quality.

Laser marking lends itself to numerous applications. You can mark alphanumeric identification codes but also barcodes, QR codes, and even greyscale photos.

Laser allows you to add special security features such as microtext, variable images, i.e. images that change depending on the angle.

How the marking process works

It is a well-known fact that laser marking can be performed on various types of material. The best result is obtained on plastic materials such as polycarbonate and paper.

The marking on plastics is done by chemical degradation. The energy transferred by the laser carries out instantaneous transformations at the molecular level. The transformations change the visual appearance of the material by creating a dark-colored mark.

Laser marking also works on multi-layered documents. The laser can even reach a transparent layer by setting a specific wavelength. Marking can, therefore, be done at deeper levels and ensure that the mark is protected by a transparent surface layer and thus more resistant.

The possibilities go even further. Deeper marking with a tactile effect can be created through laser engraving techniques.

Laser engraving acts at a deeper level than laser marking and subjects the material to wider and more radical transformations. The mark made by engraving doesn’t only have visual characteristics but also tactile ones. The combination of marking and engraving makes the ID much safer.

The laser marking process allows for results that cannot be obtained with other machining tools. Therefore it lends itself to the most advanced processes. In a world increasingly connected, having forgery-proof documents is more and more necessary. If you have such an application in mind contact us , we will help you make it happen.

Laser wire stripping is the process of removing all or part of the insulating material that covers electrical cables. In other words, it is the process used to uncover the metal core of the cables. It is typically done at the cable’s ends to make connections possible, but it can also be done in various ways along the cable.

Laser stripping’s main feature is that the laser selectively intervenes on the insulating material without affecting the cable’s metal core. This is a significant advantage over traditional stripping techniques. The high quality and precision of the laser striping process has made it a widely used technique in high-tech sectors.

Not surprisingly, the idea of ​​using lasers to remove the insulating layer of electrical cables was born in the aerospace sector. In the 1970s, NASA needed to find a solution to strip the thin Space Shuttle cables. The stripping tools used at the time did not guarantee the quality and precision necessary for an application of that type.

Traditional wire stripping methods and their drawbacks

The first is the mechanical method, which is the most widespread. In this process, blades are used to cut the electrical cables’ sheathing.

This method has many drawbacks:

• to achieve accurate results, the process becomes extremely slow
• each type of cable requires a dedicated tool
• the tools require maintenance to remain effective

The risk of damage, for example notching the cable, is one of the main risks of this technique. To solve this problem, manufacturers have produced oversized cables, so that any loss of metal would not reduce the functionality of the cable.

While this may be a solution for low-tech industries, oversizing cables is not a suitable solution for others.

In the aerospace sector, for example, weight containment is essential. Cables are designed to be very thin so that they weigh as little as possible. This means that any damage to the cable could cause it to malfunction and lead to accidents.

In addition to the mechanical method, peeling can be performed with a chemical or a thermal process.

The chemical process uses corrosive substances such as sulfuric acid to dissolve the cable coating and expose the conductive material. The disadvantage of this technique is that it is not easily controlled and is also polluting.

The thermal process uses a heat source to remove the coating. This method, however, can leave residual coating material on the metal core which would therefore have to be subjected to further processing.

Laser stripping overcomes all the previously mentioned drawbacks. It is therefore not surprising that it has established itself as the method of choice for high-tech applications.

Why laser stripping works

In most cases, the material that coats electrical cables is some kind of plastic polymer while the internal core is made of metal, very often copper. Laser technology has the ability to select only the coating’s polymers without modifying the conductor in any way.

This behaviour can be explained by the way laser radiation interacts differently with different materials.

CO2 laser emits radiation at a wavelength of 10.6 micrometers, that is, in the far infrared [far-IR] region. Polymers absorb this radiation very well while copper reflects it almost completely, without undergoing alterations.

The advantages of laser stripping

Laser stripping offers several advantages over traditional methods:

• flexibility: it is effective on almost all polymeric materials with which electrical cables are coated
• precision: it is a non-contact process, which makes it able to work on very tight tolerances and to carry out processes that would be impossible with traditional methods
• effectiveness: since laser is reflected by most metals, the process ends with the removal of the polymer without requiring any further processing

What are the different types of laser stripping

In laser stripping, the laser can perform 3 basic operations:

• laser cross cutting: the cut is carried out transversely to the cable in order to allow the removal of excess material
• laser slitting: the cut is made lengthwise. Typically this process is performed when a longer portion of cable needs to be removed and is used in conjunction with the cross cut
• laser ablation: the laser passes over the surface several times until the coating is completely eliminated. This technique is mainly used when the conductive material is immersed in the coating (otherwise known as bonded wire).

Alongside these basic operations, laser technology makes it possible to perform advanced processes such as the partial and targeted removal of the coating with the creation of windows or the removal following certain patterns. All these applications can’t be done with traditional mechanical methods.

As is often the case with lasers, the possibilities are endless.

How a laser stripping system is made

A laser cable stripping system can be implemented in various ways and with various technologies.

The most effective is certainly galvo-scanning. In this application, a scanning head is used to move the laser beam and then focus it on the work surface.

The whole system is controlled by a computer which coordinates the operation of the CO2 laser source allowing the laser to follow the pre-defined cutting path.

Implement your own laser wire stripping

Laser cable stripping lends itself to many applications. It is ideal for high-tech sectors that require great precision during the processing phase. One of the applications, for instance, is magnet wire stripping with laser.

Don’t hesitate to contact us. Our staff would be happy to advise you on the best laser solution for your needs.

Polyester is the most common synthetic fibre used in the textile industry. Whether it be fashion, design, furniture making or decorations, there is no field in which polyester hasn’t found some application. Just open your closet and have a peak at the composition of your clothes. You will find that most are fully or in part made of polyester.

The success of polyester is due to both its properties and low cost. Objects made in polyester are easy to clean, more resistant and need less upkeep. Since polyester isn’t made of natural fibres, the cost of farming the original plants doesn’t factor in. The fact that polyester can easily be treated with laser is yet another advantage.

Polyester absorbs the CO2 laser wavelength very well which makes any type of process possible. Finishing processes can be optimised, therefore reducing production costs.

This article explores the main characteristics and advantages of laser cutting of polyester fabric.

Polyester and its properties

Many thermoplastic polymers are included under the name polyester. The one most frequently used to produce clothes is made from polyethylene terephthalate. The fibres production process starts from the fusion of polyester pellets. The next step is the extrusion of the material. In other words the melted polyester is passed through a hole to create a continuous filament. This filament is then rolled around a spool of the desired length. This method allows for filaments of any shape and diameter. They in turn constitute the fibre from which fabric is made.

Polyester fabric is long lasting, resistant, cheap, easy to clean, easy to dry and waterproof. These characteristics make it perfect for the production of all kinds of objects: clothing, footwear, interior design, car upholstery, camping equipment, etc… The impermeability of polyester can also be a disadvantage. It retains humidity and doesn’t have good breathability.

Laser applications on polyester

The characteristics of polyester fabric can be greatly improved by laser processing. As is the case for other thermoplastics, this synthetic fabric undergoes well both laser cuts and perforations.

Polyester, just like other synthetic plastics, absorbs the radiation of the laser beam very well. Out of all the thermoplastics, it’s the one that gives best results for both processing and lack of waste.

Laser cut on polyester fabric

Laser cutting of polyester offers many advantages over traditional cutting techniques. The cutting process works this way: the laser beam’s energy is concentrated on the fabric and heats the polyester fabric until it melts, creating a cut. The cut obtained is already sealed and therefore avoids the problem of fraying edges.

Other advantages are:

• No production of waste
• Extreme precision
• Very clean process

The right laser sources to use

In order to get the best results, the wavelengths should be between 9.3 and 10.6 micrometers. Both types of wavelengths are in the infrared region, which is the typical region of the carbon dioxide laser. The choice of the laser source power will depend on the speed of production one wants to obtain. The higher the power of the laser source, the faster the production. In El.En’s catalogue, two types of laser sources are right for the laser cutting of polyester:

Blade RF 177G

A 150 W RF CO2 laser source, specially conceived for applications on thermoplastics. It’s 150 W power is perfect for most applications that include plastic materials.

Blade RF self-refilling

A multipurpose RF CO2 laser source that uses the self-refilling technology, developed by El.En. This laser source is available in different power options, and can reach up to 1200 W.