Thermoplastics are polymeric materials with incredible properties. Their name derives from their main property: becoming viscous when heated and solidifying once cooled.

These characteristics makes it possible to laminate and easily shape these materials. Industrial applications are endless: from the packaging to medical devices sector, without forgetting the electronics, automotive and food industries. There is no sector in which thermoplastic doesn’t have a key role.

On this blog we have already seen how thermoplastics work well with laser technology. Microperforations, cutting, kiss-cutting are but a few examples of how well thermoplastics absorb the CO2 laser wavelength and offer great flexibility and high quality results.

Now, thermoplastic polymers can also be used in a foamy state. Polymeric foams, or expanded polymer, are obtained by treating the polymer chemically or physically until the right shape is obtained. Expanded polystyrene, expanded polyurethane and expanded polyethylene all belong to this category of materials.

Expanded polyethylene (aka polyethylene foam) is one of the most popular foams used in the industrial sector, due to its lightness, insulating properties and resistance. This foam is ideal for laser cutting.

In order to cut polyethylene foam, a CO2 laser precisely and cleanly outlines the wanted shape in the polymer foam. This process is easily controlled digitally. The advantage of using laser technology is that the pieces are cut perfectly, down to the last millimeter and in a well defined shape. It is therefore ideal for highly detailed work.

An example of what co2 laser can do is tool shadowing. Basically it means cutting a layer of foam with cut outs of different sizes for each tool in your tool box. The tool will be perfectly kept still and safe inside the toolbox.

Making this application using only mechanically tools is very difficult if not impossible, because the expanded polyethylene sheet would have to be pinned down in order to cut out the shapes without ruining the material. This method works only if the shapes have straight lines. As soon as the lines are curvier or more detailed, it becomes difficult to trace the objects outline perfectly.

Laser technology makes it easy to cut polyethylene foam in the right size and shape. All you need to do is create a CAD file with the shapes to cut out. The file is then transferred to the software making it possible for even the most complicated of shapes to be created.

It is now a fact: the current pandemic has led to an explosion in online shopping and home deliveries. Contagion risks have led people to reduce any situation that include physical contact. Shopping activities have moved online for all types of goods, including basic necessities. Online shopping seems to be an increasingly common behaviour.

Forward-thinking companies have viewed these changing social trends as an opportunity to experiment with new and more advanced forms of packaging. They cater both to the new needs of home shoppers and the ones of companies that want personalised forms of packaging that better protect their goods. There is also a strong need for eco-sustainable packaging that uses fewer resources.

Laser technology has made all these things possible.

Laser manufacturing of cardboard boxes

The paper industry has now been using laser technology for several years. The CO₂ laser offers undoubted advantages to its production processes. It can be integrated into fully digital, fast and flexible production processes, which allow cardboard’s technical and material characteristics to be exploited to their fullest.

Cardboard is an ideal packaging material. It is inexpensive and light and can be processed into many shapes to create boxes and packaging to suit all kinds of needs. And what’s more interesting, laser cutting corrugated cardboad gives stunning outcomes.

The introduction of digital fabrication has made it possible to considerably expand the range of packaging products. Laser makes product customisation both economical and advantageous. The fact that it is no longer necessary to change tools to create different types of products has encouraged innovation, and the experimentation of new formats. Customisations (products made specifically to cater to a certain need) are now achievable at lower costs.

Until recently, companies that wanted to send or package their products had little choice. They had to rely on the box formats offered on the market. Box manufacturers dictated the law and only offered standard shapes and sizes. If a company needed a box shaped in a particular way or with an easy opening, it was limited to what the market had to offer.

Creating boxes and packaging with custom features was not cost-effective for manufacturers or customers, unless the number of produced pieces justified the investment in production means. For customers, the only way to obtain customised packaging at a competitive price was to secure large quantities of orders. This is not always possible, particularly for small and medium-sized companies.

The use of lasers has brought about a real revolution in the way paper products are manufactured.

The production process of cardboard boxes is based on two fundamental operations, cutting and engraving, which are at the basis for all subsequent processes. Cutting separates the shape of the box from the cardboard sheet. Engraving creates folding lines on the box or devices for easy opening, such as tear-off systems. Folding the box along the cutting lines and gluing the flaps together produces the finished product, i.e. the box.

The advantages of lasers

The advantages of laser cutting are many. The laser allows these same processes to be carried out with greater speed and precision, making the production process much more flexible.

On materials such as paper and cardboard, the laser cutting process is instantaneous. The laser immediately vaporises the paper along the cutting line, resulting in precise, clean cut edges. Laser cuts need no further finishing.

Precision is ensured by the fact that the laser is a non-contact process. This makes it possible to make cuts along particularly intricate paths even at very small sizes.

But laser technology isn’t only useful for traditional machining operations such as cutting and creasing. It can also perform tasks that traditional tools can’t.

Laser Marking is one of these processes. In marking, the laser does not perform cutting or engraving, but merely modifies the surface layers of the material, which results in the blackening of the laser-processed parts. This technique turns the laser into a real digital printer that engraves marks directly on the surface of the material. In this way, all kinds of marks can be engraved, from logistical information like QR codes, barcodes and alphanumeric codes to actual images like company logos.

This gives the production system enormous flexibility: the same laser system can perform all these processes, even on a small number of parts. Cardboard packaging manufacturers can now offer their customers a lot more choice and create customised boxes, even in smaller quantities.

Contact us

Cardboard box manufacturers agree that the CO₂ laser is an invaluable tool. It makes it possible to carry out work that cannot be done with traditional methods such as die-cutting. If you are a cardboard box manufacturer and are interested in a laser production system, please contact us. Our technicians will be happy to study the most suitable laser solution for your needs.

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 scoring is a wonderful technique to create advanced features on flexible packaging. Together with laser perforation it lets designer conceive easy opening packages, single portioned or disposable boxes, tear-apart openings that can enrich the experience of the product.

The rising success of easy to open packages has pushed producers to look for new packaging solutions. More than ever, consumers are used to easy-opening packaging.

The introduction of laser technology and digital converting processes has pushed packaging companies to find innovative solutions that were unthinkable of just a few years ago. Industrial lasers for packaging, such as the CO2 laser, give added value to a product by not only protecting it, but also making it easy to open.

Plastic film packaging, which has offered a wide scope for experimentation, is a perfect example of the added value of packaging.

As discussed in previous articles, CO2 laser can increase the breathability of the plastic film according to the product they contain. Fresh produce, for example, can be wrapped in micro-perforated bags in a modified atmosphere room to extend its longevity.

Laser scoring on plastic film bags to make packaging easy-to-open is another laser application that has many uses.

What is laser scoring?

A laser beam vaporises predetermined areas of a plastic film, thus creating the scoring. The weakening line that is created makes the packaging easy to open without the use of tools.

Laser incision has the advantage of removing the material in a precise and uniform way. This technique gives the possibility to closely control the depth of incision. By removing only the strict minimum amount of material, the integrity of the packaging remains untouched.

The right materials for laser incision

Laser incision is ideal for flexible packaging made in plastic film. These materials, which are some of the most commonly used in the packaging sector, are perfectly compatible with CO2 laser:

• polypropylene
• polyethylene
• polyester
• nylon
• multilayer films

Plastic film packaging can be used for all kinds of products: food, cosmetics, chemical products, herbal and pharmaceutical products.

Laser scoring technology

There has been a paradigm shift in the world of packaging since the introduction of laser technology. We have shifted from the mass production of standardised products to the small production of highly tailored products.

This change has only been possible because laser technology is a digital production tool. It can be completely controlled via software and is fully automated. A scoring laser system can be designed right from the beginning of the process and can work in analog work flows. Regardless of the type of work flow, laser technology brings added value to the production process, making it simple and fast.

Laser incision is a very versatile tool since the depth of incision can be controlled. By loading different vector files into the system, you can easily and quickly go from scoring to cutting through the material.

The laser can make incisions in a straight line, following the reel’s movement (down web?) or even transversally. The movement of the laser scoring is completely defined by the user. It can follow a straight line, the contour of a shape or a freeform path.

Laser technology is ideal for scoring because it is a contactless process. The lack of physical contact makes it possible to avoid problems such as the accidental rupture of the plastic film or the use of cutting tools. In order to achieve a high quality incision, the blades had to be perfectly sharp and therefore frequently changed. Production would to come to standstill in order to change machine parts which resulted in higher production costs.

The use of laser technology make all these problems obsolete. The only maintenance laser needs is a periodic gas refill. And now, with El.En.’s self-refilling technology which allows the laser source to be recharged autonomously, even this minor inconvenience can be avoided.

The right laser source for laser scoring

In conclusion, the CO2 laser is ideal for scoring of plastic film. The previously mentioned materials respond well to the CO2 laser wavelength. The laser scoring process works best with a low power laser source or with up to a 300 W power supply. One should also take into consideration that the higher the laser power, the faster the production.

The possibilities given by system integrations and configurations are endless. Once the type of application has been decided, it becomes easy to choose the best configuration.

Laser engraving and marking for fabric are some of the innovative technologies that have taken hold in the fashion and interior design sector. Indeed, their introduction has given a sector that usually relies on unchanging production processes, the impetus to experiment.

Laser marking and engraving processes are fast, accurate and flexible. These characteristics make them perfectly compatible with production processes and explain why their use has spread so widely.

The introduction of laser has made it possible to significantly reduce the environmental impact of this industrial of the fashion industry, which is one of the most polluting. The production cycle of fabrics, from production to finishing, involves the consumption of considerable quantities of water, energy and chemicals.

Laser technology has therefore also established itself as an alternative production tool, capable of replacing all traditional processes with lower costs for the company and above all for the environment and with greater benefits for the end user.

Marking or engraving? The difference between the two processes

In the textile sector, lasers are used throughout the production chain, from cutting to finishing and decorating fabrics. The marking and engraving applications are mainly used in those parts of the production process.

Both applications use the laser as an energy source to remove a layer of material of varying thickness. Depending on the amount of energy transferred by the laser to the material, the layer of material removed is more or less deep and the transformations made to the material are different. The difference between marking and laser engraving lies precisely in these differences.

We speak of laser marking when the processing involves the material’s most superficial layer and its transformation is not radical. Oppositely, we talk about laser engraving, when the laser beam removes a consistent layer of material. The engraved mark is deeper and perceptible to the touch.

Given these differences, laser marking and engraving results can differ according to the chosen type of application or material.

Based on all the aforementioned information, laser marking and engraving can suit numerous applications. Laser is a very flexible tool that adapts to all types of applications.

In general, we can say that laser marking and engraving applications on fabric fall into one of these two areas: the decoration or the application of various types of information on the material’s surface.

Laser marking and engraving for fabric decoration

Laser decorations allow designers to fully express their creativity. They can create a wide range of decorative effects and details on fabrics by using marking or laser engraving. These can range from a simple geometric pattern to the transposition of images in grayscale, all the way to the creation of decorative details with a three-dimensional effect.

The decoration of denim fabric is a perfect example of how this field of application has become popular in the clothing industry. The laser marking of demin has revolutionized the way this fabric is processed. Traditionally the denim finishing process involved various steps such as washes, sandblasting and abrasion. These processes were used to give a particular look to the jeans, a specific shade or a worn look to the garment through cuts and abrasions. The problem with these processes is that they are extremely polluting, involve a large consumption of resources and have a significant negative environmental impact.

Denim laser finishing makes it possible to significantly save on product manufacturing times, optimize the production process, perfectly replicate the various types of denim washes, and create any detail with great flexibility. All these results can be obtained through the laser’s transfer of energy on the material’s surface rather than through the previously mentioned consumption of resources.

Laser marking and engraving to communicate information

In a world where automation is becoming increasingly popular, the application of information on materials is an increasingly requested process. Laser marking and engraving can be used to apply barcodes, alphanumeric information, information on the characteristics of the product and its maintenance.

This information can serve different purposes. For example, imagine a manufacturer of fabrics destined for the semi-finished product market. By means of laser marking, he can automatically imprint information such as production batches and identification codes directly on the fabric.

The advantage of this type of application is that the information engraved or marked with the laser is indelible, resistant to wear and counterfeiting. The manufacturer can save on some production costs, and when it comes to logistics and traceability, have a fully automated production process. The product buyer also has the guarantee that important information applied to the fabric won’t be damaged by time or wear.

Fabrics that can be laser marked / engraved

All categories of fabrics can be laser marked or engraved. However, some of them are better suited to these processes. Below is a brief review of the fabrics on which laser application can be performed very easily:

• Synthetic fabrics. Synthetic fabrics are among those that are best suited to laser marking / engraving processes. These are materials made from thermoplastic polymer fibers, such as polyester. These materials respond very well to laser processing and therefore give optimal results.
• Natural fabrics.Cotton is the natural fiber that is best suited to laser marking / engraving processes. To mark cotton you need to choose fabrics with a fairly compact texture.
• Leather and faux leather . Laser marking can be applied to both natural and synthetic leather. Not only can laser technology be used to perform traditional processes, it can also create effects that could not be obtained with traditional tools.

How a laser system for marking fabrics is made

The components of a fabric laser marking / engraving system depend on the type of application needed. However, some basic components needed for typical engraving and marking applications are always necessary: a laser source and a scanning head.

The laser source is the device that generates the beam that performs the process. Their versatility when it comes to different materials makes CO2 sources the most suitable for these types of processing. Deciding how powerful the laser source should be is directly proportional to the manufacturing speed required. The more powerful the laser source is, the more instantaneous the execution.

The scanning head and attached software system can make any type of pattern in a very short time. They are therefore perfect for this type of processing, even if performed at high speeds.

An application with infinite possibilities

The laser marking and engraving of fabrics will increasingly take center stage in the fashion industry. The advantages they offer in terms of flexibility, accuracy and speed are enormous. Moreover, their greatest advantage for an industrial sector that makes innovation and design its essential strength is their endless application options.

Are you in need of a laser engraving or marking application? Contact us and we will happily put our extensive experience at your service to devise the ideal solution for your needs.

• Introduction
• Laser labeling for food: fields of application
• The advantages of laser labeling
• Speed
• Precision and cleanliness
• Flexibility
• Environmentally friendly
• Indelible
• Laser labeling for food: the laser marking process
• The technology used in laser food labeling
• Laser food labeling: choosing the right laser source
• Laser scanning head
• A safe process
• A world to explore

Laser etching of various pieces of information on fruit, vegetables and other food products is an innovative procedure that is replacing traditional methods otherwise used in the field. A CO2 laser can not only etch alphanumeric codes and barcodes, but also any type of graphical representation.

This versatility can easily makes it possible to replace traditional methods such as hot-marking, inkjet printing and adhesive labeling. CO2 technology also guarantees huge savings in terms of speed and resources. Because of the previously mentioned reasons, there has been a growing interest in laser marking of food products.

In this article we will present a general overview of laser labelling for food. We will show its main fields of application, the advantages it delivers to both the production process and the environment, the way it works and the technologies employed.

Laser labeling for food: fields of application

Food products make large use of codes, labels and other varying symbols. They serve many purposes: guarantee the safety of consumers, trace products through the various steps of the supply chain and fight the counterfeiting of products. Here is some of the information you can find on products:

• alphanumeric codes like expiry date, batch code or PLU codes
• barcode or QR code
• logos and commercial brands
• controlled origin symbol

This information can be applied to the product in different ways:

• fire branding for products such as cheese or cured meats
• ink printing for products with non edible shells like eggs
• adhesive labels for fresh produce

The use of lasers in the food industry isn’t new. Production technology has long discovered the potential of this tool. Its use centered around process control (for example, reading barcodes), bio-stimulation of produce or disinfection of products through laser with ultraviolet wavelength.

The method of laser markings on produce to replace labeling has been known for several years. The first patent dates back to the end of the 90s. This process hasn’t yet become widespread though. The high cost of laser equipment combined to the lack of specific knowledge about the process has made most producer continue using traditional methods which are quite fast and inexpensive compared to laser.

In recent years, interest in laser technology has grown to the point that it is no longer only within the purview of specialists. Some famous companies in the produce sector have chosen to adopt direct laser labeling of their products. Many factors explain this shift from traditional labeling techniques to natural branding. The cost of laser technology has gone down in recent years while the demand for natural and organic products has risen. Companies strive to optimise resources and reduce the ecological footprint caused by their production.

The fact that European institutions have dedicated resources to this technology is a clear sign that this process has its advantages. In 2010, a European project for environmental innovation has explored the possibility to replace the adhesive labels on fresh produce with laser markings directly on the surface of the produce.

This technique focuses mainly on the labeling of fruit and vegetables but isn’t its only application. Aged cheeses can easily be marked by laser. In a recent article, we have discussed how laser systems can be used to engrave cheese wheels with identifying signs.

Another type of application mentioned in this blog is the laser impression of codes on eggshells. Tracing codes, expiry dates and laying dates are different pieces of information printed on eggshells. This data is fundamental to protect the health of consumers. Ink printing is the traditional method used. Laser impression efficiently replaces inkjet printing and makes it possible to avoid food products coming into contact with chemicals such as ink.

Laser markings can be done on a wide range of elements. Generally, the best results can be obtained on produce with some type of skin, be it thick like the avocado’s, or thin like the tomato’s. Up to now, laser markings have been successfully carried out on different types of produce. Here is a partial list:

• apple
• avocado
• banana
• grape
• lemon
• orange
• grapefruit
• mandarin
• peach
• bell pepper
• plum
• tomato
• watermelon
• melon
• chestnut

The advantages of laser labeling

Compared to traditional labeling techniques, direct labeling with laser markings provides a series of considerable advantages.

Speed

Laser’s most renowned characteristic is speed of execution. A laser source integrated in a system with a conveyor belt can mark batches of around ten items a minute.

Precision and cleanliness

Thanks to numeric control, it is possible to etch characters, codes and images in high resolution on the surface of products without leaving any type of residue. This characteristic makes it easy to ‘print’ QR codes, barcodes or complex logos.

Flexibility

Laser technology’s innovative characteristic is its versatility. A simple reprogramming of the laser control software is all that is needed during production to switch from one application to another.

Environmentally friendly

The use of many potentially polluting materials can become obsolete if replaced by laser marking. Plastic or paper labels, glue and ink can all be eliminated through the use of laser labeling. This would generate an important reduction of the ecological footprint. The products would then become less harmful for the environment or for the people that consume them.

Indelible

Laser markings are applied directly to the surface of the product and are therefore impossible to erase and difficult to counterfeit. This technique is perfect for products with symbols that guarantee their origin or quality.

Laser labeling for food: the laser marking process

Laser labeling is under the wider umbrella of laser marking, a process with multiple fields of application. Laser marking consists in the removal of a thin layer of the material’s surface. This delayering is caused by a thermal process triggered by the laser beam’s energy.

When the laser beam reaches the intended surface, it makes the temperature of the material rise until it causes its sublimation (the instant passage from solid state to gaseous state).

The removed material creates a well defined contrast between the untouched surface and the one marked by the laser beam. This process is renowned and used in many sectors on materials that aren’t destined for food consumption.

The technology used in laser food labeling

A laser system for food labeling is mostly identical to any other laser marking system. The fundamental components are:

• a CO2 laser source
• a scanning head
• a software for numeric control and automation

The design for the machine layout will naturally depend on the type of plant, processes and product used. A company that distributes and commercialises apples will need a different configuration to a company that does laser markings on cured meats.

Nonetheless, both machines will need a laser source, a scanning head that moves and focuses the beam on the surface of the object and a software connected to the control unit that constitutes the interface between the user and the system.

Let’s go over the characteristics these components need to efficiently carry out laser direct food labeling.

Laser food labeling: choosing the right laser source

Among the laser sources available on the market, CO2 lasers are the ones that show the best results when it comes to the absorption of organic material. These materials can efficiently absorb the infrared wavelength (10.6 micrometres) of a CO2 laser source because of their low thermal conductivity.

A laser source capable of keeping the laser’s parametres stable is fundamental in laser marking applications. This will guarantee a result with high levels of precision. In order to achieve this, the laser medium must remain in optimal conditions.

Sadly, it isn’t always possible. In the case of the CO2 laser, the medium is made of a gas mixture, of which the biggest part is carbon dioxide. Over time, the continuous leak of gas molecules makes the ones still present in the resonance cavity thin out. This causes a gradual degradation of the laser beam’s parameters.

Mutations of the laser beam will show through a lowering of work quality. Maintenance from the producing company is usually the only way to go back to the laser’s original parameters, but it means putting the production on hold and therefore increasing costs.

In order to avoid this inconvenience – which is typical of all CO2 lasers – El.En has created a autonomously rechargeable CO2 laser source. Because of this characteristic, El.En’s laser source can maintain the fundamental parameters of the laser at an optimal level.

Laser marking on produce doesn’t require such a great power. Nonetheless, the power of the laser source will have a direct influence on the speed of production so it is something to consider.

Laser scanning head

Every laser marking application needs a scanning head to operate. We have already seen in previous articles how a laser source works and what use it has. A laser scanning head’s function is to move the laser beam on a pre-established path that coincides with the processing of the goods.

A laser beam is a light ray that goes in a straight line until it reaches an obstacle of some kind. If a laser beam doesn’t get deviated in some way, it cannot be used in production. The laser scanning head’s job is to deviate the laser beam, making it follow a pre-established path.

The scanning head uses galvo mirrors to move the laser beam along the X and Y axes of a work area.

To function properly, the laser beam has to always be well focused on the surface of the processed product. A z-linear lense will increase and decrease the focal length of the lense and maintain the laser exactly where it needs to be.

The laser source and scanning head have to work in tandem. The laser’s position, focus, power and the duration of the beam have to be decided according the requirements of the production.

The software and control unit are responsible for the coordination of all these devices. The software is the interface between the machine and the user. It translates the patterns needed for production into coordinates and parameters that the control unit sends to the scanning head and laser source.

A change of the software’s parameters or the insertion of a new CAD file makes it very simple to engrave any type of information.

A safe process

When considering the use of laser technology, some people fear it might alter the shelf life of their produce. The skin does protect from mold, bacteria and other agents that could damage its organoleptic properties making it unsafe for consumption.

In the case of cured meats or cheese, the risk is minimal since the external crust is very thick. The laser markings only go a few microns deep and are much less invasive than the ones done with traditional methods such as firebranding.

Things could have become more problematic with fresh produce, especially fruits and vegetables with a very thin skin like tomatoes or grapes. The fear was that removing a layer of skin (however thin) would cause dehydration and various types of contamination.

In reality, many studies have shown that laser marking only touches the surface of the product and doesn’t provoke any alterations. The protective function of the skin isn’t compromised and the shelf life remains the same.

The organoleptic properties also remain unaltered and we can positively say that laser labeling doesn’t alter the flavour of produce in any way.

A world to explore

Laser marking for food products is a new world just waiting to be explored. Each product has different qualities and the parameters used should change accordingly. It is therefore fundamental to study a tailor made solution with the help of a laser producer.

Plastic is one of the best suited materials for CO2 laser cutting. Polymer laser cutting is a very efficient and effective industrial process. Among all the plastic polymers that can be processed by CO2 laser, polyethylene is one of the first in terms of frequency of use. Polypropylene has an excellent laser energy absorption capacity which makes it suitable for all types of applications ranging from drilling to welding.

Polypropylene: characteristics and uses

Polypropylene is a thermoplastic polymer obtained from the polymerization of propylene.Its main feature is that the molecules making up the polymer can be arranged in an ordered or random way. In the first case, polypropylene takes on the characteristics of an isotactic polymer.

This configuration is the most commonly used commercially since it gives the material excellent chemical, physical and mechanical characteristics.

Polypropylene has a high heat resistance (greater than polyethylene), good elasticity, rigidity and the ability to absorb shocks without breaking. It also has a low density, (which makes it light), a high insulating power and good resistance to oxidizing and chemical agents.

Finally, polypropylene can be processed in a variety of forms: injection molding, thermoforming, extrusion for the creation of textile fibers.

Given these characteristics, polypropylene has found a myriad of applications in every field. One can argue that there is no industrial sector that does not make use of polypropylene in some shape or form.

Here is a list of the objects that are most often made with this material:

• Packaging, labels and containers
• Kitchen items such as dishes and food containers
• Sportswear
• Components for automobiles
• Bags,
• Sanitary objects
• Electronic object components

Can you cut polypropylene with laser?

Yes, of course. Polypropylene laser cutting is a very efficient process since this polymer absorbs the infrared wavelength of CO2 laser very efficiently. With laser, making cuts or drilling holes on polypropylene is very easy.

On a macroscopic level, laser works as a cutting blade. The cut has a smooth and well-finished straight edge with no presence of burns or charring. Burr formation or cutting irregularities due to the presence of residues are also very limited. The high energies produced by laser not only melt the plastic, but makes it evaporate by sublimation.

The quality of the cut is directly influenced by the laser power, the cutting speed and the thickness of the material. In general, a medium-power CO2 laser source is sufficient to perform most of the processes needed in polypropylene applications.

Furthermore, the quality level is also influenced by the wavelength used. For this type of material our team of El.EN engineers have devised a specific laser source: BLADE RF333P.

This tool is very well suited to label cutting applications which use the kiss cutting process. A fundamental characteristic of this process is the variation in wavelength absorption related to the type of plastic film used.

In addition to simple cutting, polypropylene also lends itself well to laser kiss cutting operations, a process used mostly in adhesive production processes. Drilling polypropylene is also a suitable application, especially useful in the fabrication of plastic bags for modified atmosphere packaging.

Implementing a laser system for polypropylene cutting

The process of laser cutting polypropylene has many advantages: it allows you to perform complex, precision machining with great speed. It is also a very flexible system, which lends itself to numerous applications.

In addition to cutting, polypropylene responds very well to other laser processes, especially drilling (perforation), marking and engraving, welding. The same laser source can carry out all these processes.

If you work with polypropylene and would like to shift to CO2 laser technology, contact us. We would be happy to help you find the most suitable laser solution for your needs.

The use of laser CO2 in food production processes has become a well accepted trend. Laser is often used to replace labeling processes or the printing of expiry dates, identifying codes and other distinguishing marks on food products. Markings on cheese or fresh products (such as fresh fruit) are some examples of laser use we have already covered in previous articles.

Another process that can be successfully achieved by laser is the marking of chicken eggs.

The traditional method used for egg marking is ink printing.

Because eggs are fresh products, it is fundamental that information such as laying or expiry date be clearly visible on each item. This data  helps the consumer to evaluate the freshness of the product, making egg consumption safer.

Ink marking can be inconvenient because:

• the ink can contain harmful substances
• the markings are not always readable
• the ink needs to dry, slowing the production line
• more resources are used

Laser marking makes it possible to overcome these obstacles. Let’s see how the process works.

A laser marking system is composed of three elements: a control software, a CO2 laser source and a galvanometric scanning head.

In this application of laser marking, the source is used in pulse mode. This mode makes it possible to reach high peaks of power for a very short amount of time, instantly removing a tiny portion of the surface area of a product.

The scanning head has a double function: it moves the laser beam over the surface on the X and Y axes and it keeps it focused on the right surface area.

The control software’s job is to coordinate the action of the laser source and the scanning head. It makes sure that the laser follows the pre-established path and that the power is regulated properly for the desired effect on the surface.

The advantages of a pulsed laser marking system are many:

• the markings are permanent
• potentially hazardous substances aren’t used
• the process is notably faster than ink marking

It has been demonstrated that the markings are superficial and in no way damage the egg as only around a fourth of the eggshell’s thickness is marked.

This technique is perfect not only for alphanumeric codes, but also for logos, pictures and other types of graphic signs.