CO2 lasers are one of the most widely employed technologies in manufacturing. The technology is so flexible and powerful that it is installed on a large number of industrial machines, used in a wide array of sectors. CO2 laser sources are well renowned for their resiliency: a machine based on this technology insures thousands of hours of high quality work.

This type of laser still needs periodical maintenance work. Its weakness is a slow but inevitable loss of power.

Gas leaks, CO2 lasers’ weakness

Excessive gas leakage has consequences on the laser’s output. Its power will either decrease over time or be reduced drastically all of a sudden during operation. This phenomenon produces a reduction in the quality of operation: the laser beam becomes unstable and precision work is compromised. When that happens, laser maintenance is necessary.

Maintaining CO2 lasers

Maintenance can be done by the producer or by a company specialised in this sort of operations. Generally, maintenance work includes disassembling the machine and refilling the gas tube. Many specialised companies offer this type of service, which often also includes the cleaning and realignment of the optics and other components of the laser source.

These operations, even when carried out by professionals, do expose the laser source to potential infiltrations of dust and other microscopic foreign bodies. This sort of infiltrations could compromise the laser beam quality and, as a result, the good working conditions of the machine. Transporting the machine to the maintenance service facilities can also expose it to accidental damage.

It is important to bear in mind that every maintenance will cause a standstill of production that can last from a few days up to a few weeks.

The advantages of El.En’s Self-Refilling technology: Never Ending Power

As a solution to the drawbacks of maintenance, El.En.’s research and development department has developed an innovative Self-Refilling technology. Thanks to Self-Refilling, gas-refilling operations can be carried out directly in-company.

The Self-Refilling system is based on disposable CO2 gas canisters. Every laser source has an in-built lid-protected slot for gas canisters. When it is time to refill the laser source, one needs to simply open the lid, take the empty canister out and put a new canister in. This way the laser source will maintain its max power and its operational standards will be preserved. Servicing operations can be carried out manually and without the laser source producer’s assistance.

The ability to independently refill a CO2 laser source brings about several advantages. Here are some:

• interruptions to production are reduced to a few minutes
• crucial parts of laser sources, such as the optics, stay sealed
• chances of infiltration of dust and foreign bodies are greatly reduced
• chances of damages from transportation are reduced

There are huge savings on resources and the laser source is always at max power and efficiency.

The Blade RF series of Self-Refilling CO2 laser sources are equipped with this innovative technology. These sources all have a compact design, come in multiple power options and can operate on a large variety of materials. Explore our range of products and discover the vast array of available applications.

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.

• 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.

In this article we will focus on one of CO2 lasers’ applications: laser heat treating of metals.

This type of treatment refers to the use of a laser as a heat source to be applied on a metal surface in order to make it more resistant to wear and mechanical fatigue.

There are several metals this operation can be applied to and results vary according to the type of metal or metal alloy. Laser heat treatment is used most on steel. This alloy is ideal for this type of treatment because of its carbon content and versatility.

Laser heat treatment can actually be divided into 3 diffferent types of processes: laser transformation hardening, laser annealing and laser surface melting.

In this article we will cover the first of these applications since it is the most widespread.

The way this process works

As opposed to traditional heat treating processes, lasers can be controlled with extreme precision. This makes it possible to contain the area and the depth of the layer that will undergo the heat treatment.

This characteristic is very useful in the processing of components subjected to mechanical or thermal stress such as, for example, cogs and mechanical components in general or work-related tools.

One of the most widespread applications on steel is the hardening process. It is caused by the transformation of the atomic structure of a layer of steel. More specifically, laser energy is applied to the surface followed by a rapid cooling. This causes a uniform diffusion of the carbon atoms which makes the surface more resistant to wear and mechanical stress.

Here is a partial list of metals on which the process can be applied:

• low-carbon steel (up to 0.30%)
• Medium and high carbon steel (up to 0.80%)
• Various types of steel alloy

As previously stated, the final results of the process are highly variable and, depending on the type of material, can either increase a metal’s resistance or pliability, or oppositely increase its ductility.

Before starting the process, it is therefore fundamental to analyse the metal’s content and understand the final use of the produced object.

Send us a message with your requirements and we will help you find the right laser solution for you.

Modified atmosphere packaging, follows unique dynamics that you do not find in regular packaging supplies. It requires a precise regulation of parameters such as gas mixture and gas exchanges. It must take into account the fact that fresh products continue to exchange gases even after being put into the package. Laser technology is perfect tool to control those parameters through the manufacturing micro perforated packaging.

The domain of flexible packaging

Plastics polymers are used a lot in the food packaging industry, most successfully for fresh produce. Their versatility and resistance to chemical agents make them perfect for this type of application.

Their high capacity for transpiration makes them ideal for fresh produce. Every material, has its own natural traspirability that is its permeability to different types of gas molecules, particularly oxygen, carbon dioxide and water vapour.

This particular characteristic is fundamental for the conservation of fresh produce. The metabolic processes aren’t interrupted once the produce is picked. Processes such as cellular respiration and maturing, continue even after the produce has been packaged. If not appropriately counteracted, these processes can be responsible for a fast deterioration of the product. This is the reason why one of the biggest challenges of the fresh food industry is to slow down the metabolic processes that make the product unfit for consumption.

Packaging technology has found different solutions to circumvent the problem of produce deterioration. Disinfecting treatments, both chemical and mechanical or antifungal, go hand in hand with protective barriers such as plastic film.

Great progress has been made after the introduction of produce packaging in controlled atmosphere. This process takes advantage of the high transpirability of plastic film. The driving principle is to find the right balance between the gases within the packaging in order to counteract the deterioration process. Because every type of fresh produce has different metabolic processes going on, it is fundamental to choose the appropriate type of film that allows the best exchange of gas between the inside of the packaging and the outside.

Unfortunately, many films don’t enable the right relationship between the gas entering and exiting the packaged product. What can be done, then? Laser microperforation can solve the problem. It makes it possible to make microscopic holes on the surface of the plastic film. Depending on the size of the perforations (that can range between 50 to 200 micrometers), it becomes possible to control the gases that go in and out and therefore maintain the right balance between gas and humidity within the packaging.

The advantage of this type of process is that it is easily integrable in a controlled atmosphere produce packaging plant. Let us imagine a company that deals with different types of produce. Each one needs to be packaged according its own specificities. The packaging has to be tailored to each product in order to have the right balance of gas inside the packaging. Laser technology allows for the optimisation of the entire production cycle. Each type of produce can be packaged without any change of machinery; a simple reprogramming of the laser control software is all that is needed.

Sound absorbing panels are used to reduce or eliminate  noise in a specific environment. They are usually used in spaces where acoustic is extremely important such as auditoriums, cinemas, concert halls, etc.

Traditionally these panels are made out of porous material. The most commonly used materials are rock wool, fabric or felt. The working principle is very simple: the porous conformation of these materials accelerates the transformation of sound wave energy into heat. The result is the deadening of sound.

Those types of sound absorbing panels are quite inexpensive but they do present some disadvantages. They can easily get worn and start shedding fibres and other particles. That’s why these kinds of materials aren’t the best for spaces where aesthetics are essential.

In the last years, to get around this problem, an alternative to porous materials has become popular: laser micro-perforated sound absorbing panels.

Laser micro-perforation for sound deadening

Micro-perforated sound absorbing panels can be made from different materials. Wood and plastic are ideal soundproofing materials and therefore some of the most frequently used. Typically, a sound absorbing panel has around a 100,000 perforations per square meter. They are microscopic holes with a dimension of a few millimetres.

The sound absorbing panels work according to a physics concept called the Helmholtz Resonance which makes it possible to efficiently reduce sound waves. Every perforation on the panel can be considered a microscopic Helmholtz resonator.

The main advantage of micro-perforated sound absorbing panels made with laser technology is that the acoustic requirements can be designed specifically to deaden a particular sound frequency. A sound absorbing panel in a concert hall will have to dim different sound frequencies compared to one in the automotive industry that has to deal with the noise of loud engines.

The parameters that determine which frequencies will be absorbed by the panel are the diameter and depth of the perforation as well as their density on the surface of the panel. Shallower holes will absorb higher frequencies while deeper holes absorb lower ones. By determining the relation between the dimension of the perforations and the frequency absorbed, it is possible to design panels perfectly calibrated to deaden specific frequencies.

The CO2 laser is an optimal tool for the production of these panels. The parameters to follow, according to the type of panel required, can be produced with extreme precision thanks to computerised programming. The laser is able to make neat and precise perforation without any imperfections thanks to the elevated power channeled towards the surface of the material. This mechanism instantly causes a thin layer of the surface to vaporise.

The speed of production depends on the number of perforations and their dimensions. The parameters to consider are the distance between the perforations that are either in horizontal or vertical line formations, and the number of lines to be made. These parameters will then determine the density of perforations on the panel. Smaller holes in tight formation will take more time to produce. On average, a sound absorbing panel takes around 10 to 15 minutes to produce.

If you need more information on this application send us a message!

One of the most frequently asked questions we receive on this blog is about the difference between fiber optic Lasers and CO₂ Lasers. These are the two types of lasers most used for industrial application. If compared to fibers lasers, CO₂ lasers have numerous advantages that fiber lasers don’t have.

Both the CO₂ laser and the fiber optic laser work in the infrared spectrum. There is however a substantial difference between them.

A typical fiber optic laser works at a wavelength of 1.064 micrometers. It is used in very specific sectors, such as metal cutting, which require a very high concentration of power.

The typical wavelengths of our CO2 lasers are 9.3, 10.2 and 10.6 micrometers. This flexibility makes it possible to work with different types of material. The area of application of carbon dioxide laser is not limited to metals only but can also be applied to wood, acrylic, glass, paper, fabric, plastics, films, leather, stone, etc.

Thanks to this feature, the use of CO₂ laser has spread to a wide variety of industrial applications in recent years. Its flexibility and versatility make CO₂ laser the most used type of laser. It offers both high quality and the ability to satisfy most customer requests.

Versatility is not the only selling point of the CO₂ laser has over fiber laser. Here are other features that make the CO₂ laser the ideal choice for most applications:

• More precise when cutting thick materials: the CO₂ laser operates at a wider wavelength therefore it is more suitable than the fiber optic laser for processing thick materials. It also leaves a much smoother finish
• Uniform quality: the quality is the same on all materials whilst with the fiber optic laser it can be slightly different depending on the density of the processed material
• Straight line cutting speed: a CO₂ laser is faster at cutting in a straight line, and also has a faster penetration time once the cut has been initialised
• Possibility of control: the CO₂ laser can work with materials of different thickness. The power and duration parameters of the laser beam can easily be adapted to the technical specifications of the material.
• Greater safety: the light emitted by the CO₂ laser does not have a blinding effect. It is therefore must simpler to make the production line safe.
• Ease of implementation: the CO₂ laser makes it possible to create light and compact machines, capable of satisfying all production needs, even those of smaller dimensions.

CO₂ laser: versatility and reliability

On the basis of what we have written, it is clear that the choice between fiber laser and carbon dioxide laser depends on the type of application, i.e. the quality of the material and the technical requirements of the production.

If the fiber laser is particularly effective on metals, the CO₂ laser offers much more versatility and control. It allows to process most plastic materials and all organic materials but it can also be used on metals for surface treatment and laser marking operations. It also has a long history of industrial applications, making it a reliable and safe tool.

The CO₂ laser is therefore the best choice in most material processing industrial applications. If you have a process in mind that could be carried out using a CO₂ laser, contact us, and we will be happy to find the application that best suits 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.

Until recently and partly still, industrial processes were focused on mass production. This encouraged a tendency to standardize products and processes, to reduce the number of possible customizations and to maximize the number of pieces produced thus increasing the company’s profit.

A production paradigm of this kind could work as long as the relationship between producers and customers was controlled by one side. The market bought what the producer offered. Recent technological advances, combined with changes in the market and client requests, have brought about a paradigm shift.

Highly customized forms of production, which were previously economically unsustainable, are now possible thanks to the use of technology and digital manufacturing processes.

Laser is the cornerstone of this change and has revolutionized many sectors allowing the reduction of production costs, the speeding up of production and the possibility of creating customized products on a mass scale.

This last statement might seem like a paradox, but to fully understand its scope, one must change the traditional way of looking at industrial production processes.

Think like a laser

The acquisition of a laser system is not just the acquisition of a new machine. It also requires the adoption of a new way of thinking about production. It becomes necessary to know the advantages that laser offers, exploit its strengths and use it productively and economically.

Let’s go over laser technology’s strengths point by point: versatility, precision, cleanliness, speed and lack of contact.

Versatility

Laser is versatile on many levels. First, CO₂ laser can work with a wide range of materials. This type of laser gives its best results on materials of organic derivation (wood, paper, cardboard, leather, fabrics, acrylic plastic materials, etc.) on which it can effectively perform any type of processing. On the other hand, CO₂ laser has a more restricted range of applications on metallic materials, particularly in the field of laser engraving and marking or for surface treatments such as paint removal.

Precision

The very nature of the laser beam makes it a highly controllable tool. Its parameters and features are easily managed with a software, and they can be set according to the desired result. This feature of laser has paved the way for precision machining and made it possible to create perfectly calibrated pieces based on the functions for which they were created.

An example of this type of application is the perforation and cutting for food industry. For this particular type of packaging, holes are made on the surface of the plastic film to improve the breathability of fruit and vegetables. The perforations vary depending on the product’s characteristics.

This is just one example of the applications made possible by laser technology. Other examples include the perforation of leather for car interiors, the manufacture of pipes for irrigation, the microperforation of instruments for the health sector.

Cleanliness

Of all the machining processes based on the removal of material from a workpiece, laser is the one that produces the least residue because the material is removed by sublimation. Even the processing waste (i.e. the parts of unused raw material) can be reduced thanks to nesting, which is managed by a special software.

Computer control makes it possible to make the most of the work surface. In most cases, one can obtain more finished pieces from the same material using this technology than with traditional methods. In this respect, laser represents a leap in quality if compared to other processes based on chip removal, or on the use of various types of abrasive fluids.

Moreover, the need to remove production waste is reduced. The laser beam concentrates high energy on the processed material which, undergoes chemical-physical alterations that cause its instant removal.

This feature makes laser ideal for all the industrial sectors where the absence of processing waste and a clean production environment are key. Consider, for example, the field of electronics, the medical device sector, and the packaging sectors.

The absence of waste and other residue also has an economic advantage: in fact, the cuts made with the CO₂ laser do not need further finishing. They are performed without leaving the slightest trace of material behind. Each piece therefore takes less time and money to produce.

Speed

In industrial processes, the speed at which work is performed is a fundamental requirement.

Laser is capable of performing work at a very high speed. This feature is particularly evident in the execution of complex design operations.

Processes such as the engraving of barcodes and identification codes, the decoration of fabrics, or the cutting of complex shapes are carried out practically instantaneously by a laser beam.

But even slow and expensive processes such as fabric finishing can be effectively replaced by a CO₂ laser. A previous article explored the finishing of denim fabric through laser scanning processes. In the past, the discoloration of jeans was performed using very slow chemical processes, which were expensive in terms of resources and extremely polluting.

The integration of laser in the production chain of these products has made it possible to significantly speed up the production process, achieve considerable savings in terms of resources, as well as reduce the ecological footprint.

Lack of contact

Laser is a non-contact process, a feature that comes with many benefits.

Firstly, tool wear is limited. As a result, maintenance costs are reduced. The laser beam, (the instrument that physically performs the processing), emits a coherent and focused beam of light. Since there is no mechanical contact between the tool and the material, it wears less.

Of course, even a laser source needs routine maintenance. The laser-producing medium, CO₂ gas, is consumed over time. The self-refilling technology developed by El.En. for its laser sources has made it possible to greatly reduce maintenance. The gas can be refilled in-house which reduces the machine’s periods of inactivity.

The lack of mechanical limitations on laser movement, the small diameter of its radius and the possibilities offered by numerical control combine to give very high tolerances during production. Engraving or cutting complex shapes become extremely simple. This is a feature that makes laser an ideal choice for all the sectors that use design to get a competitive edge, such as fashion.

It is clear that the introduction of laser in the production process is advantageous for all the applications where personalization, speed and production flexibility are decisive.

Companies that deal with productions with a high level of customization, which need precise processing, which must respond to a market with multiple demands, can compete in a cost-effective way with other companies that make economies of scale their strength.

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The food industry has long been experimenting the use of thermoplastics for food packaging. Materials such as polyester are easy  to  manipulate and inexpensive. Plus, the fact that they are sterile, strong and waterproof make them ideal for the packaging of fresh or ready to use food products.

In this article we will discuss how to seal plastic containers using a CO2 laser scanning process. This technique can substitute the traditional mechanical application based of heat and pressure. It becomes possible to notably speed up the sealing process, increase its flexibility and reduce the consumption of resources.

The packaging of food products

Traditionally, food containers are sealed by applying heat and pressure to a thermoplastic sheet. The machines used for this process are very bulky and require strong fixturing of the containers to be processed. They have to be kept perfectly still while the sealing head applies pressure and heat to the plastic film in order to seal the container.

This process has some limitations. Since it is above all a mechanical process, the parts that come into contact with each other get worn with time and have to be replaced. The tools have to be tailor-made to adapt to each type of container which makes the production line hard to change quickly. These types of machines require constant cleaning and maintenance. Finally, one needs to consider the cost of stocking and upkeeping the various pieces of machinery.

Nowadays, this type of production is hard to sustain. Flexibility and speed of execution are determining factors that will allow a company to promptly take on the changing requests of the market. The CO2 laser sealing makes it possible to overcome the previously mentioned inconveniences as well as seal plastic containers in a fast and flexible way.

How does laser sealing of food containers work?

In a laser sealing process, productivity is key. A high powered laser source that works in tandem with a highly performing laser scanning head allows for high production rates. The laser source produces the beam that generates the necessary energy and heat to seal the thermoplastic sheet to the container. The higher the power of the laser source, the shorter the production cycle.

A scanning head directs the CO2 laser exactly where needed. A highly performing laser scanning head has galvanometer mirrors with very high angular velocity, that ensure an instant response and therefore a fast production process.

Thanks to this system, the laser doesn’t only do welding: the same source can be used to finish off the product, for example, cutting off the parts that exceed the size of the container.

This process is very versatile and suitable for every type of container. It is particularly useful for multi-compartment containers. As opposed to mechanical processes, laser welding is contactless and therefore a completely sterile process which makes it perfect for the food industry. There are no costs related to maintenance or the deterioration of tools and it isn’t necessary to change any machinery pieces for different production runs. The process is fully computerised and the change of production is practically instantaneous.

In conclusion, the use of the CO2 laser for the sealing of food containers is a fast and flexible process. It makes it possible to take full advantage of the company’s resources.