Let’s continue our journey of discovery of the different CO2 laser applications for the packaging industry. In the past articles, we’ve already described how laser micro-perforation can drill accurate holes on plastic film to create packages suitable to preserve fresh food. Laser micro-perforation applications, unlike traditional mechanical micro perforation applications, offer speed, flexibility, and extreme accuracy.

In order to improve the shelf life of products, it is often necessary to continuously control gas exchanges between the interior and the exterior of a plastic bag. Laser micro-perforation allows us to tightly control these gas transmissions, allowing us to easily package fresh products as well as preserve their quality.

It is no coincidence that the CO2 laser has seen a broad application in this field. The packaging industry knows very strict production rules and specifications. Packaging must not only guarantee the quality of the product, but must also meet requirements in terms of mechanical strength, packaging hygiene, and food safety. Besides that, all requirements also have to be reconciled with an aesthetic appearance. Poor packaging could reduce the perceived quality of the product, and is thus a crucial factor in influencing consumer buying behavior.

In this article we’re going to describe another application of the CO2 laser: we will talk about sealing plastic food bags.

Conventional methods to seal plastic food bags

Why is the CO2 laser an innovative process for the sealing of food bags? To get an answer to this question we have to briefly discuss the traditional methods used to seal plastic food bags.

Traditionally the sealing of plastic food bags is a welding process achieved through the application of heat and pressure. In this process, two sheets of plastic film are joined and welded together. This process is mostly mechanical, meaning that parts of the machine have to be changed every time a different packaging process is executed, in order to meet the packaging needs of diverse products. Traditional machines are heavy, due to their working parts that need to be fastened securely.

A production line of this kind is not flexible, while food manufacturers may need to apply different packaging techniques within the same production cycle. This would mean that the manufacturers have to the change machine parts or perform other maintenance operations, which results in lower productivity.

Laser hermetic sealing plastic food bags

The process of laser sealing of plastic bags is part of the hermetic welding process of thermoplastics. The most commonly used bags in the packaging industry are transparent and made of polypropylene or polyethylene.

These materials absorb the 10.6 μ wavelength of the CO2 laser very well. The laser beam reaches the surface of the material to be welded thanks to a scanning head. Subsequently, the laser heats up the surface so as to reach the melting temperature of the material, allowing it to weld the two plastic films together.

The entire process is incredibly fast: the speed achieved with this welding method to hermetically seal plastic bags allow to seal dozens of pieces per minute.

What are the advantages of hermetic laser sealing?

The advantages of using a laser sealing system to hermetically seal plastic food bags are endless:

• You can change the shape and size of the packaging material to be sealed without the need for long breaks in the production flow. It is not necessary to create custom-made parts since the laser can be applied to any type of container and to any type of machining even within the same production cycle.
• The sealing can even be carried out on very thin plastic films without risking any damage to the material. This allows extremely accurate machining operations and reduces the amount of material used, and thus reduces industrial waste.
• The CO2 laser is compact in size and light in weight since mechanical parts or other bulky mechanisms are not required. The laser system thus fits well into production facilities with confined spaces.
• Like any other laser process, the welding of plastic bags is a non-contact process. This means, among other things, that it is aseptic, and thus perfect for the packaging of food products.

Required components for a laser system setup

You may ask yourself right now which components are required for a laser system set-up. It is difficult to define in detail the diverse components or elements that will be part of the system. Each customer has its own needs in terms of power, production speed, material to be treated, etc. However, it is possible to define the following three basic elements of a similar system.

CO2 Laser source

The CO2 Laser source generates the laser beam that will work your materials. El.En. CO2 laser sources are available in different output powers, ranging from 150W to 1200W.

Laser scanning head

The laser scanning head is a device that “moves” the laser beam while keeping it perfectly focused on the point that needs to be worked. El.En.’s scanning head executes this process at very high-speed thanks to the beryllium mirrors mounted on galvanometric motors.

Control Software

The advantage of laser processing is that the entire process is controlled digitally. Through the software, you can control all relevant machining parameters and perform on-the-fly changes without interrupting the process workflow.

Wood, paper, cardboard, plastic, PMMA. And also rubber, leather, metals, and ceramics: CO2 lasers can cut a great number of materials. For this reason, CO2 lasers have become the most widely diffused laser technology for laser material processing.

However, despite the wide use of the CO2 laser we receive a lot of questions on possible appications that can all be summed up by what materials can be cut by CO2 laser? In this article we answer to this question with a simple list of materials that can be easily cut with CO2 lasers (the links take to articles that examine each topic in depth): 

• Wood based materials
• Paper based materials
• Acrylic (PMMA) and other plastic polymers
• Leather and faux leather
• Natural and synthetic fabric
• Biologic materialAll industrial sectors that need to process these materials can thus use the laser CO2 for a faster, smoother, and more precise cutting process.

Fields of application

To go into the details, the following list displays the main applications of CO2 laser cutting, ordered by industry:

• Papermaking industry
• Cutting cardboard boxes
• Cutting paper and cardboard
• Stencil cut
• Decorations

• Woodworking industry
• The cutting of any kind, and thickness, of wood, especially Plywood and MDF
• Inlay fine wood
• Engravings of any kind

• Engravings and inlays
• Laser engraving and cutting methacrylate
• Laser engraving and cutting leather goods
• Laser engraving name and number plates
• Laser engraving and cutting textiles
• Laser engraving electronic components
• Laser engraving anodized aluminum and varnished metals. N.B.: the CO2 laser usually doesn’t cut metal but can label or mark them indelibly.
• Engraving of glass, marble, and stones
• Inlays on ivory

• Creation and Customization
• Laser cutting hollow punches
• Laser cutting for architectural models
• Laser cutting plastic, cardboard, or wooden displays.
• Contour and cut labels
• Personalizing gadgets
• Personalizing buttons
• Material machining for model making

The list above is just a short list of the many different materials that can be processed by the CO2 lasers: there are lots of other materials that can be cut with the CO2 laser. Research on the applications of the CO2 laser is still an ongoing process, of which experimentation plays an important role: only experimentation provides us with certainty about the possible applications. For this reason we invite you to contact us whereby the material you want to work is not presented in the above list. Together we will find you the solution that fits your needs!

Let’s continue exploring the applications of CO2 lasers. In this article we will be talking about acrylic and CO2 laser.

Acrylic, also known as PMMA or plexiglas is one of the plastic materials that can be laser processed with success. In particular, CO2 laser is the right to do the job.

What is acrylic and why it is so successful

Acylic was discovered in the 1920s. However, the material only really gained ground only after WWII as a cheap and effective replacement to glass. Easy to manufacture and process, rugged and flexible, acrylic has imposed itself as a successful material for a wide range of uses.

CO2 laser and acrylic

Acrylic is also known as PMMA. This acronym stands for Poly Methyl Methacrylate and refers to its chemical formula which includes atoms of carbon. For this reason acrylic materials responds very well to the wavelength of CO2 laser, which is 10.6 micrometers. At this wavelength, acrylic is opaque to CO2 laser, which is therefore absorbed very well by the material. This feature, coupled with low thermal conductivity and a relatively low sublimation point (300 °C), allows acrylic processing to be done quickly and easily. As a matter of fact, the fabrication of acrylic materis is one of the applications in which CO2 lasers give the best results.

Laser cutting acrylic

The main laser processing technique for acrylic is probably laser cutting. As se we have seen, the interaction between the laser and acrylic is very efficient. That means that when a CO2 lasers interacts with an acylic surface, the latter absorbs a large part of the energy conveyed by the laser, which is focused then on a tiny spot.

High energy on a very small surface means instantly vaporizing the material and as a result we obtain the cut. This process is called by sublimation of the material. Sublimation causes the material to evaporate and therefore does not create residues, making laser cutting an extremely clean process.

The end results of this process is extreme precision and quality. The cut has clean and smooth straight edges that don’t require further finishing.

The acrylic laser cutting process is also incredibly fast. Speed ​​is related to the thickness of the material and the power of the laser source. But whatever the thickness, the processing speed will be significantly higher than the mechanical cutting methods, even if it is a CNC method.

The possibilities of laser machining are endless and, ultimately, only limited by the designer’s imagination.

Do you need a laser cutting system?

At El.En. we have a long experience in producing laser systems for the fabrication of acrylic. We can design complete laser system or integrate our CO2 laser in existing laser. For whatever request or question you might have just contact us!

The fashion, decoration, and design sectors are generally very competitive. They require a continuous stream of products and models to be offered to the public. There is a constant search for new and original design which is capable of characterizing the designer, while at the same time being in the interest of the public. In fields like design, innovation mainly relies on the imagination of designers.

That is why introducing the CO2 laser as a decoration tool has been greeted with enthusiasm by the decoration industry. The laser allows remarkable flexibility and allows to overcome any limitation imposed by traditional decorative production processes. Especially in the ceramic tile industry the laser technology process has proved to be a great ressource. The introduction of the laser has allowed producers to deeply innovate the production processes, but has also allowed them to give space to the creativity of designers. Laser technology allows to reach quality standards that were previously unattainable, while at the same time saving ressources.

The CO2 laser decoration process of tiles is based on the removal of a superficial layer of the material. The system consists of 3 basic components:

• A CO2 laser source
• A scanning head
• Control software

The laser allows you to improve the quality of machining significantly. Thanks to the laser control software it is possible to obtain a level of control and detail on ceramic tiles surface which previously was deemed impossible using traditional decorative processes. Here are the main features of machining:

• Well-defined lines: The laser allows to obtain perfectly defined lines on the ceramics, unlike conventional mechanical methods.
• Very narrow angles: the tolerances made possible by lasers are very high. This means that even very complex designs can be easily realized.
• Almost photographic quality: By adjusting the laser parameters appropriately, such as power and speed, you can get a wide range of shades making the image surface almost photographic.

Another advantage of a laser based system is its versatility that made it possible to experiment and propose new prototypes very quickly. Manufacturing gets very easy thanks to laser technologies, a tool always at the forefront of innovation in design.

The change in consumer behavior has augmented the demand for ready-to-use food. This, in turn, has resulted in the demand for different packaging types. The food technology industry has developed along and adapted in concordance with these behavioral changes, offering increasingly advanced food packaging. Consumers no longer want to be confined to plastic bags or containers, but want packaging types that are practical in use, easy to open, and that don’t require the use of additional tools. On top of this, consumers demand packaging types that do not sacrifice the freshness of food, which is a current priority to the ever-demanding consumer of today. The shift in the packaging industry is easily visible by solely walking around in the local supermarket. From ready-to-use salad to instant noodles, packaging has changed. All of this has resulted in the need to make customized packaging.

The challenges of packaging are not trivial. Traditional methods of processing and finishing of cellulose and flexible packaging are less practical in today’s market. The market has shifted from a time where general packaging suited each product, to a market where each product requires its particular packaging type. Due to this shift, traditional packaging processes have become disadvantaged. Traditional packaging involves mechanical machining; tools for cutting, engraving, and imprinting are used for mass production. Due to this, the packaging quantity has to be augmented in order to cover costs. This traditional packaging process limits flexibility and adaptivity, solely serving the mass packaging market.

Today, however, the market is much more segmented and demanding. The winning producer is the one who is able to best adapt to consumer demands and provide real added value to their products. This is a real change of paradigm, made possible by the establishment of digital production processes.

The laser is the protagonist of this change. Laser Technologies have been established in recent years as an indispensable instrument in the processing industry of cellulose and plastic packaging. Agile, accurate, and reliable, the laser is a non-contact process that is based on software control to achieve maximum precision in machining.

Laser technology is incredibly versatile: not only provides it the possibility to perform work in a more efficient way, it also makes it possible to perform tasks that were not previously possible with traditional machining. The laser allows you to personalize packaging in any way preferred. These technologies have opened up new possibilities in the packaging world.

Let’s have a look at some of the possibilities offered by the laser.

Laser engraving

Laser engraving consists of engraving a layer of plastic material. This technique is ideal for making packaging with an “easy opening”. Easy opening bags are those where the opening is engraved: the consumer only has to pull slightly in order to open the packaging material. This processing would be very difficult to obtain and costly with traditional methods. Thanks to the laser control software it is possible to accurately set the laser parameters to obtain the desired cut depth.

Laser micro perforation

Laser micro perforation involves drilling micro holes in the plastic film. Micro perforation is used in food packaging utilizing controlled atmospheres. Laser micro perforation allows you to obtain holes of any desired size, thus enabling modified atmosphere packaging. The holes are perforated precisely in the preferred size, to ensure correct gas exchange between the inside and outside environment of the packaging, thus extending the durability and freshness of these products. Traditional methods of micro-perforation did not allow this process to be controlled accurately. Thanks to the laser, modified atmosphere packaging has been made possible, guaranteeing an expanded and improved product-lifespan.

Laser cut

Laser cutting is used to cut plastic materials from side to side. The laser cut is suitable for creating very precise details, even when cutting on small surfaces. Holes for filtering, plastic containers with special shapes or openings can be made easily and quickly thanks to laser cutting. Traditional cutting tools do not allow these complex or high precision cuts.

A flexible and easy-to-integrate tool

Laser features have revolutionized the way in which packaging is understood. Thanks to the laser, it is possible to adhere perfectly to customer requirements, providing products with real added value. These characteristics enable producers to tackle the most recent challenges in the industry.

All of this can be reached using minimum effort: to install Laser System El.En. it is not necessary to revolutionize existing lines. Our CO2 laser is compact and easily modulated for all your needs. The laser can be easily inserted into systems and adapted to the existing features. No mechanical system can ever be as fast as the laser. As a matter of fact, inserting a laser into a production line avoids bottlenecks that are often represented during the finishing process.

One of the characteristics of CO2 lasers is that it allows you to carry out processes which were impossible to perform beforehand, because of technical limitations in the past.

The CO2 laser has introduced new possibilities that have been exploited to meet market demands. One of these advantages is, for example, the laser micro perforation of plastic film. This technique has proven to be very useful for the packaging of fresh products before distributing them to mass retailers.

Micro perforated bags with laser for the packaging of fresh products

Laser microperforation is one of the newest methods to create micro holes in the packaging materials of products. To do this, the CO2 laser is used in pulsed mode. Unlike continuous mode, the pulsed mode sends high-intensity light flashes on the packaging material.

Laser micro perforation is particularly important for the packaging industry of fresh products. An increase in the demand of ready to consume fruit and vegetables, distributed via mass retailers, has led to the development of new strategies to ensure product freshness. Controlling storage temperature and modifying the atmospheric conditions within the packaging of products are the two most important factors for the quality of fresh products. The packaging thus has an important role in maintaining the freshness of the product, as it works as a regulator between the interior and exterior environment.

Laser micro perforation allows you to optimize the conservation of these products, through an improvement of the product packaging.

Objective: to improve the breathability of plastic bags

The packaging materials of fresh products in controlled atmosphere are often seen in the form of plastic bags. These bags allow optimal isolation of the products, and seal them perfectly from external contamination of molds or bacteria.

But there is a disadvantage: the breathability of these materials. Plastic film is a material that limits gas transmission with the exterior atmosphere. For a proper preservation of fresh products this is a significant disadvantage, as fresh products are subject to metabolic changes such as breathing, exchanging gases with the exterior atmosphere, and producing gas from chemical processes that take place within the fresh produce.

To improve the shelf life of a product, a continuous gas transmission between the interior and exterior atmosphere of the packaging is required. The levels of oxygen and carbon dioxide, play a big role in the conservation of the product. For this reason plastic bags must be perforated, in order to facilitate a proper gas flow between the internal and external environments. The amount of gas transmission required, however, differs from product to product. For this reason the perforation process must be properly adapted to the product needs. This aspect of adapting the perforation process, however, is difficult to achieve with traditional perforation methods.

Traditional micro perforation processes of plastic bags

Traditionally, the perforation of plastic bags is performed through two types of mechanical processes:

• Heated or unheated needles: the plastic film is perforated by needles applied with or without heat. This process, though inexpensive, is slow. In addition, the holes produced have a larger diameter and can let contaminants, such as bacteria and mold, in. It is therefore not suitable for contaminant-sensitive products.
• Electric discharge: packaging bags can also be perforated by means of electric discharge. The plastic film is passed through a high electrostatic voltage in which sparks are led through the packaging film to create micro holes. This process, even though faster than the previous one, is hard to manage. The hole parameters can not easily be checked. It is therefore unsuitable for those products that require precisely controlled gas transmission.

Laser Micro Perforation: accuracy in the service of the product

The machine that generates the best results in terms of micro perforating bags, turns out to be the CO2 laser. Micro perforation with the CO2 laser makes it possible to control the drilling process very accurately and obtain high quality results.

The CO2 laser is very well absorbed by most polymers and thermoplastics. The controlling software makes it possible to set the parameters to obtain holes of the required size and density, that let you create the optimum environment for gas transmission.

A laser micro perforation machine has the following advanta

• 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.

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