Glass is one of the many materials that can undergo CO2 laser treatments. Laser is most often used for markings or cuts. In this article, we will explore how compatible glass is with laser technology and its possible applications.

Glass composition

Glass is a material of natural origin, composed mostly of silica (SiO2). The material is heated until it reaches melting point and then left to resolidify. This process yields glass, a transparent material with a great resistance to corrosion.

Glass does have some defects, though. It is fragile and has a low resistance to thermal expansion.

Types of laserable glass

It is important to take its negative characteristics into consideration before applying laser technology to glass. Its type of composition and production will be deciding factors when choosing where to use laser.

Composition

Most of the glass available on the market isn’t composed solely of silica. Depending on the glass’ final use, other components are added to the silica to modify the material’s properties.

Adding substances to the material does alter its ‘laserability’. For example, laser technology cannot be used when metal has been added to glass. Crystal is part of this category of glass. In order to increase transparency, lead is added to the composition, thus making it incompatible with laser.

Production

Most glass is produced industrially. Nonetheless, one can still find productions of artisanal glass objects; obviously at a higher price.

The first type of glass has a more uniform structure which makes it a better candidate for laser applications. Artisanal glass, on the other hand, isn’t as easy to use with laser. The glass can contain structural and compositional inconsistencies like microfractures. This glass could easily crack when exposed to the heat generated by the laser.

How laser technology works on glass

Though laser applications usually work by sublimation for most materials, in the case of glass, the process is different. As previously mentioned, glass has a low tolerance for thermal expansion. Laser technology takes advantage of this characteristic by generating fractures at a microscopic level. These result in markings or cuts.

How does this process take place? Glass contains trapped microbubbles of air. When the laser touches upon the surface, it heats it and causes the dilatation of these bubbles. Due to the material’s lack of flexibility, this dilatation generates the aforementioned micro-fractures.

CO2 laser markings on glass

Laser marking is the most common technique applied to glass. It is usually used for decorations or the marking of codes and other information.

Productions using laser have many advantages compared to traditional methods. They are cleaner, cheaper and offer a much wider range of applications.

Markings can be done in different ways, depending on the type of glass.

Soda glass

Soda glass is the most common form of glass. It is used for windows, bottles, glass flatware and other commonly used glass objects. It works well with laser technology.

On this type of glass, markings are made by generating thousands of microfractures on the glass’s surface. Thermal shock causes the dilatation of the glass, which, due to its rigid nature, fractures at a microscopic level. The final result is an opaque marking with a satin finish. It looks very similar to results obtained using more traditional methods, but at a much lower price.

Examples of this process can be found in the decoration field (decoration of glasses and flatware, windows and cabinets), in the car industry (identifying codes markings on car windshields and windows), in the production of glassware for laboratories (measurement markings).

Quartz glass

Quartz glass is obtained from the fusion of quartz rather than silica. It has a high resistance to heat, great optic transmissibility and a high resistance to corrosion.

CO2 laser markings on quartz glass are done through superficial fusion. The material’s fusion modifies the reticular structure of glass making light refract differently on the markings compared to the rest of the surface.

Boro-silicate glass

Boro-silicate glass, known commercially as Pyrex, is obtained by adding boron and other composites to the silica. The chemical reaction produces a glass that is highly resistant to thermal expansion. It is usually used for the production of flatware and oven trays.

Boro-silicate can undergo CO2 laser markings.

Contact us for more information on laser marking of glass.

The packaging and paper goods industry are the sectors which have most benefited from the introduction of the CO2 laser. This tool has triggered innovations in applications, production methods and in products.

Most of the laser’s benefits are due to the fact that it is a contactless tool. As opposed to traditional methods, lasers can follow a complex cutting path and allows for a much more flexible production. It can be used for complex applications and guarantees extreme precision at a high production speed.

Laser applications for security paper

Its precision and flexibility make laser technology perfectly suited for government issued paper and security paper.

Government issued paper and security paper have a number of inbuilt tricks to avoid being counterfeited and guarantee their originality. Security paper is usually employed by state or government agencies in the production of goods such as:

• official documents
• I.Ds
• bank documents
• checks
• banknotes
• shares
• certificates
• visas
• government stamps
• passports

In order to avoid tampering or counterfeiting there are many possible devices which include:

• watermarks
• security thread
• surface treatments
• holograms
• security windows

Each company has its own particular applications and patents. The producers of security paper constantly strive to make their product more innovative and tamper proof.

Laser technology makes some necessary applications to prevent counterfeiting possible. The fact that lasers can perform cuts at a controlled depth and follow complex processing paths make them ideal tools for this sector.

Kiss cutting, laser marking, perforation and laser etching are some of the possible applications. Let’s take a look at them, one by one.

Laser kiss cutting

This application is often used in the production of stickers. Kiss cutting consists of a very light cut on a piece of paper. Unlike normal laser cutting, the cut doesn’t go through the paper. It makes it possible to separate the sticker from the matrix, allowing the user to remove only the sticker. It is perfect for the production of government issued paper such as revenue stamps or postage stamps.

Laser scoring

Laser scoring is used to create folding lines on a piece of paper. The process is very similar to laser kiss cutting. Laser technology offers great control over all parameters. This makes it easy to decide the depth of the incision. The scoring, for instance, can be used to prevent the reuse of stickers or stamps. As soon as they are unstuck, they become irreversibly destroyed.

Laser drilling

Laser drilling is used to make little holes on a material. These perforations can have varying diameters and even reach microscopic levels. The drilling of indelible alphanumeric codes is one of its possible applications. The code becomes an intrinsic part of the document. Passports, for example, have serial codes inserted inside them.

Laser engraving

In laser engraving (a subset of laser marking applications), the beam is used to remove a superficial layer of material. This layer can have different depths and configurations. The engraved shapes can vary greatly from logos to alphanumeric codes, from symbols to images and all are indelible. Laser engraving can be performed on paper but also on other materials such as plastic. Plastic I.D cards are an example of this.

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

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

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

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

Polyester and its properties

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

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

Laser applications on polyester

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

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

Laser cut on polyester fabric

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

Other advantages are:

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

The right laser sources to use

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

Blade RF 177G

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

Blade RF self-refilling

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

The answer is a lot! The ability to make cuts with very close tolerances, down to a fraction of a millimeter, is one of the main advantages of laser cutting. In fact, laser is not subjected to the mechanical limits of traditional cutting tools.

The characteristics of the material impose intrinsic limitations to cutting mechanisms such as blades and hollow cutters. A blade, for example, must respect certain minimum dimensions to work properly. These dimensions mean that the blade cannot perform certain types of cuts such as very narrow ones.

Laser, on the other hand, does not have any of these drawbacks as it is composed of a polarized light beam focused on a very tiny spot. A CO₂ laser scanning head, such as AZSCAN S35, can focus a beam with a diameter ranging between 140 and 450 micrometers on a surface. Just to put things into perspective, a human hair is about 70 micrometers!

The fact that in laser technology there is no contact with the surface and the working dimensions are so small, makes it very easy to achieve extremely complex cutting geometries.

Also, laser cutting works well with all types of materials, from rigid ones, such as multilayer wood, to fragile ones, such as plastic film. They can all be processed easily and accurately, minimizing the risk of breakage and waste of material.

In addition to the previously mentioned advantages, laser also offers extreme controllability of parameters and a high speed of execution. All these elements combine to make CO₂ laser an incredibly powerful working tool. Flexibility, speed and accuracy open up infinite possibilities, especially for sectors such as packaging and fashion, which rely on creativity. Contact us if you wish to know more!

The synthetic leather market has seen exponential growth in recent years. Natural leather is becoming an increasingly scarce commodity, both for economic and environmental reasons. On the one hand, the need for finished products at ever lower prices limits the use of expensive raw materials, and on the other, animal and environmental issues are driving companies to choose eco-friendly solutions.

Synthetic leather is very similar to natural leather from both a technological and sensory point of view. Unlike natural leather, it is not a breathable material. It also needs a base layer, often made of cotton or other natural fibres.

The advantages of synthetic leather over hide are many:

• production costs are very low
• the production batches are very uniform
• textures and effects that do not exist in nature can be produced
• it is easier to cut and sew

Far from being a less noble alternative to the original material, synthetic leather is a practical and modern material. It can be successfully used everywhere traditional leather was, with the same aesthetic and technical results.

The composition of artificial leather

Synthetic leather is made up of two layers, an upper one that imitates leather and a lower one acting as a base.

The upper layer is composed of a synthetic polymer. The most used materials are PVC (Polyvinyl chloride) and Polyurethane (PU). The two materials differ slightly. Most synthetic leather is made of PVC due to its low cost and greater resistance. Polyurethane, a costlier material, is less frequently used even though it feels more like real leather to the touch.

The artificial leather base is in fabric which can be made from synthetic fibres, natural ones (usually cotton) or even natural-synthetic blends.

The role of the fabric base is very important. The mechanical properties of synthetic leather rely on the strength of its base. The lifespan of synthetic leather is in direct correlation to the one of the fabric base.

Can you laser engrave faux leather?

The answer is yes, you can. Due to its thermoplastic polymer composition, synthetic leather lends itself very well to laser processing, particularly with CO₂ lasers. The interactions between materials such as PVC and Polyurethane and the laser beam achieve high energy efficiency, ensuring optimal results.

Laser marking and engraving

The marking and engraving processes are very similar. In both cases, the laser beam acts on the surface layers. The laser energy activates alterations which, depending on the intensity, can be more or less deep or radical.

In marking processes, the applied energy density is very low. The material’s transformations stay at a superficial level and are more aesthetic in nature.

In laser engraving, the applied energy density is higher and reaches deeper layers of the material. It therefore undergoes substantial chemical transformations. The marking is more visible and contrasted. The end result can have a tactile finish and even a natural texture.

Laser parameters

The system must be set according to certain parameters to achieve the desired laser marking or engraving effects. There is no universal rule one can follow to set the system. The correct parameters depend on factors such as:

• the type of material used: polyvinyl chloride and polyurethane absorb energy differently. So the settings must be regulated differently.
• the colour of the leather: light coloured leather is more reflective than a darker one. Dark leather therefore absorbs the laser beam better, resulting in greater energy efficiency and faster processing.

A correct laser setting will aim to achieve the correct energy density in order to obtain a clearly visible mark without damaging the material.

Laser Engraving Systems

Leather marking/engraving is one of the applications of galvo scanning. This category includes all processes in which the laser source is used in combination with a scanning head.

The scanning head distributes the laser beam produced by the source on the material’s surface.

Laser sources and scanning heads are available in different models depending on production needs. In order to make the right choice, it is necessary to know your particular manufacturing characteristics. Send us information about your production plant and requirements and we will be happy to design a tailor made leather laser marking/engraving system to suit your needs.

Laser material processing started a revolution in the industrial world. It has brought quantitative improvements such as an increase in production speed, and qualitative ones, such as the possibility of creating customized products with high added value, even on a small scale.

The packaging sector immediately understood that the use of laser could offer endless possibilities for innovation. Packaging is a fundamental aspect of most manufacturing sectors and laser technology is taking a strong foothold in this growing market. Laser reinforces and improves the characteristics of packaging materials, helping them perform their desired function even better.

Packaging in itself performs a wide range of functions:

• First of all, it has a protective function. Packaging must protect the product from external agents. In the case of food, it prevents deterioration and guarantees the product’s integrity
• Secondly, it has an aesthetic function. Packaging must convince the consumer to choose a specific product on a supermarket shelf. In a world increasingly rich in consumer goods, packaging can sometimes be a product’s only distinctive factor
• Thirdly, it has an informative function. Important informations such as ingredients, expiry date, production lot or barcode must be visible on the product
• Last, but not least, it has a practical function. Packaging must make the product easy to handle and use. Thanks to laser cutting, packaging can be designed in such a way as to facilitate the use of the product itself. Easy to open packaging such as food bags or easy cutting ones such as yoghurt pots are two examples of this type of packaging.

Functional and fast packaging with innovative technology is now easier than ever with laser technology.

Why process packaging with laser?

Laser-based manufacturing is extremely flexible and give the possibility to experiment on a great variety of applications. Laser, and in particular CO2 laser, achieves its maximum levels of efficiency when it processes the most commonly used packaging materials such as:

• paper and cardboard: used to produce boxes and packaging, these materials can be cut, marked and perforated. The producers can thus create boxes with original shapes that can bring out the abstract qualities of the product
• wood and derivatives (for example MDF) are used to create innovative packaging. Food crates to transport produce are but one example
• plastics and derivative: thermoplastic film polymers such as polypropylene, polyethylene and PET are among the most used materials for packaging. Plastic film can be adapted to the most diverse needs through cutting, marking or drilling processes. Food safe plastics benefit greatly from these applications. For example, containers can be perforated, to regulate the passage of air or to create filtering systems, but also be cut into complex shapes. Other applications in this sector include the cutting of plastic films used to make various types of packaging, including aluminised plastic films

Laser technology is also a great asset for the packaging sector because of the possibilities offered by automation. The benefits of a fully digitized and automated manufacturing process are significant. The automated process reduces the possibility of errors, allows changes to easily be made in real time, guarantees extremely uniform results while having standard and repeatable characteristics.

For example, imagine being a manufacturer of plastic parts for the automotive industry. A digital manufacturing workflow would allow you to automatically use laser to engrave a production batch number on a piece’s packaging, centralize this information in a database, as well as have a system that allows you to trace all the logistics, from the production to the end customer. Should there be a defect or a malfunctioning piece, the production batch (or any other information) could easily be looked up directly in the database.

Laser processing in the packaging sector

Many of the advantages derived from laser processing are due to the fact that laser is a no-contact technology. The laser beam is used as an energy source that gets concentrated on a specific area in order to perform an application. Here are some of the main applications laser systems can perform.

Laser cut

In laser cutting, the beam vaporizes a portion of material according to a defined path. The final quality of the cut depends on the material. CO2 laser cut creates extremely clean edges on most materials. The final piece does not need further finishing and is ready for use.

Laser cutting can be used to cut windows and openings on a package, to create details such as tear openings, easy-to-open tabs, filtering systems, to cut pieces of packages for later assembly.

Laser marking and engraving

Laser marking and engraving use laser to imprint a mark on a material. The two processes are very similar.

We speak of laser marking when the transformation of the material occurs only superficially. In the case of laser engraving, there is a deeper transformation of the material.

In the first case the sign, even if indelible, results in a discoloration of the material. In the second case the sign is much deeper and it is also possible to obtain a tactile sensation on the incision.

Manufacturers mostly use laser marking and engraving on packaging. Laser allows them to permanently engrave their logo in remarkable detail. Expiration dates or production batches can be applied on the packaging, taking advantage of the automation capabilities offered by laser systems. This application is known as laser coding.

Perforation and laser microperforation

Drilling machines use laser to create holes on a material. Typically the holes are made on sheets or slabs of material. Finished pieces can also be perforated.

The holes can have different dimensions. Indeed, the possibility of varying the size of the perforations in order to adapt them to a specific purpose, is the true advantage of laser perforation.

The term laser microperforation is used when the holes have microscopic dimensions. Laser perforation and microperforation have numerous applications in the packaging sector.

Laser perforation can be used to create filters and other features on the packaging, such as the creation of perspiration holes for food trays.

Laser microperforation can be used to create breathable packaging (such as modified atmosphere packaging). In this case, microperforation can be used to calibrate the packaging to the product and increase its shelf life. The processing of flexible plastic films takes great advantage of this application which allows you to create wraps capable of significantly extending the life of the product.

A sector in constant evolution

Laser technology makes it is possible to decide on a desired result and calibrate the process on it. Many laser applications have not yet been tested which means there is a whole world of opportunities to explore. The tailor made application that could bring numerous advantages to your production system could be just around the corner.

Here at El.En., we have experimented with thousands of laser applications for packaging over more than 35 years. If you work in this sector and are looking for your next personalized application, contact us and let us know what you need. We will be happy to help you build the ideal solution for your application!

Microperforation is a laser process that consists in creating micro holes on a sheet of raw material. Microperforation makes it possible to precisely choose the size, depth and quantity of holes per square centimeter. The flexibility of this technique makes it easy for the operator to change the processing characteristics according to the intended final use of the piece.

There are many examples of this processing technique from various sectors:

• the paper industry where microperforation is used to create security paper, i.e. paper products with special features to make counterfeiting very difficult
• the industry of fabrics and leathers, microperforation can be used to add decorative elements but also to improve the breathability of materials
• a similar application is in the automotive sector, where for example, microperforation is used in the finishing of leather for the internal lining of cars
• the packaging sector, microperforation is widely used. It is used to microperforate the plastic film used for packaging in modified atmosphere because the size and density of the holes can be adjusted with great precision
• Finally, a last example comes from the field of soundproofing. Sound absorbing tiles that perfectly muffle a specific type of frequency, are made with laser microperforation

The advantages of laser microperforation

Microperforation has several advantages over traditional applications. Here are two:

• Precision. Laser can perfectly calibrate the density, number, size and internal shape of the holes. Microperforation therefore allows you to create processes perfectly suited to the intended use of the product
• Flexibility. Different materials can be processed using the same laser source. CO2 laser sources are unbeatable for their flexibility of use

What materials can be processed with laser microperforation?

CO2 laser microperforation works best on flexible natural and synthetic materials. Some of them include:

• thermoplastic polymers, materials such as PMMA, polyethylene, PP and PET are among those most used in the packaging sector and suitable for this type of processing
• leather and hides
• fabrics made from natural and synthetic fiber
• paper and cardboard

Which laser source to choose to execute laser microperforation?

There are many factors to take into consideration when choosing the right laser source for microperforation.

One must consider the material being processed as well as the desired production outcome and process speed. Based on these elements, it is possible to establish the best wavelength and the power to use to get the job done.

Although finding the laser solution that best suits your needs may seem impossible, don’t worry, our experts have extensive experience on the field and will be able to help you find the laser system that’s right for you. Contact us for more information!

Laser marking has become a standard in many industrial sectors. Its advantages are flexibility, speed, precision, the quality of the etched signs, eco-friendliness.

The vast majority of laser marking applications are aimed at identifying products and components. This role is traditionally played by labels of various types, printed or engraved and subsequently applied to products. Laser marking replaces the labels and allows information to be engraved directly on the surface of the product or component.

How laser marking process works

The laser marking process takes place through the interaction between the laser beam and the surface of a material. This interaction triggers an ablation process, through which a superficial layer of variable size is removed. The final result depends on which type of material is being marked and which type of laser is being used. The CO2 laser is the most used in laser marking processes because it can be applied to many materials.

What information can be laser marked

Laser technology makes it possible to engrave all kinds of information about a product. Some examples are:

• barcodes
• QR codes
• sequences of alphanumeric characters
• production lots and expiration dates
• copyright information
• manufacturer’s logos
• compliance logos

The advantages of laser labeling

Currently, there are three main ways to apply information on the surface of a product:

• Inkjet printing. It prints alphanumeric codes using a dot-matrix printer. This type of application is used on organic products that could be damaged by the laser’s heat. However in recent years it has been found out that laser can also be used successfully to label fruit, vegetables and other organic materials. Even if ink-jet printing guarantees a high level of productivity, it isn’t always long lasting since different materials retain the ink better than others, and the maintenance of the production line can be costly.
• Metal stamping. It prints signs by plastic deformation of the material’s surface. The imprinted marks are evident and can’t be counterfeited easily. It can be applied on metal labels that are then affixed to the different components, but it is not suitable for direct marking applications on the component itself. Metal stamping requires the use of a specific imprinting tools and dies, which have high maintenance costs. Also, changing the information to print is expensive because it requires changing the printing tool.
• Self-adhesive labels. Information is printed on a self-adhesive label which is then applied to the product. Labels are not very environmentally friendly because the back of the stickers are discarded.

Compared to these marking systems, the creation of labels by laser marking has undoubted advantages.

• Quality. Laser markings are perfectly defined and never fade, however much the product is subjected to intensive use. Laser technology suits well where preventing counterfeiting is necessary.
• Cost. While it is true that laser requires a greater initial investment than the other methods, it also has much lower maintenance and processing costs. Laser is advantageous when used in production processes that foster its strengths, that is favor high levels of customization, highly automated management of processes and perfection of the output.
• Flexibility. The printed information can be modified and updated very quickly without the need to adapt work tools or its ensuing costs. Tooling changes and machine preparation are reduced to practically nothing. Laser marking makes it possible to access a piece’s recessed areas that would remain inaccessible with conventional technologies.
• Respect for the environment. Laser labeling is more eco-friendly than traditional labeling since the consumption of plastic, ink and glue for labels is reduced considerably, as well as the costs associated with the disposal of unused sticker’s support.
• Efficiency. The information on the labels can be immediately digitally processed. It is therefore possible to increase the traceability of the processed pieces. Laser marking of labels can also be made on the fly.

Applications

There are many laser marking applications which range from the traditional ones like the marking of parts and components to the more advanced ones like the laser marking of food. There are many examples of applications in this latter area:

• engraving of codes on eggshells: this case study shows how laser marking can replace ink printing on eggshells
• marking of cold cuts and cheese wheel: cheese wheels and cured meat can be easily marked with laser. In this application laser marking replaces hot marking
• marking of fresh produce: in this application, laser marking is used to engrave information and logos directly on the surface of fruit and vegetables. In this case, laser marking replaces the self-adhesive labels

Other application examples include:

• Automotive: windshield engraving, identification of car components
• Gifts: product information
• Electronics: laser marking marking of silicon boards for integrated circuits
• Engineering: marking of construction components

What is your application?

You might be considering how laser marking could help you improve your business. Here at El.En., our team of experts will be happy to help you choose the right laser system for your needs. Our laser sources and our scanning systems are used all over the world and help thousands of companies create high quality products. Contact us to learn more.

Paint stripping operations have always been an expensive and time consuming process. Removing paint from an object, especially a large painted surface, requires many hours of work. In most cases, solvents and big quantities of water are used to strip paint which has negative consequences on the health of workers and the environment.

An alternative to traditional paint stripping is laser paint removal, an effective, fast and environmentally friendly method to remove paint from a surface.

Traditional paint removal methods

Paint has been used to cover surfaces and object since ancient times. Their function is twofold: on one hand they protect the material they cover from wear and tear, on the other, they strongly contribute to the aesthetics of the object.

Practically all industrial sectors make use of paint, but for some, it is a crucial part of the production process.

This is the case, for example, in the vehicle manufacturing industry, whose objects – airplanes, ships or trains – have large painted surfaces.

Aircraft can be repainted in cases of general maintenance or after a change of ownership.

Traditionally, chemical and physical methods are used to remove paint, i.e. the paint is softened with solvents and then scrapped mechanically. This technique has other drawbacks:

• it uses of highly polluting substances
• areas that don’t need stripping need to be masked to avoid damage
• the chemicals used need to be rinsed off, which causes a high water consumption
• it produces potentially toxic waste and chemical vapors which are bad for operators and the environment

Laser depainting makes it possible to overcome these drawbacks, transforming stripping into a fast, effective and precise process.

The process of stripping paint with laser

The laser paint stripping process consists in irradiating the painted surface with a laser beam that vaporizes the paint layer.

The paint is removed practically instantly thanks to a sublimation process. Compared to traditional methods, laser paint stripping is a much faster process. In a few hours it is possible to remove tens of square meters of paint from a surface. The only consumption of resources is the electricity used to power the system.

Harmful solvents or other chemicals are unnecessary. Just apply the laser to the surface and in a few seconds, the paint is removed.

Which technology for laser paint stripping?

Defining the technology suitable for a laser stripping system in detail is difficult without knowing its specific context of use. The fundamental components of a system of this type are a laser source and scanning head.

Theoretically, the choice of the laser source depends on the chemical composition of the paint to be removed. It is a well known fact that each material absorbs a certain wavelength more or less well. The most efficient laser source has a wavelength that is best absorbed by the material it is trying to sublimate.

However, an important consideration must be made. It would not be viable to create a paint stripping machine which could only strip on one type of paint. A laser depainting machine must be able to remove the greatest number of paints on the market.

The CO2 laser offers the best compromise between reliability and versatility. A carbon dioxide laser source is therefore the most suitable tool for this application. The wavelength of 10.6 micrometers is in fact effective on most of the paints on the market because it is highly absorbable. It can remove both white and colored paints, without damaging the underlying surface.

The scanning head is the other fundamental element of a system for laser stripping. This device is used to precisely direct the laser to a specific part of the surface and to keep it focused on that work area. These two characteristics make it an extremely precise work tool.

The choice of the head depends not only on the laser used, but also on how much surface needs to be covered. Large surfaces require particular scanning heads such as the El.En. AZSCAN HR70 which manages to cover an area as big as 2300 x 2300 mm.

The fundamental components of a laser system for paint stripping are The laser source and the scanning head. However, their implementation is strongly guided by the type of work needed. The possibilities are endless and each application requires the study of a tailor-made system. Contacting our technicians is the best way to find out the possibilities this application offers.

Plastic processing was one of the sectors in which the introduction of the CO₂ laser was immediately appreciated. Laser has made it possible to carry out faster, more precise and less wasteful processes.

Flexibility has been the watchword that made new methods possible andopened up new areas of application for plastic processing.

The word “plastic” is quite inaccurate: it covers a large number of materials which have very different behaviors, mechanical characteristics, workability and possible applications.

Cutting, drilling and marking are the main processes that can be carried out with CO₂ laser. Plastic objects are cut by gradually removing the material until the laser beam penetrates through its entire thickness.

Some plastics lend themselves more to cutting than others. The best results with laser are obtained with acrylic (PMMA) and polypropylene (PP). On these plastics, the cut comes out with smooth, shiny edges and without any scorch marks.

CO₂ laser marking for plastic is based on the same principle as laser cuts; though in this case, the beam only removes a surface layer, leaving an indelible mark.

In theory, laser can mark any type of logo, code or figure on plastic, but in reality, the possible applications depend on the material used. Some materials respond better to cutting operations, while others are more suitable for marking.

But what does this great variability of behavior between one plastic and another depend on? The difference lies in the different disposition of the monomers, the repetitive molecular units within the polymer. Variations in temperature have an effect on the material properties and behaviour.

In fact, all plastics are processed with the use of heat. Depending on how they respond to it, plastics fall into two categories: thermosets and thermoplastics.

Examples of thermosetting polymers are:

• polyimide
• polyurethane
• bakelite

The main thermoplastic polymers are:

• polyethylene
• polystyrene
• polypropylene
• polyacrylic
• polyamide
• nylon
• ABS

Thermoplastic polymers, up to a certain threshold (called glass transition temperature), behave like a crystalline solid. Beyond this temperature they first transition to a rubbery state and then finally melt. These polymers are made up of linear chains, which explains why they can be melted and easily molded at certain temperatures.

Thermosetting polymers on the other hand, stiffen as the temperature increases until they reach melting point, beyond which a change of state occurs. Cross-linking within the macromolecule, makes them less susceptible to temperature differences.

Because of these substantial differences, not all plastics respond well to laser. In general, thermoplastics lend themselves better to laser processing, but even thermosets can, to some extent, be subjected to laser processing.

In the following tables we have summarized the result of the interaction between the various polymers and the laser.

As you can see, the results vary widely. A case by case analysis is recommended to understand which application works best. Plus, more plastics can undergo laser cutting: teflon (PTFE) is on of those.

How to choose the right laser system for plastic

The introduction of laser in plastic processing has paved the way for new applications. Laser processing of plastic is very convenient. Most commonly used polymers are perfectly compatible with the CO₂ laser.

But choosing the most suitable laser system is not easy. The variables to take into consideration are many: the type of application, the type of material, and the production needs.

El. En. has produced laser systems for plastic processing for over 35 years. If you have an application in mind and aren’t sure how to make it, contact us. We will be more than happy to help you.