Laser die cutting of labels is a digital converting process. In this application, the laser die cutter replaces mechanical dies in the execution of processes such as the cutting or trimming of label templates.

The use of laser technology is particularly advantageous. On the one hand, it overcomes the typical disadvantages of mechanical die cuts. On the other hand, it allows the same processes to be performed with a flexibility and precision impossible to achieve with diecuts.

In this respect, the laser die cutting process clearly shows the advantages of using lasers for labeling and packaging applications.

How the label production process works

The production of self-adhesive labels is one of the most traditional papermaking operations.

Typically, the label production process takes place in 3 steps:

• printing of the label on the master sheet
• engraving of the label template
• cutting of the label template

The die cutter is used for the operations of engraving the label and cutting it out from the master sheet to isolate the label from the sheet itself.

This processing technique has several disadvantages:

• in order to obtain new shapes to cut, manufacturers must create a new die cutter
• the mechanical properties of the tool do not allow complex shapes to be cut
• the cutting tool wears out quickly and needs maintenance to work efficiently

Given those features, a mechanical production system is only efficient if it can guarantee high production volumes. However, the market today rewards companies that are able to offer innovative, customised production processes that can support numerous orders with small production volumes. And from this point of view, a laser cutting machine is the optimal production tool.

Laser processing of labels

Laser die-cutting is based on an ablation process. The operation is carried out by a laser machine. The beam laser power, focused on the material, removes a portion of material through a chemical process called sublimation. By means of devices such as galvo laser head, it is possible to move the laser beam along a determined path. Digital control also makes it possible to precisely calibrate the instrument according to the desired type of processing. The operation is carried out at high speed.

There are two possible operations: laser kiss-cutting and laser cutting. Both are laser cutting processes, but differ in how deep they cut the material.

Laser kiss-cutting and laser cutting

Laser kiss-cutting consists of cutting the surface layer of a multilayer material. Adhesive labels are printed on master sheets. These sheets typically consist of two layers: a top layer on which the graphics are printed and a backing layer, onto which the adhesive is glued. In laser kiss-cutting, the laser engraves only the surface, freeing the adhesive template from the backing matrix.

In laser cutting, the beam passes through all the layers of material, freeing the adhesive from the matrix and reducing it to a unit.

The advantages of laser label die cutting

Laser finishing offer numerous advantages:

• the cutting path can be modified by simply loading a new file into the system
• the absence of mechanical contact allows particularly complex cutting paths to be followed
• laser cutters does not wear out and requires minimal maintenance

For a company using a digital laser die, it becomes possible to manage production in an innovative way. It can now make prototypes for the customer, start small volume production runs and accept numerous orders that wouldn’t be sustainable with traditional production methods. It is a true paradigm shift in the way we conceive production.

There is yet another advantage. In the digital converting industry, and particularly in paper converting, CO2 lasers are almost exclusively used. These laser systems are known to interact very efficiently with paper materials. This characteristic, coupled with the reduced production of processing waste, makes the laser an eco-friendly production tool.

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El.En. has developed numerous digital converting applications over the years. Contact us to find the application that best suits your needs.

Abrasives, part of a family of materials characterised by their great hardness, are used for processes such as polishing or the sanding of surfaces. They are available in a wide variety of shapes and types and lend themselves to a multitude of processes.

These materials can be moulded into a large number of shapes: discs, brushes, wheels, cutters, grinding wheels. However, traditional abrasive processing methods have limitations that can be overcome with laser processing.

In this article we will look at the 6 advantages of using laser technology in the manufacturing process of abrasive products.

1. Laser is a non-contact process

The main problem in the manufacturing of abrasives is that the abrasive action is also exerted on the tool itself. Let us take flexible abrasives as an example. In this category of abrasives, the abrasive substance is sprinkled on a backing, which is normally made of paper or a polymer material. In order to obtain the desired shapes, such as a rotating disc or wheel, tools such as dies are used, i.e. a mechanical method that uses contact between parts to separate an element from the die into the desired shape.

Operations such as die cutting of abrasive materials, however, have a drawback. The abrasive action is also exerted on the cutting tools. Blades, dies and cutters quickly get worn out and must be replaced frequently to maintain high machining quality. This increases machining costs, which consequently increases the cost of the final product.

Laser cutting of abrasive materials overcomes this disadvantage. It is characterised by a total absence of contact. The laser beam interacts remotely with the surface of the material in a non-mechanical process that avoids the problem of continuous wear of the machining tools.

2. Laser is a versatile tool

A major disadvantage of traditional machining methods is also their lack of flexibility. For example, a die made to create a specific shape can only be used to create that specific shape. To make differently shaped parts, it is necessary to create new diecuts, provided that the investment required to create them is justified by a profitable return.

Similarly, only one machining operation can be performed with traditional machining tools. A die-cutting tool can only perform one machining operation. A cutting tool can only perform cutting. To perform different machining operations, one must change the machining tool. If a manufacturer wanted to apply information to an abrasive disc such as grit size or a serial number, he would have to insert the part into a dedicated machine, such as a printing machine.

Laser systems, on the other hand, allow several machining operations to be performed in a single session. With the same system, flexible discs can be cut from a die, cuts and perforations can be made and surface information on a material can be added through laser marking. In addition, the use of lasers allows the shape or size of the piece being manufactured to be changed in real time, without any additional aids. It is precisely its high flexibility that makes the laser the trump card for this type of application.

Laser offers a true change in the very way production is understood. It gives manufacturers the possibility of enormously expanding their commercial offerings. It becomes possible to create prototypes, just-in-time production, or series of small parts for high-value customers.

3. Laser is a precise tool

Abrasives are used in many different industries. Each of them requires specific processes, and, therefore, abrasive tools that are shaped differently. This means that there are more or less specialised tools: from simple sandpaper, sold in rolls and used by carpenters and craftsmen, to customised rotating discs for high-precision machining.

However, mechanical machining tools have a tolerance limit beyond which they cannot go. The size of the machining tools, their design, and the need to avoid unwanted contact limit the complexity of the machining that can be performed.

Laser, on the other hand, allows very tight tolerances. Since there is no contact between the parts, the tool can follow intricate cutting paths, create microscopic perforations and special shapes, make surface cuts and other machining operations that would be impossible with mechanical cutting tools.

4. Laser reduces machining waste

With traditional machining tools, processing is performed by the mechanical removal of material. The process tends to produce machining waste, dust and other residues that must be managed in some way, with a variable economic and environmental cost.

Laser machining processes, on the other hand, tend not to produce waste. Material removal occurs through sublimation. The very high energy density produced by the laser on the surface allows the temperature of the material to rise, instantly vaporising it as a result of a transformation of the material state.

5. Laser respects materials

Mechanical machining processes present a risk of damage to products due to accidental contact or excessive mechanical contact. Any deformation lowers the quality of the final product.

In laser processing, there is no risk of damage from mechanical contact. Laser processing respects all materials, even the most delicate ones. They guarantee a higher quality of the finished part and are therefore ideal for the sectors in which the degree of error must be kept down to a minimum.

6. Laser is an environmentally friendly process

Laser processing offers high energy efficiency. All things being equal, laser performs the processing with much lower energy expenditure than mechanical processing. This, combined with the absence of waste, makes the laser one of the most environmentally friendly processing tools available to manufacturers.

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Laser is a cost-effective tool for the manufacturing of abrasive materials. Because the possible applications are numerous, seeking the advice of an expert can help you find the most suitable processing system for your application. El.En. CO2 laser systems are ideal for the manufacturing of abrasive materials. Contact us for more information.

CO2 laser and fiber laser are the two most widely used types of laser in the industry sector. Both technologies have proven to be reliable and efficient. They offer high productivity, flexibility of application and accuracy of results.

But no two lasers are the same. The difference between these two technologies lies in the length of the laser beam. For fiber lasers, the typical wavelength is 1064 nanometres, while for carbon dioxide lasers it is 10.6 micrometers.

This difference in wavelength is substantial because it influences the type of material that can be processed.

Fiber laser, the king on metallic materials

Fiber laser is mainly used in metal applications. Fiber technology enables higher energy densities to be achieved on the surface of metals for two reasons. The first is that metals absorb the wavelength of the fiber laser well, whereas they tend to reflect and scatter the wavelength of the carbon dioxide laser. The second, is that fiber laser allows a smaller focal diameter on the working surface than the carbon dioxide laser. As a result, the fiber laser achieves a higher energy density for the same power than the CO2 laser.

The main shortcoming of fiber laser technology is its lack of flexibility. The wavelength of the fiber laser is absorbed well by metals, but not only. A limitation of the fiber laser is that many materials absorb its wavelength. This makes it difficult to select which materials the laser should affect, especially on multilayered materials.

CO2 laser, the most versatile laser

Selectivity is one of the advantages of the CO2 laser. The 10.6 micrometer wavelength is absorbed well by all carbon-based materials. These include most of the materials used in manufacturing processes.

Below are some of the materials on which the carbon dioxide laser is most efficient:

• Plastics and polymers in general
• Wood and wood-based materials
• Paper and cardboard
• Biological materials

These materials absorb the wavelength of the CO2 laser very well, which makes these laser sources very efficient in their processing.

CO2 laser vs. fiber laser for laser engraving

Laser marking and laser engraving are two variants of the same process. In both applications, laser technology is used to remove a layer of material. In laser marking, the laser removes a very thin layer of material. The mark produced is therefore superficial. In engraving, the laser goes deeper, removing a greater layer of material. The mark is therefore deeper and can often be felt by touch.

Both carbon dioxide and fiber lasers can perform marking and engraving. Based on what we have previously said, it should be obvious that the main difference lies in the materials on which the processing is applied.

As far as fiber technology is concerned, marking and engraving is mainly used for product traceability, i.e. to indelibly engrave identification numbers, serial codes or data matrices on metal parts. The high energy density and small focal point make it ideal for this type of application on metal materials.

Marking and engraving, on the other hand, is one of the most widely used processes of the CO2 laser. This process has a wide variety of applications. In addition to the simple marking of identification codes, CO2 laser achieves more sophisticated decorative patterns, so much so that it is used in the fashion industry. One of the applications that has been developed in recent years is, for example, laser marking of denim fabric for the production of jeans.

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El.En. Laser is a company that specializes in the production of CO2 lasers. Since 1981, we have contributed to the development of this technology, which has become a great asset to the industrial sector. We produce CO2 laser sources, laser scanning heads and laser systems for Industry 4.0. Contact us for more information or to get a consultation on how to build the right laser system for your business.

Laser magnet wire stripping is one of the many applications of the laser ablation process. This process is used in the most technologically advanced sectors. In contrast to conventional stripping, laser stripping works precisely and selectively. This makes it ideal for sectors where precision and quality workmanship are necessary.

What is a magnet wire?

A magnet wire, enamelled wire or winding wire is a copper or aluminium wire covered with a thin insulating layer. Its main field of application is in the production of conductive material coils. As you can imagine, the insulating layer is used to prevent the coil from short-circuiting simply by contact between the wires.

In order to do this, manufacturers immerse the conducting wire in a bath of polymeric material which completely covers it. The thickness of the insulating layer can range from 0.08 mm to 1.6 mm. Depending on the temperature at which the enamelled wire is to operate, the insulating layer can be made of different materials. The most commonly used materials are polyester, polyurethane and polyamide, in various formulations.

The enameled wire stripping process

Enamelled wire coils have a wide range of applications. These components are fundamental in the production of devices such as inductors, transformers, electromagnets, pickups, actuators, etc. In some cases, manufacturers may need to remove all or part of the insulating layer. One reason, for example, might be to solder the coil to larger components, or to make special connections in the circuit. To achieve these results, the enamelled cable must then undergo stripping operations to remove the insulating layer and enable it to operate.

The stripping process can be done using four techniques:

• Brushing
• Chemical process
• Stripping with blades
• Thermal process

Let’s go over them one by one.

Brushing

This technique uses rotating fibreglass or steel brushes. The fibreglass brushes rotate at high speed, produce friction and thus heat, and the heat melts the insulation layer. A smooth and polished surface is achieved.

The rotating steel brushes work thanks to the sharp action of the steel bristles. The result is a rougher surface. Because the brushes have a greater abrasive effect, they are used for larger surfaces where greater force is required for welding.

Chemical process

This technique involves immersing the enamelled wire in a chemical bath with a solvent action which dissolves the insulating coating. The coil is then cleaned to remove oxides and any residue.

Stripping with blades

This type of stripping uses rotating blades which, by moving at high speed, remove the insulating layer from the electrical cable.

Thermal process

In the thermal process, heated blades are used to melt the insulating layer. The heat combined with the movement of the blades removes the insulating layer from the enamelled wire.

The laser magnet wire stripping process

Laser stripping of enamelled wire is a viable alternative to these techniques. In this application, a laser ablation process is used to remove the insulating layer from the surface of the electrical cable.

The laser easily interacts with thermoplastic polymers. Compared to traditional removal methods, the laser has some important advantages:

• It is selective, the laser only interacts with the polymeric material and not the metal.
• It is precise, the laser can intervene extremely precisely on specific points on the surface.
• It is a green, unlike other techniques, laser stripping does not produce any processing residue.

All these advantages make the laser stripping technique ideal for cases in which material removal needs to be done in an extremely precise manner, typically in high-tech applications.

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Would you like to develop a laser stripping application for enamelled wire? Contact us: our engineers will study the right application for your needs!

In recent decades, lasers have become a widely used processing tool. Its role as a production tool is increasingly established, both in traditional applications such as laser cutting, laser welding or laser marking, and in more advanced ones such as laser paint removal, laser surface treatment or laser microperforation.

The success of this tool is due to the advantages it offers in terms of process flexibility. The same laser source can be used to perform different processes such as cutting and marking on different materials such as plastic and wood, even within the same operating cycle.

This great flexibility translates into process complexity. In general the working mechanism of the laser is very simple. A laser is a light source capable of concentrating a very high energy density, so much so that it can be used as a heat source. In practice yet, the interaction between the laser and the material is influenced by numerous factors that make it very complex.

Conceptually, cutting, drilling, engraving and marking share the same processing mechanism: laser energy is used to create chemical and physical transformations in the material. These transformations can range from the simple colouring of the material, as is the case with laser marking, to the complete removal of the material by sublimation as is the case with laser cutting. In order to switch from one process to another, it is sufficient to modify the laser parameters using the appropriate control software.

For this reason, each application must be studied according to the characteristics, of the laser, of the process and of the material.

In this article we will analyse the main parameters that come into play in laser processing, with particular reference to the CO2 laser.

Laser-related parameters

Unlike traditional production tools, laser technology has a wide range of configuration options. Each parameter affects the end result of the process and must therefore be configured appropriately according to the desired result on the material.

The laser parameters to pay attention to are:

• laser source power
• beam spatial mode
• beam temporal mode
• laser wavelength
• beam polarisation

Laser source power

The power of the laser source is a very important parameter. It regulates the laser’s processing speed and the depth of the engraving. The more powerful the laser, the greater the amount of processed material in the same amount of time. Furthermore, the more powerful the laser, the thicker the material that the laser will cut can be,although, as we will see further on, this parameter depends in part on the characteristics of the material.

If you are using a low-power laser, it may not be possible to cut a material from side to side. On the other hand, a laser with a higher power than the one needed to carry out a specific process, can cut through the material, with the risk of obtaining a lower quality cut, with burnt and uneven edges due to the slag produced by the excessive power of the laser.

As a general rule, the choice of the power of a laser source should be made in excess so that the power can be lowered until the desired result is obtained.

Spatial mode of the laser beam

This parameter defines the cross-sectional profile of the laser beam. A laser beam can have several modes, i.e. it can have different profiles.

The most commonly used mode in laser cutting applications is the Gaussian mode, as it allows maximum energy density to be produced, i.e. the beam is concentrated in a very small diameter point.

In this way, it is possible to obtain cuts and engravings with very reduced dimensions, with high processing speeds and the possibility of cutting larger thicknesses.

Other spatial modes, on the other hand, allow the beam to be focused on a larger surface area, thereby achieving lower energy densities.

Time mode of the laser beam

Lasers can be used in two modes, continuous wave or pulsed mode. The continuous wave mode is the most widely used (mainly in mass production), and allows very smooth cuts and thicker materials to be cut. The pulsed mode is used for more precise work, often with a low-power laser.

Wavelength

The way different materials absorb laser radiation depends on their wavelength. While some materials absorb the wavelength of the CO2 laser very well, others require different wavelengths and therefore other types of laser.

Aluminium and copper, for example, absorb the wavelength of the CO2 laser very little and require very high powers to be cut, which reduces production efficiency. Non-metallic materials such as wood and synthetic materials such as polymer plastics, on the other hand, absorb the CO2 laser radiation perfectly. Metals such as mild steel and stainless steel can also be cut with the CO2 laser with excellent results.

Polarisation

Polarisation refers to the ability of the laser beam to radiate in only one direction. This property differentiates the laser from non-polarised light sources, which radiate in all directions.

This parameter is important insofar as it affects certain characteristics of the cut. Generally speaking, when the cutting direction and polarisation have the same orientation, very thin, sharp-edged and vertical cuts are obtained. When the direction of the cut is the opposite of the one of the polarisation, the energy absorption of the material is reduced, resulting in a reduction in the speed of machining and a wider cut with rough, irregular edges.

Material characteristics

When configuring a laser system, the characteristics of the material must be taken into account. Not all materials are laserable. Some do not absorb certain wavelengths; others produce unsatisfactory results when subjected to the laser beam.

Thermal properties and reflectivity are the parameters of a material that need to be taken into account.

Thermal properties

From the point of view of laser processability, materials can be divided into two categories, metals and non-metals. The two groups respond differently to laser radiation and therefore offer different degrees of processability.

Metals have high thermal conductivity, a higher melting point and high optical reflectivity. For this reason, laser processing is very inefficient in most cases.

Non-metals, on the other hand, absorb laser radiation very well, particularly that of the CO2 laser, and can therefore be processed very efficiently. All it takes is a small concentration of laser energy to initiate the material transformations that carry out the processing.

Reflectivity

This property is especially relevant for metals. While we can generally say that all metals have a high degree of reflectivity, it is not a fixed parameter. The reflectivity of a metal can vary as the physical properties of the metal change. For example, reflectivity decreases when a metal is heated or when shorter wavelengths are used.

The reflectivity of a metal can be limited by the use of a non-reflective film applied to the surface of the material.

The polarisation of the beam also affects the reflectivity of a material.

Process characteristics

The laser machining process can be carried out in many different ways and use different technologies.

The following features of the machining process influence the final result:

• beam travel speed
• assist gas
• nozzle shape
• stand-off distance
• focal plane position and focal length

Beam travel speed

The travel speed of the beam is crucial in determining the final processing result. The thicker the material, the slower the laser has to travel because if it is too fast, it cannot penetrate the material.

In some cases this principle can be used for a purpose, such as laser marking and engraving.

On the other hand, if the laser proceeds too slowly, the material gets too hot, increasing the heat in the affected zone, which can lead to charring and damage to the material.

The right speed is the one that achieves the best quality for the desired result, as efficiently as possible.

Gas assist

In some cutting processes, the laser emission may be accompanied by a gas jet. This technique makes it possible to improve the efficiency, speed or quality of machining.

Some of the most commonly used gases are oxygen, used to cut mild steel, nitrogen, to cut nickel alloys. Helium, argon and other inert gases and simple compressed air are also used.

The gas jet can be either coaxial to the laser beam or directed. The final decision depends on the characteristics of the desired processing.

Nozzle shape

The nozzle is the device through which the laser beam is irradiated onto the processed surface. Its configuration has an influence in determining cutting characteristics such as shape, size and edges.

Stand-off distance

This parameter is determined by the distance between the nozzle and the processed surface. The spray distance affects the gas flow. Too great a distance can cause turbulence, which creates irregularities in the cut. If, on the other hand, the nozzle is too close to the work surface, splashes of molten material can damage the laser’s focusing lens.

Focal plane e position and focal length

The laser needs to be focused on the working surface at all times. The focus point must therefore always be on the processed surface, in order to achieve maximum energy density and precision. Controlling this parameter is essential to obtain good quality and uniform processing along the entire path of the laser.

Every laser configuration is specific

In summary, it is clear that it is not possible to standardise laser applications. The processed materials, the characteristics of the process and the technical characteristics of the laser system determine the type of configuration one should use. Contact us: our experts can define a process that suits your needs!