Label laser die cutting

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.

Contact us

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

Glossary: laser microperforation

Holes drilled on the surface of a material

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!

Hermetic laser sealing of plastic food bags: what it is, how it works, and the advantages

Yellow pear in plastic bag

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.

6 advantages of laser manufacturing abrasives materials

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.

Contact us

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.

What plastics can be processed with CO2 laser?

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.

Beads of coloured plastic

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.

Beads of polystyrene

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.

Beads of Polyethylene

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.

Beads of polypropylene. It is best suited for laser cutting and marking

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.

Thermosetting polymers
Type of polymer Cutting quality Marking quality
Polyurethane Fairly good Poor
Bakelite Very poor Very good
Polyimide Very good Fairly good
Thermoplastic polymers
Type of material Cutting quality Marking quality
Polyethylene Fairly good Fairly good
Polistirene Fairly good Fairly good
Polypropylene Very good Fairly good
Polymethylmethacrylate (PMMA) Very good Very good
Polycarbonate Very poor Very good
Nylon Very good Fairly good
Polyvinyl chloride (PVC) Very poor Very good

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.

What materials can be cut by a CO2 laser?

paper-cut-laser

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 laserIn 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): 

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!

The wavelength of CO2 laser

Over the years, different types of lasers have established themselves thanks to their versatility. Apart from technical differences in construction, the particularity of each laser lies in the propagation medium used to emit energy and the resulting wavelength.

The most common are gas lasers (such as the CO2 laser), semiconductor lasers, fibre optic lasers and solid-state lasers. Depending on the medium used, the laser generates a beam at a different wavelength. The lasers manufactured so far cover the entire electromagnetic spectrum.

Why the laser wavelength is key

The wavelength is crucial in determining the possible uses of a laser. From it depends the kind of interactions between the laser and the material. Each material responds differently to a certain wavelength. Some materials, like acrylic, can absorb in the near IR or be transparent in the far IR. The optimum balance is achieved when most of the energy generated by the laser is absorbed by the material, allowing efficient processing.

Based on what we have said, it is impossible to establish an optimal wavelength. The choice depends on the characteristics of the material to be processed.

However, it is possible to give general indications. It has been demonstrated that some lasers have a wavelength which makes them suitable for a wide range of applications.

The wavelength of CO2 laser

The CO2 laser in particular has a wavelength of 10.6 micrometres, which is in the far-infrared region. This length is absorbed very well by all materials containing carbon. Wood, paper, plastic polymers, organic materials, natural and synthetic fabrics respond perfectly to CO2 laser radiation.

What’s your need?

Certainly, of all lasers, the carbon dioxide laser has proved to have the greatest versatility and has therefore established itself as the main choice for the laser processing of materials. Contact us for more information!

Laser kiss-cutting

Laser kiss cutting (or kiss die cut) consists in removing the superficial portion of a sheet of material according to a specific cutting path.

Unlike normal laser cutting, laser kiss cutting does not go through all the material but remains on the surface layer.

Due to this characteristic, kiss cutting is mainly used in the paper converting and textile industries.

Laser kiss cutting is used when the superficial layer of a material made up of two attached sheets must be cut.

Laser die cutting of labels is an example of one of the most common applications of kiss cutting. The laser cuts out the surface layer into the shape of the adhesive to facilitate its removal from the support layer.

Laser kiss cutting can also be applied to the field of fabric decoration.

Kiss cutting for digital converting

Digital converting or laser converting is used to perform paper converting processes that would be difficult or impossible to achieve with conventional mechanical methods.

Laser kiss cutting is a typical digital converting application that, as previously mentioned, is particularly used in the production of adhesive labels.

This technique makes production particularly efficient and advantageous, since the costs and time required to set up the machine are eliminated.

In this sector, the materials most used for kiss cutting are:

  • paper and derivatives
  • polyester
  • plastic film
  • adhesive tape

Kiss cutting for the textile sector

In the textile industry, laser kiss cutting and laser cutting are used to decorate both semi-finished fabrics and finished garments. In the latter case, laser kiss cutting is very useful for creating personalized decorations.

This technique makes it possible to create different effects such as embroideries, appliqués and labels of various types.

Generally speaking, in this family of applications, two pieces of fabric are sewn together.

Laser kiss cutting then cuts out a shape on the surface layer of the fabric. The upper shape is then removed making the underlying drawing visible.

Kiss cutting is applied mainly on the following textile materials:

  • synthetic fabrics in general, in particular polyester and polyethylene
  • natural fabrics, especially cotton

The advantages of laser kiss cutting

The kiss cutting technique is not a modern discovery related to laser technology but dates back to traditional printing techniques.

Compared to these mechanical cutting methods based on blades and dies, laser kiss cutting offers several advantages:

  • the cutting path can be very complex, making detailed and precise cuts
  • the possibilities for customization are innumerable even within the same production cycle
  • it can be performed on a large number of materials without interrupting production
  • cutting tools don’t get worn during production which therefore eliminates the need for maintenance
  • speed, productivity and processing quality are at their maximum
  • edges are clean cut and defined and do not need further finishing

The industries of laser kiss cutting

As we have seen, laser kiss cutting is mainly used in the digital converting and textile decoration sectors.

Examples of laser kiss cutting

Laser kiss cutting is a powerful tool for the manufacturing of sticky labels
With laser kiss cutting it is possible to cut the upper surface of a multilayered material
From textile to labels, laser kiss cutting results in very creative applications

Which laser systems are suitable for laser kiss cutting

Each laser kiss cutting application must be tailor made for each customer’s needs. In the label industry, a system consisting of a CO2 laser source and a scanning head is generally used.

The laser source

For the manufacturing of labels, high power isn’t necessary: most applications can be done with a laser source below 500W.

Keep in mind though that the power is directly proportional to the production speed. It is therefore sometimes necessary to resort to higher power because of production needs.

A small clarification on the source’s wavelength: El.En. has developed a CO2 laser source specially designed for label manufacturing, the RF333P, with a wavelength of 10.2 micrometers.

This wavelength is ideal for polypropylene (PP), of which is made the surface layer of most labels is made. This source is a variant of the Self Refilling series, which are the most suitable for paper labels.

The scanning heads

The scanning head always works in combination with a laser source. Its function is to move the laser beam on the work surface and keep it focused. To do this work the source uses mirrors mounted on galvo motors and a focusing lens on the Z axis.

El.En. produced a scanning head for CO2 lasers called GioScan. The machine is available in two models:

  • GioScan 1735, capable of operating on a surface between 135×135 mm and 800×800 mm
  • GioScan 1770HR, capable of operating on a maximum area of ​​2300×2300 mm

A laser system for each laser application

Laser kiss cutting applications are numerous and ultimately depend on the material and production needs.

The advantage of laser technology is that it is possible to create custom applications.

For over 35 years El.En. has produced laser systems for industrial applications.

If you have a production idea in mind that requires laser kiss cutting,

Laser micro-perforation of plastic bags for fresh products

micro-perforation-plastic-film

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

CO2 laser lifetime

The CO2 laser has been on the market for many decades. Over the years it has proven to be a sturdy tool, capable of providing thousands of hours of processing without having to be serviced or replaced.

Unlike for mechanical production equipment, one of the biggest advantages of laser processing is low maintenance.

Mechanical tools operate by contact between parts and rely on moving mechanisms. The friction generated during machine operation makes wear and tear on this production equipment a pressing problem. Periodically, production has to be stopped in order to carry out the necessary maintenance operations, which increases the costs of operation and processing. The die sector is but one example of an industrial process that suffers from this problem. In this type of application, the dies have to be replaced periodically to guarantee the quality of the cut.

Laser, on the other hand, is a non-contact process. The entire laser system is based on the production and transmission of electronic pulses and the generation of polarised light beams. There are no moving parts or friction and therefore no direct impact on the lifetime of the laser source.

However, this does not mean that laser sources are maintenance-free. Laser sources also wear out, albeit much more slowly. This is why they need regular maintenance.

In the case of CO2 laser sources, the main problem is the rarefaction of the gas inside the laser tube. Year after year, the gas mixture is normally depleted, resulting in around a 1-2% emitted power decrease per year. This causes a gradual deterioration of the processing and a consequent decrease in efficiency.

The only solution to this problem is to periodically regenerate the laser source. However, this is a costly and time-consuming operation that usually involves stopping the production line, resulting in a negative impact on productivity.

El.En. has created a series of laser sources based on Self-Refilling technology to overcome this very problem. These sources, called Never Ending Power, avoid the regeneration of the source thanks to the use of a cylinder that contains the propagation medium. This cylinder can easily be replaced without causing any delays and guarantees the same process parameters and power over time.

This innovative recharging technology now makes it possible to have a laser source that always functions at maximum power. The laser beam’s quality will consistently remain at its highest level and the lifespan of the laser source will practically be infinite. Contact us for more information!