Laser Marking & Engraving of Denim & Jeans by CO2 Galvo Laser System

Introduction
Laser technology is being used in garment industry from nineteenth century for various apparel manufacturing applications. Laser is used for marking, welding, engraving, cutting etc. For several years now, the CO₂ galvo laser has spread to the textile industry. Its use concerns in particular the decoration and finishing of fabrics. Thanks to its flexibility, the CO₂ laser has made it possible to replace traditional operations in this area. Operations that in most cases are polluting, slow and expensive. There are several advantages of using laser over the conventional processes in cutting, engraving, embossing, denim fading and other applications.

In fact, laser marking and engraving have replaced traditional operations such as sandblasting or washing, allowing to considerably reduce the consumption of water, chemicals and electricity. From this point of view, the laser has allowed the textile industry to embrace a more ecological type of production and therefore to reduce its footprint on the environment, which is one of the heaviest of the industrial sectors.

Since denim is one of the most used fabrics in the fashion field, it represents very well the innovations made possible by the introduction of lasers in the fabric manufacturing process. The fabric finishing for jeans has benefited greatly from the introduction of laser galvo processes such as laser marking and engraving.

Denim and CO₂ galvo laser, a perfect match
The denim fabric consists of a cotton fiber, dyed with a dye. The base colour is indigo but often other colours are also used. Denim was born as a fabric to make work clothing. The classic use is the manufacture of jeans, but today denim is used to make many other items of clothing.

Laser Engraving on jeans — Fig: Laser engraving on denim & jeans

In the finishing of jeans, the laser is used to make marking applications. In this application the laser passes very quickly on the surface of the fabric causing a physical or only optical modification of the material. This depends on the thickness of the surface involved in the machining. This thickness can range from a few fractions of microns to a few hundred microns.

In marking, the laser works only on a surface layer. This process replaces both dry and water-based bleaching processes and allows to obtain finishes with a worn look.

The engraving process, on the other hand, goes deeper. It concerns a modification of the fibers of the fabric. This is why the effect obtained is also tactile. Laser engraving can be performed both locally on the finished piece and globally on the entire fabric.

In both cases the system used is the same and is based on 3 fundamental components.

How does a CO₂ galvo laser mark and engraving system work?
A galvo laser system for marking jeans consists of a CO₂ laser source, a laser scanning head and control software.

The CO₂ laser source is the device that generates the laser beam. We have several devices that can be used for laser marking and engraving on denim and jeans such as the Blade RF Self Refilling laser source.

The laser scanning head is the device that allows you to move the laser beam across the surface. The scan head consists of 3 main elements. 2 galvanometric mirrors and a z-linear optic. Galvanometric mirrors have the task of directing the laser beam along the X and Y axes. This movement occurs at very high speed. The z-linear optic instead serves to keep the laser beam always in focus on the surface to be machined. Since the distance between the laser and the surface changes continuously, the beam must be continuously focused to focus its energy on the point to be machined. To do this, the z-linear optic intervenes, changing its in real time focal length allows to have the laser beam always in focus. Produces both complete scanning heads such as Gioscan and galvanometric and z-linear optical mirrors.

Software:
Software is the brain of the system. The software controls the power of the laser source, the speed of movement of the galvanometric mirrors and the focus. The software basically transfers the data inputs to the system in the form of drawings and projects in the most common design software in drawings to be made on the surface.

This basic system can be implemented on different types of machines. The results that can be obtained are very variable. By controlling the laser parameters, the software is able to obtain effects such as:

Lived effect
Various types of discoloration
Tactile effects
Engraving of designs and patterns engraving of various types of images

The advantages of laser marking and engraving on denim with CO₂ galvo scanner systems
Unlike traditional processes, the use of laser for engraving and marking on denim marking has undoubted advantages:

The production process can be fully automated. The laser is a digital, computer-controlled manufacturing process. The production results can be easily standardized and checked down to the smallest detail.
It is an ecological process. Laser denim decoration is a dry process. There is no waste of water, energy or potentially polluting chemicals.
It is a flexible process. The laser allows you to experiment continuously. Not only does it allow the experimentation of any geometric pattern, but it also allows images to be transferred directly onto the surface. Compared to methods such as screen printing it is much faster and cheaper.

Conclusion:
Probably the best benefit of laser completing for denim and denim items, beside its sustainability angles it is the laser’s capacity to create a broad scope of impacts that would some way or another require utilization of various compound and mechanical completing cycles utilizing a few distinct bits of hardware. This ability makes laser treatment an appealing alternative for firms focusing on tweaked and little run creation, and miniature manufacturing plant conditions where flexibility is vital. When upheld by a strong, plan centered coordinated programming programs, lasers become an integral asset in making imaginative items for specialty and select business sectors. Laser firms are beginning to investigate laser applications to materials past denim, including heap textures and weave merchandise. The move to-move machine designs offered by some laser makers, is ready to affect the creation and completing of material materials themselves later on, just as item classifications past denim.

Author of this Article:
Md. Raisul Islam Rifat
Dept. of Textile Engineering
Daffodil International University, Dhaka
Email: ririfat750@gmail.com

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