How lasers work
A high intensity beam of light is produced by the laser machine and this light is focused onto the material in localised areas less than a fraction of a millimetre, which is heated by the laser beam with incredible precision. Depending on the amount of time the material is exposed to the heat a contrast is created, and the material is vaporised or burnt removing layers of material.
As laser engraving only uses light to produce the desired finish no inks or tools are used making this a non-contact process, an advantage over other engraving and cutting methods which use tools or bit heads that can cause damage to delicate materials.
The most popular type of engraving is where the workpiece is stationary in the laser machine fixed into a jig or flat on the bed, the laser optics move over the surface in two dimensions. Cylindrical products can be turned in a rotary device this is fitted into the laser machine and rotates the product under the laser beam.
The first laser was invented by Theodore Maiman on the 16th May 1960. In a press conference in July 1960 Maiman and his employer Hughes aircraft company announced the laser to the world.
A ruby laser was used to produce the laser beam, ruby is the result when a water-clear crystal of aluminium oxide is doped with a small amount of chromium oxide impurity. The chromium is responsible for the red colour. Ruby is an extremely rugged crystal and among the hardest of gems. Ruby is a fluorescent mineral if ultraviolet light is shined through the Ruby it will produce a deep red fluorescent glow this is what sparked Maiman’s inspiration for the first laser. A patent was granted for his invention, and he received many awards and honours throughout his life.
The number of lasers in use today is astonishing, in virtually every aspect of life from science, industry, entertainment and medicine to CD players, DVD drivers or the supermarket scanners.
The majority of communications received use lasers, when talking on the telephone using the internet or watching TV this all comes from information flowing through fibre optic cables made possible by a light beam from a laser the size of a pin head. In the security industry lasers offer more secure communications and high speed data communications between networks, is the tip of the iceberg to what is possible with laser communications. Many of which derive from the lack of physical connection required, beams can connect computer chips within computers, cross land and roads or be connected as temporary networks in disaster situations all with low error rates and immunity to electromagnetic interference.
- Medical procedures have been revolutionised by laser technology with applications from cancer cures and surgery such as tumor, cataract removal and most other surgical procedures, laser surgery uses non-ionising radiation, so it does not have the same long term risks as x-rays and other types is ionising radiation.
- Cosmetic procedures have been transformed using lasers to remove moles, wrinkles as well and tattoos or to whiten teeth.
- Ophthalmology uses lasers for the treatment of glaucoma, retinal problems and even eyes can be reshaped by the laser enabling many people to see without glasses.
The term Laser stands for light amplification by stimulated emission of light, such as that from a light bulb has many wavelengths and spreads in all directions but laser light has a specific direction and is coherent and focused in a narrow beam, creating very high intensity light. As lasers can focus very accurately on precise areas, they are perfect to treat or remove tissues in place of a scalpel used in dental procedures such as endodontic/periodontics procedures and oral surgery.
Aircraft use laser gyroscope technology for navigation, in the military lasers are used as range finders to precisely measure distance. One of the most remarkable applications is LiDAR a technology which is essentially Radar except using light. Applications of Lidar are numerous and have given us everything from the rangefinder used in DIY to calculating the distance to the moon. Lidar from orbiting satellites are responsible for the most high resolution maps available today and are more precise than anything used previously.
Barcodes are now common-place but taking a look back at commerce before barcodes, inventories had to be laboriously recorded manually or in a non-standardised way across industries, until the development of lasers that made it possible to record and share information instantly this was revolutionary in commercial logistics.
Sports even use laser technology, and this is getting into the game itself, not in manufacturing but in setting up down on the field, where it can change the sports experience for fans and the participants. Laser projected marking is visible in stadium to the fans, officials and players created by `Sports Laser Technologies` the product called green line indicates the line to gain in football and shows markings in distance for events such as triple jump, long jump, hammer throw, javelin, and shot put. It can be used in other sports too such as tracking the position of vehicles in motor racing.
Lasers come in a variety of shapes, forms, sizes with beam characteristics dependent on the application and vary from the powerful multi-kilowatt variety used in industry to precise beams for eye surgery and miniature lasers used in fiber-optics.
- Manufacturing uses lasers in many ways and is the most widely used tool, especially in additive manufacturing allowing engineers to create complex features or product designs the require the most precise tolerances.
- Machining using lasers can create fine features that are impossible to make using traditional machining equipment. Cutting with lasers produces perfectly clean cuts with no burring or heat effects to the surrounding material this is a huge benefit particularly when engraving delicate materials that can be damaged easily.
- Laser technology has transformed the world in so many ways in everyday life and can help us understand more about our environment.
What is Co2 laser cutting & engraving ?
A Co2 laser machine uses light produced when electricity runs through a gas filled tube, with mirrors directing the amplified light onto the material surface. The gas used is a mixture of hydrogen, nitrogen, helium and carbon dioxide. Light from a laser is infrared so is invisible to the human eye it can cut or engrave a variety of materials wood, glass, acrylic, plastics, ceramics and textiles. The intense heat from the laser beam vaporises the material that leaving a precise and clean finish, the power and speed can be increased or decreased to give vary the finished.
The advantage of laser engraving and cutting.
- Non-contact – As the process has no mechanical parts that touch the surface of the material.
- Versatility – Many materials can be processed laser engraving and cutting wood, glass, acrylic, plastics, ceramics and textiles.
- Incredible precision – Lasers are produce highly accurate and precise the laser beam vaporises or melts the surface through intense heat with a high level of accuracy without damage to the surrounding area.
A variety of applications – Laser is not just for manufacturing processes it is widely used in product branding, medical, marine, aviation, engineering, arts and gifting.
For clearly legible product and part identification, the processes of laser marking, laser etching and laser engraving are increasing in popularity. All three of these provide a permanent marking solution, fulfilling regulations and adding distinction to your parts or products. All three techniques may seem similar, but there are actually quite a few differences between them which largely have to do with what each process does to the marking surface, including how deep the laser goes and how it changes the overall appearance.
Laser marking discolours the surface of the material while laser etching and engraving actually removes a portion of the surface area as it marks. The main difference between laser etching and engraving is the depth to which the laser penetrates the surface. Each process has its own applications and attributes that make it ideal for different jobs.
Laser marking is when the beam interacts with the surface of a material, slightly altering its properties or appearance.
It is achieved by moving the laser beam across the material using a method called discoloration, which creates high-contrast marks without disrupting the material. The laser heats the material, causing oxidation under the surface and turning the material dark grey to black. Applying temperatures to the metal to anneal the surface all of this is done while leaving the surface intact.
Laser marking differs from laser engraving and laser etching in a number of ways. It is less common and not all laser companies offer this service, it is also referred to as laser coloration or laser dark marking, as well as engraving for plastic materials and annealing for metals. There are four main types of marking colouration, carbon migration, annealing and foaming. It’s popular in the medical device industry where stainless steel and titanium parts are used due to their ability to be sterilised.
The laser process is ideal for QR codes, bar codes, UID codes logos and other product identification needs.
Laser engraving is a process where the laser beam physically removes the surface of the material to expose the core that reveals an image. The laser creates intense high heat during the engraving process, which causes the material to vaporize. It is a fast process, as the material is vaporized with each pulse. Deeper engraving is achieved using higher power or multiple passes. Although engraving is a subsection of laser marking, it still differs in many ways. This is the most popular option for product branding, personalisation and customisation. This is the fastest way to engrave with a laser perfect for parts expected to experience high wear. It’s typically used to part numbers, serial numbers, QR codes and logos plus custom designs we can engrave on almost any kind of material plastic, wood, leather, textiles, acrylic and glass. another important comparison to make is much cost is saved laser engraving compared to traditional engraving. It is more legible than traditional engraving for small products and parts with more font options with a smaller chance of product damage or deformation.
Laser etching, which is a subset of laser engraving, occurs when the heat from the beam causes the surface of the material to melt. The laser beam uses high heat to melt the surface of the material the melted material expands and causes a raised mark. unlike with engraving, the etching is typically no more than 0.001”. As laser etching changes the surface finish of metals, it alters its reflectivity and enhances contrast. it can be carried out on anodised or plated metal surfaces, as well as ceramics and polymers.