Laser Engraving machines for metal

Despite the prevalence of alternative materials, there is no doubt that metals remain the workhorse of the manufacturing industry. Metals provide a unique combination of durability, workability, heat and chemical resistance, and visual appeal that makes them the material for choice for several industrial and commercial applications. Marking and engraving of metals parts have practically become an essential part of working with metals, whether it is for traceability purposes or as a visual enhancement. To this end, laser engraving machines for metal have become a standard tool for industries that heavily use metals such as engineering, manufacturing, and jewelry making, among others.

Metal laser engraver technology has become so useful that it is now being used in both big industries and small-scale applications. Industrial parts such as pipes, fittings, pump casings, and motor parts often receive the metal engraving machine treatment for parts numbers, tracking numbers, serial numbers and company branding.

For manufacturers of these engineering parts, a good traceability system is a vital part of quality monitoring. The use of a laser etching machine for metal ensures that these traceability marks are permanent and will remain legible for a long time – especially useful for parts that undergo a lot of friction and heat.

Outside of major engineering parts, a metal etching machine can also be used to make legible marks on common engineering tools such as callipers, wrenches, and drill bits. Some of these parts are incredibly small, making laser engraving a particularly suitable technology for marking characters that are still legible at 1-point size. In the case of callipers and other measuring tools, the precision and accuracy of the markings are key. The automated process of a metal etching machine delivers superior repeatability and consistency, ensuring that engineering measuring tools have ticks and readings that are marked and positioned accurately.

Engineering parts and tools go through a lot of stress under normal use. Pipe fittings come into constant contact with reactive fluids, motor parts are in a constant state of vibration, while the regular use of tools results in eventual wear and tear. For proper traceability, it is critical that essential marks can withstand abrasion, heat, and corrosive fluids. All of these are achievable by using a metal engraving machine, although different treatments can be used for different materials and applications.

It is also essential that the structural integrity of the part or tool marked does not suffer because of the etching process. A metal engraving machine removes only a thin layer of metal material to make permanent marks – not enough to cause any structural damage. The technology of annealing metal is especially interesting, as it does not remove material at all but instead alters the metal at a molecular level to result in a change of colour.

Stainless steel is one of the most widely used metals across several industries. Prized primarily due to its corrosion resistance, stainless steel comes in different grades and variants according to the ratio of chromium and molybdenum mixed into the steel alloy material.

In addition to its distinct corrosion resistance, stainless steel also has a measure of resistance against acid attack. It is a durable and versatile material that has a visual appeal due to its characteristic lustre and can stand up to most steam cleaning and sterilisation treatments.

With the broad application of stainless steel in several fields such as construction, healthcare, and food service, stainless steel engraving has become an equally sought-out service. Laser marking stainless steel is a fast, cheap, and highly accurate process that not only produces high-quality output but retains the anti-corrosive properties of stainless steel.

CO2 and Fiber laser machines

There are two options for laser technology that can be used in stainless steel engraving and marking: CO2 lasers and fiber lasers. CO2 lasers, being the older technology, generally involves less capital cost to buy and install. However, this lower capital expense can eventually be offset by maintenance and parts replacement costs.

CO2 lasers are particularly sensitive equipment that requires frequent adjustment and realignment. Moreover, CO2 lasers are not readily compatible with cutting and engraving of reflective materials, including stainless steel. Without any pre-treatment, CO2 lasers will only recoil off of a metal surface. Marking of stainless steel using a CO2 laser often involves coating the stainless steel part with a specialist paint, which the laser then “burns” off.

On the other hand, fiber lasers have become the standard technology for metal engraving. Merely varying the wattage output of a fiber laser allows it to create different markings and engravings with different depths. A fiber laser is also very accurate – with diameters as low as 0.1mm, fiber lasers can create incredibly detailed designs. Best of all, stainless steel engraving using fiber lasers requires no pre-treatment.

The major drawback of using fiber lasers is that the purchase price of the equipment is much higher. However, fiber lasers make up for this by being incredibly robust. They generally require less maintenance and have fewer moving parts that need to be periodically replaced. A fiber laser also finishes the same amount of work faster – the output of 2 or 3 CO2 lasers can be reproduced by a single fiber laser machine. In terms of electrical efficiency, fiber lasers are clearly the winner, using only about a third of the power to produce the same amount of work as a CO2 laser.

Depending on the material you are working with, and the throughput you require, either a CO2 laser or a fiber laser can be the most effective laser marking solution for you. Each one has its strengths and drawbacks, and the appropriate selection of technology is the first step towards the successful implementation of a laser marking system.

Anodised aluminium is one of the most common metals used for laser marking purposes. Aluminium itself is a very widely used metal which is valued for its combination of being both lightweight and durable. This unique combination has made it the material of choice for aircraft and automotive products. The high electrical conductivity of aluminium has also made it an excellent material for long-distance power lines, satellite dishes, and in electrical components found in most household appliances and power systems.

Aluminium engraving for technology devices

Aluminium is a very malleable and ductile material which makes it a versatile material for many consumer goods. Modern smartphones, laptops, and tablets are made with increasingly large portions of aluminium. Being light and easy to shape, aluminium is also becoming a common component in chairs, lamps, decorative panels, and other interior design elements. Aluminium is food-safe, non-toxic, and resistant to rust – after all, aluminium cans have been used to package carbonated drinks since the 1960’s.

Anodised aluminium is essentially aluminium enhanced with a corrosive-resistant layer. Similar to how stainless steel is produced, anodised aluminium is made by a process called passivation. This is done by immersing the aluminium material in an acid electrolyte bath and passing an electrical current through the solution. The result is a thin coat of aluminium oxide that is fully integrated into the underlying aluminium substrate, making it resistant to chipping away or peeling off. The anodised layer is generally stronger and more adherent than any other anti-corrosive paint or metal plating treatment, making anodisation one of the more preferred options.

Aside from giving aluminium better UV and corrosion resistance, an anodised layer has a naturally porous surface that is especially receptive to dyes. This has allowed manufacturers of anodised aluminium to offer their product in a wide variety of colours. Without dye treatment, the anodised layer is translucent and reveals the metallic sheen of the underlying aluminium – a finish that looks good enough on its own.

The use of titanium within the medical industry

In the healthcare industry, titanium has become a standard material for surgical and dental implants due to its chemically inert and good biocompatibility characteristics. On top of being lightweight and durable, titanium is resistant to corrosive effects of the acidic or ion-rich environment inside the human body. Titanium implants are long-lasting and can last for 20 years or longer without needing to be replaced. They are also cheaper compared to other implant materials such as zirconia.

Laser marking of titanium medical implants creates marks that can withstand constant mechanical stress and corrosive conditions. Aside from the marks being permanent, the process is also inherently sterile. Laser annealing creates marks by a colour change in the surface of the metal surface without etching the material – a particularly appropriate technique for medical implants that need to remain smooth and should have no microscopic pockets for bacterial growth.

The consumer markets

In the consumer market, titanium has started to gain popularity as a material for the manufacture of high-end sports gear and jewelry. It has been used for sports gear that benefits from a high strength-to-weight ratio such as bicycle frames, football helmets, and golf clubs. In the jewelry industry, the appeal of titanium lies in the practicality of using an extremely durable material and its significantly lower price relative to precious metals such as gold and silver. Being a biocompatible material, titanium jewelry also has fewer chances of causing allergies for their wearers.

The increasing demand for customised and personalised jewelry has prompted jewelry makers to embrace the technology of titanium laser engraving. By laser engraving titanium jewelry, marks and inscriptions can be made on the outside and inside surfaces of a titanium ring. The accuracy and resolution of laser engraving have even made it possible to add inscriptions on the narrow edge of a ring. Compared to more traditional methods of jewelry inscription, laser engraving titanium is faster, produces more consistent results, and puts less mechanical stress on the jewelry item.

Cast iron is an iron alloy that contains 2 to 4 percent carbon. Depending on the desired application, cast iron can also have a varying proportion of silica and manganese, plus trace amounts of sulphur and phosphorous. Cast iron is very commonly found in cookware, such as in cast iron pans, griddles, and waffle irons due to its ability to provide even heating. It has also been used for construction and architecture and was actually used in a lot of bridges and railways before steel eventually replaced it as a common construction material. Nowadays, architectural use of cast iron is often limited to design elements such as garden features and ornamental objects.

Depending on the proportions of different alloying elements, cast iron can have a variety of physical properties. Grey cast iron, the most commonly used cast iron, exhibits better compressive strength but has less tensile strength and shock resistance. White case iron, with a higher proportion of iron carbine, has superior hardness and abrasion resistance but is brittle. Ductile and malleable cast iron, as the name implies is softer and less brittle due to the presence of small spheroidal graphite particles. In any case, cast iron, in general, has a low melting point, which improves its machinability, and exhibits excellent resistance against wear and deformation.

Copper is one of the few metals that is directly usable in its natural form, or without being combined into alloys. It is characterised by having a very high thermal and electrical conductivity, making it a valuable material in electrical wiring, printed circuit boards, thermocouples, heat exchangers, electromagnets, and electric motors. Copper is a naturally soft and malleable metal which can be fashioned into pipes and pipe fittings, or as architectural elements. The green patina that copper develops after a long period of atmospheric exposure is a particularly coveted finish by architects and designers due to its visual appeal.

Moreover, copper has excellent workability and lends itself well to processes such as brazing, welding, and soldering. Where increased hardness is desired, copper has been blended with other metals to form alloys such as brass, bronze, and sterling silver, all of which are commonly used to create jewelry.

Gold and silver are materials need little introduction. Valued for their rarity and their visual appeal, jewelry made of gold and silver have been used since the olden times to convey affluence and elevated social status.

Nowadays, these precious metals have become more accessible, with most consumers instead preferring their pieces to have a higher degree of personalisation and customisation. Pendants, rings, and charms are considered more valuable when etched with a person’s name, initials, or other personal inscriptions. Laser engraving on gold and silver has become a particularly effective and popular technology used toward this end.

Outside of jewelry, laser marking and laser cutting of precious metals has also been used to create highly intricate designs for medals and currency coins.