It is no exaggeration to say that plastics revolutionised the modern manufacturing process. Before plastics, the traditional materials used were metal or wood. Plastics quickly gained popularity for being cheaper, lighter, more versatile, and easier to manufacture. Nowadays, plastics are found in practically every industry, from food and healthcare to automobiles and infrastructure. In many of these applications, laser engraving plastic parts has been a handy tool. Laser engraving machine for plastic is an extremely flexible technology that can be used for different plastic types, such as ABS, polyamide, or polycarbonate. Owing to the versatility and reliability of the technology, more and more companies have started to offer laser marking plastic services.

Laser etching plastic

The term ‘plastic’ can be used to refer to a number of synthetic or semi-synthetic materials, commonly organic compounds. They are usually made of organic polymers. Polymers are composed of long molecular chains of repeating units, called ‘monomers’, which in this case are composed primarily of carbon atoms. Connected to the main backbone of the polymer are various ‘pendant’ groups, which may be composed of other elements (such as sulphur or oxygen) or other carbon-based molecules. The nature of the molecular bonds and pendant groups, as well as the length of the polymer chain, play a significant role in determining the properties of the resulting plastic.

Plastics have become the material of choice versus more traditional materials (such as wood or metal) due to some fundamental properties. Manufacturing and working with plastics is much cheaper and easier. Plastics are lightweight but can exhibit comparable strength and durability. They are impervious to the effects of moisture and organic decay.

With the wide variety of plastic products, the range of applications available for laser etching plastic items is virtually endless. Plastic etching has been used to label housings of electronics, tools and tool parts, various forms of packaging, automotive parts, electronic components, printed circuit boards, identification and product tags, buttons, keyboards and sensors.

With the wide variety of plastic materials in the market, laser marking and engraving technology have similarly diversified into different methods. For instance, laser engraving plastic uses a high-intensity laser to raise the temperature of an incredibly thin layer of the plastic, causing it to melt and form a modified surface upon solidification. An even higher intensity laser can be used to alter the surface of the plastic. Localised evaporation of the material causes carbonisation and a change in colour to the surface of the object.

On the other hand, a low-intensity laser is used for laser marking plastic. The foaming method uses low energy laser to induce the polymers in the plastic to form a walled foam structure, which stands out from the material with its elevated surface and lighter colour. The most common method for laser marking plastic is basic colour change, where a high-frequency laser causes a molecular change in the polymer, resulting in a change in colour. The contrast of marks made by colour change can be further enhanced by the application of additives in a process called bleaching.

Before the days of laser marking, ink printing was the technique of choice for plastic marking. However, the numerous advantages of laser marking meant that ink printing was soon pushed to the background. The ink printing process was carried out by having an image placed directly on the plastic surface using inks, which can be erased by solvents or by long-term abrasion. On the other hand, the marks made with lasers are indelible and permanent.

Laser marking is also much faster than ink printing, capable of producing up to 1,000 alphanumeric characters per second. The detail in laser marking of plastic parts can be at the level of several microns, allowing it to produce highly intricate designs.

ABS-plastic-pipe-with-laser-marking

Non-contact technology

Laser engraving for automotive parts is the only non-contact technology used to mark equipment parts and traceability codes. This means that there is very little wear and tear on the parts of the laser marking equipment, so repairs and parts and replacement should be very infrequent. Not coming into contact with the part being marked also means that there is little chance that the part will be damaged during the marking process. The same cannot be said for more traditional marking processes, such as dot-preen engraving.

Permanent and legible

Aside from being precise and accurate, the marks made by laser etching technology are also known to be legible and permanent. This is incredibly important in automotive parts that experience incredibly high temperatures and frictional forces, such as components of the braking system or piston engine parts. A detailed study has shown that the brake rotor can heat up to a temperature of 900 °F when brakes are engaged at high speed so a part number that does not degrade with heat can be particularly important.

Laser cutting of ABS plastic sheets have proven to be a great combination. Laser cutting ABS has been used to create a wide range of products, including automotive interiors, home and office appliances, architectural models, machine parts, and pipes and fittings. The quality of finish, accuracy, and ease of use of laser ABS plastic is unparalleled.

Laser technology has also been used to create permanent and legible marks on ABS parts. Laser marking has the added benefit of being able to produce marks of different contrasts depending on the laser’s optical settings or light source. For instance, laser marking can be used to create black marks on white ABS or white marks on black ABS.

The intensity and number of passes of a laser on the ABS surface can be tweaked to improve the contrast of the mark, thereby making it look clearer. All this is achieved without burning the plastic surface or otherwise compromising the integrity of the ABS material. Marks made by laser technology are high quality and long-lasting and are most often seen in labels of electronic panels and control panels.

keyboard-button-with-laser-marking-v3

Laser marking and cutting of Polycarbonate

Polycarbonates are so called because they are composed of polymers containing carbonate groups. Aside from being physically durable, polycarbonate also exhibits excellent temperature resistance and optical properties. The repeating functional groups in the polycarbonate chain are highly polar, which gives the material its unusual strength. Despite its toughness, polycarbonate is still a thermoplastic which can be shaped and reformed once treated with high temperatures.

It exhibits superior impact resistance and tensile strength, on top of being lightweight and transparent. With its impressive physical properties, polycarbonate has been used in applications that demand high levels of durability such as riot gear, scuba masks, bulletproof glass, electronic display screens, and construction materials.

Laser marking is the technology of choice for the permanent and accurate marking of polycarbonate. Both fiber lasers and CO2 lasers can be used to mark polycarbonate, with the former able to produce high contrast black marks while the latter produces yellow or light brown marks. The intensity of lasers and the exposure time can be adjusted to get the desired level of contrast, giving the operator the freedom to customise the appearance of the final mark.

Working with and cutting polycarbonate can be quite difficult due to its inherent toughness. Fabrication of polycarbonate parts can be made much easier and economical with laser cutting technology. Laser cutting polycarbonate creates perfectly clean-cut edges that will require no post-processing. It is incredibly accurate, as it can even be used to create highly intricate filigree designs without error.

As a contact-free technology, the cutting process does not result in flaking of the material or any material damage. Since the process does not use a mechanical cutting tool, there is no need to do regular tool cleaning or maintenance. There is also minimal wear and tear on the cutting equipment, lessening the need for regular parts replacement. In the long run, laser cutting will turn out to be more cost-effective than any other cutting technology.

Laser cut polycarbonate parts have been used to create membrane keyboards and switches, electrical panels for household appliances, covers for automobile panels, and battery encasements.

Laser marking and cutting of Polyamide

Polyamide, more commonly known as nylon, is a generic term for a synthetic polymer composed of repeating monomer units with amino and carboxylic acid groups. It was the earliest commercially successful synthetic polymer. Some of the initial applications of nylon remain the most well-known even today; they were first used to create nylon-bristled toothbrushes and women’s stockings or “nylons” as they were called back then. Even today, the widespread use of nylon makes it one of the most useful synthetic materials ever developed.

From the most basic form of nylon – Nylon-6,6 – several variations of nylon have been developed, such as Nylon 510 and Nylon-1,6. Other nylon variants have also been created by mixing the base polymer with other additives, such as carbon. Taking stock of the number of variants of nylon products currently available will reveal that the possibilities are practically endless and that there are a vast number of nylon variants that offer different hardness, strength, and friction characteristics.

For customised nylon pieces, a CO2 laser is the tool of choice. Laser cut polyamide has the advantages of having clean edges after cutting, requiring no further post-processing. Moreover, the high temperature of the CO2 laser melts the cut edges, fusing nylon fibers and preventing fraying.

The process is entirely contact-less. There is no need to affix the material to the printing table, nor does the material suffer any physical stress which could result in damage or deformation. With laser cutting nylon, the operator can realistically implement a no-defect manufacturing standard.

The lack of physical contact means that the equipment suffers minimal wear and tear. Not only does this ensure consistently high product quality, but it also reduces the costs associated with having to replace parts periodically.

Laser cut nylon has been used widely to create large format textiles. As an automated technology, laser cutting nylon can be incorporated into any existing manufacturing process. It can also be integrated with a mechanical cutting tool to provide an all-in-one cutting solution. It can process large formats and accommodate contours of any shape with burr-free cutting results. Being extremely accurate, it delivers precise cutting of foil sheets consistently every single time.

Summary

Plastics are one of the most widely used materials in the modern manufacturing industry. They have incredibly versatile applications, they are durable but lightweight, and are very cost effective. With the wide variety of applications of plastics, it is no wonder that laser marking of plastics has also become a highly successful industry.

In contrast to traditional marking methods such as ink printing, laser technology produces marks that are long-lasting and legible. Laser marking on plastic parts can be achieved using different plastic types, including ABS, polycarbonate, and polyamide.With technology that is fast, accurate, reliable, and efficient, laser marking on plastic parts has become the industry standard.

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