Laser Engraving and Marking on Plastic: operation, advantages and applications

 

Laser marking on plastic or laser engraving on plastic is a process by which components are labeled or marked with the aid of a laser.

 

The polymer of which the plastic parts are made determines the method used and also the amount of energy needed to carry out the laser engraving of the plastic. The result of laser marking depends on both the type of plastic and the additives used such as dyes and the type of laser used.

 

How does laser marking on plastic work?

Laser marking is an optical process in which plastic absorbs the laser beam without having any contact with it. This typical behavior is also exploited in the laser welding of plastics, a process during which one welding joint absorbs the beam while the other welding joint is transparent to the laser.

 

Many different types of plastics and thermoplastics can be laser marked. If a plastic cannot be laser marked, it can usually be processed with an additive or masterbatch suitable for laser marking plastic.

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plastic granulesBy masterbatch we mean a concentrated mixture of pigments and / or additives encapsulated during a thermal process in a support resin which is then cooled and cut into a granular form. Additives such as color pigments can also affect laser marking ability.

The key in the plastic laser engraving process is to achieve sufficient absorption of the laser beam into the material. Metals tend to reflect most of the ray, while in plastic the reflection is widespread and absorption is very high.

 

The low thermal conductivity of the plastic means that the energy loss during laser marking is low, so processing is very fast. The absorption by the macromolecular structure of the plastic is usually in the ultraviolet and infrared range.

 

Laser application on Plastic Label 

For further information read -> Why UV Lasers are used: applications, characteristics and types

 

The advantages of Laser Marking on Plastic

Procedures such as laser marking and engraving are used more and more frequently in the industrial field as they are considered particularly reliable and also offer numerous advantages over conventional marking technologies:

The marking is permanent, as it is waterproof, resistant to wear and heat, light and chemicals;

Laser marking is an extremely effective, high quality and forgery-proof process;

Maximum flexibility in the design of the marking, so it is also suitable for areas usually difficult to access;

The whole process takes place without any contact with the material;

There is no tool wear and no additional cost for extra materials such as chemicals, inks, etc;

The processed plastic is always free from pressures, tensions and fixings, in order to guarantee consistently uniform results;

Processing is simple and no pre-treatment or post-processing is required;

Thanks to the short set-up times of the laser machine and the flexibility offered, even small batches can be marked economically.

Laser-marked car buttons

Types of lasers used

During laser marking, plastics undergo optical surface changes through exposure to the aforementioned beam. For this purpose, a variety of laser supports are used, which differ in the way the beam is generated. During plastic processing, the result is influenced not only by the type of laser but also by the wavelength used.

The wavelength of the laser plays an important role in marking plastic. If solid state lasers with doubled (532 nm) or tripled (355 nm) frequency are used, the range of plastic materials on which a good laser marking result can be obtained becomes very wide.

 

Also considering the economic factor, most laser marking applications are made with infrared sources (Fiber, Nd: YAG).

 

Laser marking on plastic with infrared laser

For further information read -> From the C02 Laser to the Fiber Laser, let's discover the most popular types of lasers

 

Methods of Laser Marking on Plastic

Foaming leaves a tangible mark on the surface of all polymers, but also on some metals. The heat induced by the laser melts the surface and later, due to the rapid cooling, the bubbles remain encapsulated in the material, thus forming a positive sign, which can be touched by hand. Depending on the material this sign is light or dark in color. In this case the laser operates at a low power level and with longer pulses.

Plastic carbonization. This technique allows to obtain strong color contrasts on bright surfaces and can be used for both polymers and biopolymers. During the carbonization process, the laser heats the surface of the material which releases oxygen and hydrogen. The surface of the plastic is thus carbonized due to the concentration of carbon. This technique has slightly longer marking times than other processes.

색상 변경. 색상 변경 레이저 마킹은 착색된 거대 분자를 재정렬하거나 파괴하고 최대 가독성을 보장하는 전기 프로세스입니다. 재료가 제거되지 않고 표면이 매끄럽고 변경되지 않았지만 약간의 거품이 생길 수 있습니다. 색상 변화는 밝거나 어두울 수 있지만 대부분 어두운 색조입니다.

레이저 제거 또는 절제. 레이저 제거는 다층 플라스틱(라미네이트)에 사용됩니다. 제거 과정에서 레이저 빔은 페인트와 같은 기본 재료에 적용된 얇은 덮개 상단 레이어를 제거합니다. 이것은 다양한 레이어 간의 차이로 인해 색상 대비 효과를 만듭니다.

플라스틱 의료 기기에 레이저 조각

응용분야

레이저 마킹은 점점 더 전통적인 인쇄 방법을 대체하고 있으며, 특히 현재 선호되는 방법이 된 플라스틱 라벨링에서 그러합니다.

무엇보다 레이저는 추적 가능성 측면에서 특권을 누립니다. 플라스틱에는 종종 원산지를 식별하기 위해 바코드 또는 로트 번호가 할당됩니다. 모든 산업 분야의 수많은 응용 분야에서 다음과 같은 레이저 사용의 이점을 누릴 수 있습니다.

 

플라스틱 하우징

플라스틱 케이스

전기 콘센트

키보드

버튼 및 스위치

동물 식별 라벨

영화

센서

전자 부품

인쇄 회로

도구

추적성을 위해 플라스틱에 레이저 마킹

레이저 마킹에 적합한 플라스틱

모든 고성능 플라스틱이 본질적으로 레이저 마킹이 가능한 것은 아닙니다. 예를 들어 폴리옥시메틸렌 아세탈 수지 POM 및 열가소성 폴리아미드 PA는 첨가제로 개질되지 않은 경우 일반적으로 적외선 레이저(Fiber, Nd: YAG)로 마킹할 때 색상 변화가 나타나지 않습니다.

이 경우 특정 첨가제의 사용이 제안됩니다. 파이버 레이저를 사용하면 폴리카보네이트, ABS 및 기타 많은 상업용 플라스틱에 영구적이고 신속하며 고품질 마감 처리를 마킹할 수 있습니다.

 

레이저 마킹에 적합한 일부 플라스틱은 다음과 같습니다.

 

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