Laser marking on plastic: how it works and what results you can expect

From the automotive, to the medical, to the hobby, laser engraving and marking are used to customise different objects.

However, marking should not be confused with laser engraving, as although similar in some respects, they lead to two very different results. In fact, while the marking works to remove the layer of material, on the contrary, the engraving dissolves the material and indelibly engraves the surface. 

In general, laser marking on plastic has become an increasingly widespread processing technique. In fact, thanks to its precision and versatility, laser marking offers numerous advantages over traditional plastic marking techniques.

In this article we will explore the different types of plastic and the most commonly used laser marking techniques. 

Types of plastic

There are different types of plastic materials on the market, each with specific characteristics. To carry out the marking it is essential to understand these differences, in order to correctly set up the machine for processing.

Polyethylene (PE)

Usually used for bottles, containers, and packaging. PE can be marked using a CO2 laser. However, laser marking on PE does not produce contrast, so an additive will need to be added later to obtain a visible marking.

Polypropylene (PP)

It is strong, rigid and has a low melting point. Laser marking on PP can be done either by CO2 laser or by fibre laser. However, if you want to obtain a permanent and high-quality marking, it is preferable to use the fibre laser.

Polycarbonate (PC)

It is a transparent material, resistant to impact and heat. To obtain a marking on PC, it is advisable to use a UV laser, which produces a high-quality marking, without damaging the material.

Polyamide (PA)

Commonly known as nylon, PA is strong, flexible, and durable. For PA marking, it is preferable to use a CO2 laser or a fibre laser. Both options ensure clear and long-lasting marking.

Polyethylene terephthalate (PET)

Is a material widely used for plastic bottles and packaging. Laser marking on PET requires a CO2 laser or a fibre laser. Both techniques produce high-quality marking, but the CO2 laser can cause slight whitening of the material.

Polyvinyl chloride (PVC)

It is a rigid plastic, resistant to chemical agents and easy to work with. Laser marking on PVC requires a CO2 laser or a fibre laser. Both types of lasers offer excellent results, without damaging the material.

Laser marking techniques on plastic

There are several laser techniques for marking plastic. 

In this list we list the 4 most used types at a professional level. 

CO2 Laser

This technology uses a high-power laser beam to vaporize the surface layer of the plastic material. CO2 laser marking is suitable for a wide range of plastics, but may require the use of additives or pigments to achieve visible contrast. It is ideal for marking codes, serial numbers, and texts on plastic.

Fibre Laser

This technique uses a focused, high-intensity laser beam to create a chemical reaction on the surface of the plastic. It is particularly effective for marking on hard plastics (such as polycarbonate or polypropylene), producing a permanent, high-quality marking without the need for additives.

UV Laser

This technology leverages an ultraviolet laser beam to produce high-precision marking on a wide range of transparent plastics. The UV laser penetrates the material without damaging it and is particularly suitable for applications requiring discrete marking and on heat-sensitive materials.

Excimer Laser

This technology uses an ultraviolet pulse laser beam to create a permanent marking on specialized plastics, such as polycarbonate or polypropylene. Excimer lasers can produce markings of high quality and precision and are typically used in specialized industrial applications.

Conclusions

Laser marking on plastic offers a wide range of possibilities for industrial applications, from the automotive sector to electronics, from packaging to medicine. 

Understanding the differences between plastic types and laser marking techniques allows for optimal and long-lasting results. The choice of the appropriate laser and the correct adjustment of the parameters are essential to guarantee a clear and high-quality marking. 

In general, considering the great success of this technique and the advancement of laser technology, it can be expected that plastic marking will continue to evolve to find increasingly effective solutions.

If you need our advice, write to us. We will find the best way to respond to your needs.