Laser Microperforation

Today we are talking about one of the most widely industrialized applications in the field of laser technology: Microperforation.
You may not have noticed, but many of the objects that we usually use are microperforated to make our lives a little more comfortable, in this post you will see some examples that will surprise you.
The applications of the Laser Microperforation don’t stop increasing every day, and with the constant equipment and technique improvement, it is expected that this trend will continue for the next few years.
Then, we explain in more detail what it is, what types there are, their applications and their benefits.

What is Laser Microperforation?

Laser Microperforation consists of making very small through holes in various sheets, films or plates, using the energy provided by a laser source as a perforation method. Such holes can be up to 5 microns in diameter, but the current limit for industrial applications is usually 50 micron diameter, equivalent to the average thickness of a human hair.

Human hair Diameter 50 micronsHigh density plastic film with 50 micron perforations

Laser technology, as we have already commented on other occasions, with cleaning, marked, or in-mold microstructuration applications, is based on the accumulation of focused light at a very small point in space.
This accumulation of energy is so big so it can vaporize materials such as polymers, metals and even ceramics, and at the same time is done in such a controlled way and at such a small point, that it allows microperforations of a very good dimensional quality without negatively affecting the surrounding material.

Types of Laser Microperforation

Although we have explained what laser microperforation is, it must be pointed out that not all laser microperforations are the same. The technique used will vary depending on the diameter of the hole, the thickness of the layer to be perforated, the material and the hole geometry we want. The most common types of microperforation are the following:

• Single pulse: when the thickness of the layer to be perforated is low, a laser with the appropriate power and spot diameter can be used to get through the material in a single laser pulse. In this way, perforation with the desired characteristics is obtained, obtaining high productivity and perforation speed.
• Percussion: when the layer thickness is high, the material absorbs little energy, or the laser doesn’t have enough power to perforate the layer in a single pulse, percussion is used. This method consists of launching several pulses at the same point to gradually remove material from the surface until it is perforated.
• Clambering: this method is indicated for large microperforations, larger than the laser spot’s own diameter. In these cases, the diameter of the hole is traversed by moving the laser beam to achieve perforation. It would be like trying to cut out a circle with a punch, making lots of holes. This is the technique also used for conventional laser cutting.

It must be said that all these techniques affect how microperforation is processed, but they don’t affect the internal geometry of the holes, which are conical in themselves. This is because the laser focuses on one point in space, but as it moves away from that point, the beam increases in diameter. Due to this phenomenon, the laser incident face usually has a larger hole diameter than the posterior face. For most applications this difference is not relevant, but for applications where this is an important factor, specialized optical equipment that lengthens the focal point can be used to achieve cylindrical rather than conical holes.

Incidence faceHind face

Applications of Laser Microperforation

The applications of this type of technique are very varied and cover almost all sectors, from the typically more industrial ones such as automotive or aeronautics, to healthcare and food, through consumer goods and defense.
Then, we explain some specific examples of applications that are used depending on the type of material:

• Polymers: the use of laser microperforation in plastic films in the packaging sector to make openers is widely used, while in the food sector, it is used to prolong the life of perishable products such as fruits and vegetables, generating controlled atmospheres. One of the less widespread applications, however, is the microperforation of rigid plastic, which can be used to make invisible points of light that become visible when light passes through them. You can see in this Project that we carry out, an application to provide gaseous permeability to a film without liquids or solids.

Rigid piece of microperforated plasticFood microperforation with controlled atmosphereMicroperforated plastic film

• Metal: the main applications in the most industrial sectors have been to make injectors for turbines or automobiles, and in the sanitary sector, to manufacture medical equipment, where high precision and very small dimensions are required. However, the applications are many, like ours replacement of conventional machining by press Project.

Microperforated sheet metalMicroperforated stainless steel plate

Benefits of Laser Microperforation

Laser Microperforation has multiple advantages, but here we resume some of them:

• Minimum hole size, only achievable with this technique, due to the different optical configurations available.
• It doesn’t need consumables and is respectful with the environment, as it doesn’t generate waste.
• Ability to perforate any material if the right laser is chosen.
• Possibility of making very close holes of great precision without collapse of the surrounding material.
• Fast perforation speed, application-friendly for inline processes without the need to stop pieces.

How to carry out a Laser Microperforation Project?

First of all, it is neccesary to define the diameter and the spacing of the microperforations that we need for our application, whether it be light or gas. Depending on this diameter and the material of the substrate, the type of laser, power and optics required will be selected. Once selected, it is necessary to carry out an optimization of the laser parameters (power, pulse, frequency, separation, etc.). It is highly recommended to perform an inspection using scanning electron microscopy (SEM) of the result to check the quality of the microperforations.

Do you want to apply Laser Microperforation in any of your Projects? Contact us!