Laser marking also takes over the household
appliance industry – The POLARIS project

Since 2017, LASIT has been involved in a Research and Development project for the laser marking of Home appliance industry components, which puts companies such as BSH, Whirpool, Electrolux, Arçelik and Daewoo Electronics in first place worldwide.

Laser marking is the only technology that guarantees the permanence of its result and, the more this becomes evident, the more the big players consider lasers as the best method for marking codes, logos, texts and numbers on their components.

The precision of the laser plays an essential role: the small size of the spot, in fact, allows for even more complex, microscopic and elaborate markings, at a level of perfection not achievable with other systems.

Curved and irregular surfaces: the LASIT solution

The Home Appliance industry is characterized by a wide variety of products, which in turn are composed of irregularly shaped parts with complex and large-sized geometries, making it difficult to build versatile systems and develop the technologies needed to mark them.

LASIT thus began its POLARIS project, first carefully studying the industry needs and then proceeding with the development and implementation of a line of laser markers able to address the three main problems:

The irregularity of part surfaces, such as the fronts of washing machines and dishwashers, where the different points to be marked are located at different distances from the laser head, with a high risk of compromising marking and obtaining an imperfect result
Marking contrast and color competing with pad printing technology, which makes use of inks of any color.
Productivity, or rather creating a prototype suitable for massive production chains, handling more parts faster

Laser marking on irregular parts

The problem component surface irregularity has been solved by using:

A 3D scanner which is able to automatically detect the geometry of the part.
Customized software with a complex algorithm that allows you to process the 3D file detected by the scanner and transfer it automatically to FlyCAD (2D).
A three-axis head, with which we are able to automatically adjust the focal distance. The photographic objective lenses re-draw the Gaussian Beam formed by the dynamic expander lens on the target plane, and the movement of the dynamic expander lenses through the linear side-shifter varies the distance of the focal plane (and therefore the dynamic focus), thus achieving perfectly straight lines even on curved surfaces.

Marking quality and contrast

Marking quality was another major challenge in the implementation of the POLARIS project. In fact, even though we were sure that the best laser for ABS and PMMA was a 355nm laser, a great deal of testing had to be performed to get to the point of choosing the UV and finding the ideal parameters.

POLARIS laser system productivity

To make this laser system as productive as possible, we have equipped it with:

900×450 mm XY axes: considering only a focal marking area of 380mm, we could not have marked even a front of a washing machine (about 600mm). With axes of this length, we can not only mark the entire front, but also place two of them on the work surface. Naturally, if the parts are smaller, the number increases.
Mechanical cam rotary table: with marking during machining, the operator (or the robot) can load the second component to be marked while the first is in the cabinet to complete its cycle.

LASER vs. Pad Printing

Let’s take, for example, the alternative to lasers currently most used in the household appliance industry; namely, pad printing. This technique involves the use of a soft, flexible pad (generally made of silicone), through which an indelible ink film is transferred from an engraved steel or photopolymer plate (pad printing cliché) to the surface of the substrate.

The benefits of laser marking are clear compared to pad printing:

Savings: Pad printing paints must be replaced constantly and waste materials must be disposed of. For a high productivity chain, this means very high costs. A UV laser, with its 25,000 hours of operation – not just mere start-up avoid this problem.
Ecology: laser is the best technological choice from the point of view of environmental safety.
Zero waste materials also means less chemical and dangerous substances and, at the same time, since the laser is a DPM (Direct Part Marking) technology, we do not add additional paper or plastic components to our product.
Data dynamism: laser marking lets you manage the dynamism of data via software, automatically generating serial numbers and sequences.
Resistance: over time, prints and labels become damaged and codes and text no longer are visible, causing damage both in terms of productivity and company image.