Principle and History
Nowadays, everyone has seen these glass products with a 3D image inside. People are always amazed at how the models look inside, whether it’s a car, a sailboat, or just a company logo.
In fact, the image thus created looks like a sculpture inside a glass block. This is probably why this glass decoration technique is so popular. It is the first technique that allows you to create a ‘sculpture’ with the help of a computer (CAD). The first time that 3D models from inside the computer can be transformed into something real outside of the computer!
Sub-surface laser engraving or 3D crystal laser engraving is a style of glass decoration in which glass marks (tiny dots) are made within a glass object without disturbing the surface of the glass object.
In fact, it is not that difficult to understand how these underground laser engraving machines do their job.
Everyone, especially in their youth, has set fire to a shoelace or a piece of paper with the help of a magnifying glass. The sunbeam is focused or grouped by the magnifying glass. At the focal point, the concentrated energy of the sunbeam is so high that the material and oxygen in the air react and combustion of the material begins. The condition in this case is that the material must be able to burn in air, such as paper, wood, dry grass, shoelaces, etc.
Instead of sunlight, it is also possible to focus a laser beam with a lens. If the wavelength of the laser light is well chosen, the energy stored in the focal point of the lens can interact with the glass. For glass, that wavelength is 1064nm or 532nm. Light and also laser light travel through glass normally without any interaction. If the light energy is high enough and the laser light is the correct wavelength, then something happens to the glass. While glass is normally transparent, at that focal point that specific laser light makes it locally non-transparent. This area on the glass is then seen as a small white dot.
By moving the focal point and laser to different locations and creating points at these locations, a 3D model can be built.
In fact, the subsurface laser machine makes the model in slices. First, the machine makes the dots on a plane at the bottom of the glass cube. Then go a little higher and make the points on the next plane, doing so, over and over again, creating a 3D model.
So the fun part about this technique is that the laser light can only make spots at the focal point and the rest of the glass object it travels through remains intact.
The technique was originally invented in Russia as a derivative of the laser program during the Cold War. In the beginning, the dots were relatively large, and the models were only made up of 50 to 200 dots. But since they were the first ones to be shown at giftware fairs, everyone was really amazed.
After the Fraunhofer Institute in Aachen, Germany, the nerve center of international laser developments, invented a new type of laser in 1997, the technique became very popular. This new laser made very small dots and the writing speed was unmatched by Russian technology. This resulted in models, with, say, 50,000 points, that took just 20 seconds to etch onto a glass block.
The giftware world had a new tool for making wonderful glass products.
3D glass or glass?
The term 3D crystal laser engraving is widely used instead of underground laser engraving.
Although subsurface laser engraving describes exactly what happens, it sounds commercially more interesting to call it 3D crystal laser engraving. The word ‘crystal’ is more valuable to people than glass and that is probably the reason for this somewhat confusing name.
Although it is possible to perform subsurface laser engraving on glass and many other transparent materials, the most common material used for this technique is optical glass.
Optical glass is a type of glass that is manufactured very precisely. Any artifacts in the glass will influence the optical quality. For the 3D laser engraving process it is very important that the quality of the optical glass used is uniform throughout the block to avoid errors.
So the next time you see somewhere written “3D glass”, you’ll know that it’s actually not glass but (optical) glass.
Applications
The best known application is for corporate gifts. A glass block or any other shape with an in-house design of a company logo and text is a long-lasting gift that will definitely have a place on the recipient’s desk.
Technology has developed and objects are no longer limited to a few centimeters by a few centimeters. The massive 15cm by 15cm blocks can be completely filled with designs and text. Therefore, it is also an ideal material for glass trophies, which are often bulkier than the smaller blocks you see everywhere in stores.
The general market for gift items is the second market for these products. Images of landmarks such as the Eiffel Tower or the Taj Mahal are popular souvenir items and create a lifetime memory of that special holiday.
Personalized gifts are another growing market for 3D crystal gifts. With new camera techniques and also with software, a 3D image of the face/head is created in the blink of an eye. With a little extra text, it makes a beautiful anniversary gift, birthday present, or just beautiful home decor.
The 3D crystal laser engraving technique is constantly evolving and speeds are increasing. This paved the way for other larger applications. In offices, glass partitions with a laser-engraved internal design find their way. Glass furniture, like tables, can be decorated with this technique.
Signs for commercial purposes are becoming more and more popular. Especially the combination of these signs and LED light technology is very powerful, because the engraving lights up and the other parts of the glass remain dark.
Subsurface laser engraving has become in 15 years, from scratch, a powerful glass decoration technique that has found its place in the market and further technical improvements along with new developments for CAD will ensure that we will see much more of this technique. in the near future.
