Subsurface Laser Engraving

The Magical Engraving Technique: Subsurface Laser Engraving!















Optical glass block with 3D subsurface laser engraving




History and principle of Subsurface Laser Engraving


Subsurface laser engraving or 3D crystal laser engraving, is a style of glass decoration where glass markings (tiny dots) are made inside a glass object without disturbing the surface of the glass object. 
The decoration technique is a spin-off of the Russian laser technology which was developed during the 'Cold War'.

In the middle of the nineties the first (Russian) blocks with an internal 3D model showed up at the major giftware fairs. In those days the models were composed of about 200 to 500 'dots'. These decorative items received a lot of attention and that was not only because of the serene beauty of the product, but also because all people were questioning themselves "HOW DO THEY DO THIS?????"

In the following years more and more companies showed up at fairs with these optical glass blocks and machines for the production became available to the market. 
These first machines were all based on the same old Russian technology. It was only after Kemin Du, of the Fraunhofer Institute of Laser Technology, in Aachen, Germany, invented a new principle, that the technique was pushed to another level. 

Where the old Russian machines were able to make a 200 - 500 dot models in minutes, the technology of Kemin Du made it possible to make 500 dots per second! A few years later his next invention, based on a so called slab  laser, reached easily the astronomical marking speed of 10,000 dots per second. The dots are also smaller with this new type of laser and that results in smoother 3D models.

One of the very first 2D pictures, subsurface engraved, made in 1999

These developments made it possible for companies to make
high speed subsurface laser engraving machines for the production 
of 3D lasered objects. 
With these machines it is possible to 'subsurface laser engrave'
almost any 3D model into a glass object, from logo's to pictures
and even 3D images of people. The size of the glass object is not anymore
restricted to glass blocks but large architectural projects can also be
done.
3D laser engraving machines are fully automatic and are able to run large series of blocks or large architectural projects without any human interaction.


Still the question "How do they do it?" has not been answered, but we will try to make it crystal clear!

Everybody has, mostly in his/her youth, put a shoe string or a piece of paper on fire with the help of a magnifying glass. The sunbeam is focused or bundled by the magnifying glass. In the focal point the bundled energy of the sunbeam is so high that the material and the oxygen in the air react and so the material starts burning. The condition in this case is that the material must be able to burn in air, like paper, wood, dry grass, shoe string, etc.                                                                                
Old style 3D model with relatively large dots
and small number of dots.  (Shanghai Baolong)

Instead of sun light it is also possible to focus a laser beam with a lens. If the wavelength of the laser ligth is well chosen, the bundled energy in the focal point of the lens can interact with glass. For glass, that wavelength is 1064nm or 532nm. Normally light and laser light travel through glass without any interaction. Is the energy of the light high enough and has the laser light the right wavelength, then something happens to the glass. While glass is normally transparent, the laser light in the focal point transforms the glass locally. This area in the glass is seen as a tiny white dot. 

By moving the laser to different locations and creating dots at these locations, a 3D model can be built.
In fact the laser makes the model in slices. First the laser makes the dots in one plane, then it moves up a little higher and makes the dots in the next plane, by doing so it creates a 3D model.
So the fun part of this technique is that the laser light only can make dots at the
focal point and the rest of the glas object, through which it travels, stays untouched.

So that’s how they do it!!!!
Modern style 3D model with fine dots and large in number. (Totally Zing)

Factors that influence the quality of a 3D model 

3D Laser Engraving Machine 
There are a lot of machines offered at this moment. But as always with machinery, there are good machines and less good machines.
It is well known that the laser technology from Germany is at the highest level and a machine with parts ‘made in Germany’ usually gives the best performance. The price of a German machine is higher than a machine made in China, but the quality of the product is much better.
It’s important to make a good choice for the laser source, the laser diode, the focussing unit, the controller, the X,Y,Z-movement and the software involved. By comparing the different machines one should focus on these components.

Design 
No matter how good the laser machine, without a good design the result will not be satisfactory. 
There are plenty of people who know how to make a 3D model with programs like AutoCAD, Maya or Rhinoceros. If these designers don’t know anything about the final application, subsurface laser engraving, the transfer of their model into a glass object can give a disappointing result. 

Optical Crystal 
The term 3D crystal laser engraving sounds that this technique is done in crystal. The most used medium is optical glass but this subsurface laser engraving can be done in many different transparent materials, like glass, crystal, gemstones and even acrylic.
Optical glass is made in a very precise way. Any artefacts in the glass will lead to mistakes in the laser process. Optical glass of low quality may even cause breakage when it comes in contact with the laser.
Glass fence with 3D text (Cerion)

Applications

Sub surface laser engraving (SSLE) is today a grown up glass decoration technique. 
The first products were mainly giftware (3D model of something, like a landmark, in a block) and corporate gifts (a 3D logo in a block).

In the meantime more applications have been found. 
Archictectural applications are more and more seen, like glass dividers in offices with a 3D internal decoration or glass doors with the same. 

 3D design in glass table (Vitro)

Another new application is 3D designs in glass furniture and lighting with 3D lasered glass parts.

Shops in malls are making 3D images of visitors, with a 3D scanner, and in one hour they can pick up a glass object with, inside, there head in 3D. 
The new 3D scanners have evolved rapidly. Pictures of any object can be made, transformed into a 3D file and immediately lasered into the glass with as a result a highly detailed 3D model.

The industry has also discovered sub surface laser engraving. So is the technique used to make markings inside glass products and can tiny holes being drilled in glass, without the use of a drill but only by laser light.
Besides optical glass, this drilling and marking is also done in bottles and wine glasses of soda lime glass, in crystal items (for instance Swarovski) and in gem stones.

Consultant for subsurface laser engraving

A 3D laser engraving machine is a magnificent piece of work. It is not only fun to look at when it is operating, it can also form an important part of a company.
People who decide that subsurface laser engraving should be a glass decoration technique which they want to have, will have to decide which machine to buy. There are many suppliers of subsurface laser engraving machines and once you make a choice it means that you are connected to that supplier for parts, software, maintenance and knowledge about applications.

 
As a consultant for 3D subsurface laser engraving I help companies to make the right choice. After all there is a lot of money involved. 3D laser engraving machine prices range from 20,000 usd up to 500,000 usd.
The choice of the machine is not only about the budget, it is also about what products a company wants to make. Are you into corporate gifts and 3D crystal awards or do you want to have a shop in a mall producing personalized items on the spot? If you produce corporate gifts what will be the quantities you produce? What is a good supplier of optical glass blocks? Are you thinking about glass signs, glass furniture or architectural applications?
Buying a subsurface laser engraving machine involves even more. What spare parts do you need to have on stock, which supplier has a good service, how can you learn to do some maintenance and troubleshooting? What are the power supply requirements? How to laser a 3D model into a crystal ball? Is there any difference between a 3D crystal laser engraving machine and a subsurface laser engraving machine?

All these questions have to be answered before you buy a machine. To help companies making the right choice and avoid disappointments, I act as an independent consultant, not connected to any supplier. With the knowledge gained over the years, from 1998 until today, I can help you to make the right decisions and start up as smooth and quick as possible. This is very cost effective in the end!

I can also help for special applications like making markings online in a glassware production line or any other product.
Visit the Contact Us page, describe your subsurface laser engraving project and I will send you information how I can assist you.

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