Glass

Using aCO2 laser system, you can engrave a wide range of flat glass workpieces, such as plates, windows, and mirrors. However, with the use of a rotary attachment, you can also obtain high-quality engravings on round or conical objects, such as wine bottles, champagne flutes, water glasses, beer mugs, and vases.

Hand-blown or crystal glasses may fracture during laser processing due to stresses developed during the manufacturing process. Stresses arise because a glass cools unevenly (its exterior cools more quickly than its interior). Cast glasses, on the other hand, are well suited to laser engraving as they tend to have a relatively homogeneous structure. Commercial glassmakers use a process called "annealing" to minimize the impact of stress on their products. Typically, glasses will be heated in kilns and gradually cooled.

Mirror glass can also be engraved using a fibre laser system. The laser will remove the reflective substrate on the back of a mirror, leaving the glass surface without any markings.

A Trotec Speedy flexx system contains both CO₂ and fibre laser sources. Thus, using a single machine, you can engrave a large variety of glass workpieces.

Rough engravings may be formed on glass due to the impact of the laser beam's heat on the glass' surface. The following are a few commonly used methods to prevent this phenomenon:

1. Moist Paper Towel

White engravings are achieved with the use of a moist paper towel.

Prior to engraving your workpiece, apply a moist single-layer paper towel to its surface. Ensure that there are no air bubbles or overlaps, which would diminish the engraving quality. Turn the Air Assist function off to avoid drying the paper towel while the workpiece is being engraved. When the laser processing is complete, you can wipe away residual paper towel fragments with a damp cloth

2. Application Tape

The use of application tape results in grey-coloured engravings.

As with the paper towel method, make sure that no air bubbles and overlaps are formed. Pieces of tape or adhesive that remain after processing can be removed with a damp cloth.

3. Engraving Without Supplementary Materials

The impact of the laser beam's heat on your glass workpiece can be reduced by configuring the design in your graphics software or on JobControl®. 

Graphics Software

In your graphics software file, change the design's colour from 100% black to 70% grey before sending it to JobControl^®.

JobControl^®

In the JobControl^® Print window, select the OrderedDithering option from the Halftone menu. Keep the same processing parameters for all other settings.

As previously stated above, curved glass objects can be processed with the rotary attachment. For detailed instructions, please click here.

Glass workpieces with handles (e.g., coffee mugs) can also be processed using a rotary attachment. However, the object must be properly positioned so that the handle is not rotated into the engraving field. Ensure that the circumerence of the object is large enough to accommodate the size of the graphic. Otherwise, the design will be engraved on the handle. You can easily inspect the job preview in JobControl^® by using the What you see is what you get (WYSIWYG) feature.

To prepare your workpiece for engraving, move the Y axis (rotary motion) to the very top, and clamp the object so that the handle is slightly above the laser beam. Since the workpiece is rotated backwards, there is no risk of collision with the laser head. For safety, detach the nozzle in order to avoid collision with the rotary engraving attachment. Then focus on the engraving area of the workpiece.

You can view the exact position of your design in JobControl^® by using the What you see is what you get (WYSIWYG) or crosshairs features.

If you are using the crosshairs, simply move the Y axis into the desired position. Then place the job on the plate on the crosshairs. By moving the Y axis again, you can review the job dimensions and make any necessary corrections

Tip : Select the Minimize to Job Size option in the JobControl^® Print window to more easily position the graphic on your workpiece.

Use 70% laser power to achieve enhanced results when engraving glass. The lower amount of heat applied to the surface of the glass will create a finer engraving.

With regards to image specifications and JobControl^® settings, we recommend using a resolution of 500 dpi and selecting the Ordered Dithering option in your Print settings.