There are many different types of laser. YAG is a name given to a type of laser most commonly used for marking metals and plastics. Technically this type of machine is an Nd:YAG laser. Nd:YAG is an acronym for Neodynium:Yttrium Aluminium Garnet. These are the main elements used to form a man made crystal at the heart of the machine that creates the laser beam.
In order to reproduce your design to a consistently high quality and at an affordable rate, artwork for laser engraving should be supplied to us in a specific format. This specific format is not a special format. Any commonly available vector graphics program (like CorelDraw) is capable of saving files in the specific format.
The laser systems we use are extremely high-tech devices. The laser has about 12 'controls', or variable parameters as we call them. These parameters are controlled and adjusted to provide the desired final engraved effect. Parameters are assigned to a specific colour and line type within the graphic. If your graphic does not contain the 'right' type of colour and/or line, the laser will misinterpret the command and the engraved effect may not be desirable.
The graphic should be a black vector image with no outline and all elements combined. A typical format for this type of image would be CorelDraw (CDR) or Adobe Illustrator (AI).
The laser recognises colours by their RGB value (mixing amounts of Red Green Blue). This is a unique number from 0 to 255 for each colour element. The RGB value of Black is Red 0, Green 0, Blue 0. We define the black element of the graphic as a command to the laser to shade fill (create often thousands of small connected lines). This shade fill represents the dark part of the artwork. If you use a colour other than black it will have a different RGB value and your artwork may not be shade filled correctly, sometimes resulting in faded or even missing elements.
You can't use more than one colour in a Combined image (required format). In any case, white is a colour that is totally ignored by the laser. So, while on your screen white may show as a blank area of your image, whatever lies behind it would be engraved by the laser.
The laser uses a technique called shade filling (create often thousands of small connected lines). This shade fill represents the dark part of the artwork. Depending on the reaction of the product to the laser, shade filling is often all that's required to achieve the desired engraved effect. An outline is interpreted by the laser as a command to trace around the shaded areas of the image. In some cases, this can have an undesirable effect to the finish of the mark: example, lighten it. If necessary we can 'switch-on' the outline, by default we leave it off.
A Combined image has its own, unique, commonly shared elements of one colour fill and one outline type. The artwork format we require has only two elements: a black fill and no outline. Combining the graphic ensures that there are no hidden elements and that only one colour and outline type are used.
A Grouped image can contain almost any number of different elements, all with different attributes like colour, line width, etc. A Grouped image can contain many hidden elements. Hidden elements are invisible on your screen but often not to the laser. Using a Grouped image on the laser often results in an engraving very different to the one displayed on the computer screen.
On your computer screen an outline can vary in thickness. The laser follows thin outlines and ignores thick ones. Therefore, using thick outlines may cause the laser to 'miss-out' parts of the image. Furthermore, following an outline is a command to the laser that will give a single engraved score only the width of the laser beam (often approximately 70um), not the width of your line on screen.
Converting all font elements within the graphic to curves is the only way to ensure that the image reproduces on other computers exactly the way you created it on your computer.
Technically it can, however, engraving from bitmap artwork offers less laser control, lower quality reproduction (particularly for larger engravings) and slower productivity rates (meaning higher marking costs). Also, bitmap files are generally large in size. Electronic storage and transfer of bitmap images can be slow, costly and unreliable. Using vector graphics eliminates all of these potential problems.
Any form of engraving is only a matter of contrast. That is, the contrast between the engraved areas and the areas that are not engraved. The degree of contrast relies heavily on the reaction of the product to the laser. Defined colours are only achieved through colour infilling the engraved area. The limitations of colour infilling are that the depth required to hold the paint often reduces engraving detail, the laser intensity required to achieve the depth can create an undesirable Heat Affected Zone (HAZ) showing as slight product damage around the mark, the time taken to achieve depth and apply/clean the paint can often make the process too expensive.
Technically it can. However, the final results can be hit and miss. Much depends on the type and consistency of the material of the product itself, the artwork complexity and size, the desired processing time/price. For these reasons, shade variations for YAG laser engraving are often only used in special circumstances.
By using a special rotary attachment we are able to laser engrave 360° of a cylindrical item up to 100mm diameter. However, this process can be time consuming and therefore relatively expensive.
The laser is honed through a complex lens consisting of several layers. The marking field is constraint by the shape of the lens (round). The limits of the marking field are determined by the size of the lens. Smaller lenses restrict the size of the marking field but also reduce the size of the laser beam (focal point). A smaller focal point provides for greater achievable engraving detail. Therefore, marking field size is normally sacrificed for greater marking detail.
Technically it can. However, the final results can be hit and miss. Much depends on the type and consistency of the material of the product itself, the artwork complexity and size, the desired processing time/price. For these reasons, shade variations for YAG laser engraving are often only used in special circumstances.
For more detailed explanations of these and other technical issues please visit www.laserite.com or contact us by email to info@laserite.co.uk, by phone to 01277 811137, by fax to 01277 811138.