Popular Types of Digital Engraving Services

Engraving services are offered in multiple types, each different from the other. The various types of services differ in appearance, use of equipment, technique used,  and resulting cost of production.

Types of engraving services

There many types of engraving and related processes. The more common current methods of producing image from computer digital images are:

1.      Laser engraving

Laser is also known as CO2 engraving. ( other sources of laser are used in machines for more specialised use such as metal marking )
see also Laser engraving theory.
It is vast and the only limitation it has is the operator’s and client’s imagination of the final product. Laser engraving can require a lot of time depending on the resoloution and area to be engraved. the cost will vary with the type of work required. The time of producing your engraving can range from less than a minute to 20 minutes, depending on the art, amount of text, font, size of piece and font size. Material is removed in laser engraving by being burnt away. Depending on focus, and focal lenght of lense used on the cutting head, typical widht of a laser is 0.1 – 0.2 mm. An engraving resolution can vary from 1200 lpi ( lines per inch ) to as low as 100 lpi. For fine detail a high resolution ( lpi ) is used.
Depth of engraving varies with Speed, Power applied, Focus, and lpi. used. A special case is using grey shade image to control the power as the laser moves across the object. The result is a 3D engraving.

Engraving can be done on a range of materials, including: acrylics, wood, glass, leather, fabrics, anodised aluminium, and painted metals.

In the case of glass, ceramic, and stone, the laser breaks the surface from the thermal shock with in less than a millisecond

2.      Cermark engraving ( a technique using laser engraving )

Cermark is the newest technology available for you. It uses laser to fuse marks on bare and hard surfaces. Cermark is coated onto the item to be engraved, using one suitable for material to by marked, Most commonly metal.  There are special grades for use on ceramics and glass, and thermoset plastics. Most commonly the resulting image is black. Other colours can be achieved using particular grades, eg blue, bronze, and soft white. This method of laser engraving should not be confused with laser engraving of anodised aluminium where the anodising is engraved without any cermark coating.

3.      Mechanical or computer engraving

Computer engraving is done using a computer which dictates the movement of a mechanical engraver.

Two types are common. Routing or rotary engraving or diamond tipped scratch engraving.

• Routing or rotary engraving
  A high speed rotary cutting tool will machine away material. Various heads are used depending on detail in the engraving required. This can offer speed, but always the detail is limited by the diameter of the cutting head used. Compare this with laser engraving where typically a laser will behave as though it is a tool of about 0.1 – 0.2 mm so finer results can be achieved with laser. Modern rotary engravers can move cutting tool in x, y and z direction ( z, controlling depth of engraving ) Some have a fourth angular axis control for bevels without need to change to a bevel cutting tool.
• Diamond tipped scratch engraving
  A diamond tip is dragged over a polished or smooth surface scratching the material. This is commonly used for Trophies and Jewellery items. Most common materials are Glass, and metals.

Earlier  Computer engraving was typically limited to only 10 fonts, but with later machines and software, this is now only limited to the diameter of the head used for engraving and careful matching of drawings to suit the contour width of the cut.

4.      Impact engraving

As the name suggests engraving of computer images by impact against material being engraved.
These have grown from small desktop machines for jewellery and gifts to larger format.

Smaller machines have tungsten tip multiple tip heads with larger usually diamond tipped used for stone.

Lower cost makes these attractive in each size for shop on spot engraving to larger memorial engraving.

5.      Sublimation engraving ( Printing )

Sublimation engraving is actually a printing process but sometimes incorrectly referred to as engraving,
An inkjet printer is used to print image onto a paper called a transfer carrier. The print is done in reverse, as once printed, it is transferred to object using heat, pressure, and sometimes vacuum.

The ink contains sublistatic dye, when heated turns directly to vapour ( no liquid phase ) and this then condenses as a solid on the cooler object being printed.

Initially this method of printing was used on fabrics which are unstable or have stretch, e.g. knitted and felts. The transfer paper pre-printed in rolls was applied with heat and vacuum on a drum which would keep fabric stable during the image transfer. The revolution in this process has been the replacement of large run carrier papers printed using gravure or flexography to the more modern ink jet process. Using this method pre laid out pieces are printed on roll of carrier paper in an on demand management process, This is then transferred to final garment fabric for subsequent cutting. Some ink variations are used for fabrics when they are made of materials not suitable for sublistatic dyes.

Many shop and home craft industries have developed using this technique, and transfer print is applied using a heat press, ( or even a hot iron ) to print t-shirts, coasters, aluminium signs and a variety of crafted items.

Being a dye, one limitation is the light fastness, so internal or intermittent or short exterior use is a limitation.

6.      UV cured inkjet printing

This process of inkjet printing is ideal where exterior use and lightfastness is required. Machines can be roll fed or flatbed depending on what the needs are. There are also hybrid machines which can handle roll and flat materials with some limitations. Images can be printed in colour onto most materials from Glass, plastics, timber, metals, ceramics, and more. As the image is printed the inks are cured with UV light to make a tough surface for use in rough treatment and exterior exposure.

More recent flatbed machines have what is called 3D print capability. Used for production of textured signs and objects with stunning graphics.
Inks include colour, white, and gloss varnish. These machines are more capital intensive, but offer versatile production methods for short and longer runs See article on 3D printing