Engraving

Engravings are incisions of ornaments, fonts and ornaments in metal, such as brass, copper, silver, steel, etc., or glass, stone and other solid materials. The profession is called to a training engraver.

The classic hand engraving on metal surfaces or on glass is performed using the stylus as a tool. The aim is to create by removal of material, a surface structure that stands out against the background.

The wells created with the various forms of the stylus can also be designed with color paste and highlighted. This special technique is used for example for centuries in artistic printing technology. In metals, such as silver, a similar effect is produced by a special fusion technologies ( Niello or black spot).

Basics

The engraving, whether by hand or by machine, a machining that removes material from the workpiece locally. In glass engraving, this is also the case, as seen under a microscope, the operation of grinding is repeated, caused by the abrasive cutting operation. This differs significantly from the engraving etching, scoring, or hallmarking (eg when driving copper), the impressions are technically. Here, the operation is carried out exclusively without cutting. This is reflected especially in the expression of a representation in different ductal or manner. While with an etching or scoring the line width is only slightly changed, with an engraving with the burin line thickness can be run from very thin to very wide.

Engraving in the area of ​​gilder

Even with the gilding comes before the so-called gesso engraving. The substrate, such as a sheet of plywood is first coated with hot glue size that the pores open up and the wood fibers. Thus, there is a better connection between the ground and gesso. Now, the application of the stone substrate begins, which consists of stone Hasenleim and chalk. Optionally, added to improve the bond bit Venezianerterpentin. Uneven surfaces will be paved with a chalk putty. This is followed by the rapid application of the white ground, consisting of a combination of hide glue, champagne chalk, China chalk and / or Bologneserkreide. The contract will be times to an approximately 1 mm thick layer created about 20 repeats. Enclosed spaces and a white base temperature of max. 40 ° c are important to avoid nits. These are small air bubbles, which is only noticeable when drying the chalk ground. You may not be filled in with putty, otherwise a non-uniform surface tension arises, which leads to cracks. The surface is smoothed with sandpaper of different grit so that the optimum adhesion of the gold leaf is ensured, for the character to be able to mimic massive Metals perfectly. Then the actual engraving begins. With a hook engraved ornaments or patterns are engraved in the hard chalk ground. One must be careful not to slip manifests because a correction is unless you retransmits chalk ground up, not possible. Then the yellow and for a gloss gilding is additionally applied the red bole later. The red bolus carries one to two times. Apply the product with a fine hair brush in the crusade. The bole is composed of the colored bolus (alumina) and gelatin. Previously, the bole was gebunden.Nun with yolk of primer is given for gilding. After gild the smallest scratches and bumps can be seen immediately. This technique is very time-consuming and tiring.

Electric engraving

A particular method is the electric engraving, are used in the generated by a vibrating pen at short intervals sparks that change the material only superficially by melting and evaporation. Appropriate tools generate the vibrations through an armature in an alternating field of an electromagnet and at the same time provide the necessary current flow which causes a material change on the metal surface to be engraved with each contact. The method is related to the erosion, but is usually done by hand and without intervening liquid. Applications include the engraving of serial and batch numbers in machine parts.

Engraving machines

In the manufacture of signs or in mold engraving machine finds the application in which the material by rotating cutters ( Milling Graver ) is removed. To produce durable labels layers existing plastic materials can be used in different colors, with the engraving depth extends into a different colored layer. Also PCB prototypes can be produced in this way.

With the use of computer controlled engraving machines several vector file formats can be used. Vector data allows a lossless replication of engraving designs that would not be possible with manual production.

Laser Engraving

The most modern engraving is the Laser, here the material is heated so much by the incident laser beam, that it changed thermal contrast producing, evaporates or burns.

Application areas are the permanent marking of electronic components, the manufacture of computer keyboards, front panels, durable nameplates or decorative drinking glasses and floodlights signs of Plexiglas.

The laser beam is tracked the contour or performed with a laser scanner line by line over the workpiece and leads quickly controlled pulses, which cause at the required places a removal. By control of the pulse train or power, it is even possible to generate, for example, half-tones and to transmit in this way material on metal or glass surfaces.

Another method is the mask engraving, in which a laser beam in the opposite, forming the template mask reduced is imaged on the workpiece. This mask can be fixed or a like a daisy wheel rotating sequence of characters. The laser pulse is so energetic and short that it removes the entire contour of the mask shown with a single pulse.

A special procedure is in glass engraving ( glass engraving ), wherein the laser beam is focused in the interior of a glass block, and where three-dimensionally controlled for each laser pulse causes microscopic thermal destruction.