Impact stamps are stamps made of tool steel , with which individual letters and numbers as well as images, codes and logos with the help of a hammer in materials such. B. metal or leather or in the skin of living animals can be impressed. At one end of the stamp, which is usually elongated and square in cross-section, the character / motif to be embossed is in mirror-image relief.
A typical application for stamps is stamped serial numbers in vehicle parts. Company logos or production data are often stamped into products using stamps. Stamped numbers are more forgery-proof than nameplates. The material is compacted selectively by the impact. Even if the number is removed mechanically, it can often be made chemically visible again, as compressed metal e.g. B. reacts differently to certain acids. Brittle materials and those that only allow a slight plastic deformation tend to crack when stamping and are therefore defective. In pig farming , stamps are used to mark cattle for slaughter . According to the German Animal Welfare Act , no pain-relieving anesthesia is required. Stamp for marking slaughter pigs are only a color coding of the animal, similar to a tattoo .
Usually punch numbers are offered in a set with 36 pens, which contains the letters from A – Z, the special character "&" and the digits from 0–8 (6 = 9 when rotated by 180 °). Special characters like ä, ö and ü or the ß usually have to be procured separately.
A decimal point can be made with a center punch , hyphens and slashes, plus and minus are also possible with small flat chisels.
The 3x3 = 9-box punch numbers and the 5x5 = 25-box punch letters (without "O", which is replaced by the number zero) are inexpensive.
Handling the punch requires a lot of practice in order to achieve an even typeface. Often the characters are twisted, not on one line and the embossing depth fluctuates within a character due to the stamp not being placed at right angles or within a lettering due to different impact force. Maintaining the distances to one another is also extremely difficult. The material that has been pushed up is removed with a file or with sandpaper. The use of sandpaper has the advantage that the material can be removed more slowly and therefore more evenly.